| Message ID | 1481878257-29163-4-git-send-email-amelie.delaunay@st.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Fri, Dec 16, 2016 at 09:50:52AM +0100, Amelie Delaunay wrote: > This patch adds support for the STM32 RTC. > > Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com> > --- > drivers/rtc/Kconfig | 11 + > drivers/rtc/Makefile | 1 + > drivers/rtc/rtc-stm32.c | 776 ++++++++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 788 insertions(+) > create mode 100644 drivers/rtc/rtc-stm32.c > > diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig > index e859d14..11eb28a 100644 > --- a/drivers/rtc/Kconfig > +++ b/drivers/rtc/Kconfig > @@ -1706,6 +1706,17 @@ config RTC_DRV_PIC32 > This driver can also be built as a module. If so, the module > will be called rtc-pic32 > > +config RTC_DRV_STM32 > + tristate "STM32 RTC" > + select REGMAP_MMIO > + depends on ARCH_STM32 || COMPILE_TEST > + help > + If you say yes here you get support for the STM32 On-Chip > + Real Time Clock. > + > + This driver can also be built as a module, if so, the module > + will be called "rtc-stm32". > + > comment "HID Sensor RTC drivers" > > config RTC_DRV_HID_SENSOR_TIME > diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile > index 1ac694a..87bd9cc 100644 > --- a/drivers/rtc/Makefile > +++ b/drivers/rtc/Makefile > @@ -144,6 +144,7 @@ obj-$(CONFIG_RTC_DRV_SNVS) += rtc-snvs.o > obj-$(CONFIG_RTC_DRV_SPEAR) += rtc-spear.o > obj-$(CONFIG_RTC_DRV_STARFIRE) += rtc-starfire.o > obj-$(CONFIG_RTC_DRV_STK17TA8) += rtc-stk17ta8.o > +obj-$(CONFIG_RTC_DRV_STM32) += rtc-stm32.o > obj-$(CONFIG_RTC_DRV_STMP) += rtc-stmp3xxx.o > obj-$(CONFIG_RTC_DRV_ST_LPC) += rtc-st-lpc.o > obj-$(CONFIG_RTC_DRV_SUN4V) += rtc-sun4v.o > diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c > new file mode 100644 > index 0000000..6ce0f5a > --- /dev/null > +++ b/drivers/rtc/rtc-stm32.c > @@ -0,0 +1,776 @@ > +/* > + * Copyright (C) Amelie Delaunay 2016 > + * Author: Amelie Delaunay <amelie.delaunay@st.com> > + * License terms: GNU General Public License (GPL), version 2 > + */ > + > +#include <linux/bcd.h> > +#include <linux/clk.h> > +#include <linux/iopoll.h> > +#include <linux/ioport.h> > +#include <linux/mfd/syscon.h> > +#include <linux/module.h> > +#include <linux/of_device.h> > +#include <linux/regmap.h> > +#include <linux/rtc.h> > +#include <linux/spinlock.h> > + > +#define DRIVER_NAME "stm32_rtc" > + > +/* STM32 RTC registers */ > +#define STM32_RTC_TR 0x00 > +#define STM32_RTC_DR 0x04 > +#define STM32_RTC_CR 0x08 > +#define STM32_RTC_ISR 0x0C > +#define STM32_RTC_PRER 0x10 > +#define STM32_RTC_ALRMAR 0x1C > +#define STM32_RTC_WPR 0x24 > + > +/* STM32_RTC_TR bit fields */ > +#define STM32_RTC_TR_SEC_SHIFT 0 > +#define STM32_RTC_TR_SEC GENMASK(6, 0) > +#define STM32_RTC_TR_MIN_SHIFT 8 > +#define STM32_RTC_TR_MIN GENMASK(14, 8) > +#define STM32_RTC_TR_HOUR_SHIFT 16 > +#define STM32_RTC_TR_HOUR GENMASK(21, 16) > + > +/* STM32_RTC_DR bit fields */ > +#define STM32_RTC_DR_DATE_SHIFT 0 > +#define STM32_RTC_DR_DATE GENMASK(5, 0) > +#define STM32_RTC_DR_MONTH_SHIFT 8 > +#define STM32_RTC_DR_MONTH GENMASK(12, 8) > +#define STM32_RTC_DR_WDAY_SHIFT 13 > +#define STM32_RTC_DR_WDAY GENMASK(15, 13) > +#define STM32_RTC_DR_YEAR_SHIFT 16 > +#define STM32_RTC_DR_YEAR GENMASK(23, 16) > + > +/* STM32_RTC_CR bit fields */ > +#define STM32_RTC_CR_FMT BIT(6) > +#define STM32_RTC_CR_ALRAE BIT(8) > +#define STM32_RTC_CR_ALRAIE BIT(12) > + > +/* STM32_RTC_ISR bit fields */ > +#define STM32_RTC_ISR_ALRAWF BIT(0) > +#define STM32_RTC_ISR_INITS BIT(4) > +#define STM32_RTC_ISR_RSF BIT(5) > +#define STM32_RTC_ISR_INITF BIT(6) > +#define STM32_RTC_ISR_INIT BIT(7) > +#define STM32_RTC_ISR_ALRAF BIT(8) > + > +/* STM32_RTC_PRER bit fields */ > +#define STM32_RTC_PRER_PRED_S_SHIFT 0 > +#define STM32_RTC_PRER_PRED_S GENMASK(14, 0) > +#define STM32_RTC_PRER_PRED_A_SHIFT 16 > +#define STM32_RTC_PRER_PRED_A GENMASK(22, 16) > + > +/* STM32_RTC_ALRMAR and STM32_RTC_ALRMBR bit fields */ > +#define STM32_RTC_ALRMXR_SEC_SHIFT 0 > +#define STM32_RTC_ALRMXR_SEC GENMASK(6, 0) > +#define STM32_RTC_ALRMXR_SEC_MASK BIT(7) > +#define STM32_RTC_ALRMXR_MIN_SHIFT 8 > +#define STM32_RTC_ALRMXR_MIN GENMASK(14, 8) > +#define STM32_RTC_ALRMXR_MIN_MASK BIT(15) > +#define STM32_RTC_ALRMXR_HOUR_SHIFT 16 > +#define STM32_RTC_ALRMXR_HOUR GENMASK(21, 16) > +#define STM32_RTC_ALRMXR_PM BIT(22) > +#define STM32_RTC_ALRMXR_HOUR_MASK BIT(23) > +#define STM32_RTC_ALRMXR_DATE_SHIFT 24 > +#define STM32_RTC_ALRMXR_DATE GENMASK(29, 24) > +#define STM32_RTC_ALRMXR_WDSEL BIT(30) > +#define STM32_RTC_ALRMXR_WDAY_SHIFT 24 > +#define STM32_RTC_ALRMXR_WDAY GENMASK(27, 24) > +#define STM32_RTC_ALRMXR_DATE_MASK BIT(31) > + > +/* STM32_RTC_WPR key constants */ > +#define RTC_WPR_1ST_KEY 0xCA > +#define RTC_WPR_2ND_KEY 0x53 > +#define RTC_WPR_WRONG_KEY 0xFF > + > +/* > + * RTC registers are protected agains parasitic write access. > + * PWR_CR_DBP bit must be set to enable write access to RTC registers. > + */ > +/* STM32_PWR_CR */ > +#define PWR_CR 0x00 > +/* STM32_PWR_CR bit field */ > +#define PWR_CR_DBP BIT(8) > + > +static struct regmap *dbp; > + > +struct stm32_rtc { > + struct rtc_device *rtc_dev; > + void __iomem *base; > + struct clk *ck_rtc; > + spinlock_t lock; /* Protects registers accesses */ > + int irq_alarm; > +}; > + > +static void stm32_rtc_wpr_unlock(struct stm32_rtc *rtc) > +{ > + writel_relaxed(RTC_WPR_1ST_KEY, rtc->base + STM32_RTC_WPR); > + writel_relaxed(RTC_WPR_2ND_KEY, rtc->base + STM32_RTC_WPR); > +} > + > +static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc) > +{ > + writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + STM32_RTC_WPR); > +} > + > +static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc) > +{ > + unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR); > + > + if (!(isr & STM32_RTC_ISR_INITF)) { > + isr |= STM32_RTC_ISR_INIT; > + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); > + > + /* > + * It takes around 2 ck_rtc clock cycles to enter in > + * initialization phase mode (and have INITF flag set). As > + * slowest ck_rtc frequency may be 32kHz and highest should be > + * 1MHz, we poll every 10 us with a timeout of 100ms. > + */ > + return readl_relaxed_poll_timeout_atomic( > + rtc->base + STM32_RTC_ISR, > + isr, (isr & STM32_RTC_ISR_INITF), > + 10, 100000); > + } > + > + return 0; > +} > + > +static void stm32_rtc_exit_init_mode(struct stm32_rtc *rtc) > +{ > + unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR); > + > + isr &= ~STM32_RTC_ISR_INIT; > + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); > +} > + > +static int stm32_rtc_wait_sync(struct stm32_rtc *rtc) > +{ > + unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR); > + > + isr &= ~STM32_RTC_ISR_RSF; > + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); > + > + /* > + * Wait for RSF to be set to ensure the calendar registers are > + * synchronised, it takes around 2 ck_rtc clock cycles > + */ > + return readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR, > + isr, > + (isr & STM32_RTC_ISR_RSF), > + 10, 100000); > +} > + > +static irqreturn_t stm32_rtc_alarm_irq(int irq, void *dev_id) > +{ > + struct stm32_rtc *rtc = (struct stm32_rtc *)dev_id; > + unsigned int isr, cr; > + > + mutex_lock(&rtc->rtc_dev->ops_lock); > + > + isr = readl_relaxed(rtc->base + STM32_RTC_ISR); > + cr = readl_relaxed(rtc->base + STM32_RTC_CR); > + > + if ((isr & STM32_RTC_ISR_ALRAF) && > + (cr & STM32_RTC_CR_ALRAIE)) { > + /* Alarm A flag - Alarm interrupt */ > + dev_dbg(&rtc->rtc_dev->dev, "Alarm occurred\n"); > + > + /* Pass event to the kernel */ > + rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF); > + > + /* Clear event flag, otherwise new events won't be received */ > + writel_relaxed(isr & ~STM32_RTC_ISR_ALRAF, > + rtc->base + STM32_RTC_ISR); > + } > + > + mutex_unlock(&rtc->rtc_dev->ops_lock); > + > + return IRQ_HANDLED; > +} > + > +/* Convert rtc_time structure from bin to bcd format */ > +static void tm2bcd(struct rtc_time *tm) > +{ > + tm->tm_sec = bin2bcd(tm->tm_sec); > + tm->tm_min = bin2bcd(tm->tm_min); > + tm->tm_hour = bin2bcd(tm->tm_hour); > + > + tm->tm_mday = bin2bcd(tm->tm_mday); > + tm->tm_mon = bin2bcd(tm->tm_mon + 1); > + tm->tm_year = bin2bcd(tm->tm_year - 100); > + /* > + * Number of days since Sunday > + * - on kernel side, 0=Sunday...6=Saturday > + * - on rtc side, 0=invalid,1=Monday...7=Sunday > + */ > + tm->tm_wday = (!tm->tm_wday) ? 7 : tm->tm_wday; > +} > + > +/* Convert rtc_time structure from bcd to bin format */ > +static void bcd2tm(struct rtc_time *tm) > +{ > + tm->tm_sec = bcd2bin(tm->tm_sec); > + tm->tm_min = bcd2bin(tm->tm_min); > + tm->tm_hour = bcd2bin(tm->tm_hour); > + > + tm->tm_mday = bcd2bin(tm->tm_mday); > + tm->tm_mon = bcd2bin(tm->tm_mon) - 1; > + tm->tm_year = bcd2bin(tm->tm_year) + 100; > + /* > + * Number of days since Sunday > + * - on kernel side, 0=Sunday...6=Saturday > + * - on rtc side, 0=invalid,1=Monday...7=Sunday > + */ > + tm->tm_wday %= 7; > +} > + > +static int stm32_rtc_read_time(struct device *dev, struct rtc_time *tm) > +{ > + struct stm32_rtc *rtc = dev_get_drvdata(dev); > + unsigned int tr, dr; > + unsigned long irqflags; > + > + spin_lock_irqsave(&rtc->lock, irqflags); > + > + /* Time and Date in BCD format */ > + tr = readl_relaxed(rtc->base + STM32_RTC_TR); > + dr = readl_relaxed(rtc->base + STM32_RTC_DR); > + > + spin_unlock_irqrestore(&rtc->lock, irqflags); > + > + tm->tm_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT; > + tm->tm_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT; > + tm->tm_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT; > + > + tm->tm_mday = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT; > + tm->tm_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT; > + tm->tm_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT; > + tm->tm_wday = (dr & STM32_RTC_DR_WDAY) >> STM32_RTC_DR_WDAY_SHIFT; > + > + /* We don't report tm_yday and tm_isdst */ > + > + bcd2tm(tm); > + > + if (rtc_valid_tm(tm) < 0) { > + dev_err(dev, "%s: rtc_time is not valid.\n", __func__); > + return -EINVAL; > + } > + > + return 0; > +} > + > +static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm) > +{ > + struct stm32_rtc *rtc = dev_get_drvdata(dev); > + unsigned int tr, dr; > + unsigned long irqflags; > + int ret = 0; > + > + if (rtc_valid_tm(tm) < 0) { > + dev_err(dev, "%s: rtc_time is not valid.\n", __func__); > + return -EINVAL; > + } > + > + tm2bcd(tm); > + > + /* Time in BCD format */ > + tr = ((tm->tm_sec << STM32_RTC_TR_SEC_SHIFT) & STM32_RTC_TR_SEC) | > + ((tm->tm_min << STM32_RTC_TR_MIN_SHIFT) & STM32_RTC_TR_MIN) | > + ((tm->tm_hour << STM32_RTC_TR_HOUR_SHIFT) & STM32_RTC_TR_HOUR); > + > + /* Date in BCD format */ > + dr = ((tm->tm_mday << STM32_RTC_DR_DATE_SHIFT) & STM32_RTC_DR_DATE) | > + ((tm->tm_mon << STM32_RTC_DR_MONTH_SHIFT) & STM32_RTC_DR_MONTH) | > + ((tm->tm_year << STM32_RTC_DR_YEAR_SHIFT) & STM32_RTC_DR_YEAR) | > + ((tm->tm_wday << STM32_RTC_DR_WDAY_SHIFT) & STM32_RTC_DR_WDAY); > + > + spin_lock_irqsave(&rtc->lock, irqflags); > + > + stm32_rtc_wpr_unlock(rtc); > + > + ret = stm32_rtc_enter_init_mode(rtc); > + if (ret) { > + dev_err(dev, "Can't enter in init mode. Set time aborted.\n"); > + goto end; > + } > + > + writel_relaxed(tr, rtc->base + STM32_RTC_TR); > + writel_relaxed(dr, rtc->base + STM32_RTC_DR); > + > + stm32_rtc_exit_init_mode(rtc); > + > + ret = stm32_rtc_wait_sync(rtc); > +end: > + stm32_rtc_wpr_lock(rtc); > + > + spin_unlock_irqrestore(&rtc->lock, irqflags); > + > + return ret; > +} > + > +static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) > +{ > + struct stm32_rtc *rtc = dev_get_drvdata(dev); > + struct rtc_time *tm = &alrm->time; > + unsigned int alrmar, cr, isr; > + unsigned long irqflags; > + > + spin_lock_irqsave(&rtc->lock, irqflags); > + > + alrmar = readl_relaxed(rtc->base + STM32_RTC_ALRMAR); > + cr = readl_relaxed(rtc->base + STM32_RTC_CR); > + isr = readl_relaxed(rtc->base + STM32_RTC_ISR); > + > + spin_unlock_irqrestore(&rtc->lock, irqflags); > + > + if (alrmar & STM32_RTC_ALRMXR_DATE_MASK) { > + /* > + * Date/day doesn't matter in Alarm comparison so alarm > + * triggers every day > + */ > + tm->tm_mday = -1; > + tm->tm_wday = -1; > + } else { > + if (alrmar & STM32_RTC_ALRMXR_WDSEL) { > + /* Alarm is set to a day of week */ > + tm->tm_mday = -1; > + tm->tm_wday = (alrmar & STM32_RTC_ALRMXR_WDAY) >> > + STM32_RTC_ALRMXR_WDAY_SHIFT; > + tm->tm_wday %= 7; > + } else { > + /* Alarm is set to a day of month */ > + tm->tm_wday = -1; > + tm->tm_mday = (alrmar & STM32_RTC_ALRMXR_DATE) >> > + STM32_RTC_ALRMXR_DATE_SHIFT; > + } > + } > + > + if (alrmar & STM32_RTC_ALRMXR_HOUR_MASK) { > + /* Hours don't matter in Alarm comparison */ > + tm->tm_hour = -1; > + } else { > + tm->tm_hour = (alrmar & STM32_RTC_ALRMXR_HOUR) >> > + STM32_RTC_ALRMXR_HOUR_SHIFT; > + if (alrmar & STM32_RTC_ALRMXR_PM) > + tm->tm_hour += 12; > + } > + > + if (alrmar & STM32_RTC_ALRMXR_MIN_MASK) { > + /* Minutes don't matter in Alarm comparison */ > + tm->tm_min = -1; > + } else { > + tm->tm_min = (alrmar & STM32_RTC_ALRMXR_MIN) >> > + STM32_RTC_ALRMXR_MIN_SHIFT; > + } > + > + if (alrmar & STM32_RTC_ALRMXR_SEC_MASK) { > + /* Seconds don't matter in Alarm comparison */ > + tm->tm_sec = -1; > + } else { > + tm->tm_sec = (alrmar & STM32_RTC_ALRMXR_SEC) >> > + STM32_RTC_ALRMXR_SEC_SHIFT; > + } > + > + bcd2tm(tm); > + > + alrm->enabled = (cr & STM32_RTC_CR_ALRAE) ? 1 : 0; > + alrm->pending = (isr & STM32_RTC_ISR_ALRAF) ? 1 : 0; > + > + return 0; > +} > + > +static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) > +{ > + struct stm32_rtc *rtc = dev_get_drvdata(dev); > + unsigned long irqflags; > + unsigned int isr, cr; > + > + spin_lock_irqsave(&rtc->lock, irqflags); > + > + cr = readl_relaxed(rtc->base + STM32_RTC_CR); > + > + stm32_rtc_wpr_unlock(rtc); > + > + /* We expose Alarm A to the kernel */ > + if (enabled) > + cr |= (STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE); > + else > + cr &= ~(STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE); > + writel_relaxed(cr, rtc->base + STM32_RTC_CR); > + > + /* Clear event irqflags, otherwise new events won't be received */ > + isr = readl_relaxed(rtc->base + STM32_RTC_ISR); > + isr &= ~STM32_RTC_ISR_ALRAF; > + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); > + > + stm32_rtc_wpr_lock(rtc); > + > + spin_unlock_irqrestore(&rtc->lock, irqflags); > + > + return 0; > +} > + > +static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm) > +{ > + unsigned int cur_day, cur_mon, cur_year, cur_hour, cur_min, cur_sec; > + unsigned int dr = readl_relaxed(rtc->base + STM32_RTC_DR); > + unsigned int tr = readl_relaxed(rtc->base + STM32_RTC_TR); > + > + cur_day = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT; > + cur_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT; > + cur_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT; > + cur_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT; > + cur_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT; > + cur_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT; > + > + /* > + * Assuming current date is M-D-Y H:M:S. > + * RTC alarm can't be set on a specific month and year. > + * So the valid alarm range is: > + * M-D-Y H:M:S < alarm <= (M+1)-D-Y H:M:S > + * with a specific case for December... > + */ > + if ((((tm->tm_year > cur_year) && > + (tm->tm_mon == 0x1) && (cur_mon == 0x12)) || > + ((tm->tm_year == cur_year) && > + (tm->tm_mon <= cur_mon + 1))) && > + ((tm->tm_mday < cur_day) || > + ((tm->tm_mday == cur_day) && > + ((tm->tm_hour < cur_hour) || > + ((tm->tm_hour == cur_hour) && (tm->tm_min < cur_min)) || > + ((tm->tm_hour == cur_hour) && (tm->tm_min == cur_min) && > + (tm->tm_sec <= cur_sec)))))) > + return 0; > + > + return -EINVAL; > +} > + > +static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) > +{ > + struct stm32_rtc *rtc = dev_get_drvdata(dev); > + struct rtc_time *tm = &alrm->time; > + unsigned long irqflags; > + unsigned int cr, isr, alrmar; > + int ret = 0; > + > + if (rtc_valid_tm(tm)) { > + dev_err(dev, "Alarm time not valid.\n"); > + return -EINVAL; > + } > + > + tm2bcd(tm); > + > + /* > + * RTC alarm can't be set on a specific date, unless this date is > + * up to the same day of month next month. > + */ > + if (stm32_rtc_valid_alrm(rtc, tm) < 0) { > + dev_err(dev, "Alarm can be set only on upcoming month.\n"); > + return -EINVAL; > + } > + > + spin_lock_irqsave(&rtc->lock, irqflags); > + > + stm32_rtc_wpr_unlock(rtc); > + > + /* Disable Alarm */ > + cr = readl_relaxed(rtc->base + STM32_RTC_CR); > + cr &= ~STM32_RTC_CR_ALRAE; > + writel_relaxed(cr, rtc->base + STM32_RTC_CR); > + > + /* > + * Poll Alarm write flag to be sure that Alarm update is allowed: it > + * takes around 2 ck_rtc clock cycles > + */ > + ret = readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR, > + isr, > + (isr & STM32_RTC_ISR_ALRAWF), > + 10, 100000); > + > + if (ret) { > + dev_err(dev, "Alarm update not allowed\n"); > + goto end; > + } > + > + alrmar = 0; > + /* tm_year and tm_mon are not used because not supported by RTC */ > + alrmar |= (tm->tm_mday << STM32_RTC_ALRMXR_DATE_SHIFT) & > + STM32_RTC_ALRMXR_DATE; > + /* 24-hour format */ > + alrmar &= ~STM32_RTC_ALRMXR_PM; > + alrmar |= (tm->tm_hour << STM32_RTC_ALRMXR_HOUR_SHIFT) & > + STM32_RTC_ALRMXR_HOUR; > + alrmar |= (tm->tm_min << STM32_RTC_ALRMXR_MIN_SHIFT) & > + STM32_RTC_ALRMXR_MIN; > + alrmar |= (tm->tm_sec << STM32_RTC_ALRMXR_SEC_SHIFT) & > + STM32_RTC_ALRMXR_SEC; All this work on alrmar is done while the spinlock is held. If I'm not mistaking nothing prevents you from doing that processing before taking the spinlock. > + > + /* Write to Alarm register */ > + writel_relaxed(alrmar, rtc->base + STM32_RTC_ALRMAR); > + > + if (alrm->enabled) > + stm32_rtc_alarm_irq_enable(dev, 1); > + else > + stm32_rtc_alarm_irq_enable(dev, 0); > + > +end: > + stm32_rtc_wpr_lock(rtc); > + > + spin_unlock_irqrestore(&rtc->lock, irqflags); > + > + return ret; > +} > + > +static const struct rtc_class_ops stm32_rtc_ops = { > + .read_time = stm32_rtc_read_time, > + .set_time = stm32_rtc_set_time, > + .read_alarm = stm32_rtc_read_alarm, > + .set_alarm = stm32_rtc_set_alarm, > + .alarm_irq_enable = stm32_rtc_alarm_irq_enable, > +}; > + > +#ifdef CONFIG_OF > +static const struct of_device_id stm32_rtc_of_match[] = { > + { .compatible = "st,stm32-rtc" }, > + {} > +}; > +MODULE_DEVICE_TABLE(of, stm32_rtc_of_match); > +#endif > + > +static int stm32_rtc_init(struct platform_device *pdev, > + struct stm32_rtc *rtc) > +{ > + unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr; > + unsigned int rate; > + unsigned long irqflags; > + int ret = 0; > + > + rate = clk_get_rate(rtc->ck_rtc); > + > + /* Find prediv_a and prediv_s to obtain the 1Hz calendar clock */ > + pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT; > + pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT; > + > + for (pred_a = pred_a_max; pred_a >= 0; pred_a--) { > + pred_s = (rate / (pred_a + 1)) - 1; > + > + if (((pred_s + 1) * (pred_a + 1)) == rate) > + break; > + } > + > + /* > + * Can't find a 1Hz, so give priority to RTC power consumption > + * by choosing the higher possible value for prediv_a > + */ > + if ((pred_s > pred_s_max) || (pred_a > pred_a_max)) { > + pred_a = pred_a_max; > + pred_s = (rate / (pred_a + 1)) - 1; > + > + dev_warn(&pdev->dev, "ck_rtc is %s\n", > + (rate - ((pred_a + 1) * (pred_s + 1)) < 0) ? > + "fast" : "slow"); > + } > + > + spin_lock_irqsave(&rtc->lock, irqflags); > + > + stm32_rtc_wpr_unlock(rtc); > + > + ret = stm32_rtc_enter_init_mode(rtc); > + if (ret) { > + dev_err(&pdev->dev, > + "Can't enter in init mode. Prescaler config failed.\n"); > + goto end; > + } > + > + prer = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & STM32_RTC_PRER_PRED_S; > + writel_relaxed(prer, rtc->base + STM32_RTC_PRER); > + prer |= (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & STM32_RTC_PRER_PRED_A; > + writel_relaxed(prer, rtc->base + STM32_RTC_PRER); > + > + /* Force 24h time format */ > + cr = readl_relaxed(rtc->base + STM32_RTC_CR); > + cr &= ~STM32_RTC_CR_FMT; > + writel_relaxed(cr, rtc->base + STM32_RTC_CR); > + > + stm32_rtc_exit_init_mode(rtc); > + > + ret = stm32_rtc_wait_sync(rtc); > +end: > + stm32_rtc_wpr_lock(rtc); > + > + spin_unlock_irqrestore(&rtc->lock, irqflags); > + > + return ret; > +} > + > +static int stm32_rtc_probe(struct platform_device *pdev) > +{ > + struct stm32_rtc *rtc; > + struct resource *res; > + int ret; > + > + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); > + if (!rtc) > + return -ENOMEM; > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + rtc->base = devm_ioremap_resource(&pdev->dev, res); > + if (IS_ERR(rtc->base)) > + return PTR_ERR(rtc->base); > + > + dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "st,syscfg"); > + if (IS_ERR(dbp)) { > + dev_err(&pdev->dev, "no st,syscfg\n"); > + return PTR_ERR(dbp); > + } > + > + spin_lock_init(&rtc->lock); > + > + rtc->ck_rtc = devm_clk_get(&pdev->dev, NULL); > + if (IS_ERR(rtc->ck_rtc)) { > + dev_err(&pdev->dev, "no ck_rtc clock"); > + return PTR_ERR(rtc->ck_rtc); > + } > + > + ret = clk_prepare_enable(rtc->ck_rtc); > + if (ret) > + return ret; > + > + regmap_update_bits(dbp, PWR_CR, PWR_CR_DBP, PWR_CR_DBP); > + > + /* > + * After a system reset, RTC_ISR.INITS flag can be read to check if > + * the calendar has been initalized or not. INITS flag is reset by a > + * power-on reset (no vbat, no power-supply). It is not reset if > + * ck_rtc parent clock has changed (so RTC prescalers need to be > + * changed). That's why we cannot rely on this flag to know if RTC > + * init has to be done. > + */ > + ret = stm32_rtc_init(pdev, rtc); > + if (ret) > + goto err; > + > + rtc->irq_alarm = platform_get_irq(pdev, 0); > + if (rtc->irq_alarm <= 0) { > + dev_err(&pdev->dev, "no alarm irq\n"); > + ret = -ENOENT; Function platform_get_irq() returns a wealth of error codes that are lost here. Doing 'ret = rtc->irq_alarm;' would prevent that from happening. > + goto err; > + } > + > + platform_set_drvdata(pdev, rtc); > + > + ret = device_init_wakeup(&pdev->dev, true); > + if (ret) > + dev_warn(&pdev->dev, > + "alarm won't be able to wake up the system"); > + > + rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name, > + &stm32_rtc_ops, THIS_MODULE); > + if (IS_ERR(rtc->rtc_dev)) { > + ret = PTR_ERR(rtc->rtc_dev); > + dev_err(&pdev->dev, "rtc device registration failed, err=%d\n", > + ret); > + goto err; > + } > + > + /* Handle RTC alarm interrupts */ > + ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_alarm, NULL, > + stm32_rtc_alarm_irq, > + IRQF_TRIGGER_RISING | IRQF_ONESHOT, > + pdev->name, rtc); > + if (ret) { > + dev_err(&pdev->dev, "IRQ%d (alarm interrupt) already claimed\n", > + rtc->irq_alarm); > + goto err; > + } > + > + /* > + * If INITS flag is reset (calendar year field set to 0x00), calendar > + * must be initialized > + */ > + if (!(readl_relaxed(rtc->base + STM32_RTC_ISR) & STM32_RTC_ISR_INITS)) > + dev_warn(&pdev->dev, "Date/Time must be initialized\n"); > + > + return 0; > +err: > + clk_disable_unprepare(rtc->ck_rtc); > + > + regmap_update_bits(dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP); > + > + device_init_wakeup(&pdev->dev, false); > + > + return ret; > +} > + > +static int __exit stm32_rtc_remove(struct platform_device *pdev) > +{ > + struct stm32_rtc *rtc = platform_get_drvdata(pdev); > + unsigned int cr; > + > + /* Disable interrupts */ > + stm32_rtc_wpr_unlock(rtc); > + cr = readl_relaxed(rtc->base + STM32_RTC_CR); > + cr &= ~STM32_RTC_CR_ALRAIE; > + writel_relaxed(cr, rtc->base + STM32_RTC_CR); > + stm32_rtc_wpr_lock(rtc); > + > + clk_disable_unprepare(rtc->ck_rtc); > + > + /* Enable backup domain write protection */ > + regmap_update_bits(dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP); > + > + device_init_wakeup(&pdev->dev, false); > + > + return 0; > +} > + > +#ifdef CONFIG_PM_SLEEP > +static int stm32_rtc_suspend(struct device *dev) > +{ > + struct stm32_rtc *rtc = dev_get_drvdata(dev); > + > + if (device_may_wakeup(dev)) > + return enable_irq_wake(rtc->irq_alarm); > + > + return 0; > +} > + > +static int stm32_rtc_resume(struct device *dev) > +{ > + struct stm32_rtc *rtc = dev_get_drvdata(dev); > + int ret = 0; > + > + ret = stm32_rtc_wait_sync(rtc); > + if (ret < 0) > + return ret; > + > + if (device_may_wakeup(dev)) > + return disable_irq_wake(rtc->irq_alarm); > + > + return ret; > +} > +#endif > + > +static SIMPLE_DEV_PM_OPS(stm32_rtc_pm_ops, > + stm32_rtc_suspend, stm32_rtc_resume); > + > +static struct platform_driver stm32_rtc_driver = { > + .probe = stm32_rtc_probe, > + .remove = stm32_rtc_remove, > + .driver = { > + .name = DRIVER_NAME, > + .pm = &stm32_rtc_pm_ops, > + .of_match_table = stm32_rtc_of_match, > + }, > +}; > + > +module_platform_driver(stm32_rtc_driver); > + > +MODULE_ALIAS("platform:" DRIVER_NAME); > +MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>"); > +MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver"); > +MODULE_LICENSE("GPL v2"); > -- > 1.9.1 >
Hi Mathieu, Thanks for reviewing, On 12/16/2016 08:08 PM, Mathieu Poirier wrote: > On Fri, Dec 16, 2016 at 09:50:52AM +0100, Amelie Delaunay wrote: >> This patch adds support for the STM32 RTC. >> >> Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com> >> --- >> drivers/rtc/Kconfig | 11 + >> drivers/rtc/Makefile | 1 + >> drivers/rtc/rtc-stm32.c | 776 ++++++++++++++++++++++++++++++++++++++++++++++++ >> 3 files changed, 788 insertions(+) >> create mode 100644 drivers/rtc/rtc-stm32.c >> >> diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig >> index e859d14..11eb28a 100644 >> --- a/drivers/rtc/Kconfig >> +++ b/drivers/rtc/Kconfig >> @@ -1706,6 +1706,17 @@ config RTC_DRV_PIC32 >> This driver can also be built as a module. If so, the module >> will be called rtc-pic32 >> >> +config RTC_DRV_STM32 >> + tristate "STM32 RTC" >> + select REGMAP_MMIO >> + depends on ARCH_STM32 || COMPILE_TEST >> + help >> + If you say yes here you get support for the STM32 On-Chip >> + Real Time Clock. >> + >> + This driver can also be built as a module, if so, the module >> + will be called "rtc-stm32". >> + >> comment "HID Sensor RTC drivers" >> >> config RTC_DRV_HID_SENSOR_TIME >> diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile >> index 1ac694a..87bd9cc 100644 >> --- a/drivers/rtc/Makefile >> +++ b/drivers/rtc/Makefile >> @@ -144,6 +144,7 @@ obj-$(CONFIG_RTC_DRV_SNVS) += rtc-snvs.o >> obj-$(CONFIG_RTC_DRV_SPEAR) += rtc-spear.o >> obj-$(CONFIG_RTC_DRV_STARFIRE) += rtc-starfire.o >> obj-$(CONFIG_RTC_DRV_STK17TA8) += rtc-stk17ta8.o >> +obj-$(CONFIG_RTC_DRV_STM32) += rtc-stm32.o >> obj-$(CONFIG_RTC_DRV_STMP) += rtc-stmp3xxx.o >> obj-$(CONFIG_RTC_DRV_ST_LPC) += rtc-st-lpc.o >> obj-$(CONFIG_RTC_DRV_SUN4V) += rtc-sun4v.o >> diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c >> new file mode 100644 >> index 0000000..6ce0f5a >> --- /dev/null >> +++ b/drivers/rtc/rtc-stm32.c >> @@ -0,0 +1,776 @@ >> +/* >> + * Copyright (C) Amelie Delaunay 2016 >> + * Author: Amelie Delaunay <amelie.delaunay@st.com> >> + * License terms: GNU General Public License (GPL), version 2 >> + */ >> + >> +#include <linux/bcd.h> >> +#include <linux/clk.h> >> +#include <linux/iopoll.h> >> +#include <linux/ioport.h> >> +#include <linux/mfd/syscon.h> >> +#include <linux/module.h> >> +#include <linux/of_device.h> >> +#include <linux/regmap.h> >> +#include <linux/rtc.h> >> +#include <linux/spinlock.h> >> + >> +#define DRIVER_NAME "stm32_rtc" >> + >> +/* STM32 RTC registers */ >> +#define STM32_RTC_TR 0x00 >> +#define STM32_RTC_DR 0x04 >> +#define STM32_RTC_CR 0x08 >> +#define STM32_RTC_ISR 0x0C >> +#define STM32_RTC_PRER 0x10 >> +#define STM32_RTC_ALRMAR 0x1C >> +#define STM32_RTC_WPR 0x24 >> + >> +/* STM32_RTC_TR bit fields */ >> +#define STM32_RTC_TR_SEC_SHIFT 0 >> +#define STM32_RTC_TR_SEC GENMASK(6, 0) >> +#define STM32_RTC_TR_MIN_SHIFT 8 >> +#define STM32_RTC_TR_MIN GENMASK(14, 8) >> +#define STM32_RTC_TR_HOUR_SHIFT 16 >> +#define STM32_RTC_TR_HOUR GENMASK(21, 16) >> + >> +/* STM32_RTC_DR bit fields */ >> +#define STM32_RTC_DR_DATE_SHIFT 0 >> +#define STM32_RTC_DR_DATE GENMASK(5, 0) >> +#define STM32_RTC_DR_MONTH_SHIFT 8 >> +#define STM32_RTC_DR_MONTH GENMASK(12, 8) >> +#define STM32_RTC_DR_WDAY_SHIFT 13 >> +#define STM32_RTC_DR_WDAY GENMASK(15, 13) >> +#define STM32_RTC_DR_YEAR_SHIFT 16 >> +#define STM32_RTC_DR_YEAR GENMASK(23, 16) >> + >> +/* STM32_RTC_CR bit fields */ >> +#define STM32_RTC_CR_FMT BIT(6) >> +#define STM32_RTC_CR_ALRAE BIT(8) >> +#define STM32_RTC_CR_ALRAIE BIT(12) >> + >> +/* STM32_RTC_ISR bit fields */ >> +#define STM32_RTC_ISR_ALRAWF BIT(0) >> +#define STM32_RTC_ISR_INITS BIT(4) >> +#define STM32_RTC_ISR_RSF BIT(5) >> +#define STM32_RTC_ISR_INITF BIT(6) >> +#define STM32_RTC_ISR_INIT BIT(7) >> +#define STM32_RTC_ISR_ALRAF BIT(8) >> + >> +/* STM32_RTC_PRER bit fields */ >> +#define STM32_RTC_PRER_PRED_S_SHIFT 0 >> +#define STM32_RTC_PRER_PRED_S GENMASK(14, 0) >> +#define STM32_RTC_PRER_PRED_A_SHIFT 16 >> +#define STM32_RTC_PRER_PRED_A GENMASK(22, 16) >> + >> +/* STM32_RTC_ALRMAR and STM32_RTC_ALRMBR bit fields */ >> +#define STM32_RTC_ALRMXR_SEC_SHIFT 0 >> +#define STM32_RTC_ALRMXR_SEC GENMASK(6, 0) >> +#define STM32_RTC_ALRMXR_SEC_MASK BIT(7) >> +#define STM32_RTC_ALRMXR_MIN_SHIFT 8 >> +#define STM32_RTC_ALRMXR_MIN GENMASK(14, 8) >> +#define STM32_RTC_ALRMXR_MIN_MASK BIT(15) >> +#define STM32_RTC_ALRMXR_HOUR_SHIFT 16 >> +#define STM32_RTC_ALRMXR_HOUR GENMASK(21, 16) >> +#define STM32_RTC_ALRMXR_PM BIT(22) >> +#define STM32_RTC_ALRMXR_HOUR_MASK BIT(23) >> +#define STM32_RTC_ALRMXR_DATE_SHIFT 24 >> +#define STM32_RTC_ALRMXR_DATE GENMASK(29, 24) >> +#define STM32_RTC_ALRMXR_WDSEL BIT(30) >> +#define STM32_RTC_ALRMXR_WDAY_SHIFT 24 >> +#define STM32_RTC_ALRMXR_WDAY GENMASK(27, 24) >> +#define STM32_RTC_ALRMXR_DATE_MASK BIT(31) >> + >> +/* STM32_RTC_WPR key constants */ >> +#define RTC_WPR_1ST_KEY 0xCA >> +#define RTC_WPR_2ND_KEY 0x53 >> +#define RTC_WPR_WRONG_KEY 0xFF >> + >> +/* >> + * RTC registers are protected agains parasitic write access. >> + * PWR_CR_DBP bit must be set to enable write access to RTC registers. >> + */ >> +/* STM32_PWR_CR */ >> +#define PWR_CR 0x00 >> +/* STM32_PWR_CR bit field */ >> +#define PWR_CR_DBP BIT(8) >> + >> +static struct regmap *dbp; >> + >> +struct stm32_rtc { >> + struct rtc_device *rtc_dev; >> + void __iomem *base; >> + struct clk *ck_rtc; >> + spinlock_t lock; /* Protects registers accesses */ >> + int irq_alarm; >> +}; >> + >> +static void stm32_rtc_wpr_unlock(struct stm32_rtc *rtc) >> +{ >> + writel_relaxed(RTC_WPR_1ST_KEY, rtc->base + STM32_RTC_WPR); >> + writel_relaxed(RTC_WPR_2ND_KEY, rtc->base + STM32_RTC_WPR); >> +} >> + >> +static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc) >> +{ >> + writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + STM32_RTC_WPR); >> +} >> + >> +static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc) >> +{ >> + unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR); >> + >> + if (!(isr & STM32_RTC_ISR_INITF)) { >> + isr |= STM32_RTC_ISR_INIT; >> + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); >> + >> + /* >> + * It takes around 2 ck_rtc clock cycles to enter in >> + * initialization phase mode (and have INITF flag set). As >> + * slowest ck_rtc frequency may be 32kHz and highest should be >> + * 1MHz, we poll every 10 us with a timeout of 100ms. >> + */ >> + return readl_relaxed_poll_timeout_atomic( >> + rtc->base + STM32_RTC_ISR, >> + isr, (isr & STM32_RTC_ISR_INITF), >> + 10, 100000); >> + } >> + >> + return 0; >> +} >> + >> +static void stm32_rtc_exit_init_mode(struct stm32_rtc *rtc) >> +{ >> + unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR); >> + >> + isr &= ~STM32_RTC_ISR_INIT; >> + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); >> +} >> + >> +static int stm32_rtc_wait_sync(struct stm32_rtc *rtc) >> +{ >> + unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR); >> + >> + isr &= ~STM32_RTC_ISR_RSF; >> + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); >> + >> + /* >> + * Wait for RSF to be set to ensure the calendar registers are >> + * synchronised, it takes around 2 ck_rtc clock cycles >> + */ >> + return readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR, >> + isr, >> + (isr & STM32_RTC_ISR_RSF), >> + 10, 100000); >> +} >> + >> +static irqreturn_t stm32_rtc_alarm_irq(int irq, void *dev_id) >> +{ >> + struct stm32_rtc *rtc = (struct stm32_rtc *)dev_id; >> + unsigned int isr, cr; >> + >> + mutex_lock(&rtc->rtc_dev->ops_lock); >> + >> + isr = readl_relaxed(rtc->base + STM32_RTC_ISR); >> + cr = readl_relaxed(rtc->base + STM32_RTC_CR); >> + >> + if ((isr & STM32_RTC_ISR_ALRAF) && >> + (cr & STM32_RTC_CR_ALRAIE)) { >> + /* Alarm A flag - Alarm interrupt */ >> + dev_dbg(&rtc->rtc_dev->dev, "Alarm occurred\n"); >> + >> + /* Pass event to the kernel */ >> + rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF); >> + >> + /* Clear event flag, otherwise new events won't be received */ >> + writel_relaxed(isr & ~STM32_RTC_ISR_ALRAF, >> + rtc->base + STM32_RTC_ISR); >> + } >> + >> + mutex_unlock(&rtc->rtc_dev->ops_lock); >> + >> + return IRQ_HANDLED; >> +} >> + >> +/* Convert rtc_time structure from bin to bcd format */ >> +static void tm2bcd(struct rtc_time *tm) >> +{ >> + tm->tm_sec = bin2bcd(tm->tm_sec); >> + tm->tm_min = bin2bcd(tm->tm_min); >> + tm->tm_hour = bin2bcd(tm->tm_hour); >> + >> + tm->tm_mday = bin2bcd(tm->tm_mday); >> + tm->tm_mon = bin2bcd(tm->tm_mon + 1); >> + tm->tm_year = bin2bcd(tm->tm_year - 100); >> + /* >> + * Number of days since Sunday >> + * - on kernel side, 0=Sunday...6=Saturday >> + * - on rtc side, 0=invalid,1=Monday...7=Sunday >> + */ >> + tm->tm_wday = (!tm->tm_wday) ? 7 : tm->tm_wday; >> +} >> + >> +/* Convert rtc_time structure from bcd to bin format */ >> +static void bcd2tm(struct rtc_time *tm) >> +{ >> + tm->tm_sec = bcd2bin(tm->tm_sec); >> + tm->tm_min = bcd2bin(tm->tm_min); >> + tm->tm_hour = bcd2bin(tm->tm_hour); >> + >> + tm->tm_mday = bcd2bin(tm->tm_mday); >> + tm->tm_mon = bcd2bin(tm->tm_mon) - 1; >> + tm->tm_year = bcd2bin(tm->tm_year) + 100; >> + /* >> + * Number of days since Sunday >> + * - on kernel side, 0=Sunday...6=Saturday >> + * - on rtc side, 0=invalid,1=Monday...7=Sunday >> + */ >> + tm->tm_wday %= 7; >> +} >> + >> +static int stm32_rtc_read_time(struct device *dev, struct rtc_time *tm) >> +{ >> + struct stm32_rtc *rtc = dev_get_drvdata(dev); >> + unsigned int tr, dr; >> + unsigned long irqflags; >> + >> + spin_lock_irqsave(&rtc->lock, irqflags); >> + >> + /* Time and Date in BCD format */ >> + tr = readl_relaxed(rtc->base + STM32_RTC_TR); >> + dr = readl_relaxed(rtc->base + STM32_RTC_DR); >> + >> + spin_unlock_irqrestore(&rtc->lock, irqflags); >> + >> + tm->tm_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT; >> + tm->tm_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT; >> + tm->tm_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT; >> + >> + tm->tm_mday = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT; >> + tm->tm_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT; >> + tm->tm_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT; >> + tm->tm_wday = (dr & STM32_RTC_DR_WDAY) >> STM32_RTC_DR_WDAY_SHIFT; >> + >> + /* We don't report tm_yday and tm_isdst */ >> + >> + bcd2tm(tm); >> + >> + if (rtc_valid_tm(tm) < 0) { >> + dev_err(dev, "%s: rtc_time is not valid.\n", __func__); >> + return -EINVAL; >> + } >> + >> + return 0; >> +} >> + >> +static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm) >> +{ >> + struct stm32_rtc *rtc = dev_get_drvdata(dev); >> + unsigned int tr, dr; >> + unsigned long irqflags; >> + int ret = 0; >> + >> + if (rtc_valid_tm(tm) < 0) { >> + dev_err(dev, "%s: rtc_time is not valid.\n", __func__); >> + return -EINVAL; >> + } >> + >> + tm2bcd(tm); >> + >> + /* Time in BCD format */ >> + tr = ((tm->tm_sec << STM32_RTC_TR_SEC_SHIFT) & STM32_RTC_TR_SEC) | >> + ((tm->tm_min << STM32_RTC_TR_MIN_SHIFT) & STM32_RTC_TR_MIN) | >> + ((tm->tm_hour << STM32_RTC_TR_HOUR_SHIFT) & STM32_RTC_TR_HOUR); >> + >> + /* Date in BCD format */ >> + dr = ((tm->tm_mday << STM32_RTC_DR_DATE_SHIFT) & STM32_RTC_DR_DATE) | >> + ((tm->tm_mon << STM32_RTC_DR_MONTH_SHIFT) & STM32_RTC_DR_MONTH) | >> + ((tm->tm_year << STM32_RTC_DR_YEAR_SHIFT) & STM32_RTC_DR_YEAR) | >> + ((tm->tm_wday << STM32_RTC_DR_WDAY_SHIFT) & STM32_RTC_DR_WDAY); >> + >> + spin_lock_irqsave(&rtc->lock, irqflags); >> + >> + stm32_rtc_wpr_unlock(rtc); >> + >> + ret = stm32_rtc_enter_init_mode(rtc); >> + if (ret) { >> + dev_err(dev, "Can't enter in init mode. Set time aborted.\n"); >> + goto end; >> + } >> + >> + writel_relaxed(tr, rtc->base + STM32_RTC_TR); >> + writel_relaxed(dr, rtc->base + STM32_RTC_DR); >> + >> + stm32_rtc_exit_init_mode(rtc); >> + >> + ret = stm32_rtc_wait_sync(rtc); >> +end: >> + stm32_rtc_wpr_lock(rtc); >> + >> + spin_unlock_irqrestore(&rtc->lock, irqflags); >> + >> + return ret; >> +} >> + >> +static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) >> +{ >> + struct stm32_rtc *rtc = dev_get_drvdata(dev); >> + struct rtc_time *tm = &alrm->time; >> + unsigned int alrmar, cr, isr; >> + unsigned long irqflags; >> + >> + spin_lock_irqsave(&rtc->lock, irqflags); >> + >> + alrmar = readl_relaxed(rtc->base + STM32_RTC_ALRMAR); >> + cr = readl_relaxed(rtc->base + STM32_RTC_CR); >> + isr = readl_relaxed(rtc->base + STM32_RTC_ISR); >> + >> + spin_unlock_irqrestore(&rtc->lock, irqflags); >> + >> + if (alrmar & STM32_RTC_ALRMXR_DATE_MASK) { >> + /* >> + * Date/day doesn't matter in Alarm comparison so alarm >> + * triggers every day >> + */ >> + tm->tm_mday = -1; >> + tm->tm_wday = -1; >> + } else { >> + if (alrmar & STM32_RTC_ALRMXR_WDSEL) { >> + /* Alarm is set to a day of week */ >> + tm->tm_mday = -1; >> + tm->tm_wday = (alrmar & STM32_RTC_ALRMXR_WDAY) >> >> + STM32_RTC_ALRMXR_WDAY_SHIFT; >> + tm->tm_wday %= 7; >> + } else { >> + /* Alarm is set to a day of month */ >> + tm->tm_wday = -1; >> + tm->tm_mday = (alrmar & STM32_RTC_ALRMXR_DATE) >> >> + STM32_RTC_ALRMXR_DATE_SHIFT; >> + } >> + } >> + >> + if (alrmar & STM32_RTC_ALRMXR_HOUR_MASK) { >> + /* Hours don't matter in Alarm comparison */ >> + tm->tm_hour = -1; >> + } else { >> + tm->tm_hour = (alrmar & STM32_RTC_ALRMXR_HOUR) >> >> + STM32_RTC_ALRMXR_HOUR_SHIFT; >> + if (alrmar & STM32_RTC_ALRMXR_PM) >> + tm->tm_hour += 12; >> + } >> + >> + if (alrmar & STM32_RTC_ALRMXR_MIN_MASK) { >> + /* Minutes don't matter in Alarm comparison */ >> + tm->tm_min = -1; >> + } else { >> + tm->tm_min = (alrmar & STM32_RTC_ALRMXR_MIN) >> >> + STM32_RTC_ALRMXR_MIN_SHIFT; >> + } >> + >> + if (alrmar & STM32_RTC_ALRMXR_SEC_MASK) { >> + /* Seconds don't matter in Alarm comparison */ >> + tm->tm_sec = -1; >> + } else { >> + tm->tm_sec = (alrmar & STM32_RTC_ALRMXR_SEC) >> >> + STM32_RTC_ALRMXR_SEC_SHIFT; >> + } >> + >> + bcd2tm(tm); >> + >> + alrm->enabled = (cr & STM32_RTC_CR_ALRAE) ? 1 : 0; >> + alrm->pending = (isr & STM32_RTC_ISR_ALRAF) ? 1 : 0; >> + >> + return 0; >> +} >> + >> +static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) >> +{ >> + struct stm32_rtc *rtc = dev_get_drvdata(dev); >> + unsigned long irqflags; >> + unsigned int isr, cr; >> + >> + spin_lock_irqsave(&rtc->lock, irqflags); >> + >> + cr = readl_relaxed(rtc->base + STM32_RTC_CR); >> + >> + stm32_rtc_wpr_unlock(rtc); >> + >> + /* We expose Alarm A to the kernel */ >> + if (enabled) >> + cr |= (STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE); >> + else >> + cr &= ~(STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE); >> + writel_relaxed(cr, rtc->base + STM32_RTC_CR); >> + >> + /* Clear event irqflags, otherwise new events won't be received */ >> + isr = readl_relaxed(rtc->base + STM32_RTC_ISR); >> + isr &= ~STM32_RTC_ISR_ALRAF; >> + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); >> + >> + stm32_rtc_wpr_lock(rtc); >> + >> + spin_unlock_irqrestore(&rtc->lock, irqflags); >> + >> + return 0; >> +} >> + >> +static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm) >> +{ >> + unsigned int cur_day, cur_mon, cur_year, cur_hour, cur_min, cur_sec; >> + unsigned int dr = readl_relaxed(rtc->base + STM32_RTC_DR); >> + unsigned int tr = readl_relaxed(rtc->base + STM32_RTC_TR); >> + >> + cur_day = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT; >> + cur_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT; >> + cur_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT; >> + cur_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT; >> + cur_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT; >> + cur_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT; >> + >> + /* >> + * Assuming current date is M-D-Y H:M:S. >> + * RTC alarm can't be set on a specific month and year. >> + * So the valid alarm range is: >> + * M-D-Y H:M:S < alarm <= (M+1)-D-Y H:M:S >> + * with a specific case for December... >> + */ >> + if ((((tm->tm_year > cur_year) && >> + (tm->tm_mon == 0x1) && (cur_mon == 0x12)) || >> + ((tm->tm_year == cur_year) && >> + (tm->tm_mon <= cur_mon + 1))) && >> + ((tm->tm_mday < cur_day) || >> + ((tm->tm_mday == cur_day) && >> + ((tm->tm_hour < cur_hour) || >> + ((tm->tm_hour == cur_hour) && (tm->tm_min < cur_min)) || >> + ((tm->tm_hour == cur_hour) && (tm->tm_min == cur_min) && >> + (tm->tm_sec <= cur_sec)))))) >> + return 0; >> + >> + return -EINVAL; >> +} >> + >> +static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) >> +{ >> + struct stm32_rtc *rtc = dev_get_drvdata(dev); >> + struct rtc_time *tm = &alrm->time; >> + unsigned long irqflags; >> + unsigned int cr, isr, alrmar; >> + int ret = 0; >> + >> + if (rtc_valid_tm(tm)) { >> + dev_err(dev, "Alarm time not valid.\n"); >> + return -EINVAL; >> + } >> + >> + tm2bcd(tm); >> + >> + /* >> + * RTC alarm can't be set on a specific date, unless this date is >> + * up to the same day of month next month. >> + */ >> + if (stm32_rtc_valid_alrm(rtc, tm) < 0) { >> + dev_err(dev, "Alarm can be set only on upcoming month.\n"); >> + return -EINVAL; >> + } >> + >> + spin_lock_irqsave(&rtc->lock, irqflags); >> + >> + stm32_rtc_wpr_unlock(rtc); >> + >> + /* Disable Alarm */ >> + cr = readl_relaxed(rtc->base + STM32_RTC_CR); >> + cr &= ~STM32_RTC_CR_ALRAE; >> + writel_relaxed(cr, rtc->base + STM32_RTC_CR); >> + >> + /* >> + * Poll Alarm write flag to be sure that Alarm update is allowed: it >> + * takes around 2 ck_rtc clock cycles >> + */ >> + ret = readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR, >> + isr, >> + (isr & STM32_RTC_ISR_ALRAWF), >> + 10, 100000); >> + >> + if (ret) { >> + dev_err(dev, "Alarm update not allowed\n"); >> + goto end; >> + } >> + >> + alrmar = 0; >> + /* tm_year and tm_mon are not used because not supported by RTC */ >> + alrmar |= (tm->tm_mday << STM32_RTC_ALRMXR_DATE_SHIFT) & >> + STM32_RTC_ALRMXR_DATE; >> + /* 24-hour format */ >> + alrmar &= ~STM32_RTC_ALRMXR_PM; >> + alrmar |= (tm->tm_hour << STM32_RTC_ALRMXR_HOUR_SHIFT) & >> + STM32_RTC_ALRMXR_HOUR; >> + alrmar |= (tm->tm_min << STM32_RTC_ALRMXR_MIN_SHIFT) & >> + STM32_RTC_ALRMXR_MIN; >> + alrmar |= (tm->tm_sec << STM32_RTC_ALRMXR_SEC_SHIFT) & >> + STM32_RTC_ALRMXR_SEC; > > All this work on alrmar is done while the spinlock is held. If I'm not > mistaking nothing prevents you from doing that processing before taking the > spinlock. > Yes, I'll move alrmar processing above, just before taking the spinlock. >> + >> + /* Write to Alarm register */ >> + writel_relaxed(alrmar, rtc->base + STM32_RTC_ALRMAR); >> + >> + if (alrm->enabled) >> + stm32_rtc_alarm_irq_enable(dev, 1); >> + else >> + stm32_rtc_alarm_irq_enable(dev, 0); >> + >> +end: >> + stm32_rtc_wpr_lock(rtc); >> + >> + spin_unlock_irqrestore(&rtc->lock, irqflags); >> + >> + return ret; >> +} >> + >> +static const struct rtc_class_ops stm32_rtc_ops = { >> + .read_time = stm32_rtc_read_time, >> + .set_time = stm32_rtc_set_time, >> + .read_alarm = stm32_rtc_read_alarm, >> + .set_alarm = stm32_rtc_set_alarm, >> + .alarm_irq_enable = stm32_rtc_alarm_irq_enable, >> +}; >> + >> +#ifdef CONFIG_OF >> +static const struct of_device_id stm32_rtc_of_match[] = { >> + { .compatible = "st,stm32-rtc" }, >> + {} >> +}; >> +MODULE_DEVICE_TABLE(of, stm32_rtc_of_match); >> +#endif >> + >> +static int stm32_rtc_init(struct platform_device *pdev, >> + struct stm32_rtc *rtc) >> +{ >> + unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr; >> + unsigned int rate; >> + unsigned long irqflags; >> + int ret = 0; >> + >> + rate = clk_get_rate(rtc->ck_rtc); >> + >> + /* Find prediv_a and prediv_s to obtain the 1Hz calendar clock */ >> + pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT; >> + pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT; >> + >> + for (pred_a = pred_a_max; pred_a >= 0; pred_a--) { >> + pred_s = (rate / (pred_a + 1)) - 1; >> + >> + if (((pred_s + 1) * (pred_a + 1)) == rate) >> + break; >> + } >> + >> + /* >> + * Can't find a 1Hz, so give priority to RTC power consumption >> + * by choosing the higher possible value for prediv_a >> + */ >> + if ((pred_s > pred_s_max) || (pred_a > pred_a_max)) { >> + pred_a = pred_a_max; >> + pred_s = (rate / (pred_a + 1)) - 1; >> + >> + dev_warn(&pdev->dev, "ck_rtc is %s\n", >> + (rate - ((pred_a + 1) * (pred_s + 1)) < 0) ? >> + "fast" : "slow"); >> + } >> + >> + spin_lock_irqsave(&rtc->lock, irqflags); >> + >> + stm32_rtc_wpr_unlock(rtc); >> + >> + ret = stm32_rtc_enter_init_mode(rtc); >> + if (ret) { >> + dev_err(&pdev->dev, >> + "Can't enter in init mode. Prescaler config failed.\n"); >> + goto end; >> + } >> + >> + prer = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & STM32_RTC_PRER_PRED_S; >> + writel_relaxed(prer, rtc->base + STM32_RTC_PRER); >> + prer |= (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & STM32_RTC_PRER_PRED_A; >> + writel_relaxed(prer, rtc->base + STM32_RTC_PRER); >> + >> + /* Force 24h time format */ >> + cr = readl_relaxed(rtc->base + STM32_RTC_CR); >> + cr &= ~STM32_RTC_CR_FMT; >> + writel_relaxed(cr, rtc->base + STM32_RTC_CR); >> + >> + stm32_rtc_exit_init_mode(rtc); >> + >> + ret = stm32_rtc_wait_sync(rtc); >> +end: >> + stm32_rtc_wpr_lock(rtc); >> + >> + spin_unlock_irqrestore(&rtc->lock, irqflags); >> + >> + return ret; >> +} >> + >> +static int stm32_rtc_probe(struct platform_device *pdev) >> +{ >> + struct stm32_rtc *rtc; >> + struct resource *res; >> + int ret; >> + >> + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); >> + if (!rtc) >> + return -ENOMEM; >> + >> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> + rtc->base = devm_ioremap_resource(&pdev->dev, res); >> + if (IS_ERR(rtc->base)) >> + return PTR_ERR(rtc->base); >> + >> + dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "st,syscfg"); >> + if (IS_ERR(dbp)) { >> + dev_err(&pdev->dev, "no st,syscfg\n"); >> + return PTR_ERR(dbp); >> + } >> + >> + spin_lock_init(&rtc->lock); >> + >> + rtc->ck_rtc = devm_clk_get(&pdev->dev, NULL); >> + if (IS_ERR(rtc->ck_rtc)) { >> + dev_err(&pdev->dev, "no ck_rtc clock"); >> + return PTR_ERR(rtc->ck_rtc); >> + } >> + >> + ret = clk_prepare_enable(rtc->ck_rtc); >> + if (ret) >> + return ret; >> + >> + regmap_update_bits(dbp, PWR_CR, PWR_CR_DBP, PWR_CR_DBP); >> + >> + /* >> + * After a system reset, RTC_ISR.INITS flag can be read to check if >> + * the calendar has been initalized or not. INITS flag is reset by a >> + * power-on reset (no vbat, no power-supply). It is not reset if >> + * ck_rtc parent clock has changed (so RTC prescalers need to be >> + * changed). That's why we cannot rely on this flag to know if RTC >> + * init has to be done. >> + */ >> + ret = stm32_rtc_init(pdev, rtc); >> + if (ret) >> + goto err; >> + >> + rtc->irq_alarm = platform_get_irq(pdev, 0); >> + if (rtc->irq_alarm <= 0) { >> + dev_err(&pdev->dev, "no alarm irq\n"); >> + ret = -ENOENT; > > Function platform_get_irq() returns a wealth of error codes that are lost here. > Doing 'ret = rtc->irq_alarm;' would prevent that from happening. > OK >> + goto err; >> + } >> + >> + platform_set_drvdata(pdev, rtc); >> + >> + ret = device_init_wakeup(&pdev->dev, true); >> + if (ret) >> + dev_warn(&pdev->dev, >> + "alarm won't be able to wake up the system"); >> + >> + rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name, >> + &stm32_rtc_ops, THIS_MODULE); >> + if (IS_ERR(rtc->rtc_dev)) { >> + ret = PTR_ERR(rtc->rtc_dev); >> + dev_err(&pdev->dev, "rtc device registration failed, err=%d\n", >> + ret); >> + goto err; >> + } >> + >> + /* Handle RTC alarm interrupts */ >> + ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_alarm, NULL, >> + stm32_rtc_alarm_irq, >> + IRQF_TRIGGER_RISING | IRQF_ONESHOT, >> + pdev->name, rtc); >> + if (ret) { >> + dev_err(&pdev->dev, "IRQ%d (alarm interrupt) already claimed\n", >> + rtc->irq_alarm); >> + goto err; >> + } >> + >> + /* >> + * If INITS flag is reset (calendar year field set to 0x00), calendar >> + * must be initialized >> + */ >> + if (!(readl_relaxed(rtc->base + STM32_RTC_ISR) & STM32_RTC_ISR_INITS)) >> + dev_warn(&pdev->dev, "Date/Time must be initialized\n"); >> + >> + return 0; >> +err: >> + clk_disable_unprepare(rtc->ck_rtc); >> + >> + regmap_update_bits(dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP); >> + >> + device_init_wakeup(&pdev->dev, false); >> + >> + return ret; >> +} >> + >> +static int __exit stm32_rtc_remove(struct platform_device *pdev) >> +{ >> + struct stm32_rtc *rtc = platform_get_drvdata(pdev); >> + unsigned int cr; >> + >> + /* Disable interrupts */ >> + stm32_rtc_wpr_unlock(rtc); >> + cr = readl_relaxed(rtc->base + STM32_RTC_CR); >> + cr &= ~STM32_RTC_CR_ALRAIE; >> + writel_relaxed(cr, rtc->base + STM32_RTC_CR); >> + stm32_rtc_wpr_lock(rtc); >> + >> + clk_disable_unprepare(rtc->ck_rtc); >> + >> + /* Enable backup domain write protection */ >> + regmap_update_bits(dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP); >> + >> + device_init_wakeup(&pdev->dev, false); >> + >> + return 0; >> +} >> + >> +#ifdef CONFIG_PM_SLEEP >> +static int stm32_rtc_suspend(struct device *dev) >> +{ >> + struct stm32_rtc *rtc = dev_get_drvdata(dev); >> + >> + if (device_may_wakeup(dev)) >> + return enable_irq_wake(rtc->irq_alarm); >> + >> + return 0; >> +} >> + >> +static int stm32_rtc_resume(struct device *dev) >> +{ >> + struct stm32_rtc *rtc = dev_get_drvdata(dev); >> + int ret = 0; >> + >> + ret = stm32_rtc_wait_sync(rtc); >> + if (ret < 0) >> + return ret; >> + >> + if (device_may_wakeup(dev)) >> + return disable_irq_wake(rtc->irq_alarm); >> + >> + return ret; >> +} >> +#endif >> + >> +static SIMPLE_DEV_PM_OPS(stm32_rtc_pm_ops, >> + stm32_rtc_suspend, stm32_rtc_resume); >> + >> +static struct platform_driver stm32_rtc_driver = { >> + .probe = stm32_rtc_probe, >> + .remove = stm32_rtc_remove, >> + .driver = { >> + .name = DRIVER_NAME, >> + .pm = &stm32_rtc_pm_ops, >> + .of_match_table = stm32_rtc_of_match, >> + }, >> +}; >> + >> +module_platform_driver(stm32_rtc_driver); >> + >> +MODULE_ALIAS("platform:" DRIVER_NAME); >> +MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>"); >> +MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver"); >> +MODULE_LICENSE("GPL v2"); >> -- >> 1.9.1 >> Happy New Year! Amelie
diff --git a/drivers/rtc/Kconfig b/drivers/rtc/Kconfig index e859d14..11eb28a 100644 --- a/drivers/rtc/Kconfig +++ b/drivers/rtc/Kconfig @@ -1706,6 +1706,17 @@ config RTC_DRV_PIC32 This driver can also be built as a module. If so, the module will be called rtc-pic32 +config RTC_DRV_STM32 + tristate "STM32 RTC" + select REGMAP_MMIO + depends on ARCH_STM32 || COMPILE_TEST + help + If you say yes here you get support for the STM32 On-Chip + Real Time Clock. + + This driver can also be built as a module, if so, the module + will be called "rtc-stm32". + comment "HID Sensor RTC drivers" config RTC_DRV_HID_SENSOR_TIME diff --git a/drivers/rtc/Makefile b/drivers/rtc/Makefile index 1ac694a..87bd9cc 100644 --- a/drivers/rtc/Makefile +++ b/drivers/rtc/Makefile @@ -144,6 +144,7 @@ obj-$(CONFIG_RTC_DRV_SNVS) += rtc-snvs.o obj-$(CONFIG_RTC_DRV_SPEAR) += rtc-spear.o obj-$(CONFIG_RTC_DRV_STARFIRE) += rtc-starfire.o obj-$(CONFIG_RTC_DRV_STK17TA8) += rtc-stk17ta8.o +obj-$(CONFIG_RTC_DRV_STM32) += rtc-stm32.o obj-$(CONFIG_RTC_DRV_STMP) += rtc-stmp3xxx.o obj-$(CONFIG_RTC_DRV_ST_LPC) += rtc-st-lpc.o obj-$(CONFIG_RTC_DRV_SUN4V) += rtc-sun4v.o diff --git a/drivers/rtc/rtc-stm32.c b/drivers/rtc/rtc-stm32.c new file mode 100644 index 0000000..6ce0f5a --- /dev/null +++ b/drivers/rtc/rtc-stm32.c @@ -0,0 +1,776 @@ +/* + * Copyright (C) Amelie Delaunay 2016 + * Author: Amelie Delaunay <amelie.delaunay@st.com> + * License terms: GNU General Public License (GPL), version 2 + */ + +#include <linux/bcd.h> +#include <linux/clk.h> +#include <linux/iopoll.h> +#include <linux/ioport.h> +#include <linux/mfd/syscon.h> +#include <linux/module.h> +#include <linux/of_device.h> +#include <linux/regmap.h> +#include <linux/rtc.h> +#include <linux/spinlock.h> + +#define DRIVER_NAME "stm32_rtc" + +/* STM32 RTC registers */ +#define STM32_RTC_TR 0x00 +#define STM32_RTC_DR 0x04 +#define STM32_RTC_CR 0x08 +#define STM32_RTC_ISR 0x0C +#define STM32_RTC_PRER 0x10 +#define STM32_RTC_ALRMAR 0x1C +#define STM32_RTC_WPR 0x24 + +/* STM32_RTC_TR bit fields */ +#define STM32_RTC_TR_SEC_SHIFT 0 +#define STM32_RTC_TR_SEC GENMASK(6, 0) +#define STM32_RTC_TR_MIN_SHIFT 8 +#define STM32_RTC_TR_MIN GENMASK(14, 8) +#define STM32_RTC_TR_HOUR_SHIFT 16 +#define STM32_RTC_TR_HOUR GENMASK(21, 16) + +/* STM32_RTC_DR bit fields */ +#define STM32_RTC_DR_DATE_SHIFT 0 +#define STM32_RTC_DR_DATE GENMASK(5, 0) +#define STM32_RTC_DR_MONTH_SHIFT 8 +#define STM32_RTC_DR_MONTH GENMASK(12, 8) +#define STM32_RTC_DR_WDAY_SHIFT 13 +#define STM32_RTC_DR_WDAY GENMASK(15, 13) +#define STM32_RTC_DR_YEAR_SHIFT 16 +#define STM32_RTC_DR_YEAR GENMASK(23, 16) + +/* STM32_RTC_CR bit fields */ +#define STM32_RTC_CR_FMT BIT(6) +#define STM32_RTC_CR_ALRAE BIT(8) +#define STM32_RTC_CR_ALRAIE BIT(12) + +/* STM32_RTC_ISR bit fields */ +#define STM32_RTC_ISR_ALRAWF BIT(0) +#define STM32_RTC_ISR_INITS BIT(4) +#define STM32_RTC_ISR_RSF BIT(5) +#define STM32_RTC_ISR_INITF BIT(6) +#define STM32_RTC_ISR_INIT BIT(7) +#define STM32_RTC_ISR_ALRAF BIT(8) + +/* STM32_RTC_PRER bit fields */ +#define STM32_RTC_PRER_PRED_S_SHIFT 0 +#define STM32_RTC_PRER_PRED_S GENMASK(14, 0) +#define STM32_RTC_PRER_PRED_A_SHIFT 16 +#define STM32_RTC_PRER_PRED_A GENMASK(22, 16) + +/* STM32_RTC_ALRMAR and STM32_RTC_ALRMBR bit fields */ +#define STM32_RTC_ALRMXR_SEC_SHIFT 0 +#define STM32_RTC_ALRMXR_SEC GENMASK(6, 0) +#define STM32_RTC_ALRMXR_SEC_MASK BIT(7) +#define STM32_RTC_ALRMXR_MIN_SHIFT 8 +#define STM32_RTC_ALRMXR_MIN GENMASK(14, 8) +#define STM32_RTC_ALRMXR_MIN_MASK BIT(15) +#define STM32_RTC_ALRMXR_HOUR_SHIFT 16 +#define STM32_RTC_ALRMXR_HOUR GENMASK(21, 16) +#define STM32_RTC_ALRMXR_PM BIT(22) +#define STM32_RTC_ALRMXR_HOUR_MASK BIT(23) +#define STM32_RTC_ALRMXR_DATE_SHIFT 24 +#define STM32_RTC_ALRMXR_DATE GENMASK(29, 24) +#define STM32_RTC_ALRMXR_WDSEL BIT(30) +#define STM32_RTC_ALRMXR_WDAY_SHIFT 24 +#define STM32_RTC_ALRMXR_WDAY GENMASK(27, 24) +#define STM32_RTC_ALRMXR_DATE_MASK BIT(31) + +/* STM32_RTC_WPR key constants */ +#define RTC_WPR_1ST_KEY 0xCA +#define RTC_WPR_2ND_KEY 0x53 +#define RTC_WPR_WRONG_KEY 0xFF + +/* + * RTC registers are protected agains parasitic write access. + * PWR_CR_DBP bit must be set to enable write access to RTC registers. + */ +/* STM32_PWR_CR */ +#define PWR_CR 0x00 +/* STM32_PWR_CR bit field */ +#define PWR_CR_DBP BIT(8) + +static struct regmap *dbp; + +struct stm32_rtc { + struct rtc_device *rtc_dev; + void __iomem *base; + struct clk *ck_rtc; + spinlock_t lock; /* Protects registers accesses */ + int irq_alarm; +}; + +static void stm32_rtc_wpr_unlock(struct stm32_rtc *rtc) +{ + writel_relaxed(RTC_WPR_1ST_KEY, rtc->base + STM32_RTC_WPR); + writel_relaxed(RTC_WPR_2ND_KEY, rtc->base + STM32_RTC_WPR); +} + +static void stm32_rtc_wpr_lock(struct stm32_rtc *rtc) +{ + writel_relaxed(RTC_WPR_WRONG_KEY, rtc->base + STM32_RTC_WPR); +} + +static int stm32_rtc_enter_init_mode(struct stm32_rtc *rtc) +{ + unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR); + + if (!(isr & STM32_RTC_ISR_INITF)) { + isr |= STM32_RTC_ISR_INIT; + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); + + /* + * It takes around 2 ck_rtc clock cycles to enter in + * initialization phase mode (and have INITF flag set). As + * slowest ck_rtc frequency may be 32kHz and highest should be + * 1MHz, we poll every 10 us with a timeout of 100ms. + */ + return readl_relaxed_poll_timeout_atomic( + rtc->base + STM32_RTC_ISR, + isr, (isr & STM32_RTC_ISR_INITF), + 10, 100000); + } + + return 0; +} + +static void stm32_rtc_exit_init_mode(struct stm32_rtc *rtc) +{ + unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR); + + isr &= ~STM32_RTC_ISR_INIT; + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); +} + +static int stm32_rtc_wait_sync(struct stm32_rtc *rtc) +{ + unsigned int isr = readl_relaxed(rtc->base + STM32_RTC_ISR); + + isr &= ~STM32_RTC_ISR_RSF; + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); + + /* + * Wait for RSF to be set to ensure the calendar registers are + * synchronised, it takes around 2 ck_rtc clock cycles + */ + return readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR, + isr, + (isr & STM32_RTC_ISR_RSF), + 10, 100000); +} + +static irqreturn_t stm32_rtc_alarm_irq(int irq, void *dev_id) +{ + struct stm32_rtc *rtc = (struct stm32_rtc *)dev_id; + unsigned int isr, cr; + + mutex_lock(&rtc->rtc_dev->ops_lock); + + isr = readl_relaxed(rtc->base + STM32_RTC_ISR); + cr = readl_relaxed(rtc->base + STM32_RTC_CR); + + if ((isr & STM32_RTC_ISR_ALRAF) && + (cr & STM32_RTC_CR_ALRAIE)) { + /* Alarm A flag - Alarm interrupt */ + dev_dbg(&rtc->rtc_dev->dev, "Alarm occurred\n"); + + /* Pass event to the kernel */ + rtc_update_irq(rtc->rtc_dev, 1, RTC_IRQF | RTC_AF); + + /* Clear event flag, otherwise new events won't be received */ + writel_relaxed(isr & ~STM32_RTC_ISR_ALRAF, + rtc->base + STM32_RTC_ISR); + } + + mutex_unlock(&rtc->rtc_dev->ops_lock); + + return IRQ_HANDLED; +} + +/* Convert rtc_time structure from bin to bcd format */ +static void tm2bcd(struct rtc_time *tm) +{ + tm->tm_sec = bin2bcd(tm->tm_sec); + tm->tm_min = bin2bcd(tm->tm_min); + tm->tm_hour = bin2bcd(tm->tm_hour); + + tm->tm_mday = bin2bcd(tm->tm_mday); + tm->tm_mon = bin2bcd(tm->tm_mon + 1); + tm->tm_year = bin2bcd(tm->tm_year - 100); + /* + * Number of days since Sunday + * - on kernel side, 0=Sunday...6=Saturday + * - on rtc side, 0=invalid,1=Monday...7=Sunday + */ + tm->tm_wday = (!tm->tm_wday) ? 7 : tm->tm_wday; +} + +/* Convert rtc_time structure from bcd to bin format */ +static void bcd2tm(struct rtc_time *tm) +{ + tm->tm_sec = bcd2bin(tm->tm_sec); + tm->tm_min = bcd2bin(tm->tm_min); + tm->tm_hour = bcd2bin(tm->tm_hour); + + tm->tm_mday = bcd2bin(tm->tm_mday); + tm->tm_mon = bcd2bin(tm->tm_mon) - 1; + tm->tm_year = bcd2bin(tm->tm_year) + 100; + /* + * Number of days since Sunday + * - on kernel side, 0=Sunday...6=Saturday + * - on rtc side, 0=invalid,1=Monday...7=Sunday + */ + tm->tm_wday %= 7; +} + +static int stm32_rtc_read_time(struct device *dev, struct rtc_time *tm) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + unsigned int tr, dr; + unsigned long irqflags; + + spin_lock_irqsave(&rtc->lock, irqflags); + + /* Time and Date in BCD format */ + tr = readl_relaxed(rtc->base + STM32_RTC_TR); + dr = readl_relaxed(rtc->base + STM32_RTC_DR); + + spin_unlock_irqrestore(&rtc->lock, irqflags); + + tm->tm_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT; + tm->tm_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT; + tm->tm_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT; + + tm->tm_mday = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT; + tm->tm_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT; + tm->tm_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT; + tm->tm_wday = (dr & STM32_RTC_DR_WDAY) >> STM32_RTC_DR_WDAY_SHIFT; + + /* We don't report tm_yday and tm_isdst */ + + bcd2tm(tm); + + if (rtc_valid_tm(tm) < 0) { + dev_err(dev, "%s: rtc_time is not valid.\n", __func__); + return -EINVAL; + } + + return 0; +} + +static int stm32_rtc_set_time(struct device *dev, struct rtc_time *tm) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + unsigned int tr, dr; + unsigned long irqflags; + int ret = 0; + + if (rtc_valid_tm(tm) < 0) { + dev_err(dev, "%s: rtc_time is not valid.\n", __func__); + return -EINVAL; + } + + tm2bcd(tm); + + /* Time in BCD format */ + tr = ((tm->tm_sec << STM32_RTC_TR_SEC_SHIFT) & STM32_RTC_TR_SEC) | + ((tm->tm_min << STM32_RTC_TR_MIN_SHIFT) & STM32_RTC_TR_MIN) | + ((tm->tm_hour << STM32_RTC_TR_HOUR_SHIFT) & STM32_RTC_TR_HOUR); + + /* Date in BCD format */ + dr = ((tm->tm_mday << STM32_RTC_DR_DATE_SHIFT) & STM32_RTC_DR_DATE) | + ((tm->tm_mon << STM32_RTC_DR_MONTH_SHIFT) & STM32_RTC_DR_MONTH) | + ((tm->tm_year << STM32_RTC_DR_YEAR_SHIFT) & STM32_RTC_DR_YEAR) | + ((tm->tm_wday << STM32_RTC_DR_WDAY_SHIFT) & STM32_RTC_DR_WDAY); + + spin_lock_irqsave(&rtc->lock, irqflags); + + stm32_rtc_wpr_unlock(rtc); + + ret = stm32_rtc_enter_init_mode(rtc); + if (ret) { + dev_err(dev, "Can't enter in init mode. Set time aborted.\n"); + goto end; + } + + writel_relaxed(tr, rtc->base + STM32_RTC_TR); + writel_relaxed(dr, rtc->base + STM32_RTC_DR); + + stm32_rtc_exit_init_mode(rtc); + + ret = stm32_rtc_wait_sync(rtc); +end: + stm32_rtc_wpr_lock(rtc); + + spin_unlock_irqrestore(&rtc->lock, irqflags); + + return ret; +} + +static int stm32_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + struct rtc_time *tm = &alrm->time; + unsigned int alrmar, cr, isr; + unsigned long irqflags; + + spin_lock_irqsave(&rtc->lock, irqflags); + + alrmar = readl_relaxed(rtc->base + STM32_RTC_ALRMAR); + cr = readl_relaxed(rtc->base + STM32_RTC_CR); + isr = readl_relaxed(rtc->base + STM32_RTC_ISR); + + spin_unlock_irqrestore(&rtc->lock, irqflags); + + if (alrmar & STM32_RTC_ALRMXR_DATE_MASK) { + /* + * Date/day doesn't matter in Alarm comparison so alarm + * triggers every day + */ + tm->tm_mday = -1; + tm->tm_wday = -1; + } else { + if (alrmar & STM32_RTC_ALRMXR_WDSEL) { + /* Alarm is set to a day of week */ + tm->tm_mday = -1; + tm->tm_wday = (alrmar & STM32_RTC_ALRMXR_WDAY) >> + STM32_RTC_ALRMXR_WDAY_SHIFT; + tm->tm_wday %= 7; + } else { + /* Alarm is set to a day of month */ + tm->tm_wday = -1; + tm->tm_mday = (alrmar & STM32_RTC_ALRMXR_DATE) >> + STM32_RTC_ALRMXR_DATE_SHIFT; + } + } + + if (alrmar & STM32_RTC_ALRMXR_HOUR_MASK) { + /* Hours don't matter in Alarm comparison */ + tm->tm_hour = -1; + } else { + tm->tm_hour = (alrmar & STM32_RTC_ALRMXR_HOUR) >> + STM32_RTC_ALRMXR_HOUR_SHIFT; + if (alrmar & STM32_RTC_ALRMXR_PM) + tm->tm_hour += 12; + } + + if (alrmar & STM32_RTC_ALRMXR_MIN_MASK) { + /* Minutes don't matter in Alarm comparison */ + tm->tm_min = -1; + } else { + tm->tm_min = (alrmar & STM32_RTC_ALRMXR_MIN) >> + STM32_RTC_ALRMXR_MIN_SHIFT; + } + + if (alrmar & STM32_RTC_ALRMXR_SEC_MASK) { + /* Seconds don't matter in Alarm comparison */ + tm->tm_sec = -1; + } else { + tm->tm_sec = (alrmar & STM32_RTC_ALRMXR_SEC) >> + STM32_RTC_ALRMXR_SEC_SHIFT; + } + + bcd2tm(tm); + + alrm->enabled = (cr & STM32_RTC_CR_ALRAE) ? 1 : 0; + alrm->pending = (isr & STM32_RTC_ISR_ALRAF) ? 1 : 0; + + return 0; +} + +static int stm32_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + unsigned long irqflags; + unsigned int isr, cr; + + spin_lock_irqsave(&rtc->lock, irqflags); + + cr = readl_relaxed(rtc->base + STM32_RTC_CR); + + stm32_rtc_wpr_unlock(rtc); + + /* We expose Alarm A to the kernel */ + if (enabled) + cr |= (STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE); + else + cr &= ~(STM32_RTC_CR_ALRAIE | STM32_RTC_CR_ALRAE); + writel_relaxed(cr, rtc->base + STM32_RTC_CR); + + /* Clear event irqflags, otherwise new events won't be received */ + isr = readl_relaxed(rtc->base + STM32_RTC_ISR); + isr &= ~STM32_RTC_ISR_ALRAF; + writel_relaxed(isr, rtc->base + STM32_RTC_ISR); + + stm32_rtc_wpr_lock(rtc); + + spin_unlock_irqrestore(&rtc->lock, irqflags); + + return 0; +} + +static int stm32_rtc_valid_alrm(struct stm32_rtc *rtc, struct rtc_time *tm) +{ + unsigned int cur_day, cur_mon, cur_year, cur_hour, cur_min, cur_sec; + unsigned int dr = readl_relaxed(rtc->base + STM32_RTC_DR); + unsigned int tr = readl_relaxed(rtc->base + STM32_RTC_TR); + + cur_day = (dr & STM32_RTC_DR_DATE) >> STM32_RTC_DR_DATE_SHIFT; + cur_mon = (dr & STM32_RTC_DR_MONTH) >> STM32_RTC_DR_MONTH_SHIFT; + cur_year = (dr & STM32_RTC_DR_YEAR) >> STM32_RTC_DR_YEAR_SHIFT; + cur_sec = (tr & STM32_RTC_TR_SEC) >> STM32_RTC_TR_SEC_SHIFT; + cur_min = (tr & STM32_RTC_TR_MIN) >> STM32_RTC_TR_MIN_SHIFT; + cur_hour = (tr & STM32_RTC_TR_HOUR) >> STM32_RTC_TR_HOUR_SHIFT; + + /* + * Assuming current date is M-D-Y H:M:S. + * RTC alarm can't be set on a specific month and year. + * So the valid alarm range is: + * M-D-Y H:M:S < alarm <= (M+1)-D-Y H:M:S + * with a specific case for December... + */ + if ((((tm->tm_year > cur_year) && + (tm->tm_mon == 0x1) && (cur_mon == 0x12)) || + ((tm->tm_year == cur_year) && + (tm->tm_mon <= cur_mon + 1))) && + ((tm->tm_mday < cur_day) || + ((tm->tm_mday == cur_day) && + ((tm->tm_hour < cur_hour) || + ((tm->tm_hour == cur_hour) && (tm->tm_min < cur_min)) || + ((tm->tm_hour == cur_hour) && (tm->tm_min == cur_min) && + (tm->tm_sec <= cur_sec)))))) + return 0; + + return -EINVAL; +} + +static int stm32_rtc_set_alarm(struct device *dev, struct rtc_wkalrm *alrm) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + struct rtc_time *tm = &alrm->time; + unsigned long irqflags; + unsigned int cr, isr, alrmar; + int ret = 0; + + if (rtc_valid_tm(tm)) { + dev_err(dev, "Alarm time not valid.\n"); + return -EINVAL; + } + + tm2bcd(tm); + + /* + * RTC alarm can't be set on a specific date, unless this date is + * up to the same day of month next month. + */ + if (stm32_rtc_valid_alrm(rtc, tm) < 0) { + dev_err(dev, "Alarm can be set only on upcoming month.\n"); + return -EINVAL; + } + + spin_lock_irqsave(&rtc->lock, irqflags); + + stm32_rtc_wpr_unlock(rtc); + + /* Disable Alarm */ + cr = readl_relaxed(rtc->base + STM32_RTC_CR); + cr &= ~STM32_RTC_CR_ALRAE; + writel_relaxed(cr, rtc->base + STM32_RTC_CR); + + /* + * Poll Alarm write flag to be sure that Alarm update is allowed: it + * takes around 2 ck_rtc clock cycles + */ + ret = readl_relaxed_poll_timeout_atomic(rtc->base + STM32_RTC_ISR, + isr, + (isr & STM32_RTC_ISR_ALRAWF), + 10, 100000); + + if (ret) { + dev_err(dev, "Alarm update not allowed\n"); + goto end; + } + + alrmar = 0; + /* tm_year and tm_mon are not used because not supported by RTC */ + alrmar |= (tm->tm_mday << STM32_RTC_ALRMXR_DATE_SHIFT) & + STM32_RTC_ALRMXR_DATE; + /* 24-hour format */ + alrmar &= ~STM32_RTC_ALRMXR_PM; + alrmar |= (tm->tm_hour << STM32_RTC_ALRMXR_HOUR_SHIFT) & + STM32_RTC_ALRMXR_HOUR; + alrmar |= (tm->tm_min << STM32_RTC_ALRMXR_MIN_SHIFT) & + STM32_RTC_ALRMXR_MIN; + alrmar |= (tm->tm_sec << STM32_RTC_ALRMXR_SEC_SHIFT) & + STM32_RTC_ALRMXR_SEC; + + /* Write to Alarm register */ + writel_relaxed(alrmar, rtc->base + STM32_RTC_ALRMAR); + + if (alrm->enabled) + stm32_rtc_alarm_irq_enable(dev, 1); + else + stm32_rtc_alarm_irq_enable(dev, 0); + +end: + stm32_rtc_wpr_lock(rtc); + + spin_unlock_irqrestore(&rtc->lock, irqflags); + + return ret; +} + +static const struct rtc_class_ops stm32_rtc_ops = { + .read_time = stm32_rtc_read_time, + .set_time = stm32_rtc_set_time, + .read_alarm = stm32_rtc_read_alarm, + .set_alarm = stm32_rtc_set_alarm, + .alarm_irq_enable = stm32_rtc_alarm_irq_enable, +}; + +#ifdef CONFIG_OF +static const struct of_device_id stm32_rtc_of_match[] = { + { .compatible = "st,stm32-rtc" }, + {} +}; +MODULE_DEVICE_TABLE(of, stm32_rtc_of_match); +#endif + +static int stm32_rtc_init(struct platform_device *pdev, + struct stm32_rtc *rtc) +{ + unsigned int prer, pred_a, pred_s, pred_a_max, pred_s_max, cr; + unsigned int rate; + unsigned long irqflags; + int ret = 0; + + rate = clk_get_rate(rtc->ck_rtc); + + /* Find prediv_a and prediv_s to obtain the 1Hz calendar clock */ + pred_a_max = STM32_RTC_PRER_PRED_A >> STM32_RTC_PRER_PRED_A_SHIFT; + pred_s_max = STM32_RTC_PRER_PRED_S >> STM32_RTC_PRER_PRED_S_SHIFT; + + for (pred_a = pred_a_max; pred_a >= 0; pred_a--) { + pred_s = (rate / (pred_a + 1)) - 1; + + if (((pred_s + 1) * (pred_a + 1)) == rate) + break; + } + + /* + * Can't find a 1Hz, so give priority to RTC power consumption + * by choosing the higher possible value for prediv_a + */ + if ((pred_s > pred_s_max) || (pred_a > pred_a_max)) { + pred_a = pred_a_max; + pred_s = (rate / (pred_a + 1)) - 1; + + dev_warn(&pdev->dev, "ck_rtc is %s\n", + (rate - ((pred_a + 1) * (pred_s + 1)) < 0) ? + "fast" : "slow"); + } + + spin_lock_irqsave(&rtc->lock, irqflags); + + stm32_rtc_wpr_unlock(rtc); + + ret = stm32_rtc_enter_init_mode(rtc); + if (ret) { + dev_err(&pdev->dev, + "Can't enter in init mode. Prescaler config failed.\n"); + goto end; + } + + prer = (pred_s << STM32_RTC_PRER_PRED_S_SHIFT) & STM32_RTC_PRER_PRED_S; + writel_relaxed(prer, rtc->base + STM32_RTC_PRER); + prer |= (pred_a << STM32_RTC_PRER_PRED_A_SHIFT) & STM32_RTC_PRER_PRED_A; + writel_relaxed(prer, rtc->base + STM32_RTC_PRER); + + /* Force 24h time format */ + cr = readl_relaxed(rtc->base + STM32_RTC_CR); + cr &= ~STM32_RTC_CR_FMT; + writel_relaxed(cr, rtc->base + STM32_RTC_CR); + + stm32_rtc_exit_init_mode(rtc); + + ret = stm32_rtc_wait_sync(rtc); +end: + stm32_rtc_wpr_lock(rtc); + + spin_unlock_irqrestore(&rtc->lock, irqflags); + + return ret; +} + +static int stm32_rtc_probe(struct platform_device *pdev) +{ + struct stm32_rtc *rtc; + struct resource *res; + int ret; + + rtc = devm_kzalloc(&pdev->dev, sizeof(*rtc), GFP_KERNEL); + if (!rtc) + return -ENOMEM; + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + rtc->base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(rtc->base)) + return PTR_ERR(rtc->base); + + dbp = syscon_regmap_lookup_by_phandle(pdev->dev.of_node, "st,syscfg"); + if (IS_ERR(dbp)) { + dev_err(&pdev->dev, "no st,syscfg\n"); + return PTR_ERR(dbp); + } + + spin_lock_init(&rtc->lock); + + rtc->ck_rtc = devm_clk_get(&pdev->dev, NULL); + if (IS_ERR(rtc->ck_rtc)) { + dev_err(&pdev->dev, "no ck_rtc clock"); + return PTR_ERR(rtc->ck_rtc); + } + + ret = clk_prepare_enable(rtc->ck_rtc); + if (ret) + return ret; + + regmap_update_bits(dbp, PWR_CR, PWR_CR_DBP, PWR_CR_DBP); + + /* + * After a system reset, RTC_ISR.INITS flag can be read to check if + * the calendar has been initalized or not. INITS flag is reset by a + * power-on reset (no vbat, no power-supply). It is not reset if + * ck_rtc parent clock has changed (so RTC prescalers need to be + * changed). That's why we cannot rely on this flag to know if RTC + * init has to be done. + */ + ret = stm32_rtc_init(pdev, rtc); + if (ret) + goto err; + + rtc->irq_alarm = platform_get_irq(pdev, 0); + if (rtc->irq_alarm <= 0) { + dev_err(&pdev->dev, "no alarm irq\n"); + ret = -ENOENT; + goto err; + } + + platform_set_drvdata(pdev, rtc); + + ret = device_init_wakeup(&pdev->dev, true); + if (ret) + dev_warn(&pdev->dev, + "alarm won't be able to wake up the system"); + + rtc->rtc_dev = devm_rtc_device_register(&pdev->dev, pdev->name, + &stm32_rtc_ops, THIS_MODULE); + if (IS_ERR(rtc->rtc_dev)) { + ret = PTR_ERR(rtc->rtc_dev); + dev_err(&pdev->dev, "rtc device registration failed, err=%d\n", + ret); + goto err; + } + + /* Handle RTC alarm interrupts */ + ret = devm_request_threaded_irq(&pdev->dev, rtc->irq_alarm, NULL, + stm32_rtc_alarm_irq, + IRQF_TRIGGER_RISING | IRQF_ONESHOT, + pdev->name, rtc); + if (ret) { + dev_err(&pdev->dev, "IRQ%d (alarm interrupt) already claimed\n", + rtc->irq_alarm); + goto err; + } + + /* + * If INITS flag is reset (calendar year field set to 0x00), calendar + * must be initialized + */ + if (!(readl_relaxed(rtc->base + STM32_RTC_ISR) & STM32_RTC_ISR_INITS)) + dev_warn(&pdev->dev, "Date/Time must be initialized\n"); + + return 0; +err: + clk_disable_unprepare(rtc->ck_rtc); + + regmap_update_bits(dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP); + + device_init_wakeup(&pdev->dev, false); + + return ret; +} + +static int __exit stm32_rtc_remove(struct platform_device *pdev) +{ + struct stm32_rtc *rtc = platform_get_drvdata(pdev); + unsigned int cr; + + /* Disable interrupts */ + stm32_rtc_wpr_unlock(rtc); + cr = readl_relaxed(rtc->base + STM32_RTC_CR); + cr &= ~STM32_RTC_CR_ALRAIE; + writel_relaxed(cr, rtc->base + STM32_RTC_CR); + stm32_rtc_wpr_lock(rtc); + + clk_disable_unprepare(rtc->ck_rtc); + + /* Enable backup domain write protection */ + regmap_update_bits(dbp, PWR_CR, PWR_CR_DBP, ~PWR_CR_DBP); + + device_init_wakeup(&pdev->dev, false); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int stm32_rtc_suspend(struct device *dev) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + + if (device_may_wakeup(dev)) + return enable_irq_wake(rtc->irq_alarm); + + return 0; +} + +static int stm32_rtc_resume(struct device *dev) +{ + struct stm32_rtc *rtc = dev_get_drvdata(dev); + int ret = 0; + + ret = stm32_rtc_wait_sync(rtc); + if (ret < 0) + return ret; + + if (device_may_wakeup(dev)) + return disable_irq_wake(rtc->irq_alarm); + + return ret; +} +#endif + +static SIMPLE_DEV_PM_OPS(stm32_rtc_pm_ops, + stm32_rtc_suspend, stm32_rtc_resume); + +static struct platform_driver stm32_rtc_driver = { + .probe = stm32_rtc_probe, + .remove = stm32_rtc_remove, + .driver = { + .name = DRIVER_NAME, + .pm = &stm32_rtc_pm_ops, + .of_match_table = stm32_rtc_of_match, + }, +}; + +module_platform_driver(stm32_rtc_driver); + +MODULE_ALIAS("platform:" DRIVER_NAME); +MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>"); +MODULE_DESCRIPTION("STMicroelectronics STM32 Real Time Clock driver"); +MODULE_LICENSE("GPL v2");
This patch adds support for the STM32 RTC. Signed-off-by: Amelie Delaunay <amelie.delaunay@st.com> --- drivers/rtc/Kconfig | 11 + drivers/rtc/Makefile | 1 + drivers/rtc/rtc-stm32.c | 776 ++++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 788 insertions(+) create mode 100644 drivers/rtc/rtc-stm32.c