| Message ID | 305eacc9c57c2404795b6be76a08915808e23108.1624771446.git.baruch@tkos.co.il (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v4,1/3] pwm: driver for qualcomm ipq6018 pwm block | expand |
Hello Baruch, On Sun, Jun 27, 2021 at 08:24:04AM +0300, Baruch Siach wrote: > Driver for the PWM block in Qualcomm IPQ6018 line of SoCs. Based on > driver from downstream Codeaurora kernel tree. Removed support for older > (V1) variants because I have no access to that hardware. > > Tested on IPQ6010 based hardware. > > Signed-off-by: Baruch Siach <baruch@tkos.co.il> > --- > v4: > > Use div64_u64() to fix link for 32-bit targets ((kernel test robot > <lkp@intel.com>, Uwe Kleine-König) > > v3: > > s/qcom,pwm-ipq6018/qcom,ipq6018-pwm/ (Rob Herring) > > Fix integer overflow on 32-bit targets (kernel test robot <lkp@intel.com>) > > v2: > > Address Uwe Kleine-König review comments: > > Fix period calculation when out of range > > Don't set period larger than requested > > Remove PWM disable on configuration change > > Implement .apply instead of non-atomic .config/.enable/.disable > > Don't modify PWM on .request/.free > > Check pwm_div underflow > > Fix various code and comment formatting issues > > Other changes: > > Use u64 divisor safe division > > Remove now empty .request/.free > --- > drivers/pwm/Kconfig | 12 +++ > drivers/pwm/Makefile | 1 + > drivers/pwm/pwm-ipq.c | 238 ++++++++++++++++++++++++++++++++++++++++++ > 3 files changed, 251 insertions(+) > create mode 100644 drivers/pwm/pwm-ipq.c > > diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig > index c76adedd58c9..08add845596f 100644 > --- a/drivers/pwm/Kconfig > +++ b/drivers/pwm/Kconfig > @@ -260,6 +260,18 @@ config PWM_INTEL_LGM > To compile this driver as a module, choose M here: the module > will be called pwm-intel-lgm. > > +config PWM_IPQ > + tristate "IPQ PWM support" > + depends on ARCH_QCOM || COMPILE_TEST > + depends on HAVE_CLK && HAS_IOMEM > + help > + Generic PWM framework driver for IPQ PWM block which supports > + 4 pwm channels. Each of the these channels can be configured > + independent of each other. > + > + To compile this driver as a module, choose M here: the module > + will be called pwm-ipq. > + > config PWM_IQS620A > tristate "Azoteq IQS620A PWM support" > depends on MFD_IQS62X || COMPILE_TEST > diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile > index 708840b7fba8..7402feae4b36 100644 > --- a/drivers/pwm/Makefile > +++ b/drivers/pwm/Makefile > @@ -22,6 +22,7 @@ obj-$(CONFIG_PWM_IMX1) += pwm-imx1.o > obj-$(CONFIG_PWM_IMX27) += pwm-imx27.o > obj-$(CONFIG_PWM_IMX_TPM) += pwm-imx-tpm.o > obj-$(CONFIG_PWM_INTEL_LGM) += pwm-intel-lgm.o > +obj-$(CONFIG_PWM_IPQ) += pwm-ipq.o > obj-$(CONFIG_PWM_IQS620A) += pwm-iqs620a.o > obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o > obj-$(CONFIG_PWM_KEEMBAY) += pwm-keembay.o > diff --git a/drivers/pwm/pwm-ipq.c b/drivers/pwm/pwm-ipq.c > new file mode 100644 > index 000000000000..966b051573c8 > --- /dev/null > +++ b/drivers/pwm/pwm-ipq.c > @@ -0,0 +1,238 @@ > +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 > +/* > + * Copyright (c) 2016-2017, 2020 The Linux Foundation. All rights reserved. > + */ > + > +#include <linux/module.h> > +#include <linux/platform_device.h> > +#include <linux/pwm.h> > +#include <linux/clk.h> > +#include <linux/io.h> > +#include <linux/math64.h> > +#include <linux/of_device.h> > + > +#define CLK_SRC_FREQ (100*1000*1000) > +#define MAX_PWM_DEVICES 4 MAX_PWM_DEVICES is only used once, in my book this doesn't need a define then. (But if you still want to keep it, that's fine for me, too.) > +/* > + * Enable bit is set to enable output toggling in pwm device. > + * Update bit is set to reflect the changed divider and high duration > + * values in register. > + */ > +#define PWM_ENABLE 0x80000000 > +#define PWM_UPDATE 0x40000000 > + > +/* The frequency range supported is 1Hz to 100MHz */ > +#define MIN_PERIOD_NS 10 > +#define MAX_PERIOD_NS 1000000000 Please use a driver prefix for these defines. > + > +/* > + * The max value specified for each field is based on the number of bits > + * in the pwm control register for that field > + */ > +#define MAX_PWM_CFG 0xFFFF > + > +#define PWM_CTRL_HI_SHIFT 16 > + > +#define PWM_CFG_REG0 0 /*PWM_DIV PWM_HI*/ > +#define PWM_CFG_REG1 1 /*ENABLE UPDATE PWM_PRE_DIV*/ > + > +struct ipq_pwm_chip { > + struct pwm_chip chip; > + struct clk *clk; > + void __iomem *mem; > +}; > + > +static struct ipq_pwm_chip *to_ipq_pwm_chip(struct pwm_chip *chip) > +{ > + return container_of(chip, struct ipq_pwm_chip, chip); > +} > + > +static unsigned ipq_pwm_reg_offset(struct pwm_device *pwm, unsigned reg) > +{ > + return ((pwm->hwpwm * 2) + reg) * 4; > +} > + > +static void config_div_and_duty(struct pwm_device *pwm, int pre_div, > + unsigned long long pwm_div, unsigned long period_ns, > + unsigned long long duty_ns) Please also use a consistent prefix for function names. I suggest to use u64 for some of the parameters. While this doesn't change anything, it is cleaner as the caller passes variables of this type. > +{ > + unsigned long hi_dur; > + unsigned long long quotient; > + unsigned long val = 0; > + struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(pwm->chip); > + > + /* > + * high duration = pwm duty * (pwm div + 1) > + * pwm duty = duty_ns / period_ns > + */ > + quotient = (pwm_div + 1) * duty_ns; > + hi_dur = div64_u64(quotient, period_ns); > + > + val |= ((hi_dur & MAX_PWM_CFG) << PWM_CTRL_HI_SHIFT); > + val |= (pwm_div & MAX_PWM_CFG); > + writel(val, ipq_chip->mem + ipq_pwm_reg_offset(pwm, PWM_CFG_REG0)); I consider it a bit irritating that the mask is called ...CFG but the shift define is called ..._CTRL_.... I suggest something like: #define IPQ_PWM_REG0 ... #define IPQ_PWM_REG0_HI 0xffff0000 #define IPQ_PWM_REG0_DIV 0x0000ffff ... val = FIELD_PREP(IPQ_PWM_REG0_HI, hi_dur) | FIELD_PREP(IPQ_PWM_REG0_DIV, pwm_div); ipq_pwm_writel(ipq_chip, val, PWM_CFG_REG0); > + val = pre_div & MAX_PWM_CFG; > + writel(val, ipq_chip->mem + ipq_pwm_reg_offset(pwm, PWM_CFG_REG1)); > +} > + > +static int ipq_pwm_enable(struct pwm_device *pwm) This is only called once. The caller (ipq_pwm_apply()) just before called config_div_and_duty() which already wrote PWM_CFG_REG1. If you unroll these calls you might fix a glitch or make it more unlikely. > +{ > + struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(pwm->chip); > + unsigned offset = ipq_pwm_reg_offset(pwm, PWM_CFG_REG1); > + unsigned long val; > + > + val = readl(ipq_chip->mem + offset); > + val |= PWM_ENABLE | PWM_UPDATE; > + writel(val, ipq_chip->mem + offset); > + > + return 0; > +} > + > +static void ipq_pwm_disable(struct pwm_device *pwm) > +{ > + struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(pwm->chip); > + unsigned offset = ipq_pwm_reg_offset(pwm, PWM_CFG_REG1); > + unsigned long val; > + > + val = readl(ipq_chip->mem + offset); > + val |= PWM_UPDATE; > + val &= ~PWM_ENABLE; > + writel(val, ipq_chip->mem + offset); > +} > + > +static int ipq_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > + const struct pwm_state *state) > +{ > + struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(chip); > + unsigned long freq; > + int pre_div, close_pre_div, close_pwm_div; > + int pwm_div; > + long long diff; > + unsigned long rate = clk_get_rate(ipq_chip->clk); > + unsigned long min_diff = rate; > + uint64_t fin_ps; > + u64 period_ns, duty_ns; > + > + if (state->period < MIN_PERIOD_NS) > + return -ERANGE; MIN_PERIOD_NS depends on clk_get_rate(ipq_chip->clk), doesn't it? > + period_ns = min_t(u64, state->period, MAX_PERIOD_NS); > + duty_ns = min_t(u64, state->duty_cycle, period_ns); If you define MAX_PERIOD_NS as (u64)1000000000 you can just use min(). > + > + /* freq in Hz for period in nano second*/ Space before the closing */ please > + freq = div64_u64(NSEC_PER_SEC, period_ns); > + fin_ps = div64_u64(NSEC_PER_SEC * 1000ULL, rate); > + close_pre_div = MAX_PWM_CFG; > + close_pwm_div = MAX_PWM_CFG; > + > + for (pre_div = 0; pre_div <= MAX_PWM_CFG; pre_div++) { > + pwm_div = DIV64_U64_ROUND_CLOSEST(period_ns * 1000, > + fin_ps * (pre_div + 1)); > + pwm_div--; > + if (pwm_div < 0 || pwm_div > MAX_PWM_CFG) > + continue; > + > + diff = ((uint64_t)freq * (pre_div + 1) * (pwm_div + 1)) > + - (uint64_t)rate; > + > + if (diff < 0) /* period larger than requested */ > + continue; > + if (diff == 0) { /* bingo */ > + close_pre_div = pre_div; > + close_pwm_div = pwm_div; > + break; > + } > + if (diff < min_diff) { > + min_diff = diff; > + close_pre_div = pre_div; > + close_pwm_div = pwm_div; > + } I didn't check deeply, but I assume this calculation can be done more efficiently. Also I wonder if DIV64_U64_ROUND_CLOSEST is right. When you implement a .get_state() callback (which usually helps me to understand how the hardware works) I'm willing to take a closer look. > + } > + > + /* config divider values for the closest possible frequency */ > + config_div_and_duty(pwm, close_pre_div, close_pwm_div, > + period_ns, duty_ns); > + if (state->enabled) > + ipq_pwm_enable(pwm); > + else > + ipq_pwm_disable(pwm); > + > + return 0; > +} > + > +static struct pwm_ops ipq_pwm_ops = { > + .apply = ipq_pwm_apply, Please implement a .get_state() function. (And in general, test your patch with PWM_DEBUG enabled.) > + .owner = THIS_MODULE, > +}; > + > +static int ipq_pwm_probe(struct platform_device *pdev) > +{ > + struct ipq_pwm_chip *pwm; > + struct device *dev; > + int ret; > + > + dev = &pdev->dev; This can go to the line declaring dev. > + pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL); > + if (!pwm) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, pwm); > + > + pwm->mem = devm_platform_ioremap_resource(pdev, 0); > + if (IS_ERR(pwm->mem)) > + return PTR_ERR(pwm->mem); > + > + pwm->clk = devm_clk_get(dev, "core"); > + if (IS_ERR(pwm->clk)) Error message please. Preferably using dev_err_probe(). > + return PTR_ERR(pwm->clk); > + > + ret = clk_set_rate(pwm->clk, CLK_SRC_FREQ); > + if (ret) ditto. > + return ret; empty line here? > + ret = clk_prepare_enable(pwm->clk); > + if (ret) ditto. > + return ret; > + > + pwm->chip.dev = dev; > + pwm->chip.ops = &ipq_pwm_ops; > + pwm->chip.npwm = MAX_PWM_DEVICES; > + > + ret = pwmchip_add(&pwm->chip); > + if (ret < 0) { > + dev_err_probe(dev, ret, "pwmchip_add() failed\n"); > + clk_disable_unprepare(pwm->clk); > + return ret; > + } > + > + return 0; > +} > + > +static int ipq_pwm_remove(struct platform_device *pdev) > +{ > + struct ipq_pwm_chip *pwm = platform_get_drvdata(pdev); > + > + pwmchip_remove(&pwm->chip); clk_disable_unprepare missing here. > + > + return 0; > +} > + > +static const struct of_device_id pwm_ipq_dt_match[] = { > + { .compatible = "qcom,ipq6018-pwm", }, > + {} > +}; > +MODULE_DEVICE_TABLE(of, pwm_ipq_dt_match); > + > +static struct platform_driver ipq_pwm_driver = { > + .driver = { > + .name = "ipq-pwm", > + .owner = THIS_MODULE, Setting owner isn't necessary any more since v3.11 (commit 9447057eaff8 ("platform_device: use a macro instead of platform_driver_register"). > + .of_match_table = pwm_ipq_dt_match, > + }, > + .probe = ipq_pwm_probe, > + .remove = ipq_pwm_remove, > +}; > + > +module_platform_driver(ipq_pwm_driver); > + > +MODULE_LICENSE("Dual BSD/GPL"); > -- > 2.30.2 > >
Hi Uwe, Thanks for taking the time to review this patch. I have a few comment below. On Mon, Jul 05 2021, Uwe Kleine-König wrote: > On Sun, Jun 27, 2021 at 08:24:04AM +0300, Baruch Siach wrote: >> +/* >> + * Enable bit is set to enable output toggling in pwm device. >> + * Update bit is set to reflect the changed divider and high duration >> + * values in register. >> + */ >> +#define PWM_ENABLE 0x80000000 >> +#define PWM_UPDATE 0x40000000 >> + >> +/* The frequency range supported is 1Hz to 100MHz */ >> +#define MIN_PERIOD_NS 10 >> +#define MAX_PERIOD_NS 1000000000 > > Please use a driver prefix for these defines. I take this to refer also to the defines below, right? >> + >> +/* >> + * The max value specified for each field is based on the number of bits >> + * in the pwm control register for that field >> + */ >> +#define MAX_PWM_CFG 0xFFFF >> + >> +#define PWM_CTRL_HI_SHIFT 16 >> + >> +#define PWM_CFG_REG0 0 /*PWM_DIV PWM_HI*/ >> +#define PWM_CFG_REG1 1 /*ENABLE UPDATE PWM_PRE_DIV*/ ... >> +static void config_div_and_duty(struct pwm_device *pwm, int pre_div, >> + unsigned long long pwm_div, unsigned long period_ns, >> + unsigned long long duty_ns) > > Please also use a consistent prefix for function names. > > I suggest to use u64 for some of the parameters. While this doesn't > change anything, it is cleaner as the caller passes variables of this > type. Actually for pre_div and pwm_div the caller passes int values. I agree this is inconsistent. ... >> +static int ipq_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, >> + const struct pwm_state *state) >> +{ >> + struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(chip); >> + unsigned long freq; >> + int pre_div, close_pre_div, close_pwm_div; >> + int pwm_div; >> + long long diff; >> + unsigned long rate = clk_get_rate(ipq_chip->clk); >> + unsigned long min_diff = rate; >> + uint64_t fin_ps; >> + u64 period_ns, duty_ns; >> + >> + if (state->period < MIN_PERIOD_NS) >> + return -ERANGE; > > MIN_PERIOD_NS depends on clk_get_rate(ipq_chip->clk), doesn't it? probe sets this clock to the fixed 100MHz rate (CLK_SRC_FREQ). Would you prefer to derive MIN_PERIOD_NS from CLK_SRC_FREQ? >> + period_ns = min_t(u64, state->period, MAX_PERIOD_NS); >> + duty_ns = min_t(u64, state->duty_cycle, period_ns); > > If you define MAX_PERIOD_NS as (u64)1000000000 you can just use min(). > >> + >> + /* freq in Hz for period in nano second*/ > > Space before the closing */ please > >> + freq = div64_u64(NSEC_PER_SEC, period_ns); >> + fin_ps = div64_u64(NSEC_PER_SEC * 1000ULL, rate); >> + close_pre_div = MAX_PWM_CFG; >> + close_pwm_div = MAX_PWM_CFG; >> + >> + for (pre_div = 0; pre_div <= MAX_PWM_CFG; pre_div++) { >> + pwm_div = DIV64_U64_ROUND_CLOSEST(period_ns * 1000, >> + fin_ps * (pre_div + 1)); >> + pwm_div--; >> + if (pwm_div < 0 || pwm_div > MAX_PWM_CFG) >> + continue; >> + >> + diff = ((uint64_t)freq * (pre_div + 1) * (pwm_div + 1)) >> + - (uint64_t)rate; >> + >> + if (diff < 0) /* period larger than requested */ >> + continue; >> + if (diff == 0) { /* bingo */ >> + close_pre_div = pre_div; >> + close_pwm_div = pwm_div; >> + break; >> + } >> + if (diff < min_diff) { >> + min_diff = diff; >> + close_pre_div = pre_div; >> + close_pwm_div = pwm_div; >> + } > > I didn't check deeply, but I assume this calculation can be done more > efficiently. The thing is that we have two dividers to play with. I can't think of a cleaner way to find the best match for a given target frequency. > Also I wonder if DIV64_U64_ROUND_CLOSEST is right. When you implement > a .get_state() callback (which usually helps me to understand how the > hardware works) I'm willing to take a closer look. Thanks, baruch
Hello Baruch, On Wed, Jul 07, 2021 at 07:58:01AM +0300, Baruch Siach wrote: > On Mon, Jul 05 2021, Uwe Kleine-König wrote: > > On Sun, Jun 27, 2021 at 08:24:04AM +0300, Baruch Siach wrote: > >> +/* > >> + * Enable bit is set to enable output toggling in pwm device. > >> + * Update bit is set to reflect the changed divider and high duration > >> + * values in register. > >> + */ > >> +#define PWM_ENABLE 0x80000000 > >> +#define PWM_UPDATE 0x40000000 > >> + > >> +/* The frequency range supported is 1Hz to 100MHz */ > >> +#define MIN_PERIOD_NS 10 > >> +#define MAX_PERIOD_NS 1000000000 > > > > Please use a driver prefix for these defines. > > I take this to refer also to the defines below, right? right. > >> + > >> +/* > >> + * The max value specified for each field is based on the number of bits > >> + * in the pwm control register for that field > >> + */ > >> +#define MAX_PWM_CFG 0xFFFF > >> + > >> +#define PWM_CTRL_HI_SHIFT 16 > >> + > >> +#define PWM_CFG_REG0 0 /*PWM_DIV PWM_HI*/ > >> +#define PWM_CFG_REG1 1 /*ENABLE UPDATE PWM_PRE_DIV*/ > > ... > > >> +static void config_div_and_duty(struct pwm_device *pwm, int pre_div, > >> + unsigned long long pwm_div, unsigned long period_ns, > >> + unsigned long long duty_ns) > > > > Please also use a consistent prefix for function names. > > > > I suggest to use u64 for some of the parameters. While this doesn't > > change anything, it is cleaner as the caller passes variables of this > > type. > > Actually for pre_div and pwm_div the caller passes int values. I agree > this is inconsistent. > > ... > > >> +static int ipq_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, > >> + const struct pwm_state *state) > >> +{ > >> + struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(chip); > >> + unsigned long freq; > >> + int pre_div, close_pre_div, close_pwm_div; > >> + int pwm_div; > >> + long long diff; > >> + unsigned long rate = clk_get_rate(ipq_chip->clk); > >> + unsigned long min_diff = rate; > >> + uint64_t fin_ps; > >> + u64 period_ns, duty_ns; > >> + > >> + if (state->period < MIN_PERIOD_NS) > >> + return -ERANGE; > > > > MIN_PERIOD_NS depends on clk_get_rate(ipq_chip->clk), doesn't it? > > probe sets this clock to the fixed 100MHz rate (CLK_SRC_FREQ). Would you > prefer to derive MIN_PERIOD_NS from CLK_SRC_FREQ? I'd like to either have all of ipq_pwm_apply use this information that the clock rate is 100MHz or nothing, but having MIN_PERIOD_NS hardcoding that information and use clk_get_rate(ipq_chip->clk) for calculating fin_ps is strange. > >> + freq = div64_u64(NSEC_PER_SEC, period_ns); > >> + fin_ps = div64_u64(NSEC_PER_SEC * 1000ULL, rate); > >> + close_pre_div = MAX_PWM_CFG; > >> + close_pwm_div = MAX_PWM_CFG; > >> + > >> + for (pre_div = 0; pre_div <= MAX_PWM_CFG; pre_div++) { > >> + pwm_div = DIV64_U64_ROUND_CLOSEST(period_ns * 1000, > >> + fin_ps * (pre_div + 1)); > >> + pwm_div--; > >> + if (pwm_div < 0 || pwm_div > MAX_PWM_CFG) > >> + continue; > >> + > >> + diff = ((uint64_t)freq * (pre_div + 1) * (pwm_div + 1)) > >> + - (uint64_t)rate; > >> + > >> + if (diff < 0) /* period larger than requested */ > >> + continue; > >> + if (diff == 0) { /* bingo */ > >> + close_pre_div = pre_div; > >> + close_pwm_div = pwm_div; > >> + break; > >> + } > >> + if (diff < min_diff) { > >> + min_diff = diff; > >> + close_pre_div = pre_div; > >> + close_pwm_div = pwm_div; > >> + } > > > > I didn't check deeply, but I assume this calculation can be done more > > efficiently. > > The thing is that we have two dividers to play with. I can't think of a > cleaner way to find the best match for a given target frequency. OK, with two equal dividers it might indeed be necessary to do it this way. After seeing a get_state implemententation I will think about this some more. Best regards Uwe
diff --git a/drivers/pwm/Kconfig b/drivers/pwm/Kconfig index c76adedd58c9..08add845596f 100644 --- a/drivers/pwm/Kconfig +++ b/drivers/pwm/Kconfig @@ -260,6 +260,18 @@ config PWM_INTEL_LGM To compile this driver as a module, choose M here: the module will be called pwm-intel-lgm. +config PWM_IPQ + tristate "IPQ PWM support" + depends on ARCH_QCOM || COMPILE_TEST + depends on HAVE_CLK && HAS_IOMEM + help + Generic PWM framework driver for IPQ PWM block which supports + 4 pwm channels. Each of the these channels can be configured + independent of each other. + + To compile this driver as a module, choose M here: the module + will be called pwm-ipq. + config PWM_IQS620A tristate "Azoteq IQS620A PWM support" depends on MFD_IQS62X || COMPILE_TEST diff --git a/drivers/pwm/Makefile b/drivers/pwm/Makefile index 708840b7fba8..7402feae4b36 100644 --- a/drivers/pwm/Makefile +++ b/drivers/pwm/Makefile @@ -22,6 +22,7 @@ obj-$(CONFIG_PWM_IMX1) += pwm-imx1.o obj-$(CONFIG_PWM_IMX27) += pwm-imx27.o obj-$(CONFIG_PWM_IMX_TPM) += pwm-imx-tpm.o obj-$(CONFIG_PWM_INTEL_LGM) += pwm-intel-lgm.o +obj-$(CONFIG_PWM_IPQ) += pwm-ipq.o obj-$(CONFIG_PWM_IQS620A) += pwm-iqs620a.o obj-$(CONFIG_PWM_JZ4740) += pwm-jz4740.o obj-$(CONFIG_PWM_KEEMBAY) += pwm-keembay.o diff --git a/drivers/pwm/pwm-ipq.c b/drivers/pwm/pwm-ipq.c new file mode 100644 index 000000000000..966b051573c8 --- /dev/null +++ b/drivers/pwm/pwm-ipq.c @@ -0,0 +1,238 @@ +// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0 +/* + * Copyright (c) 2016-2017, 2020 The Linux Foundation. All rights reserved. + */ + +#include <linux/module.h> +#include <linux/platform_device.h> +#include <linux/pwm.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/math64.h> +#include <linux/of_device.h> + +#define CLK_SRC_FREQ (100*1000*1000) +#define MAX_PWM_DEVICES 4 + +/* + * Enable bit is set to enable output toggling in pwm device. + * Update bit is set to reflect the changed divider and high duration + * values in register. + */ +#define PWM_ENABLE 0x80000000 +#define PWM_UPDATE 0x40000000 + +/* The frequency range supported is 1Hz to 100MHz */ +#define MIN_PERIOD_NS 10 +#define MAX_PERIOD_NS 1000000000 + +/* + * The max value specified for each field is based on the number of bits + * in the pwm control register for that field + */ +#define MAX_PWM_CFG 0xFFFF + +#define PWM_CTRL_HI_SHIFT 16 + +#define PWM_CFG_REG0 0 /*PWM_DIV PWM_HI*/ +#define PWM_CFG_REG1 1 /*ENABLE UPDATE PWM_PRE_DIV*/ + +struct ipq_pwm_chip { + struct pwm_chip chip; + struct clk *clk; + void __iomem *mem; +}; + +static struct ipq_pwm_chip *to_ipq_pwm_chip(struct pwm_chip *chip) +{ + return container_of(chip, struct ipq_pwm_chip, chip); +} + +static unsigned ipq_pwm_reg_offset(struct pwm_device *pwm, unsigned reg) +{ + return ((pwm->hwpwm * 2) + reg) * 4; +} + +static void config_div_and_duty(struct pwm_device *pwm, int pre_div, + unsigned long long pwm_div, unsigned long period_ns, + unsigned long long duty_ns) +{ + unsigned long hi_dur; + unsigned long long quotient; + unsigned long val = 0; + struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(pwm->chip); + + /* + * high duration = pwm duty * (pwm div + 1) + * pwm duty = duty_ns / period_ns + */ + quotient = (pwm_div + 1) * duty_ns; + hi_dur = div64_u64(quotient, period_ns); + + val |= ((hi_dur & MAX_PWM_CFG) << PWM_CTRL_HI_SHIFT); + val |= (pwm_div & MAX_PWM_CFG); + writel(val, ipq_chip->mem + ipq_pwm_reg_offset(pwm, PWM_CFG_REG0)); + val = pre_div & MAX_PWM_CFG; + writel(val, ipq_chip->mem + ipq_pwm_reg_offset(pwm, PWM_CFG_REG1)); +} + +static int ipq_pwm_enable(struct pwm_device *pwm) +{ + struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(pwm->chip); + unsigned offset = ipq_pwm_reg_offset(pwm, PWM_CFG_REG1); + unsigned long val; + + val = readl(ipq_chip->mem + offset); + val |= PWM_ENABLE | PWM_UPDATE; + writel(val, ipq_chip->mem + offset); + + return 0; +} + +static void ipq_pwm_disable(struct pwm_device *pwm) +{ + struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(pwm->chip); + unsigned offset = ipq_pwm_reg_offset(pwm, PWM_CFG_REG1); + unsigned long val; + + val = readl(ipq_chip->mem + offset); + val |= PWM_UPDATE; + val &= ~PWM_ENABLE; + writel(val, ipq_chip->mem + offset); +} + +static int ipq_pwm_apply(struct pwm_chip *chip, struct pwm_device *pwm, + const struct pwm_state *state) +{ + struct ipq_pwm_chip *ipq_chip = to_ipq_pwm_chip(chip); + unsigned long freq; + int pre_div, close_pre_div, close_pwm_div; + int pwm_div; + long long diff; + unsigned long rate = clk_get_rate(ipq_chip->clk); + unsigned long min_diff = rate; + uint64_t fin_ps; + u64 period_ns, duty_ns; + + if (state->period < MIN_PERIOD_NS) + return -ERANGE; + + period_ns = min_t(u64, state->period, MAX_PERIOD_NS); + duty_ns = min_t(u64, state->duty_cycle, period_ns); + + /* freq in Hz for period in nano second*/ + freq = div64_u64(NSEC_PER_SEC, period_ns); + fin_ps = div64_u64(NSEC_PER_SEC * 1000ULL, rate); + close_pre_div = MAX_PWM_CFG; + close_pwm_div = MAX_PWM_CFG; + + for (pre_div = 0; pre_div <= MAX_PWM_CFG; pre_div++) { + pwm_div = DIV64_U64_ROUND_CLOSEST(period_ns * 1000, + fin_ps * (pre_div + 1)); + pwm_div--; + if (pwm_div < 0 || pwm_div > MAX_PWM_CFG) + continue; + + diff = ((uint64_t)freq * (pre_div + 1) * (pwm_div + 1)) + - (uint64_t)rate; + + if (diff < 0) /* period larger than requested */ + continue; + if (diff == 0) { /* bingo */ + close_pre_div = pre_div; + close_pwm_div = pwm_div; + break; + } + if (diff < min_diff) { + min_diff = diff; + close_pre_div = pre_div; + close_pwm_div = pwm_div; + } + } + + /* config divider values for the closest possible frequency */ + config_div_and_duty(pwm, close_pre_div, close_pwm_div, + period_ns, duty_ns); + if (state->enabled) + ipq_pwm_enable(pwm); + else + ipq_pwm_disable(pwm); + + return 0; +} + +static struct pwm_ops ipq_pwm_ops = { + .apply = ipq_pwm_apply, + .owner = THIS_MODULE, +}; + +static int ipq_pwm_probe(struct platform_device *pdev) +{ + struct ipq_pwm_chip *pwm; + struct device *dev; + int ret; + + dev = &pdev->dev; + pwm = devm_kzalloc(dev, sizeof(*pwm), GFP_KERNEL); + if (!pwm) + return -ENOMEM; + + platform_set_drvdata(pdev, pwm); + + pwm->mem = devm_platform_ioremap_resource(pdev, 0); + if (IS_ERR(pwm->mem)) + return PTR_ERR(pwm->mem); + + pwm->clk = devm_clk_get(dev, "core"); + if (IS_ERR(pwm->clk)) + return PTR_ERR(pwm->clk); + + ret = clk_set_rate(pwm->clk, CLK_SRC_FREQ); + if (ret) + return ret; + ret = clk_prepare_enable(pwm->clk); + if (ret) + return ret; + + pwm->chip.dev = dev; + pwm->chip.ops = &ipq_pwm_ops; + pwm->chip.npwm = MAX_PWM_DEVICES; + + ret = pwmchip_add(&pwm->chip); + if (ret < 0) { + dev_err_probe(dev, ret, "pwmchip_add() failed\n"); + clk_disable_unprepare(pwm->clk); + return ret; + } + + return 0; +} + +static int ipq_pwm_remove(struct platform_device *pdev) +{ + struct ipq_pwm_chip *pwm = platform_get_drvdata(pdev); + + pwmchip_remove(&pwm->chip); + + return 0; +} + +static const struct of_device_id pwm_ipq_dt_match[] = { + { .compatible = "qcom,ipq6018-pwm", }, + {} +}; +MODULE_DEVICE_TABLE(of, pwm_ipq_dt_match); + +static struct platform_driver ipq_pwm_driver = { + .driver = { + .name = "ipq-pwm", + .owner = THIS_MODULE, + .of_match_table = pwm_ipq_dt_match, + }, + .probe = ipq_pwm_probe, + .remove = ipq_pwm_remove, +}; + +module_platform_driver(ipq_pwm_driver); + +MODULE_LICENSE("Dual BSD/GPL");
Driver for the PWM block in Qualcomm IPQ6018 line of SoCs. Based on driver from downstream Codeaurora kernel tree. Removed support for older (V1) variants because I have no access to that hardware. Tested on IPQ6010 based hardware. Signed-off-by: Baruch Siach <baruch@tkos.co.il> --- v4: Use div64_u64() to fix link for 32-bit targets ((kernel test robot <lkp@intel.com>, Uwe Kleine-König) v3: s/qcom,pwm-ipq6018/qcom,ipq6018-pwm/ (Rob Herring) Fix integer overflow on 32-bit targets (kernel test robot <lkp@intel.com>) v2: Address Uwe Kleine-König review comments: Fix period calculation when out of range Don't set period larger than requested Remove PWM disable on configuration change Implement .apply instead of non-atomic .config/.enable/.disable Don't modify PWM on .request/.free Check pwm_div underflow Fix various code and comment formatting issues Other changes: Use u64 divisor safe division Remove now empty .request/.free --- drivers/pwm/Kconfig | 12 +++ drivers/pwm/Makefile | 1 + drivers/pwm/pwm-ipq.c | 238 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 251 insertions(+) create mode 100644 drivers/pwm/pwm-ipq.c