| Message ID | 1418183832-24793-3-git-send-email-rjui@broadcom.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Hello, On Tue, Dec 09, 2014 at 07:57:11PM -0800, Ray Jui wrote: > Add initial support to the Broadcom iProc I2C controller found in the > iProc family of SoCs. > > The iProc I2C controller has separate internal TX and RX FIFOs, each has > a size of 64 bytes. The iProc I2C controller supports two bus speeds > including standard mode (100kHz) and fast mode (400kHz) > > Signed-off-by: Ray Jui <rjui@broadcom.com> > Reviewed-by: Scott Branden <sbranden@broadcom.com> > --- > drivers/i2c/busses/Kconfig | 10 + > drivers/i2c/busses/Makefile | 1 + > drivers/i2c/busses/i2c-bcm-iproc.c | 500 ++++++++++++++++++++++++++++++++++++ > 3 files changed, 511 insertions(+) > create mode 100644 drivers/i2c/busses/i2c-bcm-iproc.c > > diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig > index c1351d9..df21366 100644 > --- a/drivers/i2c/busses/Kconfig > +++ b/drivers/i2c/busses/Kconfig > @@ -372,6 +372,16 @@ config I2C_BCM2835 > This support is also available as a module. If so, the module > will be called i2c-bcm2835. > > +config I2C_BCM_IPROC > + tristate "Broadcom iProc I2C controller" > + depends on ARCH_BCM_IPROC > + default y It would be nice to have the following here to improve compile coverage testing: depends on ARCH_BCM_IPROC || COMPILE_TEST default ARCH_BCM_IPROC > + help > + If you say yes to this option, support will be included for the > + Broadcom iProc I2C controller. > + > + If you don't know what to do here, say N. > + > config I2C_BCM_KONA > tristate "BCM Kona I2C adapter" > depends on ARCH_BCM_MOBILE > diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile > index 5e6c822..216e7be 100644 > --- a/drivers/i2c/busses/Makefile > +++ b/drivers/i2c/busses/Makefile > @@ -33,6 +33,7 @@ obj-$(CONFIG_I2C_AT91) += i2c-at91.o > obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o > obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o > obj-$(CONFIG_I2C_BCM2835) += i2c-bcm2835.o > +obj-$(CONFIG_I2C_BCM_IPROC) += i2c-bcm-iproc.o > obj-$(CONFIG_I2C_BLACKFIN_TWI) += i2c-bfin-twi.o > obj-$(CONFIG_I2C_CADENCE) += i2c-cadence.o > obj-$(CONFIG_I2C_CBUS_GPIO) += i2c-cbus-gpio.o > diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c > new file mode 100644 > index 0000000..35ac497 > --- /dev/null > +++ b/drivers/i2c/busses/i2c-bcm-iproc.c > @@ -0,0 +1,500 @@ > +/* > + * Copyright (C) 2014 Broadcom Corporation > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License as > + * published by the Free Software Foundation version 2. > + * > + * This program is distributed "as is" WITHOUT ANY WARRANTY of any > + * kind, whether express or implied; without even the implied warranty > + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + */ > + > +#include <linux/device.h> > +#include <linux/kernel.h> > +#include <linux/module.h> > +#include <linux/sched.h> > +#include <linux/i2c.h> > +#include <linux/interrupt.h> > +#include <linux/platform_device.h> > +#include <linux/clk.h> > +#include <linux/io.h> > +#include <linux/slab.h> > +#include <linux/delay.h> > + > +#define CFG_OFFSET 0x00 > +#define CFG_RESET_SHIFT 31 > +#define CFG_EN_SHIFT 30 > +#define CFG_M_RETRY_CNT_SHIFT 16 > +#define CFG_M_RETRY_CNT_MASK 0x0f > + > +#define TIM_CFG_OFFSET 0x04 > +#define TIME_CFG_MODE_400_SHIFT 31 > + > +#define M_FIFO_CTRL_OFFSET 0x0c > +#define M_FIFO_RX_FLUSH_SHIFT 31 > +#define M_FIFO_TX_FLUSH_SHIFT 30 > +#define M_FIFO_RX_CNT_SHIFT 16 > +#define M_FIFO_RX_CNT_MASK 0x7f > +#define M_FIFO_RX_THLD_SHIFT 8 > +#define M_FIFO_RX_THLD_MASK 0x3f > + > +#define M_CMD_OFFSET 0x30 > +#define M_CMD_START_BUSY_SHIFT 31 > +#define M_CMD_STATUS_SHIFT 25 > +#define M_CMD_STATUS_MASK 0x07 > +#define M_CMD_STATUS_SUCCESS 0x0 > +#define M_CMD_STATUS_LOST_ARB 0x1 > +#define M_CMD_STATUS_NACK_ADDR 0x2 > +#define M_CMD_STATUS_NACK_DATA 0x3 > +#define M_CMD_STATUS_TIMEOUT 0x4 > +#define M_CMD_PROTOCOL_SHIFT 9 > +#define M_CMD_PROTOCOL_MASK 0xf > +#define M_CMD_PROTOCOL_BLK_WR 0x7 > +#define M_CMD_PROTOCOL_BLK_RD 0x8 > +#define M_CMD_PEC_SHIFT 8 > +#define M_CMD_RD_CNT_SHIFT 0 > +#define M_CMD_RD_CNT_MASK 0xff > + > +#define IE_OFFSET 0x38 > +#define IE_M_RX_FIFO_FULL_SHIFT 31 > +#define IE_M_RX_THLD_SHIFT 30 > +#define IE_M_START_BUSY_SHIFT 28 > + > +#define IS_OFFSET 0x3c > +#define IS_M_RX_FIFO_FULL_SHIFT 31 > +#define IS_M_RX_THLD_SHIFT 30 > +#define IS_M_START_BUSY_SHIFT 28 > + > +#define M_TX_OFFSET 0x40 > +#define M_TX_WR_STATUS_SHIFT 31 > +#define M_TX_DATA_SHIFT 0 > +#define M_TX_DATA_MASK 0xff > + > +#define M_RX_OFFSET 0x44 > +#define M_RX_STATUS_SHIFT 30 > +#define M_RX_STATUS_MASK 0x03 > +#define M_RX_PEC_ERR_SHIFT 29 > +#define M_RX_DATA_SHIFT 0 > +#define M_RX_DATA_MASK 0xff > + > +#define I2C_TIMEOUT_MESC 100 > +#define M_TX_RX_FIFO_SIZE 64 > + > +enum bus_speed_index { > + I2C_SPD_100K = 0, > + I2C_SPD_400K, > +}; > + > +struct bcm_iproc_i2c_dev { > + struct device *device; > + > + void __iomem *base; > + struct i2c_msg *msg; > + > + struct i2c_adapter adapter; > + > + struct completion done; > +}; > + > +/* > + * Can be expanded in the future if more interrupt status bits are utilized > + */ > +#define ISR_MASK (1 << IS_M_START_BUSY_SHIFT) > + > +static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) > +{ > + struct bcm_iproc_i2c_dev *dev = data; > + u32 status = readl(dev->base + IS_OFFSET); > + > + status &= ISR_MASK; > + > + if (!status) > + return IRQ_NONE; > + > + writel(status, dev->base + IS_OFFSET); > + complete_all(&dev->done); > + > + return IRQ_HANDLED; > +} > + > +static int __wait_for_bus_idle(struct bcm_iproc_i2c_dev *dev) > +{ > + unsigned long timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT_MESC); > + > + while (readl(dev->base + M_CMD_OFFSET) & > + (1 << M_CMD_START_BUSY_SHIFT)) { > + if (time_after(jiffies, timeout)) { > + dev_err(dev->device, "wait for bus idle timeout\n"); > + return -ETIMEDOUT; > + } Add a call to cpu_relax here. Do you really need a tight loop here? > + } > + > + return 0; > +} > + > +static int bcm_iproc_i2c_format_addr(struct bcm_iproc_i2c_dev *dev, > + struct i2c_msg *msg, u8 *addr) > +{ > + > + if (msg->flags & I2C_M_TEN) { > + dev_err(dev->device, "no support for 10-bit address\n"); > + return -EINVAL; > + } > + > + *addr = (msg->addr << 1) & 0xfe; I don't see what difference the & 0xfe makes. I think you can drop that. > + > + if (msg->flags & I2C_M_RD) > + *addr |= 1; > + > + return 0; > +} > + > +static int bcm_iproc_i2c_check_status(struct bcm_iproc_i2c_dev *dev) > +{ > + u32 val; > + > + val = readl(dev->base + M_CMD_OFFSET); > + val = (val >> M_CMD_STATUS_SHIFT) & M_CMD_STATUS_MASK; > + > + switch (val) { > + case M_CMD_STATUS_SUCCESS: > + return 0; > + > + case M_CMD_STATUS_LOST_ARB: > + dev_err(dev->device, "lost bus arbitration\n"); I wouldn't dev_err that, only dev_dbg. I'm not sure how usual the errors for the next two cases is, maybe degrade them to dev_dbg, too? > + return -EREMOTEIO; > + > + case M_CMD_STATUS_NACK_ADDR: > + dev_err(dev->device, "NAK addr:0x%02x\n", dev->msg->addr); > + return -EREMOTEIO; > + > + case M_CMD_STATUS_NACK_DATA: > + dev_err(dev->device, "NAK data\n"); > + return -EREMOTEIO; > + > + case M_CMD_STATUS_TIMEOUT: > + dev_err(dev->device, "bus timeout\n"); > + return -ETIMEDOUT; > + > + default: > + dev_err(dev->device, "unknown error code=%d\n", val); > + return -EREMOTEIO; > + } > + > + return -EREMOTEIO; > +} > + > +static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *dev, > + struct i2c_msg *msg) > +{ > + int ret, i; > + u8 addr; > + u32 val; > + unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MESC); > + > + if (msg->len < 1 || msg->len > M_TX_RX_FIFO_SIZE - 1) { > + dev_err(dev->device, > + "supported data length is 1 - %u bytes\n", > + M_TX_RX_FIFO_SIZE - 1); > + return -EINVAL; > + } > + > + dev->msg = msg; > + ret = __wait_for_bus_idle(dev); > + if (ret) > + return ret; > + > + ret = bcm_iproc_i2c_format_addr(dev, msg, &addr); > + if (ret) > + return ret; > + > + /* load slave address into the TX FIFO */ > + writel(addr, dev->base + M_TX_OFFSET); > + > + /* for a write transaction, load data into the TX FIFO */ > + if (!(msg->flags & I2C_M_RD)) { > + for (i = 0; i < msg->len; i++) { > + val = msg->buf[i]; > + > + /* mark the last byte */ > + if (i == msg->len - 1) > + val |= 1 << M_TX_WR_STATUS_SHIFT; > + > + writel(val, dev->base + M_TX_OFFSET); > + } > + } > + > + /* mark as incomplete before starting the transaction */ > + reinit_completion(&dev->done); > + > + /* > + * Enable the "start busy" interrupt, which will be triggered after > + * the transaction is done This sound's wrong. I'd expect "start busy" to trigger as soon as the controller gets hold of the bus. > + */ > + writel(1 << IE_M_START_BUSY_SHIFT, dev->base + IE_OFFSET); > + > + /* > + * Now we can activate the transfer. For a read operation, specify the > + * number of bytes to read > + */ > + val = 1 << M_CMD_START_BUSY_SHIFT; > + if (msg->flags & I2C_M_RD) { > + val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) | > + (msg->len << M_CMD_RD_CNT_SHIFT); > + } else { > + val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT); > + } > + writel(val, dev->base + M_CMD_OFFSET); > + > + time_left = wait_for_completion_timeout(&dev->done, time_left); > + > + /* disable all interrupts */ > + writel(0, dev->base + IE_OFFSET); > + > + if (!time_left) { > + dev_err(dev->device, "transaction times out\n"); > + > + /* flush FIFOs */ > + val = (1 << M_FIFO_RX_FLUSH_SHIFT) | > + (1 << M_FIFO_TX_FLUSH_SHIFT); > + writel(val, dev->base + M_FIFO_CTRL_OFFSET); > + return -EREMOTEIO; > + } > + > + ret = bcm_iproc_i2c_check_status(dev); > + if (ret) { > + /* flush both TX/RX FIFOs */ > + val = (1 << M_FIFO_RX_FLUSH_SHIFT) | > + (1 << M_FIFO_TX_FLUSH_SHIFT); > + writel(val, dev->base + M_FIFO_CTRL_OFFSET); > + return ret; > + } > + > + /* > + * For a read operation, we now need to load the data from FIFO > + * into the memory buffer > + */ > + if (msg->flags & I2C_M_RD) { > + for (i = 0; i < msg->len; i++) { > + msg->buf[i] = (readl(dev->base + M_RX_OFFSET) >> > + M_RX_DATA_SHIFT) & M_RX_DATA_MASK; > + } > + } > + > + dev_dbg(dev->device, "xfer %c, addr=0x%02x, len=%d\n", > + (msg->flags & I2C_M_RD) ? 'R' : 'W', msg->addr, > + msg->len); > + dev_dbg(dev->device, "**** data start ****\n"); > + for (i = 0; i < msg->len; i++) > + dev_dbg(dev->device, "0x%02x ", msg->buf[i]); > + dev_dbg(dev->device, "**** data end ****\n"); > + > + return 0; > +} > + > +static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter, > + struct i2c_msg msgs[], int num) > +{ > + struct bcm_iproc_i2c_dev *dev = i2c_get_adapdata(adapter); > + int ret, i; > + > + /* go through all messages */ > + for (i = 0; i < num; i++) { > + ret = bcm_iproc_i2c_xfer_single_msg(dev, &msgs[i]); > + if (ret) { > + dev_err(dev->device, "xfer failed\n"); > + return ret; > + } > + } > + > + return num; > +} > + > +static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap) > +{ > + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; > +} > + > +static const struct i2c_algorithm bcm_iproc_algo = { > + .master_xfer = bcm_iproc_i2c_xfer, > + .functionality = bcm_iproc_i2c_functionality, > +}; > + > +static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *dev) > +{ > + unsigned int bus_speed, speed_bit; > + u32 val; > + int ret = of_property_read_u32(dev->device->of_node, "clock-frequency", > + &bus_speed); Inconsistent coding style. At most other places you use 2 tabs to indent a continued line. (Well you use this style for breaks in function declarations. Using the same style for both cases would be nice.) > + if (ret < 0) { > + dev_err(dev->device, "missing clock-frequency property\n"); > + return -ENODEV; > + } > + > + switch (bus_speed) { > + case 100000: > + speed_bit = 0; > + break; > + case 400000: > + speed_bit = 1; > + break; > + default: > + dev_err(dev->device, "%d Hz bus speed not supported\n", > + bus_speed); > + dev_err(dev->device, "valid speeds are 100khz and 400khz\n"); > + return -EINVAL; > + } I'd be more graceful here: if (bus_speed < 100000) error_out; else if (bus_speed < 400000) speed_bit = 0; else /* >= 400000 */ speed_bit = 1; > + > + val = readl(dev->base + TIM_CFG_OFFSET); > + val &= ~(1 << TIME_CFG_MODE_400_SHIFT); > + val |= speed_bit << TIME_CFG_MODE_400_SHIFT; > + writel(val, dev->base + TIM_CFG_OFFSET); > + > + dev_info(dev->device, "bus set to %u Hz\n", bus_speed); > + > + return 0; > +} > + > +static int bcm_iproc_i2c_init(struct bcm_iproc_i2c_dev *dev) > +{ > + u32 val; > + > + /* put controller in reset */ > + val = readl(dev->base + CFG_OFFSET); > + val |= 1 << CFG_RESET_SHIFT; > + val &= ~(1 << CFG_EN_SHIFT); > + writel(val, dev->base + CFG_OFFSET); > + > + /* wait 100 usec per spec */ > + udelay(100); > + > + /* bring controller out of reset */ > + val = readl(dev->base + CFG_OFFSET); Is it necessary to reread the register value here? > + val &= ~(1 << CFG_RESET_SHIFT); > + writel(val, dev->base + CFG_OFFSET); > + > + /* flush TX/RX FIFOs and set RX FIFO threshold to zero */ > + val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT); > + writel(val, dev->base + M_FIFO_CTRL_OFFSET); > + > + /* disable all interrupts */ > + val = 0; > + writel(val, dev->base + IE_OFFSET); writel(0, dev->base + IE_OFFSET); > + /* clear all pending interrupts */ > + val = readl(dev->base + IS_OFFSET); > + writel(val, dev->base + IS_OFFSET); writel(0xffffffff, dev->base + IS_OFFSET); ?? > + > + return 0; > +} > + > +static void bcm_iproc_i2c_enable(struct bcm_iproc_i2c_dev *dev) > +{ > + u32 val; > + > + val = readl(dev->base + CFG_OFFSET); > + val |= 1 << CFG_EN_SHIFT; > + writel(val, dev->base + CFG_OFFSET); > +} > + > +static void bcm_iproc_i2c_disable(struct bcm_iproc_i2c_dev *dev) > +{ > + u32 val; > + > + val = readl(dev->base + CFG_OFFSET); > + val &= ~(1 << CFG_EN_SHIFT); > + writel(val, dev->base + CFG_OFFSET); > +} > + > +static int bcm_iproc_i2c_probe(struct platform_device *pdev) > +{ > + int irq, ret = 0; > + struct bcm_iproc_i2c_dev *dev; "dev" is a misleading name here. I'd call this bcm_iproc_i2c_ddata *ddata; > + struct i2c_adapter *adap; > + struct resource *res; > + > + dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL); > + if (!dev) > + return -ENOMEM; > + > + platform_set_drvdata(pdev, dev); > + dev->device = &pdev->dev; > + init_completion(&dev->done); > + > + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); > + dev->base = devm_ioremap_resource(dev->device, res); > + if (IS_ERR(dev->base)) > + return -ENOMEM; return PTR_ERR(dev->base); > + > + ret = bcm_iproc_i2c_init(dev); > + if (ret) > + return ret; > + > + ret = bcm_iproc_i2c_cfg_speed(dev); > + if (ret) > + return ret; > + > + irq = platform_get_irq(pdev, 0); > + if (irq < 0) { irq == 0 should be handled as error, too. > + dev_err(dev->device, "no irq resource\n"); > + return irq; > + } > + > + ret = devm_request_irq(&pdev->dev, irq, bcm_iproc_i2c_isr, > + IRQF_SHARED, pdev->name, dev); > + if (ret) { > + dev_err(dev->device, "unable to request irq %i\n", irq); > + return ret; > + } > + > + bcm_iproc_i2c_enable(dev); > + > + adap = &dev->adapter; > + i2c_set_adapdata(adap, dev); > + strlcpy(adap->name, "Broadcom iProc I2C adapter", sizeof(adap->name)); > + adap->algo = &bcm_iproc_algo; > + adap->dev.parent = &pdev->dev; > + adap->dev.of_node = pdev->dev.of_node; > + > + ret = i2c_add_adapter(adap); > + if (ret) { > + dev_err(dev->device, "failed to add adapter\n"); > + return ret; > + } > + > + dev_info(dev->device, "device registered successfully\n"); This just clutters the boot log. Please remove. > + > + return 0; > +} > + > +static int bcm_iproc_i2c_remove(struct platform_device *pdev) > +{ > + struct bcm_iproc_i2c_dev *dev = platform_get_drvdata(pdev); > + > + i2c_del_adapter(&dev->adapter); > + bcm_iproc_i2c_disable(dev); I think you have a problem here if bcm_iproc_i2c_remove is called while an irq is still being serviced. I'm not sure how to prevent this properly for a shared interrupt. > + > + return 0; > +} > + > +static const struct of_device_id bcm_iproc_i2c_of_match[] = { > + {.compatible = "brcm,iproc-i2c",}, > + {}, > +}; > +MODULE_DEVICE_TABLE(of, bcm_iproc_i2c_of_match); > + > +static struct platform_driver bcm_iproc_i2c_driver = { > + .driver = { > + .name = "bcm-iproc-i2c", > + .of_match_table = bcm_iproc_i2c_of_match, > + }, Inconsistent indention. > + .probe = bcm_iproc_i2c_probe, > + .remove = bcm_iproc_i2c_remove, > +}; > +module_platform_driver(bcm_iproc_i2c_driver); > + > +MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>"); > +MODULE_DESCRIPTION("Broadcom iProc I2C Driver"); > +MODULE_LICENSE("GPL v2");
On 1/13/2015 2:50 PM, Uwe Kleine-König wrote: > Hello, > > On Tue, Dec 09, 2014 at 07:57:11PM -0800, Ray Jui wrote: >> Add initial support to the Broadcom iProc I2C controller found in the >> iProc family of SoCs. >> >> The iProc I2C controller has separate internal TX and RX FIFOs, each has >> a size of 64 bytes. The iProc I2C controller supports two bus speeds >> including standard mode (100kHz) and fast mode (400kHz) >> >> Signed-off-by: Ray Jui <rjui@broadcom.com> >> Reviewed-by: Scott Branden <sbranden@broadcom.com> >> --- >> drivers/i2c/busses/Kconfig | 10 + >> drivers/i2c/busses/Makefile | 1 + >> drivers/i2c/busses/i2c-bcm-iproc.c | 500 ++++++++++++++++++++++++++++++++++++ >> 3 files changed, 511 insertions(+) >> create mode 100644 drivers/i2c/busses/i2c-bcm-iproc.c >> >> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig >> index c1351d9..df21366 100644 >> --- a/drivers/i2c/busses/Kconfig >> +++ b/drivers/i2c/busses/Kconfig >> @@ -372,6 +372,16 @@ config I2C_BCM2835 >> This support is also available as a module. If so, the module >> will be called i2c-bcm2835. >> >> +config I2C_BCM_IPROC >> + tristate "Broadcom iProc I2C controller" >> + depends on ARCH_BCM_IPROC >> + default y > It would be nice to have the following here to improve compile coverage > testing: > > depends on ARCH_BCM_IPROC || COMPILE_TEST > default ARCH_BCM_IPROC > Sure will do! >> + help >> + If you say yes to this option, support will be included for the >> + Broadcom iProc I2C controller. >> + >> + If you don't know what to do here, say N. >> + >> config I2C_BCM_KONA >> tristate "BCM Kona I2C adapter" >> depends on ARCH_BCM_MOBILE >> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile >> index 5e6c822..216e7be 100644 >> --- a/drivers/i2c/busses/Makefile >> +++ b/drivers/i2c/busses/Makefile >> @@ -33,6 +33,7 @@ obj-$(CONFIG_I2C_AT91) += i2c-at91.o >> obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o >> obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o >> obj-$(CONFIG_I2C_BCM2835) += i2c-bcm2835.o >> +obj-$(CONFIG_I2C_BCM_IPROC) += i2c-bcm-iproc.o >> obj-$(CONFIG_I2C_BLACKFIN_TWI) += i2c-bfin-twi.o >> obj-$(CONFIG_I2C_CADENCE) += i2c-cadence.o >> obj-$(CONFIG_I2C_CBUS_GPIO) += i2c-cbus-gpio.o >> diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c >> new file mode 100644 >> index 0000000..35ac497 >> --- /dev/null >> +++ b/drivers/i2c/busses/i2c-bcm-iproc.c >> @@ -0,0 +1,500 @@ >> +/* >> + * Copyright (C) 2014 Broadcom Corporation >> + * >> + * This program is free software; you can redistribute it and/or >> + * modify it under the terms of the GNU General Public License as >> + * published by the Free Software Foundation version 2. >> + * >> + * This program is distributed "as is" WITHOUT ANY WARRANTY of any >> + * kind, whether express or implied; without even the implied warranty >> + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> + * GNU General Public License for more details. >> + */ >> + >> +#include <linux/device.h> >> +#include <linux/kernel.h> >> +#include <linux/module.h> >> +#include <linux/sched.h> >> +#include <linux/i2c.h> >> +#include <linux/interrupt.h> >> +#include <linux/platform_device.h> >> +#include <linux/clk.h> >> +#include <linux/io.h> >> +#include <linux/slab.h> >> +#include <linux/delay.h> >> + >> +#define CFG_OFFSET 0x00 >> +#define CFG_RESET_SHIFT 31 >> +#define CFG_EN_SHIFT 30 >> +#define CFG_M_RETRY_CNT_SHIFT 16 >> +#define CFG_M_RETRY_CNT_MASK 0x0f >> + >> +#define TIM_CFG_OFFSET 0x04 >> +#define TIME_CFG_MODE_400_SHIFT 31 >> + >> +#define M_FIFO_CTRL_OFFSET 0x0c >> +#define M_FIFO_RX_FLUSH_SHIFT 31 >> +#define M_FIFO_TX_FLUSH_SHIFT 30 >> +#define M_FIFO_RX_CNT_SHIFT 16 >> +#define M_FIFO_RX_CNT_MASK 0x7f >> +#define M_FIFO_RX_THLD_SHIFT 8 >> +#define M_FIFO_RX_THLD_MASK 0x3f >> + >> +#define M_CMD_OFFSET 0x30 >> +#define M_CMD_START_BUSY_SHIFT 31 >> +#define M_CMD_STATUS_SHIFT 25 >> +#define M_CMD_STATUS_MASK 0x07 >> +#define M_CMD_STATUS_SUCCESS 0x0 >> +#define M_CMD_STATUS_LOST_ARB 0x1 >> +#define M_CMD_STATUS_NACK_ADDR 0x2 >> +#define M_CMD_STATUS_NACK_DATA 0x3 >> +#define M_CMD_STATUS_TIMEOUT 0x4 >> +#define M_CMD_PROTOCOL_SHIFT 9 >> +#define M_CMD_PROTOCOL_MASK 0xf >> +#define M_CMD_PROTOCOL_BLK_WR 0x7 >> +#define M_CMD_PROTOCOL_BLK_RD 0x8 >> +#define M_CMD_PEC_SHIFT 8 >> +#define M_CMD_RD_CNT_SHIFT 0 >> +#define M_CMD_RD_CNT_MASK 0xff >> + >> +#define IE_OFFSET 0x38 >> +#define IE_M_RX_FIFO_FULL_SHIFT 31 >> +#define IE_M_RX_THLD_SHIFT 30 >> +#define IE_M_START_BUSY_SHIFT 28 >> + >> +#define IS_OFFSET 0x3c >> +#define IS_M_RX_FIFO_FULL_SHIFT 31 >> +#define IS_M_RX_THLD_SHIFT 30 >> +#define IS_M_START_BUSY_SHIFT 28 >> + >> +#define M_TX_OFFSET 0x40 >> +#define M_TX_WR_STATUS_SHIFT 31 >> +#define M_TX_DATA_SHIFT 0 >> +#define M_TX_DATA_MASK 0xff >> + >> +#define M_RX_OFFSET 0x44 >> +#define M_RX_STATUS_SHIFT 30 >> +#define M_RX_STATUS_MASK 0x03 >> +#define M_RX_PEC_ERR_SHIFT 29 >> +#define M_RX_DATA_SHIFT 0 >> +#define M_RX_DATA_MASK 0xff >> + >> +#define I2C_TIMEOUT_MESC 100 >> +#define M_TX_RX_FIFO_SIZE 64 >> + >> +enum bus_speed_index { >> + I2C_SPD_100K = 0, >> + I2C_SPD_400K, >> +}; >> + >> +struct bcm_iproc_i2c_dev { >> + struct device *device; >> + >> + void __iomem *base; >> + struct i2c_msg *msg; >> + >> + struct i2c_adapter adapter; >> + >> + struct completion done; >> +}; >> + >> +/* >> + * Can be expanded in the future if more interrupt status bits are utilized >> + */ >> +#define ISR_MASK (1 << IS_M_START_BUSY_SHIFT) >> + >> +static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) >> +{ >> + struct bcm_iproc_i2c_dev *dev = data; >> + u32 status = readl(dev->base + IS_OFFSET); >> + >> + status &= ISR_MASK; >> + >> + if (!status) >> + return IRQ_NONE; >> + >> + writel(status, dev->base + IS_OFFSET); >> + complete_all(&dev->done); >> + >> + return IRQ_HANDLED; >> +} >> + >> +static int __wait_for_bus_idle(struct bcm_iproc_i2c_dev *dev) >> +{ >> + unsigned long timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT_MESC); >> + >> + while (readl(dev->base + M_CMD_OFFSET) & >> + (1 << M_CMD_START_BUSY_SHIFT)) { >> + if (time_after(jiffies, timeout)) { >> + dev_err(dev->device, "wait for bus idle timeout\n"); >> + return -ETIMEDOUT; >> + } > Add a call to cpu_relax here. Do you really need a tight loop here? > Yes, thanks! >> + } >> + >> + return 0; >> +} >> + >> +static int bcm_iproc_i2c_format_addr(struct bcm_iproc_i2c_dev *dev, >> + struct i2c_msg *msg, u8 *addr) >> +{ >> + >> + if (msg->flags & I2C_M_TEN) { >> + dev_err(dev->device, "no support for 10-bit address\n"); >> + return -EINVAL; >> + } >> + >> + *addr = (msg->addr << 1) & 0xfe; > I don't see what difference the & 0xfe makes. I think you can drop that. > Yeah just see this now. Thanks! >> + >> + if (msg->flags & I2C_M_RD) >> + *addr |= 1; >> + >> + return 0; >> +} >> + >> +static int bcm_iproc_i2c_check_status(struct bcm_iproc_i2c_dev *dev) >> +{ >> + u32 val; >> + >> + val = readl(dev->base + M_CMD_OFFSET); >> + val = (val >> M_CMD_STATUS_SHIFT) & M_CMD_STATUS_MASK; >> + >> + switch (val) { >> + case M_CMD_STATUS_SUCCESS: >> + return 0; >> + >> + case M_CMD_STATUS_LOST_ARB: >> + dev_err(dev->device, "lost bus arbitration\n"); > I wouldn't dev_err that, only dev_dbg. I'm not sure how usual the errors > for the next two cases is, maybe degrade them to dev_dbg, too? > These errors are rare, and it's nice to keep them at the dev_err level so the user will be more aware. >> + return -EREMOTEIO; >> + >> + case M_CMD_STATUS_NACK_ADDR: >> + dev_err(dev->device, "NAK addr:0x%02x\n", dev->msg->addr); >> + return -EREMOTEIO; >> + >> + case M_CMD_STATUS_NACK_DATA: >> + dev_err(dev->device, "NAK data\n"); >> + return -EREMOTEIO; >> + >> + case M_CMD_STATUS_TIMEOUT: >> + dev_err(dev->device, "bus timeout\n"); >> + return -ETIMEDOUT; >> + >> + default: >> + dev_err(dev->device, "unknown error code=%d\n", val); >> + return -EREMOTEIO; >> + } >> + >> + return -EREMOTEIO; >> +} >> + >> +static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *dev, >> + struct i2c_msg *msg) >> +{ >> + int ret, i; >> + u8 addr; >> + u32 val; >> + unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MESC); >> + >> + if (msg->len < 1 || msg->len > M_TX_RX_FIFO_SIZE - 1) { >> + dev_err(dev->device, >> + "supported data length is 1 - %u bytes\n", >> + M_TX_RX_FIFO_SIZE - 1); >> + return -EINVAL; >> + } >> + >> + dev->msg = msg; >> + ret = __wait_for_bus_idle(dev); >> + if (ret) >> + return ret; >> + >> + ret = bcm_iproc_i2c_format_addr(dev, msg, &addr); >> + if (ret) >> + return ret; >> + >> + /* load slave address into the TX FIFO */ >> + writel(addr, dev->base + M_TX_OFFSET); >> + >> + /* for a write transaction, load data into the TX FIFO */ >> + if (!(msg->flags & I2C_M_RD)) { >> + for (i = 0; i < msg->len; i++) { >> + val = msg->buf[i]; >> + >> + /* mark the last byte */ >> + if (i == msg->len - 1) >> + val |= 1 << M_TX_WR_STATUS_SHIFT; >> + >> + writel(val, dev->base + M_TX_OFFSET); >> + } >> + } >> + >> + /* mark as incomplete before starting the transaction */ >> + reinit_completion(&dev->done); >> + >> + /* >> + * Enable the "start busy" interrupt, which will be triggered after >> + * the transaction is done > This sound's wrong. I'd expect "start busy" to trigger as soon as the > controller gets hold of the bus. > Okay maybe the naming is misleading. But this is the real name used in the register description from the datasheet. I'll add more comment in the code to make it more clear. Basically this enables the interrupt that triggers when the controller internal start_busy bit transitions from 1 to 0, i.e., after a transaction finishes. The interrupt won't be triggered when a new transaction starts since it causes the start_busy bit to transit from 0 to 1. >> + */ >> + writel(1 << IE_M_START_BUSY_SHIFT, dev->base + IE_OFFSET); >> + >> + /* >> + * Now we can activate the transfer. For a read operation, specify the >> + * number of bytes to read >> + */ >> + val = 1 << M_CMD_START_BUSY_SHIFT; >> + if (msg->flags & I2C_M_RD) { >> + val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) | >> + (msg->len << M_CMD_RD_CNT_SHIFT); >> + } else { >> + val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT); >> + } >> + writel(val, dev->base + M_CMD_OFFSET); >> + >> + time_left = wait_for_completion_timeout(&dev->done, time_left); >> + >> + /* disable all interrupts */ >> + writel(0, dev->base + IE_OFFSET); >> + >> + if (!time_left) { >> + dev_err(dev->device, "transaction times out\n"); >> + >> + /* flush FIFOs */ >> + val = (1 << M_FIFO_RX_FLUSH_SHIFT) | >> + (1 << M_FIFO_TX_FLUSH_SHIFT); >> + writel(val, dev->base + M_FIFO_CTRL_OFFSET); >> + return -EREMOTEIO; >> + } >> + >> + ret = bcm_iproc_i2c_check_status(dev); >> + if (ret) { >> + /* flush both TX/RX FIFOs */ >> + val = (1 << M_FIFO_RX_FLUSH_SHIFT) | >> + (1 << M_FIFO_TX_FLUSH_SHIFT); >> + writel(val, dev->base + M_FIFO_CTRL_OFFSET); >> + return ret; >> + } >> + >> + /* >> + * For a read operation, we now need to load the data from FIFO >> + * into the memory buffer >> + */ >> + if (msg->flags & I2C_M_RD) { >> + for (i = 0; i < msg->len; i++) { >> + msg->buf[i] = (readl(dev->base + M_RX_OFFSET) >> >> + M_RX_DATA_SHIFT) & M_RX_DATA_MASK; >> + } >> + } >> + >> + dev_dbg(dev->device, "xfer %c, addr=0x%02x, len=%d\n", >> + (msg->flags & I2C_M_RD) ? 'R' : 'W', msg->addr, >> + msg->len); >> + dev_dbg(dev->device, "**** data start ****\n"); >> + for (i = 0; i < msg->len; i++) >> + dev_dbg(dev->device, "0x%02x ", msg->buf[i]); >> + dev_dbg(dev->device, "**** data end ****\n"); >> + >> + return 0; >> +} >> + >> +static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter, >> + struct i2c_msg msgs[], int num) >> +{ >> + struct bcm_iproc_i2c_dev *dev = i2c_get_adapdata(adapter); >> + int ret, i; >> + >> + /* go through all messages */ >> + for (i = 0; i < num; i++) { >> + ret = bcm_iproc_i2c_xfer_single_msg(dev, &msgs[i]); >> + if (ret) { >> + dev_err(dev->device, "xfer failed\n"); >> + return ret; >> + } >> + } >> + >> + return num; >> +} >> + >> +static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap) >> +{ >> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; >> +} >> + >> +static const struct i2c_algorithm bcm_iproc_algo = { >> + .master_xfer = bcm_iproc_i2c_xfer, >> + .functionality = bcm_iproc_i2c_functionality, >> +}; >> + >> +static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *dev) >> +{ >> + unsigned int bus_speed, speed_bit; >> + u32 val; >> + int ret = of_property_read_u32(dev->device->of_node, "clock-frequency", >> + &bus_speed); > Inconsistent coding style. At most other places you use 2 tabs to indent > a continued line. (Well you use this style for breaks in function > declarations. Using the same style for both cases would be nice.) > Will try to use this style for both continued lines and function declarations. Thanks! >> + if (ret < 0) { >> + dev_err(dev->device, "missing clock-frequency property\n"); >> + return -ENODEV; >> + } >> + >> + switch (bus_speed) { >> + case 100000: >> + speed_bit = 0; >> + break; >> + case 400000: >> + speed_bit = 1; >> + break; >> + default: >> + dev_err(dev->device, "%d Hz bus speed not supported\n", >> + bus_speed); >> + dev_err(dev->device, "valid speeds are 100khz and 400khz\n"); >> + return -EINVAL; >> + } > I'd be more graceful here: > > if (bus_speed < 100000) > error_out; > else if (bus_speed < 400000) > speed_bit = 0; > else > /* >= 400000 */ > speed_bit = 1; > Okay I can do that. Thanks. >> + >> + val = readl(dev->base + TIM_CFG_OFFSET); >> + val &= ~(1 << TIME_CFG_MODE_400_SHIFT); >> + val |= speed_bit << TIME_CFG_MODE_400_SHIFT; >> + writel(val, dev->base + TIM_CFG_OFFSET); >> + >> + dev_info(dev->device, "bus set to %u Hz\n", bus_speed); >> + >> + return 0; >> +} >> + >> +static int bcm_iproc_i2c_init(struct bcm_iproc_i2c_dev *dev) >> +{ >> + u32 val; >> + >> + /* put controller in reset */ >> + val = readl(dev->base + CFG_OFFSET); >> + val |= 1 << CFG_RESET_SHIFT; >> + val &= ~(1 << CFG_EN_SHIFT); >> + writel(val, dev->base + CFG_OFFSET); >> + >> + /* wait 100 usec per spec */ >> + udelay(100); >> + >> + /* bring controller out of reset */ >> + val = readl(dev->base + CFG_OFFSET); > Is it necessary to reread the register value here? > I guess not, since there's no one else modifies this register. Will get rid of the redundant read here. Thanks! >> + val &= ~(1 << CFG_RESET_SHIFT); >> + writel(val, dev->base + CFG_OFFSET); >> + >> + /* flush TX/RX FIFOs and set RX FIFO threshold to zero */ >> + val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT); >> + writel(val, dev->base + M_FIFO_CTRL_OFFSET); >> + >> + /* disable all interrupts */ >> + val = 0; >> + writel(val, dev->base + IE_OFFSET); > writel(0, dev->base + IE_OFFSET); > Right. >> + /* clear all pending interrupts */ >> + val = readl(dev->base + IS_OFFSET); >> + writel(val, dev->base + IS_OFFSET); > writel(0xffffffff, dev->base + IS_OFFSET); ?? > Yes, better. >> + >> + return 0; >> +} >> + >> +static void bcm_iproc_i2c_enable(struct bcm_iproc_i2c_dev *dev) >> +{ >> + u32 val; >> + >> + val = readl(dev->base + CFG_OFFSET); >> + val |= 1 << CFG_EN_SHIFT; >> + writel(val, dev->base + CFG_OFFSET); >> +} >> + >> +static void bcm_iproc_i2c_disable(struct bcm_iproc_i2c_dev *dev) >> +{ >> + u32 val; >> + >> + val = readl(dev->base + CFG_OFFSET); >> + val &= ~(1 << CFG_EN_SHIFT); >> + writel(val, dev->base + CFG_OFFSET); >> +} >> + >> +static int bcm_iproc_i2c_probe(struct platform_device *pdev) >> +{ >> + int irq, ret = 0; >> + struct bcm_iproc_i2c_dev *dev; > "dev" is a misleading name here. I'd call this > > bcm_iproc_i2c_ddata *ddata; > I will change it to iproc_i2c; >> + struct i2c_adapter *adap; >> + struct resource *res; >> + >> + dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL); >> + if (!dev) >> + return -ENOMEM; >> + >> + platform_set_drvdata(pdev, dev); >> + dev->device = &pdev->dev; >> + init_completion(&dev->done); >> + >> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); >> + dev->base = devm_ioremap_resource(dev->device, res); >> + if (IS_ERR(dev->base)) >> + return -ENOMEM; > return PTR_ERR(dev->base); > Okay. Thanks. >> + >> + ret = bcm_iproc_i2c_init(dev); >> + if (ret) >> + return ret; >> + >> + ret = bcm_iproc_i2c_cfg_speed(dev); >> + if (ret) >> + return ret; >> + >> + irq = platform_get_irq(pdev, 0); >> + if (irq < 0) { > irq == 0 should be handled as error, too. > Ah. I thought zero is a valid global interrupt number, and I see other drivers checking against < 0 as well. Is my understanding incorrect? >> + dev_err(dev->device, "no irq resource\n"); >> + return irq; >> + } >> + >> + ret = devm_request_irq(&pdev->dev, irq, bcm_iproc_i2c_isr, >> + IRQF_SHARED, pdev->name, dev); >> + if (ret) { >> + dev_err(dev->device, "unable to request irq %i\n", irq); >> + return ret; >> + } >> + >> + bcm_iproc_i2c_enable(dev); >> + >> + adap = &dev->adapter; >> + i2c_set_adapdata(adap, dev); >> + strlcpy(adap->name, "Broadcom iProc I2C adapter", sizeof(adap->name)); >> + adap->algo = &bcm_iproc_algo; >> + adap->dev.parent = &pdev->dev; >> + adap->dev.of_node = pdev->dev.of_node; >> + >> + ret = i2c_add_adapter(adap); >> + if (ret) { >> + dev_err(dev->device, "failed to add adapter\n"); >> + return ret; >> + } >> + >> + dev_info(dev->device, "device registered successfully\n"); > This just clutters the boot log. Please remove. > Okay. >> + >> + return 0; >> +} >> + >> +static int bcm_iproc_i2c_remove(struct platform_device *pdev) >> +{ >> + struct bcm_iproc_i2c_dev *dev = platform_get_drvdata(pdev); >> + >> + i2c_del_adapter(&dev->adapter); >> + bcm_iproc_i2c_disable(dev); > I think you have a problem here if bcm_iproc_i2c_remove is called while > an irq is still being serviced. I'm not sure how to prevent this > properly for a shared interrupt. > Can I grab i2c_lock_adapter to ensure the bus is locked (so there's no outstanding transactions or IRQs by the time we remove the adapter)? But I see no I2C bus driver does this in their remove function... >> + >> + return 0; >> +} >> + >> +static const struct of_device_id bcm_iproc_i2c_of_match[] = { >> + {.compatible = "brcm,iproc-i2c",}, >> + {}, >> +}; >> +MODULE_DEVICE_TABLE(of, bcm_iproc_i2c_of_match); >> + >> +static struct platform_driver bcm_iproc_i2c_driver = { >> + .driver = { >> + .name = "bcm-iproc-i2c", >> + .of_match_table = bcm_iproc_i2c_of_match, >> + }, > Inconsistent indention. > Sorry. Will fix. >> + .probe = bcm_iproc_i2c_probe, >> + .remove = bcm_iproc_i2c_remove, >> +}; >> +module_platform_driver(bcm_iproc_i2c_driver); >> + >> +MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>"); >> +MODULE_DESCRIPTION("Broadcom iProc I2C Driver"); >> +MODULE_LICENSE("GPL v2"); >
Hello, On Tue, Jan 13, 2015 at 06:14:17PM -0800, Ray Jui wrote: > >> + irq = platform_get_irq(pdev, 0); > >> + if (irq < 0) { > > irq == 0 should be handled as error, too. > > > Ah. I thought zero is a valid global interrupt number, and I see other > drivers checking against < 0 as well. Is my understanding incorrect? These are wrong, too. 0 should never be a valid interrupt number. There are some exceptions but mostly for historic reasons. The right handling is used for example in drivers/i2c/busses/i2c-efm32.c. > >> + dev_err(dev->device, "no irq resource\n"); > >> + return irq; > >> + } > [...] > >> +static int bcm_iproc_i2c_remove(struct platform_device *pdev) > >> +{ > >> + struct bcm_iproc_i2c_dev *dev = platform_get_drvdata(pdev); > >> + > >> + i2c_del_adapter(&dev->adapter); > >> + bcm_iproc_i2c_disable(dev); > > I think you have a problem here if bcm_iproc_i2c_remove is called while > > an irq is still being serviced. I'm not sure how to prevent this > > properly for a shared interrupt. > > > Can I grab i2c_lock_adapter to ensure the bus is locked (so there's no > outstanding transactions or IRQs by the time we remove the adapter)? But > I see no I2C bus driver does this in their remove function... The problem I pointed out is the reason for some driver authors not to use devm_request_irq. If you use plain request_irq and the matching free_irq in the .remove callback you can be sure that the irq isn't running any more as soon as free_irq returns. BTW, if you use vim, you can add set cinoptions=(,: if has("autocmd") filetype plugin indent on endif to your .vimrc. Then while typing vim does the indention right and consistent, and with the = command you can reindent. Best regards Uwe
On 1/13/2015 11:51 PM, Uwe Kleine-König wrote: > Hello, > > On Tue, Jan 13, 2015 at 06:14:17PM -0800, Ray Jui wrote: >>>> + irq = platform_get_irq(pdev, 0); >>>> + if (irq < 0) { >>> irq == 0 should be handled as error, too. >>> >> Ah. I thought zero is a valid global interrupt number, and I see other >> drivers checking against < 0 as well. Is my understanding incorrect? > These are wrong, too. 0 should never be a valid interrupt number. There > are some exceptions but mostly for historic reasons. The right handling > is used for example in drivers/i2c/busses/i2c-efm32.c. > Okay. Will check against <= 0. Thanks. >>>> + dev_err(dev->device, "no irq resource\n"); >>>> + return irq; >>>> + } >> [...] >>>> +static int bcm_iproc_i2c_remove(struct platform_device *pdev) >>>> +{ >>>> + struct bcm_iproc_i2c_dev *dev = platform_get_drvdata(pdev); >>>> + >>>> + i2c_del_adapter(&dev->adapter); >>>> + bcm_iproc_i2c_disable(dev); >>> I think you have a problem here if bcm_iproc_i2c_remove is called while >>> an irq is still being serviced. I'm not sure how to prevent this >>> properly for a shared interrupt. >>> >> Can I grab i2c_lock_adapter to ensure the bus is locked (so there's no >> outstanding transactions or IRQs by the time we remove the adapter)? But >> I see no I2C bus driver does this in their remove function... > The problem I pointed out is the reason for some driver authors not to > use devm_request_irq. If you use plain request_irq and the matching > free_irq in the .remove callback you can be sure that the irq isn't > running any more as soon as free_irq returns. > Okay. Will change to use request_irq and make sure that it's freed in the remove function. Also, the interrupt is dedicated to the I2C controller, so I'll remove the IRQF_SHARED flag. > BTW, if you use vim, you can add > > set cinoptions=(,: > if has("autocmd") > filetype plugin indent on > endif > > to your .vimrc. Then while typing vim does the indention right and > consistent, and with the = command you can reindent. > Wow this is excellent! Just tried and it works perfectly. Thanks a lot!!! > Best regards > Uwe >
> >> + case M_CMD_STATUS_LOST_ARB: > >> + dev_err(dev->device, "lost bus arbitration\n"); > > I wouldn't dev_err that, only dev_dbg. I'm not sure how usual the errors > > for the next two cases is, maybe degrade them to dev_dbg, too? > > > These errors are rare, and it's nice to keep them at the dev_err level > so the user will be more aware. This is wrong. Arbitration lost and NACK is pretty standard stuff on an I2C bus. User doesn't need to know about it, it is just noise in the logs. Timeout is different, you can report that (although I should probably move such a message into the core). Please also use the proper errno codes defined in Documentation/i2c/fault-codes. They should be distinct enough to drop the messages. > > >> + return -EREMOTEIO; > >> + > >> + case M_CMD_STATUS_NACK_ADDR: > >> + dev_err(dev->device, "NAK addr:0x%02x\n", dev->msg->addr); > >> + return -EREMOTEIO; > >> + > >> + case M_CMD_STATUS_NACK_DATA: > >> + dev_err(dev->device, "NAK data\n"); > >> + return -EREMOTEIO; > >> + > >> + case M_CMD_STATUS_TIMEOUT: > >> + dev_err(dev->device, "bus timeout\n"); > >> + return -ETIMEDOUT; > >> + > >> + default: > >> + dev_err(dev->device, "unknown error code=%d\n", val); > >> + return -EREMOTEIO; > >> + } > >> + > >> + return -EREMOTEIO; > >> +}
On 1/15/2015 3:59 AM, Wolfram Sang wrote: >>>> + case M_CMD_STATUS_LOST_ARB: >>>> + dev_err(dev->device, "lost bus arbitration\n"); >>> I wouldn't dev_err that, only dev_dbg. I'm not sure how usual the errors >>> for the next two cases is, maybe degrade them to dev_dbg, too? >>> >> These errors are rare, and it's nice to keep them at the dev_err level >> so the user will be more aware. > > This is wrong. Arbitration lost and NACK is pretty standard stuff on an > I2C bus. User doesn't need to know about it, it is just noise in the > logs. Timeout is different, you can report that (although I should > probably move such a message into the core). Please also use the proper > errno codes defined in Documentation/i2c/fault-codes. They should be > distinct enough to drop the messages. > Okay will do. >> >>>> + return -EREMOTEIO; >>>> + >>>> + case M_CMD_STATUS_NACK_ADDR: >>>> + dev_err(dev->device, "NAK addr:0x%02x\n", dev->msg->addr); >>>> + return -EREMOTEIO; >>>> + >>>> + case M_CMD_STATUS_NACK_DATA: >>>> + dev_err(dev->device, "NAK data\n"); >>>> + return -EREMOTEIO; >>>> + >>>> + case M_CMD_STATUS_TIMEOUT: >>>> + dev_err(dev->device, "bus timeout\n"); >>>> + return -ETIMEDOUT; >>>> + >>>> + default: >>>> + dev_err(dev->device, "unknown error code=%d\n", val); >>>> + return -EREMOTEIO; >>>> + } >>>> + >>>> + return -EREMOTEIO; >>>> +}
diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig index c1351d9..df21366 100644 --- a/drivers/i2c/busses/Kconfig +++ b/drivers/i2c/busses/Kconfig @@ -372,6 +372,16 @@ config I2C_BCM2835 This support is also available as a module. If so, the module will be called i2c-bcm2835. +config I2C_BCM_IPROC + tristate "Broadcom iProc I2C controller" + depends on ARCH_BCM_IPROC + default y + help + If you say yes to this option, support will be included for the + Broadcom iProc I2C controller. + + If you don't know what to do here, say N. + config I2C_BCM_KONA tristate "BCM Kona I2C adapter" depends on ARCH_BCM_MOBILE diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile index 5e6c822..216e7be 100644 --- a/drivers/i2c/busses/Makefile +++ b/drivers/i2c/busses/Makefile @@ -33,6 +33,7 @@ obj-$(CONFIG_I2C_AT91) += i2c-at91.o obj-$(CONFIG_I2C_AU1550) += i2c-au1550.o obj-$(CONFIG_I2C_AXXIA) += i2c-axxia.o obj-$(CONFIG_I2C_BCM2835) += i2c-bcm2835.o +obj-$(CONFIG_I2C_BCM_IPROC) += i2c-bcm-iproc.o obj-$(CONFIG_I2C_BLACKFIN_TWI) += i2c-bfin-twi.o obj-$(CONFIG_I2C_CADENCE) += i2c-cadence.o obj-$(CONFIG_I2C_CBUS_GPIO) += i2c-cbus-gpio.o diff --git a/drivers/i2c/busses/i2c-bcm-iproc.c b/drivers/i2c/busses/i2c-bcm-iproc.c new file mode 100644 index 0000000..35ac497 --- /dev/null +++ b/drivers/i2c/busses/i2c-bcm-iproc.c @@ -0,0 +1,500 @@ +/* + * Copyright (C) 2014 Broadcom Corporation + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation version 2. + * + * This program is distributed "as is" WITHOUT ANY WARRANTY of any + * kind, whether express or implied; without even the implied warranty + * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + */ + +#include <linux/device.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/sched.h> +#include <linux/i2c.h> +#include <linux/interrupt.h> +#include <linux/platform_device.h> +#include <linux/clk.h> +#include <linux/io.h> +#include <linux/slab.h> +#include <linux/delay.h> + +#define CFG_OFFSET 0x00 +#define CFG_RESET_SHIFT 31 +#define CFG_EN_SHIFT 30 +#define CFG_M_RETRY_CNT_SHIFT 16 +#define CFG_M_RETRY_CNT_MASK 0x0f + +#define TIM_CFG_OFFSET 0x04 +#define TIME_CFG_MODE_400_SHIFT 31 + +#define M_FIFO_CTRL_OFFSET 0x0c +#define M_FIFO_RX_FLUSH_SHIFT 31 +#define M_FIFO_TX_FLUSH_SHIFT 30 +#define M_FIFO_RX_CNT_SHIFT 16 +#define M_FIFO_RX_CNT_MASK 0x7f +#define M_FIFO_RX_THLD_SHIFT 8 +#define M_FIFO_RX_THLD_MASK 0x3f + +#define M_CMD_OFFSET 0x30 +#define M_CMD_START_BUSY_SHIFT 31 +#define M_CMD_STATUS_SHIFT 25 +#define M_CMD_STATUS_MASK 0x07 +#define M_CMD_STATUS_SUCCESS 0x0 +#define M_CMD_STATUS_LOST_ARB 0x1 +#define M_CMD_STATUS_NACK_ADDR 0x2 +#define M_CMD_STATUS_NACK_DATA 0x3 +#define M_CMD_STATUS_TIMEOUT 0x4 +#define M_CMD_PROTOCOL_SHIFT 9 +#define M_CMD_PROTOCOL_MASK 0xf +#define M_CMD_PROTOCOL_BLK_WR 0x7 +#define M_CMD_PROTOCOL_BLK_RD 0x8 +#define M_CMD_PEC_SHIFT 8 +#define M_CMD_RD_CNT_SHIFT 0 +#define M_CMD_RD_CNT_MASK 0xff + +#define IE_OFFSET 0x38 +#define IE_M_RX_FIFO_FULL_SHIFT 31 +#define IE_M_RX_THLD_SHIFT 30 +#define IE_M_START_BUSY_SHIFT 28 + +#define IS_OFFSET 0x3c +#define IS_M_RX_FIFO_FULL_SHIFT 31 +#define IS_M_RX_THLD_SHIFT 30 +#define IS_M_START_BUSY_SHIFT 28 + +#define M_TX_OFFSET 0x40 +#define M_TX_WR_STATUS_SHIFT 31 +#define M_TX_DATA_SHIFT 0 +#define M_TX_DATA_MASK 0xff + +#define M_RX_OFFSET 0x44 +#define M_RX_STATUS_SHIFT 30 +#define M_RX_STATUS_MASK 0x03 +#define M_RX_PEC_ERR_SHIFT 29 +#define M_RX_DATA_SHIFT 0 +#define M_RX_DATA_MASK 0xff + +#define I2C_TIMEOUT_MESC 100 +#define M_TX_RX_FIFO_SIZE 64 + +enum bus_speed_index { + I2C_SPD_100K = 0, + I2C_SPD_400K, +}; + +struct bcm_iproc_i2c_dev { + struct device *device; + + void __iomem *base; + struct i2c_msg *msg; + + struct i2c_adapter adapter; + + struct completion done; +}; + +/* + * Can be expanded in the future if more interrupt status bits are utilized + */ +#define ISR_MASK (1 << IS_M_START_BUSY_SHIFT) + +static irqreturn_t bcm_iproc_i2c_isr(int irq, void *data) +{ + struct bcm_iproc_i2c_dev *dev = data; + u32 status = readl(dev->base + IS_OFFSET); + + status &= ISR_MASK; + + if (!status) + return IRQ_NONE; + + writel(status, dev->base + IS_OFFSET); + complete_all(&dev->done); + + return IRQ_HANDLED; +} + +static int __wait_for_bus_idle(struct bcm_iproc_i2c_dev *dev) +{ + unsigned long timeout = jiffies + msecs_to_jiffies(I2C_TIMEOUT_MESC); + + while (readl(dev->base + M_CMD_OFFSET) & + (1 << M_CMD_START_BUSY_SHIFT)) { + if (time_after(jiffies, timeout)) { + dev_err(dev->device, "wait for bus idle timeout\n"); + return -ETIMEDOUT; + } + } + + return 0; +} + +static int bcm_iproc_i2c_format_addr(struct bcm_iproc_i2c_dev *dev, + struct i2c_msg *msg, u8 *addr) +{ + + if (msg->flags & I2C_M_TEN) { + dev_err(dev->device, "no support for 10-bit address\n"); + return -EINVAL; + } + + *addr = (msg->addr << 1) & 0xfe; + + if (msg->flags & I2C_M_RD) + *addr |= 1; + + return 0; +} + +static int bcm_iproc_i2c_check_status(struct bcm_iproc_i2c_dev *dev) +{ + u32 val; + + val = readl(dev->base + M_CMD_OFFSET); + val = (val >> M_CMD_STATUS_SHIFT) & M_CMD_STATUS_MASK; + + switch (val) { + case M_CMD_STATUS_SUCCESS: + return 0; + + case M_CMD_STATUS_LOST_ARB: + dev_err(dev->device, "lost bus arbitration\n"); + return -EREMOTEIO; + + case M_CMD_STATUS_NACK_ADDR: + dev_err(dev->device, "NAK addr:0x%02x\n", dev->msg->addr); + return -EREMOTEIO; + + case M_CMD_STATUS_NACK_DATA: + dev_err(dev->device, "NAK data\n"); + return -EREMOTEIO; + + case M_CMD_STATUS_TIMEOUT: + dev_err(dev->device, "bus timeout\n"); + return -ETIMEDOUT; + + default: + dev_err(dev->device, "unknown error code=%d\n", val); + return -EREMOTEIO; + } + + return -EREMOTEIO; +} + +static int bcm_iproc_i2c_xfer_single_msg(struct bcm_iproc_i2c_dev *dev, + struct i2c_msg *msg) +{ + int ret, i; + u8 addr; + u32 val; + unsigned long time_left = msecs_to_jiffies(I2C_TIMEOUT_MESC); + + if (msg->len < 1 || msg->len > M_TX_RX_FIFO_SIZE - 1) { + dev_err(dev->device, + "supported data length is 1 - %u bytes\n", + M_TX_RX_FIFO_SIZE - 1); + return -EINVAL; + } + + dev->msg = msg; + ret = __wait_for_bus_idle(dev); + if (ret) + return ret; + + ret = bcm_iproc_i2c_format_addr(dev, msg, &addr); + if (ret) + return ret; + + /* load slave address into the TX FIFO */ + writel(addr, dev->base + M_TX_OFFSET); + + /* for a write transaction, load data into the TX FIFO */ + if (!(msg->flags & I2C_M_RD)) { + for (i = 0; i < msg->len; i++) { + val = msg->buf[i]; + + /* mark the last byte */ + if (i == msg->len - 1) + val |= 1 << M_TX_WR_STATUS_SHIFT; + + writel(val, dev->base + M_TX_OFFSET); + } + } + + /* mark as incomplete before starting the transaction */ + reinit_completion(&dev->done); + + /* + * Enable the "start busy" interrupt, which will be triggered after + * the transaction is done + */ + writel(1 << IE_M_START_BUSY_SHIFT, dev->base + IE_OFFSET); + + /* + * Now we can activate the transfer. For a read operation, specify the + * number of bytes to read + */ + val = 1 << M_CMD_START_BUSY_SHIFT; + if (msg->flags & I2C_M_RD) { + val |= (M_CMD_PROTOCOL_BLK_RD << M_CMD_PROTOCOL_SHIFT) | + (msg->len << M_CMD_RD_CNT_SHIFT); + } else { + val |= (M_CMD_PROTOCOL_BLK_WR << M_CMD_PROTOCOL_SHIFT); + } + writel(val, dev->base + M_CMD_OFFSET); + + time_left = wait_for_completion_timeout(&dev->done, time_left); + + /* disable all interrupts */ + writel(0, dev->base + IE_OFFSET); + + if (!time_left) { + dev_err(dev->device, "transaction times out\n"); + + /* flush FIFOs */ + val = (1 << M_FIFO_RX_FLUSH_SHIFT) | + (1 << M_FIFO_TX_FLUSH_SHIFT); + writel(val, dev->base + M_FIFO_CTRL_OFFSET); + return -EREMOTEIO; + } + + ret = bcm_iproc_i2c_check_status(dev); + if (ret) { + /* flush both TX/RX FIFOs */ + val = (1 << M_FIFO_RX_FLUSH_SHIFT) | + (1 << M_FIFO_TX_FLUSH_SHIFT); + writel(val, dev->base + M_FIFO_CTRL_OFFSET); + return ret; + } + + /* + * For a read operation, we now need to load the data from FIFO + * into the memory buffer + */ + if (msg->flags & I2C_M_RD) { + for (i = 0; i < msg->len; i++) { + msg->buf[i] = (readl(dev->base + M_RX_OFFSET) >> + M_RX_DATA_SHIFT) & M_RX_DATA_MASK; + } + } + + dev_dbg(dev->device, "xfer %c, addr=0x%02x, len=%d\n", + (msg->flags & I2C_M_RD) ? 'R' : 'W', msg->addr, + msg->len); + dev_dbg(dev->device, "**** data start ****\n"); + for (i = 0; i < msg->len; i++) + dev_dbg(dev->device, "0x%02x ", msg->buf[i]); + dev_dbg(dev->device, "**** data end ****\n"); + + return 0; +} + +static int bcm_iproc_i2c_xfer(struct i2c_adapter *adapter, + struct i2c_msg msgs[], int num) +{ + struct bcm_iproc_i2c_dev *dev = i2c_get_adapdata(adapter); + int ret, i; + + /* go through all messages */ + for (i = 0; i < num; i++) { + ret = bcm_iproc_i2c_xfer_single_msg(dev, &msgs[i]); + if (ret) { + dev_err(dev->device, "xfer failed\n"); + return ret; + } + } + + return num; +} + +static uint32_t bcm_iproc_i2c_functionality(struct i2c_adapter *adap) +{ + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; +} + +static const struct i2c_algorithm bcm_iproc_algo = { + .master_xfer = bcm_iproc_i2c_xfer, + .functionality = bcm_iproc_i2c_functionality, +}; + +static int bcm_iproc_i2c_cfg_speed(struct bcm_iproc_i2c_dev *dev) +{ + unsigned int bus_speed, speed_bit; + u32 val; + int ret = of_property_read_u32(dev->device->of_node, "clock-frequency", + &bus_speed); + if (ret < 0) { + dev_err(dev->device, "missing clock-frequency property\n"); + return -ENODEV; + } + + switch (bus_speed) { + case 100000: + speed_bit = 0; + break; + case 400000: + speed_bit = 1; + break; + default: + dev_err(dev->device, "%d Hz bus speed not supported\n", + bus_speed); + dev_err(dev->device, "valid speeds are 100khz and 400khz\n"); + return -EINVAL; + } + + val = readl(dev->base + TIM_CFG_OFFSET); + val &= ~(1 << TIME_CFG_MODE_400_SHIFT); + val |= speed_bit << TIME_CFG_MODE_400_SHIFT; + writel(val, dev->base + TIM_CFG_OFFSET); + + dev_info(dev->device, "bus set to %u Hz\n", bus_speed); + + return 0; +} + +static int bcm_iproc_i2c_init(struct bcm_iproc_i2c_dev *dev) +{ + u32 val; + + /* put controller in reset */ + val = readl(dev->base + CFG_OFFSET); + val |= 1 << CFG_RESET_SHIFT; + val &= ~(1 << CFG_EN_SHIFT); + writel(val, dev->base + CFG_OFFSET); + + /* wait 100 usec per spec */ + udelay(100); + + /* bring controller out of reset */ + val = readl(dev->base + CFG_OFFSET); + val &= ~(1 << CFG_RESET_SHIFT); + writel(val, dev->base + CFG_OFFSET); + + /* flush TX/RX FIFOs and set RX FIFO threshold to zero */ + val = (1 << M_FIFO_RX_FLUSH_SHIFT) | (1 << M_FIFO_TX_FLUSH_SHIFT); + writel(val, dev->base + M_FIFO_CTRL_OFFSET); + + /* disable all interrupts */ + val = 0; + writel(val, dev->base + IE_OFFSET); + + /* clear all pending interrupts */ + val = readl(dev->base + IS_OFFSET); + writel(val, dev->base + IS_OFFSET); + + return 0; +} + +static void bcm_iproc_i2c_enable(struct bcm_iproc_i2c_dev *dev) +{ + u32 val; + + val = readl(dev->base + CFG_OFFSET); + val |= 1 << CFG_EN_SHIFT; + writel(val, dev->base + CFG_OFFSET); +} + +static void bcm_iproc_i2c_disable(struct bcm_iproc_i2c_dev *dev) +{ + u32 val; + + val = readl(dev->base + CFG_OFFSET); + val &= ~(1 << CFG_EN_SHIFT); + writel(val, dev->base + CFG_OFFSET); +} + +static int bcm_iproc_i2c_probe(struct platform_device *pdev) +{ + int irq, ret = 0; + struct bcm_iproc_i2c_dev *dev; + struct i2c_adapter *adap; + struct resource *res; + + dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL); + if (!dev) + return -ENOMEM; + + platform_set_drvdata(pdev, dev); + dev->device = &pdev->dev; + init_completion(&dev->done); + + res = platform_get_resource(pdev, IORESOURCE_MEM, 0); + dev->base = devm_ioremap_resource(dev->device, res); + if (IS_ERR(dev->base)) + return -ENOMEM; + + ret = bcm_iproc_i2c_init(dev); + if (ret) + return ret; + + ret = bcm_iproc_i2c_cfg_speed(dev); + if (ret) + return ret; + + irq = platform_get_irq(pdev, 0); + if (irq < 0) { + dev_err(dev->device, "no irq resource\n"); + return irq; + } + + ret = devm_request_irq(&pdev->dev, irq, bcm_iproc_i2c_isr, + IRQF_SHARED, pdev->name, dev); + if (ret) { + dev_err(dev->device, "unable to request irq %i\n", irq); + return ret; + } + + bcm_iproc_i2c_enable(dev); + + adap = &dev->adapter; + i2c_set_adapdata(adap, dev); + strlcpy(adap->name, "Broadcom iProc I2C adapter", sizeof(adap->name)); + adap->algo = &bcm_iproc_algo; + adap->dev.parent = &pdev->dev; + adap->dev.of_node = pdev->dev.of_node; + + ret = i2c_add_adapter(adap); + if (ret) { + dev_err(dev->device, "failed to add adapter\n"); + return ret; + } + + dev_info(dev->device, "device registered successfully\n"); + + return 0; +} + +static int bcm_iproc_i2c_remove(struct platform_device *pdev) +{ + struct bcm_iproc_i2c_dev *dev = platform_get_drvdata(pdev); + + i2c_del_adapter(&dev->adapter); + bcm_iproc_i2c_disable(dev); + + return 0; +} + +static const struct of_device_id bcm_iproc_i2c_of_match[] = { + {.compatible = "brcm,iproc-i2c",}, + {}, +}; +MODULE_DEVICE_TABLE(of, bcm_iproc_i2c_of_match); + +static struct platform_driver bcm_iproc_i2c_driver = { + .driver = { + .name = "bcm-iproc-i2c", + .of_match_table = bcm_iproc_i2c_of_match, + }, + .probe = bcm_iproc_i2c_probe, + .remove = bcm_iproc_i2c_remove, +}; +module_platform_driver(bcm_iproc_i2c_driver); + +MODULE_AUTHOR("Ray Jui <rjui@broadcom.com>"); +MODULE_DESCRIPTION("Broadcom iProc I2C Driver"); +MODULE_LICENSE("GPL v2");