Re: [PATCH 2/4] i2c: iproc: Add Broadcom iProc I2C Driver

Ray Jui
2014-12-10T01:42:00Z

On 12/9/2014 5:33 PM, Varka Bhadram wrote:
>
> On Wednesday 10 December 2014 06:24 AM, 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 | 9 +
>> drivers/i2c/busses/Makefile | 1 +
>> drivers/i2c/busses/i2c-bcm-iproc.c | 503
>> ++++++++++++++++++++++++++++++++++++
>> 3 files changed, 513 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..8a2eb7e 100644
>> --- a/drivers/i2c/busses/Kconfig
>> +++ b/drivers/i2c/busses/Kconfig
>> @@ -372,6 +372,15 @@ 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
>> + 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..0e6e603
>> --- /dev/null
>> +++ b/drivers/i2c/busses/i2c-bcm-iproc.c
>> @@ -0,0 +1,503 @@
>> +/*
>> + * 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)
>> +{
>
> Match open parenthesis..
>
> static int bcm_iproc_i2c_format_addr(struct bcm_iproc_i2c_dev *dev,
> struct i2c_msg *msg, u8 *addr)
>
>
Okay I can make this change.
>> +
>> + 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)
>> +{
>
> dto...
>
One more indent? Sure.

>> + 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);
>> + if (!res)
>> + return -ENODEV;
>
> We can remove this resource check. This checking will happen with
> devm_ioremap_resource()
>
Don't you need to obtain a valid resource and pass it into
devm_ioremap_resource? Without 'res' being assigned a valid resource,
devm_ioremap_resource will reject with "invalid resource".

>> + 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",
>> + .owner = THIS_MODULE,
>
> No need to update this field. Its updated by module_platform_driver().
>
Okay will get rid of .owner = THIS_MODULES,

>> + .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");
>