Hi Barry,
I'm not too familiar with I2C, so just a couple of general comments
inline, but otherwise looks good to me.
Jamie
On Wed, Nov 02, 2011 at 03:10:10AM -0700, Barry Song wrote:
> From: Zhiwu Song <Zhiwu.Song@xxxxxxx>
>
> SiRFprimaII is the latest generation application processor from CSR’s
> multi-function SoC product family.
> The SoC support codes are in arch/arm/mach-prima2 from Linux mainline
> 3.0.
> There are two I2C controllers on primaII, features include:
> ■ Two I2C controller modules are on chip
> ■ RISC I/O bus read write register
> ■ Up to 16 bytes data buffer for issuing commands and writing data at the same time
> ■ Up to 16 commands, and receiving read data 16 bytes at a time
> ■ Error INT report (ACK check)
> ■ No-ACK bus protocols (SCCB bus protocols)
>
> Signed-off-by: Zhiwu Song <Zhiwu.Song@xxxxxxx>
> Signed-off-by: Xiangzhen Ye <Xiangzhen.Ye@xxxxxxx>
> Signed-off-by: Barry Song <Baohua.Song@xxxxxxx>
> ---
[...]
> diff --git a/drivers/i2c/busses/i2c-sirf.c b/drivers/i2c/busses/i2c-sirf.c
> new file mode 100644
> index 0000000..d4ccba7
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-sirf.c
> @@ -0,0 +1,425 @@
> +/*
> + * I2C bus driver for CSR SiRFprimaII
> + *
> + * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
> + *
> + * Licensed under GPLv2 or later.
> + */
> +
> +#include <linux/interrupt.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>
> +#include <linux/slab.h>
> +#include <linux/init.h>
> +#include <linux/sched.h>
> +#include <linux/platform_device.h>
> +#include <linux/i2c.h>
> +#include <linux/clk.h>
> +#include <linux/err.h>
> +#include <linux/io.h>
> +
> +#include "i2c-sirf.h"
> +
> +#define SIRFSOC_I2C_DEFAULT_SPEED 100000
> +
> +struct sirfsoc_i2c {
> + void *base;
This should be void __iomem *base;
> + struct clk *clk;
> + unsigned long speed; /* I2C SCL frequency */
> + int irq;
> + u32 cmd_ptr; /* Current position in CMD buffer */
> + u8 *buf; /* Buffer passed by user */
> + u32 msg_len; /* Message length */
> + u32 finished_len; /* number of bytes read/written */
> + u32 read_cmd_len; /* number of read cmd sent */
> + int msg_read; /* 1 indicates a read message */
> + int err_status; /* 1 indicates an error on bus */
> +
> + u32 sda_delay; /* For suspend/resume */
> + u32 clk_div;
> + int last; /* Last message in transfer, STOP cmd can be sent */
> +
> + struct completion done; /* indicates completion of message transfer */
> + struct i2c_adapter *adapter;
> +};
> +
> +static void i2c_sirfsoc_read_data(struct sirfsoc_i2c *siic)
> +{
> + u32 data = 0;
> + int i = 0;
> +
> + for (i = 0; i < siic->read_cmd_len; i++) {
> + if (!(i & 0x3))
> + data = readl(siic->base + SIRFSOC_I2C_DATA_BUF + i);
> + siic->buf[siic->finished_len++] =
> + (unsigned char)((data & SIRFSOC_I2C_DATA_MASK(i)) >>
> + SIRFSOC_I2C_DATA_SHIFT(i));
> +
> + BUG_ON(siic->finished_len > siic->msg_len);
> + }
> +}
> +
> +static void i2c_sirfsoc_queue_cmd(struct sirfsoc_i2c *siic)
> +{
> + u32 regval;
> + int i = 0;
> +
> + if (siic->msg_read) {
> + while (((siic->finished_len + i) < siic->msg_len)
> + && (siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX)) {
> + regval = SIRFSOC_I2C_READ | SIRFSOC_I2C_CMD_RP(0);
> + if (((siic->finished_len + i) ==
> + (siic->msg_len - 1)) && siic->last)
> + regval |= SIRFSOC_I2C_STOP | SIRFSOC_I2C_NACK;
> + writel(regval,
> + siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
> + i++;
> + }
> +
> + siic->read_cmd_len = i;
> + } else {
> + while ((siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX - 1)
> + && (siic->finished_len < siic->msg_len)) {
> + regval = SIRFSOC_I2C_WRITE | SIRFSOC_I2C_CMD_RP(0);
> + if ((siic->finished_len == (siic->msg_len - 1))
> + && siic->last)
> + regval |= SIRFSOC_I2C_STOP;
> + writel(regval,
> + siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
> + writel(siic->buf[siic->finished_len++],
> + siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
> + }
> + }
> + siic->cmd_ptr = 0;
> +
> + /* Trigger the transfer */
> + writel(SIRFSOC_I2C_START_CMD, siic->base + SIRFSOC_I2C_CMD_START);
> +}
> +
> +static irqreturn_t i2c_sirfsoc_irq(int irq, void *dev_id)
> +{
> + struct sirfsoc_i2c *siic = (struct sirfsoc_i2c *)dev_id;
> + u32 i2c_stat = readl(siic->base + SIRFSOC_I2C_STATUS);
> +
> + if (i2c_stat & SIRFSOC_I2C_STAT_ERR) {
> + /* Error conditions */
> + siic->err_status = 1;
> + writel(SIRFSOC_I2C_STAT_ERR, siic->base + SIRFSOC_I2C_STATUS);
> +
> + if (i2c_stat & SIRFSOC_I2C_STAT_NACK)
> + dev_err(&siic->adapter->dev, "ACK not received\n");
> + else
> + dev_err(&siic->adapter->dev, "I2C error\n");
> +
> + complete(&siic->done);
> + } else if (i2c_stat & SIRFSOC_I2C_STAT_CMD_DONE) {
> + /* CMD buffer execution complete */
> + if (siic->msg_read)
> + i2c_sirfsoc_read_data(siic);
> + if (siic->finished_len == siic->msg_len)
> + complete(&siic->done);
> + else /* Fill a new CMD buffer for left data */
> + i2c_sirfsoc_queue_cmd(siic);
> +
> + writel(SIRFSOC_I2C_STAT_CMD_DONE, siic->base + SIRFSOC_I2C_STATUS);
> + }
> +
> + return IRQ_HANDLED;
> +}
> +
> +static void i2c_sirfsoc_set_address(struct sirfsoc_i2c *siic,
> + struct i2c_msg *msg)
> +{
> + unsigned char addr;
> + u32 regval = SIRFSOC_I2C_START | SIRFSOC_I2C_CMD_RP(0) | SIRFSOC_I2C_WRITE;
> +
> + /* no data and last message -> add STOP */
> + if (siic->last && (msg->len == 0))
> + regval |= SIRFSOC_I2C_STOP;
> +
> + writel(regval, siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
> +
> + addr = msg->addr << 1; /* Generate address */
> + if (msg->flags & I2C_M_RD)
> + addr |= 1;
> + if (msg->flags & I2C_M_REV_DIR_ADDR) /* Reverse direction bit */
> + addr ^= 1;
> +
> + writel(addr, siic->base + SIRFSOC_I2C_CMD(siic->cmd_ptr++));
> +}
> +
> +static int i2c_sirfsoc_xfer_msg(struct sirfsoc_i2c *siic, struct i2c_msg *msg)
> +{
> + u32 regval = readl(siic->base + SIRFSOC_I2C_CTRL);
> + int timeout = (msg->len + 1) * 50;
> + int ret = 0;
> +
> + i2c_sirfsoc_set_address(siic, msg);
> +
> + writel(regval | SIRFSOC_I2C_CMD_DONE_EN | SIRFSOC_I2C_ERR_INT_EN,
> + siic->base + SIRFSOC_I2C_CTRL);
> + i2c_sirfsoc_queue_cmd(siic);
> +
> + if (wait_for_completion_timeout(&siic->done, timeout) == 0) {
> + siic->err_status = 1;
> + dev_err(&siic->adapter->dev, "Transfer timeout\n");
> + }
> +
> + writel(regval & ~(SIRFSOC_I2C_CMD_DONE_EN | SIRFSOC_I2C_ERR_INT_EN),
> + siic->base + SIRFSOC_I2C_CTRL);
> + writel(0, siic->base + SIRFSOC_I2C_CMD_START);
> +
> + if (siic->err_status) {
> + writel(readl(siic->base + SIRFSOC_I2C_CTRL) | SIRFSOC_I2C_RESET,
> + siic->base + SIRFSOC_I2C_CTRL);
> + while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)
> + cpu_relax();
> +
> + ret = -EIO;
> + }
> +
> + return ret;
> +}
> +
> +static u32 i2c_sirfsoc_func(struct i2c_adapter *adap)
> +{
> + return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
> +}
> +
> +static int i2c_sirfsoc_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs,
> + int num)
> +{
> + struct sirfsoc_i2c *siic = adap->algo_data;
> + int i, ret;
> +
> + for (i = 0; i < num; i++) {
> + siic->buf = msgs[i].buf;
> + siic->msg_len = msgs[i].len;
> +
> + if (msgs[i].flags & I2C_M_RD)
> + siic->msg_read = 1;
> + else
> + siic->msg_read = 0;
> +
> + siic->err_status = 0;
> + siic->cmd_ptr = 0;
> + siic->finished_len = 0;
> + if (i == (num - 1))
> + siic->last = 1;
> + else
> + siic->last = 0;
> +
> + ret = i2c_sirfsoc_xfer_msg(siic, &msgs[i]);
> + if (ret)
> + return ret;
> + }
> +
> + return num;
> +}
> +
> +/* I2C algorithms associated with this master controller driver */
> +static struct i2c_algorithm i2c_sirfsoc_algo = {
> + .master_xfer = i2c_sirfsoc_xfer,
> + .functionality = i2c_sirfsoc_func,
> +};
const?
> +
> +static int __devinit i2c_sirfsoc_probe(struct platform_device *pdev)
> +{
> + struct sirfsoc_i2c *siic;
> + struct i2c_adapter *new_adapter;
> + struct resource *mem_res;
> + struct clk *clk;
> + int ctrl_speed;
> +
> + int err;
> + u32 regval;
> +
> + clk = clk_get(&pdev->dev, NULL);
> + if (IS_ERR(clk)) {
> + err = PTR_ERR(clk);
> + dev_err(&pdev->dev, "Clock get failed\n");
> + goto out;
> + }
> +
> + clk_enable(clk);
The return value of clk_enable() should really be checked.
> + ctrl_speed = clk_get_rate(clk);
> +
> + new_adapter = kzalloc(sizeof(*new_adapter), GFP_KERNEL);
If you do:
new_adapter = devm_kzalloc(&pdev->dev, sizeof(*new_adapter),
GFP_KERNEL);
then devres will handle cleanup on failure for you and also device
removal so you can get rid of a lot of the error handling and just
return early. The same applies for the ioremap, irq requesting and
other allocations.
> + if (!new_adapter) {
> + dev_err(&pdev->dev,
> + "Can't allocate new i2c adapter!\n");
> + err = -ENOMEM;
> + goto clk_out;
> + }
> +
> + siic = kzalloc(sizeof(*siic), GFP_KERNEL);
> + if (!siic) {
> + dev_err(&pdev->dev, "Can't allocate driver data\n");
> + err = -ENOMEM;
> + goto free_adapter;
> + }
> + new_adapter->class = I2C_CLASS_HWMON | I2C_CLASS_DDC | I2C_CLASS_SPD;
> + siic->adapter = new_adapter;
> +
> + mem_res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (mem_res == NULL) {
> + dev_err(&pdev->dev, "Unable to get MEM resource\n");
> + err = -EINVAL;
> + goto free_data;
> + }
> +
> + siic->base =
> + ioremap(mem_res->start, (mem_res->end - mem_res->start + 1));
> + if (siic->base == NULL) {
> + dev_err(&pdev->dev, "IO remap failed!\n");
> + err = -ENOMEM;
> + goto free_data;
> + }
> +
> + siic->irq = platform_get_irq(pdev, 0);
> + if (!siic->irq) {
> + err = -EINVAL;
> + goto free_base;
> + }
> + err = request_irq(siic->irq, i2c_sirfsoc_irq, 0,
> + dev_name(&pdev->dev), siic);
> + if (err)
> + goto free_base;
> +
> + new_adapter->algo = &i2c_sirfsoc_algo;
> + new_adapter->algo_data = siic;
> +
> + new_adapter->dev.parent = &pdev->dev;
> + new_adapter->nr = pdev->id;
> +
> + strlcpy(new_adapter->name, "sirfsoc-i2c", sizeof(new_adapter->name));
> +
> + platform_set_drvdata(pdev, new_adapter);
> + init_completion(&siic->done);
> +
> + /* Controller Initalisation */
> +
> + writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL);
> + while (readl(siic->base + SIRFSOC_I2C_CTRL) & SIRFSOC_I2C_RESET)
> + cpu_relax();
> + writel(SIRFSOC_I2C_CORE_EN | SIRFSOC_I2C_MASTER_MODE,
> + siic->base + SIRFSOC_I2C_CTRL);
> +
> + siic->clk = clk;
> + siic->speed = SIRFSOC_I2C_DEFAULT_SPEED;
> + if (siic->speed < 100000)
> + regval =
> + (2 * ctrl_speed) / (2 * siic->speed * 11);
> + else
> + regval = ctrl_speed / (siic->speed * 5);
> +
> + writel(regval, siic->base + SIRFSOC_I2C_CLK_CTRL);
> + if (regval > 0xFF)
> + writel(0xFF, siic->base + SIRFSOC_I2C_SDA_DELAY);
> + else
> + writel(regval, siic->base + SIRFSOC_I2C_SDA_DELAY);
> +
> + err = i2c_add_numbered_adapter(new_adapter);
> + if (err < 0) {
> + dev_err(&pdev->dev, "Can't add new i2c adapter\n");
> + goto free_irq;
> + }
> +
> + dev_info(&pdev->dev, "I2C adapter ready to operate\n");
> +
> + return 0;
> +
> +free_irq:
> + free_irq(siic->irq, siic);
> +free_base:
> + iounmap(siic->base);
> +free_data:
> + kfree(siic);
> +free_adapter:
> + kfree(new_adapter);
> +clk_out:
> + clk_disable(clk);
> + clk_put(clk);
> +out:
> + return err;
> +}
> +
> +static int __devexit i2c_sirfsoc_remove(struct platform_device *pdev)
> +{
> + struct i2c_adapter *adapter = platform_get_drvdata(pdev);
> + struct sirfsoc_i2c *siic = adapter->algo_data;
> +
> + writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL);
> + i2c_del_adapter(adapter);
> + free_irq(siic->irq, siic);
> + iounmap(siic->base);
> + kfree(siic);
> + kfree(adapter);
> + clk_disable(siic->clk);
> + clk_put(siic->clk);
> + return 0;
> +}
> +
> +#ifdef CONFIG_PM
> +static int i2c_sirfsoc_suspend(struct platform_device *pdev, pm_message_t msg)
> +{
> + struct i2c_adapter *adapter = platform_get_drvdata(pdev);
> + struct sirfsoc_i2c *siic = adapter->algo_data;
> +
> + siic->sda_delay = readl(siic->base + SIRFSOC_I2C_SDA_DELAY);
> + siic->clk_div = readl(siic->base + SIRFSOC_I2C_CLK_CTRL);
> + return 0;
> +}
> +
> +static int i2c_sirfsoc_resume(struct platform_device *pdev)
> +{
> + struct i2c_adapter *adapter = platform_get_drvdata(pdev);
> + struct sirfsoc_i2c *siic = adapter->algo_data;
> +
> + writel(SIRFSOC_I2C_RESET, siic->base + SIRFSOC_I2C_CTRL);
> + writel(SIRFSOC_I2C_CORE_EN | SIRFSOC_I2C_MASTER_MODE,
> + siic->base + SIRFSOC_I2C_CTRL);
> + writel(siic->clk_div, siic->base + SIRFSOC_I2C_CLK_CTRL);
> + writel(siic->sda_delay, siic->base + SIRFSOC_I2C_SDA_DELAY);
> + return 0;
> +}
> +#else
> +#define i2c_sirfsoc_suspend NULL
> +#define i2c_sirfsoc_resume NULL
> +#endif
> +
> +static const struct of_device_id sirfsoc_i2c_of_match[] __devinitconst = {
> + { .compatible = "sirf,prima2-i2c", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, sirfsoc_i2c_of_match);
> +
> +static struct platform_driver i2c_sirfsoc_driver = {
> + .driver = {
> + .name = "sirfsoc_i2c",
> + .owner = THIS_MODULE,
> + .of_match_table = sirfsoc_i2c_of_match,
> + },
> + .probe = i2c_sirfsoc_probe,
> + .remove = __devexit_p(i2c_sirfsoc_remove),
> + .suspend = i2c_sirfsoc_suspend,
> + .resume = i2c_sirfsoc_resume,
> +};
> +
> +static int __init i2c_sirfsoc_init(void)
> +{
> + return platform_driver_register(&i2c_sirfsoc_driver);
> +}
> +arch_initcall(i2c_sirfsoc_init);
> +
> +static void __exit i2c_sirfsoc_exit(void)
> +{
> + platform_driver_unregister(&i2c_sirfsoc_driver);
> +}
> +module_exit(i2c_sirfsoc_exit);
> +
> +MODULE_DESCRIPTION("SiRF SoC I2C master controller driver");
> +MODULE_AUTHOR("Zhiwu Song <Zhiwu.Song@xxxxxxx>, "
> + "Xiangzhen Ye <Xiangzhen.Ye@xxxxxxx>");
> +MODULE_LICENSE("GPL v2");
> diff --git a/drivers/i2c/busses/i2c-sirf.h b/drivers/i2c/busses/i2c-sirf.h
> new file mode 100644
> index 0000000..28f4ada
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-sirf.h
> @@ -0,0 +1,61 @@
> +/*
> + * I2C bus drivers for CSR SiRFprimaII
> + *
> + * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
> + *
> + * Licensed under GPLv2 or later.
> + */
> +
> +#ifndef _SIRFSOC_I2C_BUS_H_
> +#define _SIRFSOC_I2C_BUS_H_
> +
> +#include <linux/bitops.h>
> +
> +#define SIRFSOC_I2C_CLK_CTRL 0x00
It may be worth moving the contents of this file into the .c file as
they don't get used anywhere else.
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