Hi,
On Sun, Jan 29, 2012 at 10:17:48PM +0800, Barry Song wrote:

From: Zhiwu Song <redacted>

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 <redacted>
Signed-off-by: Xiangzhen Ye <redacted>
Signed-off-by: Yuping Luo <redacted>
Signed-off-by: Barry Song <redacted>

Thanks for your contribution! Is there a free datasheet for this controller
available?

Sorting is broken, same with Makefile.

Do you really need those two?

+	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;

Why a pointer and not the struct itself?

+};
+
+static void i2c_sirfsoc_read_data(struct sirfsoc_i2c *siic)
+{
+	u32 data = 0;
+	int i = 0;

i doesn't need to be initialized. data neither, but compilers fail on that sometimes.

+
+	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));

buf is declared u8.

+
+		BUG_ON(siic->finished_len > siic->msg_len);

BUG? Can't we handle this more gracefully?

+	}
+}
+
+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)) {

Either use a different indentation for the above line or add a newline below.
It is hard to see where the while() ends and the code block starts.

+			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;

No need to cast.

+	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;

You don't support MANGLING according to .functionality().

+
+	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;

That looks broken. What is 50 here?

+	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;
+
+	clk_enable(siic->clk);
+
+	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->msg_read = !!(flag & mask)?

+
+		siic->err_status = 0;
+		siic->cmd_ptr = 0;
+		siic->finished_len = 0;
+		if (i == (num - 1))
+			siic->last = 1;
+		else
+			siic->last = 0;
+

siic->last = i == (num - 1)?

+		ret = i2c_sirfsoc_xfer_msg(siic, &msgs[i]);
+		if (ret) {
+			clk_disable(siic->clk);
+			return ret;
+		}
+	}
+
+	clk_disable(siic->clk);
+	return num;
+}
+
+/* I2C algorithms associated with this master controller driver */
+static const struct i2c_algorithm i2c_sirfsoc_algo = {
+	.master_xfer = i2c_sirfsoc_xfer,
+	.functionality = i2c_sirfsoc_func,
+};
+
+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 err_get_clk;
+	}
+
+	err = clk_prepare(clk);
+	if (err) {
+		dev_err(&pdev->dev, "Clock prepare failed\n");
+		goto  err_clk_prep;

Double space. Not only here.

+	}
+
+	err = clk_enable(clk);
+	if (err) {
+		dev_err(&pdev->dev, "Clock enable failed\n");
+		goto  err_clk_en;
+	}
+
+	ctrl_speed = clk_get_rate(clk);
+
+	new_adapter = devm_kzalloc(&pdev->dev, sizeof(*new_adapter), GFP_KERNEL);
+	if (!new_adapter) {
+		dev_err(&pdev->dev,
+			"Can't allocate new i2c adapter!\n");
+		err = -ENOMEM;
+		goto out;
+	}
+
+	siic = devm_kzalloc(&pdev->dev, sizeof(*siic), GFP_KERNEL);
+	if (!siic) {
+		dev_err(&pdev->dev, "Can't allocate driver data\n");
+		err = -ENOMEM;
+		goto out;
+	}
+	new_adapter->class = I2C_CLASS_HWMON | I2C_CLASS_DDC | I2C_CLASS_SPD;

Do you really need the class?

+	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 out;
+	}
+
+	siic->base = devm_request_and_ioremap(&pdev->dev, mem_res);
+	if (siic->base == NULL) {
+		dev_err(&pdev->dev, "IO remap failed!\n");
+		err = -ENOMEM;
+		goto out;
+	}
+
+	siic->irq = platform_get_irq(pdev, 0);
+	if (siic->irq < 0) {
+		err = -EINVAL;
+		goto out;
+	}

return the error code here?

+	err = devm_request_irq(&pdev->dev, siic->irq, i2c_sirfsoc_irq, 0,
+		dev_name(&pdev->dev), siic);
+	if (err)
+		goto out;
+
+	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 out;
+	}
+
+	clk_disable(clk);
+
+	dev_info(&pdev->dev, " I2C adapter ready to operate\n");
+
+	return 0;
+
+out:
+	clk_disable(clk);
+err_clk_en:
+	clk_unprepare(clk);
+err_clk_prep:
+	clk_put(clk);
+err_get_clk:
+	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);
+	clk_unprepare(siic->clk);
+	clk_put(siic->clk);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int i2c_sirfsoc_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct i2c_adapter *adapter = platform_get_drvdata(pdev);
+	struct sirfsoc_i2c *siic = adapter->algo_data;
+
+	clk_enable(siic->clk);
+	siic->sda_delay = readl(siic->base + SIRFSOC_I2C_SDA_DELAY);
+	siic->clk_div = readl(siic->base + SIRFSOC_I2C_CLK_CTRL);
+	clk_disable(siic->clk);
+	return 0;
+}
+
+static int i2c_sirfsoc_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct i2c_adapter *adapter = platform_get_drvdata(pdev);
+	struct sirfsoc_i2c *siic = adapter->algo_data;
+
+	clk_enable(siic->clk);
+	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);
+	clk_disable(siic->clk);
+	return 0;
+}
+
+static const struct dev_pm_ops i2c_sirfsoc_pm_ops = {
+	.suspend = i2c_sirfsoc_suspend,
+	.resume = i2c_sirfsoc_resume,
+};
+#endif
+
+static const struct of_device_id sirfsoc_i2c_of_match[] __devinitconst = {
+	{ .compatible = "sirf,prima2-i2c", },
+	{},
+};

Is the binding documented?

+MODULE_DEVICE_TABLE(of, sirfsoc_i2c_of_match);
+
+static struct platform_driver i2c_sirfsoc_driver = {
+	.driver = {
+		.name = "sirfsoc_i2c",
+		.owner = THIS_MODULE,
+#ifdef CONFIG_PM
+		.pm = &i2c_sirfsoc_pm_ops,
+#endif
+		.of_match_table = sirfsoc_i2c_of_match,
+	},
+	.probe = i2c_sirfsoc_probe,
+	.remove = __devexit_p(i2c_sirfsoc_remove),
+};
+
+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_platform_driver()

Regards,

   Wolfram