[PATCH v5] I2C: add CSR SiRFprimaII on-chip I2C controllers driver

[PATCH v5] I2C: add CSR SiRFprimaII on-chip I2C controllers driver

[Barry Song]

From: Zhiwu Song <Zhiwu.Song@csr.com>

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@csr.com>
Signed-off-by: Xiangzhen Ye <Xiangzhen.Ye@csr.com>
Signed-off-by: Yuping Luo <Yuping.Luo@csr.com>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
---
 -v5: don't disable already disabled clock as pointed out by Russell

 drivers/i2c/busses/Kconfig    |   10 +
 drivers/i2c/busses/Makefile   |    1 +
 drivers/i2c/busses/i2c-sirf.c |  439 +++++++++++++++++++++++++++++++++++++++++
 drivers/i2c/busses/i2c-sirf.h |   61 ++++++
 4 files changed, 511 insertions(+), 0 deletions(-)
 create mode 100644 drivers/i2c/busses/i2c-sirf.c
 create mode 100644 drivers/i2c/busses/i2c-sirf.h

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index 3101dd5..a3c43fc 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -618,6 +618,16 @@ config I2C_SH_MOBILE
 	  This driver can also be built as a module.  If so, the module
 	  will be called i2c-sh_mobile.
 
+config I2C_SIRF
+	tristate "CSR SiRFprimaII I2C interface"
+	depends on ARCH_PRIMA2
+	help
+	  If you say yes to this option, support will be included for the
+	  CSR SiRFprimaII I2C interface.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called i2c-sirf.
+
 config I2C_SIMTEC
 	tristate "Simtec Generic I2C interface"
 	select I2C_ALGOBIT
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index fba6da6..c30db66 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -62,6 +62,7 @@ obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
 obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
 obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
 obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
+obj-$(CONFIG_I2C_SIRF)		+= i2c-sirf.o
 obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
 obj-$(CONFIG_I2C_STU300)	+= i2c-stu300.o
 obj-$(CONFIG_I2C_TEGRA)		+= i2c-tegra.o
diff --git a/drivers/i2c/busses/i2c-sirf.c b/drivers/i2c/busses/i2c-sirf.c
new file mode 100644
index 0000000..6432d35
--- /dev/null
+++ b/drivers/i2c/busses/i2c-sirf.c
@@ -0,0 +1,439 @@
+/*
+ * 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/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 __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;
+
+	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->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) {
+			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;
+	}
+
+	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;
+	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;
+	}
+	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", },
+	{},
+};
+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_DESCRIPTION("SiRF SoC I2C master controller driver");
+MODULE_AUTHOR("Zhiwu Song <Zhiwu.Song@csr.com>, "
+	"Xiangzhen Ye <Xiangzhen.Ye@csr.com>");
+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
+#define SIRFSOC_I2C_STATUS		0x0C
+#define SIRFSOC_I2C_CTRL		0x10
+#define SIRFSOC_I2C_IO_CTRL		0x14
+#define SIRFSOC_I2C_SDA_DELAY		0x18
+#define SIRFSOC_I2C_CMD_START		0x1C
+#define SIRFSOC_I2C_CMD_BUF		0x30
+#define SIRFSOC_I2C_DATA_BUF		0x80
+
+#define SIRFSOC_I2C_CMD_BUF_MAX		16
+#define SIRFSOC_I2C_DATA_BUF_MAX	16
+
+#define SIRFSOC_I2C_CMD(x)		(SIRFSOC_I2C_CMD_BUF + (x)*0x04)
+#define SIRFSOC_I2C_DATA_MASK(x)        (0xFF<<(((x)&3)*8))
+#define SIRFSOC_I2C_DATA_SHIFT(x)       (((x)&3)*8)
+
+#define SIRFSOC_I2C_DIV_MASK		(0xFFFF)
+
+/* I2C status flags */
+#define SIRFSOC_I2C_STAT_BUSY		BIT(0)
+#define SIRFSOC_I2C_STAT_TIP		BIT(1)
+#define SIRFSOC_I2C_STAT_NACK		BIT(2)
+#define SIRFSOC_I2C_STAT_TR_INT		BIT(4)
+#define SIRFSOC_I2C_STAT_STOP		BIT(6)
+#define SIRFSOC_I2C_STAT_CMD_DONE	BIT(8)
+#define SIRFSOC_I2C_STAT_ERR		BIT(9)
+#define SIRFSOC_I2C_CMD_INDEX		(0x1F<<16)
+
+/* I2C control flags */
+#define SIRFSOC_I2C_RESET		BIT(0)
+#define SIRFSOC_I2C_CORE_EN		BIT(1)
+#define SIRFSOC_I2C_MASTER_MODE		BIT(2)
+#define SIRFSOC_I2C_CMD_DONE_EN		BIT(11)
+#define SIRFSOC_I2C_ERR_INT_EN		BIT(12)
+
+#define SIRFSOC_I2C_SDA_DELAY_MASK	(0xFF)
+#define SIRFSOC_I2C_SCLF_FILTER		(3<<8)
+
+#define SIRFSOC_I2C_START_CMD		BIT(0)
+
+#define SIRFSOC_I2C_CMD_RP(x)		((x)&0x7)
+#define SIRFSOC_I2C_NACK		BIT(3)
+#define SIRFSOC_I2C_WRITE		BIT(4)
+#define SIRFSOC_I2C_READ		BIT(5)
+#define SIRFSOC_I2C_STOP		BIT(6)
+#define SIRFSOC_I2C_START		BIT(7)
+
+#endif
-- 
1.7.0.4

[PATCH v5] I2C: add CSR SiRFprimaII on-chip I2C controllers driver

[Wolfram Sang]

Hi,
On Sun, Jan 29, 2012 at 10:17:48PM +0800, Barry Song wrote:
> From: Zhiwu Song <Zhiwu.Song@csr.com>
> 
> 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@csr.com>
> Signed-off-by: Xiangzhen Ye <Xiangzhen.Ye@csr.com>
> Signed-off-by: Yuping Luo <Yuping.Luo@csr.com>
> Signed-off-by: Barry Song <Baohua.Song@csr.com>

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

> ---
>  -v5: don't disable already disabled clock as pointed out by Russell
> 
>  drivers/i2c/busses/Kconfig    |   10 +
>  drivers/i2c/busses/Makefile   |    1 +
>  drivers/i2c/busses/i2c-sirf.c |  439 +++++++++++++++++++++++++++++++++++++++++
>  drivers/i2c/busses/i2c-sirf.h |   61 ++++++
>  4 files changed, 511 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/i2c/busses/i2c-sirf.c
>  create mode 100644 drivers/i2c/busses/i2c-sirf.h
> 
> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
> index 3101dd5..a3c43fc 100644
> --- a/drivers/i2c/busses/Kconfig
> +++ b/drivers/i2c/busses/Kconfig
> @@ -618,6 +618,16 @@ config I2C_SH_MOBILE
>  	  This driver can also be built as a module.  If so, the module
>  	  will be called i2c-sh_mobile.
>  
> +config I2C_SIRF
> +	tristate "CSR SiRFprimaII I2C interface"
> +	depends on ARCH_PRIMA2
> +	help
> +	  If you say yes to this option, support will be included for the
> +	  CSR SiRFprimaII I2C interface.
> +
> +	  This driver can also be built as a module.  If so, the module
> +	  will be called i2c-sirf.
> +

Sorting is broken, same with Makefile.

>  config I2C_SIMTEC
>  	tristate "Simtec Generic I2C interface"
>  	select I2C_ALGOBIT
> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
> index fba6da6..c30db66 100644
> --- a/drivers/i2c/busses/Makefile
> +++ b/drivers/i2c/busses/Makefile
> @@ -62,6 +62,7 @@ obj-$(CONFIG_I2C_S3C2410)	+= i2c-s3c2410.o
>  obj-$(CONFIG_I2C_S6000)		+= i2c-s6000.o
>  obj-$(CONFIG_I2C_SH7760)	+= i2c-sh7760.o
>  obj-$(CONFIG_I2C_SH_MOBILE)	+= i2c-sh_mobile.o
> +obj-$(CONFIG_I2C_SIRF)		+= i2c-sirf.o
>  obj-$(CONFIG_I2C_SIMTEC)	+= i2c-simtec.o
>  obj-$(CONFIG_I2C_STU300)	+= i2c-stu300.o
>  obj-$(CONFIG_I2C_TEGRA)		+= i2c-tegra.o
> diff --git a/drivers/i2c/busses/i2c-sirf.c b/drivers/i2c/busses/i2c-sirf.c
> new file mode 100644
> index 0000000..6432d35
> --- /dev/null
> +++ b/drivers/i2c/busses/i2c-sirf.c
> @@ -0,0 +1,439 @@
> +/*
> + * 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/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 __iomem *base;
> +	struct clk *clk;
> +	unsigned long speed;	/* I2C SCL frequency */
> +	int irq;

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()

> +
> +MODULE_DESCRIPTION("SiRF SoC I2C master controller driver");
> +MODULE_AUTHOR("Zhiwu Song <Zhiwu.Song@csr.com>, "
> +	"Xiangzhen Ye <Xiangzhen.Ye@csr.com>");
> +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
> +#define SIRFSOC_I2C_STATUS		0x0C
> +#define SIRFSOC_I2C_CTRL		0x10
> +#define SIRFSOC_I2C_IO_CTRL		0x14
> +#define SIRFSOC_I2C_SDA_DELAY		0x18
> +#define SIRFSOC_I2C_CMD_START		0x1C
> +#define SIRFSOC_I2C_CMD_BUF		0x30
> +#define SIRFSOC_I2C_DATA_BUF		0x80
> +
> +#define SIRFSOC_I2C_CMD_BUF_MAX		16
> +#define SIRFSOC_I2C_DATA_BUF_MAX	16
> +
> +#define SIRFSOC_I2C_CMD(x)		(SIRFSOC_I2C_CMD_BUF + (x)*0x04)
> +#define SIRFSOC_I2C_DATA_MASK(x)        (0xFF<<(((x)&3)*8))
> +#define SIRFSOC_I2C_DATA_SHIFT(x)       (((x)&3)*8)
> +
> +#define SIRFSOC_I2C_DIV_MASK		(0xFFFF)
> +
> +/* I2C status flags */
> +#define SIRFSOC_I2C_STAT_BUSY		BIT(0)
> +#define SIRFSOC_I2C_STAT_TIP		BIT(1)
> +#define SIRFSOC_I2C_STAT_NACK		BIT(2)
> +#define SIRFSOC_I2C_STAT_TR_INT		BIT(4)
> +#define SIRFSOC_I2C_STAT_STOP		BIT(6)
> +#define SIRFSOC_I2C_STAT_CMD_DONE	BIT(8)
> +#define SIRFSOC_I2C_STAT_ERR		BIT(9)
> +#define SIRFSOC_I2C_CMD_INDEX		(0x1F<<16)
> +
> +/* I2C control flags */
> +#define SIRFSOC_I2C_RESET		BIT(0)
> +#define SIRFSOC_I2C_CORE_EN		BIT(1)
> +#define SIRFSOC_I2C_MASTER_MODE		BIT(2)
> +#define SIRFSOC_I2C_CMD_DONE_EN		BIT(11)
> +#define SIRFSOC_I2C_ERR_INT_EN		BIT(12)
> +
> +#define SIRFSOC_I2C_SDA_DELAY_MASK	(0xFF)
> +#define SIRFSOC_I2C_SCLF_FILTER		(3<<8)
> +
> +#define SIRFSOC_I2C_START_CMD		BIT(0)
> +
> +#define SIRFSOC_I2C_CMD_RP(x)		((x)&0x7)
> +#define SIRFSOC_I2C_NACK		BIT(3)
> +#define SIRFSOC_I2C_WRITE		BIT(4)
> +#define SIRFSOC_I2C_READ		BIT(5)
> +#define SIRFSOC_I2C_STOP		BIT(6)
> +#define SIRFSOC_I2C_START		BIT(7)
> +
> +#endif

Regards,

   Wolfram

[PATCH v5] I2C: add CSR SiRFprimaII on-chip I2C controllers driver

[Barry Song]

hi Wolfram,
thanks for reviewing.

2012/2/6 Wolfram Sang <ninja@nekote.pengutronix.de>:
> Hi,
> On Sun, Jan 29, 2012 at 10:17:48PM +0800, Barry Song wrote:
>> From: Zhiwu Song <Zhiwu.Song@csr.com>
>>
>> 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@csr.com>
>> Signed-off-by: Xiangzhen Ye <Xiangzhen.Ye@csr.com>
>> Signed-off-by: Yuping Luo <Yuping.Luo@csr.com>
>> Signed-off-by: Barry Song <Baohua.Song@csr.com>
>
> Thanks for your contribution! Is there a free datasheet for this controller
> available?

sorry. not available to public yet.

>
>> ---
>> ?-v5: don't disable already disabled clock as pointed out by Russell
>>
>> ?drivers/i2c/busses/Kconfig ? ?| ? 10 +
>> ?drivers/i2c/busses/Makefile ? | ? ?1 +
>> ?drivers/i2c/busses/i2c-sirf.c | ?439 +++++++++++++++++++++++++++++++++++++++++
>> ?drivers/i2c/busses/i2c-sirf.h | ? 61 ++++++
>> ?4 files changed, 511 insertions(+), 0 deletions(-)
>> ?create mode 100644 drivers/i2c/busses/i2c-sirf.c
>> ?create mode 100644 drivers/i2c/busses/i2c-sirf.h
>>
>> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
>> index 3101dd5..a3c43fc 100644
>> --- a/drivers/i2c/busses/Kconfig
>> +++ b/drivers/i2c/busses/Kconfig
>> @@ -618,6 +618,16 @@ config I2C_SH_MOBILE
>> ? ? ? ? This driver can also be built as a module. ?If so, the module
>> ? ? ? ? will be called i2c-sh_mobile.
>>
>> +config I2C_SIRF
>> + ? ? tristate "CSR SiRFprimaII I2C interface"
>> + ? ? depends on ARCH_PRIMA2
>> + ? ? help
>> + ? ? ? If you say yes to this option, support will be included for the
>> + ? ? ? CSR SiRFprimaII I2C interface.
>> +
>> + ? ? ? This driver can also be built as a module. ?If so, the module
>> + ? ? ? will be called i2c-sirf.
>> +
>
> Sorting is broken, same with Makefile.

sorry. i don't get this. I2C_SIRF have be placed in "I2C system bus
drivers (mostly embedded / system-on-chip)" submenu and placed between
"I2C_SH_MOBILE" and "I2C_SIMTEC".
what is the problem?

>
>> ?config I2C_SIMTEC
>> ? ? ? tristate "Simtec Generic I2C interface"
>> ? ? ? select I2C_ALGOBIT
>> diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
>> index fba6da6..c30db66 100644
>> --- a/drivers/i2c/busses/Makefile
>> +++ b/drivers/i2c/busses/Makefile
>> @@ -62,6 +62,7 @@ obj-$(CONFIG_I2C_S3C2410) ? += i2c-s3c2410.o
>> ?obj-$(CONFIG_I2C_S6000) ? ? ? ? ? ? ?+= i2c-s6000.o
>> ?obj-$(CONFIG_I2C_SH7760) ? ? += i2c-sh7760.o
>> ?obj-$(CONFIG_I2C_SH_MOBILE) ?+= i2c-sh_mobile.o
>> +obj-$(CONFIG_I2C_SIRF) ? ? ? ? ? ? ? += i2c-sirf.o
>> ?obj-$(CONFIG_I2C_SIMTEC) ? ? += i2c-simtec.o
>> ?obj-$(CONFIG_I2C_STU300) ? ? += i2c-stu300.o
>> ?obj-$(CONFIG_I2C_TEGRA) ? ? ? ? ? ? ?+= i2c-tegra.o
>> diff --git a/drivers/i2c/busses/i2c-sirf.c b/drivers/i2c/busses/i2c-sirf.c
>> new file mode 100644
>> index 0000000..6432d35
>> --- /dev/null
>> +++ b/drivers/i2c/busses/i2c-sirf.c
>> @@ -0,0 +1,439 @@
>> +/*
>> + * 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/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 __iomem *base;
>> + ? ? struct clk *clk;
>> + ? ? unsigned long speed; ? ?/* I2C SCL frequency */
>> + ? ? int irq;
>
> Do you really need those two?

irq can be deleted. speed is not really needed if you don't like.

>
>> + ? ? 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?

looks like most people use a struct directly, ok, we can move too.

>
>> +};
>> +
>> +static void i2c_sirfsoc_read_data(struct sirfsoc_i2c *siic)
>> +{
>> + ? ? u32 data = 0;
>> + ? ? int i = 0;
>
> it doesn't need to be initialized. data neither, but compilers fail on that sometimes.
ok.

>
>> +
>> + ? ? 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.

ok.
siic->buf[siic->finished_len++] =
                        (u8)((data & SIRFSOC_I2C_DATA_MASK(i)) >>
                                SIRFSOC_I2C_DATA_SHIFT(i));

>
>> +
>> + ? ? ? ? ? ? BUG_ON(siic->finished_len > siic->msg_len);
>
> BUG? Can't we handle this more gracefully?

this should not have happened. if it happens, there is something wrong
in SW. actually, i can totally delete it.

>
>> + ? ? }
>> +}
>> +
>> +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.

i just want to make sure what you want is:

             while (((siic->finished_len + i) < siic->msg_len)
                     &&(siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX)
                     ) {
?
or something else?

>
>> + ? ? ? ? ? ? ? ? ? ? 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.

ok.

>
>> + ? ? 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().

ok.

>
>> +
>> + ? ? 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?

just multiple of xfer bytes for defining a timeout. i might have a comment 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)?

ok.

>
>> + ? ? ? ? ? ? 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.

ok. fix.

>
>> + ? ? }
>> +
>> + ? ? 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?

out lable will free resources and return error code.
out:
        clk_disable(clk);
err_clk_en:
        clk_unprepare(clk);
err_clk_prep:
        clk_put(clk);
err_get_clk:
        return err;

>
>> + ? ? 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?

miss this. will add.

>
>> +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()

ok.

>
>> +
>> +MODULE_DESCRIPTION("SiRF SoC I2C master controller driver");
>> +MODULE_AUTHOR("Zhiwu Song <Zhiwu.Song@csr.com>, "
>> + ? ? "Xiangzhen Ye <Xiangzhen.Ye@csr.com>");
>> +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
>> +#define SIRFSOC_I2C_STATUS ? ? ? ? ? 0x0C
>> +#define SIRFSOC_I2C_CTRL ? ? ? ? ? ? 0x10
>> +#define SIRFSOC_I2C_IO_CTRL ? ? ? ? ?0x14
>> +#define SIRFSOC_I2C_SDA_DELAY ? ? ? ? ? ? ? ?0x18
>> +#define SIRFSOC_I2C_CMD_START ? ? ? ? ? ? ? ?0x1C
>> +#define SIRFSOC_I2C_CMD_BUF ? ? ? ? ?0x30
>> +#define SIRFSOC_I2C_DATA_BUF ? ? ? ? 0x80
>> +
>> +#define SIRFSOC_I2C_CMD_BUF_MAX ? ? ? ? ? ? ?16
>> +#define SIRFSOC_I2C_DATA_BUF_MAX ? ? 16
>> +
>> +#define SIRFSOC_I2C_CMD(x) ? ? ? ? ? (SIRFSOC_I2C_CMD_BUF + (x)*0x04)
>> +#define SIRFSOC_I2C_DATA_MASK(x) ? ? ? ?(0xFF<<(((x)&3)*8))
>> +#define SIRFSOC_I2C_DATA_SHIFT(x) ? ? ? (((x)&3)*8)
>> +
>> +#define SIRFSOC_I2C_DIV_MASK ? ? ? ? (0xFFFF)
>> +
>> +/* I2C status flags */
>> +#define SIRFSOC_I2C_STAT_BUSY ? ? ? ? ? ? ? ?BIT(0)
>> +#define SIRFSOC_I2C_STAT_TIP ? ? ? ? BIT(1)
>> +#define SIRFSOC_I2C_STAT_NACK ? ? ? ? ? ? ? ?BIT(2)
>> +#define SIRFSOC_I2C_STAT_TR_INT ? ? ? ? ? ? ?BIT(4)
>> +#define SIRFSOC_I2C_STAT_STOP ? ? ? ? ? ? ? ?BIT(6)
>> +#define SIRFSOC_I2C_STAT_CMD_DONE ? ?BIT(8)
>> +#define SIRFSOC_I2C_STAT_ERR ? ? ? ? BIT(9)
>> +#define SIRFSOC_I2C_CMD_INDEX ? ? ? ? ? ? ? ?(0x1F<<16)
>> +
>> +/* I2C control flags */
>> +#define SIRFSOC_I2C_RESET ? ? ? ? ? ?BIT(0)
>> +#define SIRFSOC_I2C_CORE_EN ? ? ? ? ?BIT(1)
>> +#define SIRFSOC_I2C_MASTER_MODE ? ? ? ? ? ? ?BIT(2)
>> +#define SIRFSOC_I2C_CMD_DONE_EN ? ? ? ? ? ? ?BIT(11)
>> +#define SIRFSOC_I2C_ERR_INT_EN ? ? ? ? ? ? ? BIT(12)
>> +
>> +#define SIRFSOC_I2C_SDA_DELAY_MASK ? (0xFF)
>> +#define SIRFSOC_I2C_SCLF_FILTER ? ? ? ? ? ? ?(3<<8)
>> +
>> +#define SIRFSOC_I2C_START_CMD ? ? ? ? ? ? ? ?BIT(0)
>> +
>> +#define SIRFSOC_I2C_CMD_RP(x) ? ? ? ? ? ? ? ?((x)&0x7)
>> +#define SIRFSOC_I2C_NACK ? ? ? ? ? ? BIT(3)
>> +#define SIRFSOC_I2C_WRITE ? ? ? ? ? ?BIT(4)
>> +#define SIRFSOC_I2C_READ ? ? ? ? ? ? BIT(5)
>> +#define SIRFSOC_I2C_STOP ? ? ? ? ? ? BIT(6)
>> +#define SIRFSOC_I2C_START ? ? ? ? ? ?BIT(7)
>> +
>> +#endif
>
> Regards,
>
> ? Wolfram

-barry

[PATCH v5] I2C: add CSR SiRFprimaII on-chip I2C controllers driver

[Barry Song]

>>> diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
>>> index 3101dd5..a3c43fc 100644
>>> --- a/drivers/i2c/busses/Kconfig
>>> +++ b/drivers/i2c/busses/Kconfig
>>> @@ -618,6 +618,16 @@ config I2C_SH_MOBILE
>>> ? ? ? ? This driver can also be built as a module. ?If so, the module
>>> ? ? ? ? will be called i2c-sh_mobile.
>>>
>>> +config I2C_SIRF
>>> + ? ? tristate "CSR SiRFprimaII I2C interface"
>>> + ? ? depends on ARCH_PRIMA2
>>> + ? ? help
>>> + ? ? ? If you say yes to this option, support will be included for the
>>> + ? ? ? CSR SiRFprimaII I2C interface.
>>> +
>>> + ? ? ? This driver can also be built as a module. ?If so, the module
>>> + ? ? ? will be called i2c-sirf.
>>> +
>>
>> Sorting is broken, same with Makefile.
>
> sorry. i don't get this. I2C_SIRF have be placed in "I2C system bus
> drivers (mostly embedded / system-on-chip)" submenu and placed between
> "I2C_SH_MOBILE" and "I2C_SIMTEC".
> what is the problem?
>

Oh.... i was making some stupid mistake. i thought R is earlier than
M. in fact,  it is L->M->N->O->P->Q->R, so move I2C_SIRF behind
"I2C_SIMTEC".
-barry

[PATCH v5] I2C: add CSR SiRFprimaII on-chip I2C controllers driver

[Wolfram Sang]

> > Thanks for your contribution! Is there a free datasheet for this controller
> > available?
> 
> sorry. not available to public yet.

:( Can you cite what "SIRFSOC_I2C_NACK" does?
> 
> >> +struct sirfsoc_i2c {
> >> + ? ? void __iomem *base;
> >> + ? ? struct clk *clk;
> >> + ? ? unsigned long speed; ? ?/* I2C SCL frequency */
> >> + ? ? int irq;
> >
> > Do you really need those two?
> 
> irq can be deleted. speed is not really needed if you don't like.

It is not about "like". It is not needed, or?

> >> +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.
> 
> i just want to make sure what you want is:
> 
>              while (((siic->finished_len + i) < siic->msg_len)
>                      &&(siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX)
>                      ) {
> ?
> or something else?

I thought of (which is simpler IMO):

>              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);


The other solution would be (not sure if it fits the line length):

> >> + ? ? ? ? ? ? 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);

The idea is to make it easier (visually) what is the while-condition and where
is the code of the while-block. I thought that was difficult in original version.

> >> +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?
> 
> just multiple of xfer bytes for defining a timeout. i might have a comment here.

That probably won't help. I'd think you want a *_to_jiffies() here to define a
proper timeout value in usecs/msecs?

> >> + ? ? siic->irq = platform_get_irq(pdev, 0);
> >> + ? ? if (siic->irq < 0) {
> >> + ? ? ? ? ? ? err = -EINVAL;
> >> + ? ? ? ? ? ? goto out;
> >> + ? ? }
> >
> > return the error code here?
> 
> out lable will free resources and return error code.

Sorry, I meant the error code you received which is in siic->irq.

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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[PATCH v5] I2C: add CSR SiRFprimaII on-chip I2C controllers driver

[Barry Song]

hi Wolfram,

2012/2/7 Wolfram Sang <w.sang@pengutronix.de>:
>
>> > Thanks for your contribution! Is there a free datasheet for this controller
>> > available?
>>
>> sorry. not available to public yet.
>
> :( Can you cite what "SIRFSOC_I2C_NACK" does?

if ACK is not received, an interrupt will be got and related register
status can show this error. that is just a common feature in almost
all i2c controllers? so the naming is confused. i just copied it from
the spec.

>>
>> >> +struct sirfsoc_i2c {
>> >> + ? ? void __iomem *base;
>> >> + ? ? struct clk *clk;
>> >> + ? ? unsigned long speed; ? ?/* I2C SCL frequency */
>> >> + ? ? int irq;
>> >
>> > Do you really need those two?
>>
>> irq can be deleted. speed is not really needed if you don't like.
>
> It is not about "like". It is not needed, or?

it is not needed.

>
>> >> +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.
>>
>> i just want to make sure what you want is:
>>
>> ? ? ? ? ? ? ?while (((siic->finished_len + i) < siic->msg_len)
>> ? ? ? ? ? ? ? ? ? ? ?&&(siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX)
>> ? ? ? ? ? ? ? ? ? ? ?) {
>> ?
>> or something else?
>
> I thought of (which is simpler IMO):
>
>> ? ? ? ? ? ? ?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);
>
>
> The other solution would be (not sure if it fits the line length):
>
>> >> + ? ? ? ? ? ? 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);
>
> The idea is to make it easier (visually) what is the while-condition and where
> is the code of the while-block. I thought that was difficult in original version.

the mail webpages and clients really fails to show the difference. i
guess you mean:
 while (((siic->finished_len + i) < siic->msg_len)
 [ tab ][ tab ]&& (siic->cmd_ptr < SIRFSOC_I2C_CMD_BUF_MAX)) {
?

or can you describle the indentation by something like [space][space][tab][tab]?

>
>> >> +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?
>>
>> just multiple of xfer bytes for defining a timeout. i might have a comment here.
>
> That probably won't help. I'd think you want a *_to_jiffies() here to define a
> proper timeout value in usecs/msecs?

ok. make sense.

>
>> >> + ? ? siic->irq = platform_get_irq(pdev, 0);
>> >> + ? ? if (siic->irq < 0) {
>> >> + ? ? ? ? ? ? err = -EINVAL;
>> >> + ? ? ? ? ? ? goto out;
>> >> + ? ? }
>> >
>> > return the error code here?
>>
>> out lable will free resources and return error code.
>
> Sorry, I meant the error code you received which is in siic->irq.

ok. err = -ENXIO

>
> Regards,
>
> ? Wolfram

-barry

[PATCH v5] I2C: add CSR SiRFprimaII on-chip I2C controllers driver

[Wolfram Sang]

Hi Barry,

> if ACK is not received, an interrupt will be got and related register
> status can show this error. that is just a common feature in almost
> all i2c controllers? so the naming is confused. i just copied it from
> the spec.

Yes, this is common and yes, the naming is confusing :) This is why I
asked if it really does what I believed it does. All is fine, no need
for a change.

> the mail webpages and clients really fails to show the difference. i

Not all of them. gmane looks OK both in web-interface and via NNTP.

> >> >> + ? ? siic->irq = platform_get_irq(pdev, 0);
> >> >> + ? ? if (siic->irq < 0) {
> >> >> + ? ? ? ? ? ? err = -EINVAL;
> >> >> + ? ? ? ? ? ? goto out;
> >> >> + ? ? }
> >> >
> >> > return the error code here?
> >>
> >> out lable will free resources and return error code.
> >
> > Sorry, I meant the error code you received which is in siic->irq.
> 
> ok. err = -ENXIO

err = ssic->irq?

Regards,

   Wolfram

-- 
Pengutronix e.K.                           | Wolfram Sang                |
Industrial Linux Solutions                 | http://www.pengutronix.de/  |
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