[PATCH 1/2] i2c: s3c24xx: Add device tree support

[Thomas Abraham <thomas.abraham-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>]

Add device tree support for Samsung's s3c24xx i2c driver. It adds
support for parsing platform data from device tree and initialize
all the slave devices specified as child nodes.

Signed-off-by: Thomas Abraham <thomas.abraham-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>
---
 .../devicetree/bindings/i2c/samsung-i2c.txt        |   43 ++++++++++
 drivers/i2c/busses/i2c-s3c2410.c                   |   87 ++++++++++++++++----
 2 files changed, 115 insertions(+), 15 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/i2c/samsung-i2c.txt

diff --git a/Documentation/devicetree/bindings/i2c/samsung-i2c.txt b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
new file mode 100644
index 0000000..73191c3
--- /dev/null
+++ b/Documentation/devicetree/bindings/i2c/samsung-i2c.txt
@@ -0,0 +1,43 @@
+* Samsung's I2C controller
+
+The Samsung's I2C controller is used to interface with I2C devices.
+
+Required properties:
+  - compatible: value should be either of the following.
+      (a) "samsung, s3c2410-i2c", for i2c compatible with s3c2410 i2c.
+      (b) "samsung, s3c2440-i2c", for i2c compatible with s3c2440 i2c.
+
+  - reg: physical base address of the controller and length of memory mapped
+    region.
+
+  - interrupts : interrupt number to the cpu.
+
+  - samsung,i2c-bus-number: Specifies the i2c bus number.
+
+  - samsung,i2c-sda-delay: Delay (in ns) applied to data line (SDA) edges.
+
+Optional properties:
+  - samsung,i2c-slave-addr: Slave address in multi-master enviroment. If not
+    specified, default value is 0x10.
+
+  - samsung,i2c-max-bus-freq: Desired frequency in Hz of the bus. If not
+    specified, the default value in Hz is 100000.
+
+Example:
+
+	i2c@13870000 {
+		compatible = "samsung,s3c2440-i2c";
+		reg = <0x13870000 0x100>;
+		interrupts = <345>;
+		samsung,i2c-bus-number = <1>;
+		samsung,i2c-slave-addr = <16>;
+		samsung,i2c-sda-delay = <100>;
+		samsung,i2c-max-bus-freq = <100000>;
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		wm8994@1a {
+			compatible = "wlf,wm8994";
+			reg = <0x1a>;
+		};
+	};
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 6c00c10..5a84a0b 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -35,6 +35,9 @@
 #include <linux/cpufreq.h>
 #include <linux/slab.h>
 #include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_i2c.h>
+#include <linux/of_device.h>
 
 #include <asm/irq.h>
 
@@ -83,6 +86,33 @@ struct s3c24xx_i2c {
 #endif
 };
 
+#ifdef CONFIG_OF
+static enum s3c24xx_i2c_type samsung_i2c_types[] = {
+	TYPE_S3C2410,
+	TYPE_S3C2440
+};
+
+static const struct of_device_id s3c24xx_i2c_match[] = {
+	{ .compatible = "samsung,s3c2410-i2c", .data = &samsung_i2c_types[0], },
+	{ .compatible = "samsung,s3c2440-i2c", .data = &samsung_i2c_types[1], },
+	{},
+};
+MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
+
+static const struct
+of_device_id *s3c24xx_i2c_get_of_device_id(struct platform_device *pdev)
+{
+	return of_match_device(s3c24xx_i2c_match, &pdev->dev);
+}
+#else
+#define s3c24xx_i2c_match NULL
+static const struct
+of_device_id *s3c24xx_i2c_get_of_device_id(struct platform_device *pdev)
+{
+	return NULL;
+}
+#endif
+
 /* default platform data removed, dev should always carry data. */
 
 /* s3c24xx_i2c_is2440()
@@ -93,9 +123,15 @@ struct s3c24xx_i2c {
 static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c)
 {
 	struct platform_device *pdev = to_platform_device(i2c->dev);
+	const struct of_device_id *i2c_of_id;
 	enum s3c24xx_i2c_type type;
 
-	type = platform_get_device_id(pdev)->driver_data;
+	i2c_of_id = s3c24xx_i2c_get_of_device_id(pdev);
+	if (platform_get_device_id(pdev))
+		type = platform_get_device_id(pdev)->driver_data;
+	else
+		type = *(enum s3c24xx_i2c_type *)i2c_of_id->data;
+
 	return type == TYPE_S3C2440;
 }
 
@@ -630,16 +666,21 @@ static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 	unsigned long clkin = clk_get_rate(i2c->clk);
 	unsigned int divs, div1;
 	unsigned long target_frequency;
+	unsigned int max_freq = 0;
 	u32 iiccon;
 	int freq;
 
 	i2c->clkrate = clkin;
 	clkin /= 1000;		/* clkin now in KHz */
 
-	dev_dbg(i2c->dev, "pdata desired frequency %lu\n", pdata->frequency);
-
-	target_frequency = pdata->frequency ? pdata->frequency : 100000;
+	if (i2c->dev->of_node)
+		of_property_read_u32(i2c->dev->of_node,
+				"samsung,i2c-max-bus-freq", &max_freq);
+	else
+		max_freq = pdata->frequency;
+	dev_dbg(i2c->dev, "desired frequency %u\n", max_freq);
 
+	target_frequency = max_freq ? max_freq : 100000;
 	target_frequency /= 1000; /* Target frequency now in KHz */
 
 	freq = s3c24xx_i2c_calcdivisor(clkin, target_frequency, &div1, &divs);
@@ -663,19 +704,24 @@ static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
 	writel(iiccon, i2c->regs + S3C2410_IICCON);
 
 	if (s3c24xx_i2c_is2440(i2c)) {
-		unsigned long sda_delay;
+		unsigned int sda_delay = 0;
 
-		if (pdata->sda_delay) {
-			sda_delay = clkin * pdata->sda_delay;
+		if (i2c->dev->of_node)
+			of_property_read_u32(i2c->dev->of_node,
+				"samsung,i2c-sda-delay", &sda_delay);
+		else
+			sda_delay = pdata->sda_delay;
+
+		if (sda_delay) {
+			sda_delay *= clkin;
 			sda_delay = DIV_ROUND_UP(sda_delay, 1000000);
 			sda_delay = DIV_ROUND_UP(sda_delay, 5);
 			if (sda_delay > 3)
 				sda_delay = 3;
 			sda_delay |= S3C2410_IICLC_FILTER_ON;
-		} else
-			sda_delay = 0;
+		}
 
-		dev_dbg(i2c->dev, "IICLC=%08lx\n", sda_delay);
+		dev_dbg(i2c->dev, "IICLC=%08x\n", sda_delay);
 		writel(sda_delay, i2c->regs + S3C2440_IICLC);
 	}
 
@@ -751,7 +797,7 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 {
 	unsigned long iicon = S3C2410_IICCON_IRQEN | S3C2410_IICCON_ACKEN;
 	struct s3c2410_platform_i2c *pdata;
-	unsigned int freq;
+	unsigned int freq, slave_addr = 0x10;
 
 	/* get the plafrom data */
 
@@ -763,10 +809,14 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 		pdata->cfg_gpio(to_platform_device(i2c->dev));
 
 	/* write slave address */
+	if (i2c->dev->of_node)
+		of_property_read_u32(i2c->dev->of_node,
+				"samsung,i2c-slave-addr", &slave_addr);
+	else
+		slave_addr = pdata->slave_addr;
+	writeb(slave_addr, i2c->regs + S3C2410_IICADD);
 
-	writeb(pdata->slave_addr, i2c->regs + S3C2410_IICADD);
-
-	dev_info(i2c->dev, "slave address 0x%02x\n", pdata->slave_addr);
+	dev_info(i2c->dev, "slave address 0x%02x\n", slave_addr);
 
 	writel(iicon, i2c->regs + S3C2410_IICCON);
 
@@ -904,7 +954,12 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
 	 * being bus 0.
 	 */
 
-	i2c->adap.nr = pdata->bus_num;
+	if (i2c->dev->of_node)
+		of_property_read_u32(i2c->dev->of_node,
+				"samsung,i2c-bus-number", &i2c->adap.nr);
+	else
+		i2c->adap.nr = pdata->bus_num;
+	i2c->adap.dev.of_node = pdev->dev.of_node;
 
 	ret = i2c_add_numbered_adapter(&i2c->adap);
 	if (ret < 0) {
@@ -912,6 +967,7 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
 		goto err_cpufreq;
 	}
 
+	of_i2c_register_devices(&i2c->adap);
 	platform_set_drvdata(pdev, i2c);
 
 	dev_info(&pdev->dev, "%s: S3C I2C adapter\n", dev_name(&i2c->adap.dev));
@@ -1021,6 +1077,7 @@ static struct platform_driver s3c24xx_i2c_driver = {
 		.owner	= THIS_MODULE,
 		.name	= "s3c-i2c",
 		.pm	= S3C24XX_DEV_PM_OPS,
+		.of_match_table	= s3c24xx_i2c_match,
 	},
 };
 
-- 
1.7.1