i2c-s3c2410: Add device tree support

Add device tree probe support for Samsung's s3c2410 i2c driver.

Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Thomas Abraham <thomas.abraham@linaro.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Ben Dooks <ben-linux@fluff.org>

1 files changed, 106 insertions, 4 deletions

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 266dd83a3ec2..9c00ad1f50a2 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -35,6 +35,8 @@
 #include <linux/cpufreq.h>
 #include <linux/slab.h>
 #include <linux/io.h>
+#include <linux/of_i2c.h>
+#include <linux/of_gpio.h>
 
 #include <asm/irq.h>
 
@@ -79,6 +81,7 @@ struct s3c24xx_i2c {
         struct i2c_adapter      adap;
 
         struct s3c2410_platform_i2c     *pdata;
+        int                     gpios[2];
 #ifdef CONFIG_CPU_FREQ
         struct notifier_block   freq_transition;
 #endif
@@ -96,6 +99,12 @@ static inline int s3c24xx_i2c_is2440(struct s3c24xx_i2c *i2c)
         struct platform_device *pdev = to_platform_device(i2c->dev);
         enum s3c24xx_i2c_type type;
 
+#ifdef CONFIG_OF
+        if (i2c->dev->of_node)
+                return of_device_is_compatible(i2c->dev->of_node,
+                                "samsung,s3c2440-i2c");
+#endif
+
         type = platform_get_device_id(pdev)->driver_data;
         return type == TYPE_S3C2440;
 }
@@ -742,6 +751,49 @@ static inline void s3c24xx_i2c_deregister_cpufreq(struct s3c24xx_i2c *i2c)
 }
 #endif
 
+#ifdef CONFIG_OF
+static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
+{
+        int idx, gpio, ret;
+
+        for (idx = 0; idx < 2; idx++) {
+                gpio = of_get_gpio(i2c->dev->of_node, idx);
+                if (!gpio_is_valid(gpio)) {
+                        dev_err(i2c->dev, "invalid gpio[%d]: %d\n", idx, gpio);
+                        goto free_gpio;
+                }
+
+                ret = gpio_request(gpio, "i2c-bus");
+                if (ret) {
+                        dev_err(i2c->dev, "gpio [%d] request failed\n", gpio);
+                        goto free_gpio;
+                }
+        }
+        return 0;
+
+free_gpio:
+        while (--idx >= 0)
+                gpio_free(i2c->gpios[idx]);
+        return -EINVAL;
+}
+
+static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
+{
+        unsigned int idx;
+        for (idx = 0; idx < 2; idx++)
+                gpio_free(i2c->gpios[idx]);
+}
+#else
+static int s3c24xx_i2c_parse_dt_gpio(struct s3c24xx_i2c *i2c)
+{
+        return -EINVAL;
+}
+
+static void s3c24xx_i2c_dt_gpio_free(struct s3c24xx_i2c *i2c)
+{
+}
+#endif
+
 /* s3c24xx_i2c_init
  *
  * initialise the controller, set the IO lines and frequency
@@ -761,6 +813,9 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
 
         if (pdata->cfg_gpio)
                 pdata->cfg_gpio(to_platform_device(i2c->dev));
+        else
+                if (s3c24xx_i2c_parse_dt_gpio(i2c))
+                        return -EINVAL;
 
         /* write slave address */
 
@@ -786,6 +841,34 @@ static int s3c24xx_i2c_init(struct s3c24xx_i2c *i2c)
         return 0;
 }
 
+#ifdef CONFIG_OF
+/* s3c24xx_i2c_parse_dt
+ *
+ * Parse the device tree node and retreive the platform data.
+*/
+
+static void
+s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
+{
+        struct s3c2410_platform_i2c *pdata = i2c->pdata;
+
+        if (!np)
+                return;
+
+        pdata->bus_num = -1; /* i2c bus number is dynamically assigned */
+        of_property_read_u32(np, "samsung,i2c-sda-delay", &pdata->sda_delay);
+        of_property_read_u32(np, "samsung,i2c-slave-addr", &pdata->slave_addr);
+        of_property_read_u32(np, "samsung,i2c-max-bus-freq",
+                                (u32 *)&pdata->frequency);
+}
+#else
+static void
+s3c24xx_i2c_parse_dt(struct device_node *np, struct s3c24xx_i2c *i2c)
+{
+        return;
+}
+#endif
+
 /* s3c24xx_i2c_probe
  *
  * called by the bus driver when a suitable device is found
@@ -798,10 +881,12 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
         struct resource *res;
         int ret;
 
-        pdata = pdev->dev.platform_data;
-        if (!pdata) {
-                dev_err(&pdev->dev, "no platform data\n");
-                return -EINVAL;
+        if (!pdev->dev.of_node) {
+                pdata = pdev->dev.platform_data;
+                if (!pdata) {
+                        dev_err(&pdev->dev, "no platform data\n");
+                        return -EINVAL;
+                }
         }
 
         i2c = kzalloc(sizeof(struct s3c24xx_i2c), GFP_KERNEL);
@@ -818,6 +903,8 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
 
         if (pdata)
                 memcpy(i2c->pdata, pdata, sizeof(*pdata));
+        else
+                s3c24xx_i2c_parse_dt(pdev->dev.of_node, i2c);
 
         strlcpy(i2c->adap.name, "s3c2410-i2c", sizeof(i2c->adap.name));
         i2c->adap.owner   = THIS_MODULE;
@@ -914,6 +1001,7 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
          */
 
         i2c->adap.nr = i2c->pdata->bus_num;
+        i2c->adap.dev.of_node = pdev->dev.of_node;
 
         ret = i2c_add_numbered_adapter(&i2c->adap);
         if (ret < 0) {
@@ -921,6 +1009,7 @@ 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));
@@ -969,6 +1058,7 @@ static int s3c24xx_i2c_remove(struct platform_device *pdev)
         iounmap(i2c->regs);
 
         release_resource(i2c->ioarea);
+        s3c24xx_i2c_dt_gpio_free(i2c);
         kfree(i2c->ioarea);
         kfree(i2c);
 
@@ -1022,6 +1112,17 @@ static struct platform_device_id s3c24xx_driver_ids[] = {
 };
 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
 
+#ifdef CONFIG_OF
+static const struct of_device_id s3c24xx_i2c_match[] = {
+        { .compatible = "samsung,s3c2410-i2c" },
+        { .compatible = "samsung,s3c2440-i2c" },
+        {},
+};
+MODULE_DEVICE_TABLE(of, s3c24xx_i2c_match);
+#else
+#define s3c24xx_i2c_match NULL
+#endif
+
 static struct platform_driver s3c24xx_i2c_driver = {
         .probe          = s3c24xx_i2c_probe,
         .remove         = s3c24xx_i2c_remove,
@@ -1030,6 +1131,7 @@ static struct platform_driver s3c24xx_i2c_driver = {
                 .owner  = THIS_MODULE,
                 .name   = "s3c-i2c",
                 .pm     = S3C24XX_DEV_PM_OPS,
+                .of_match_table = s3c24xx_i2c_match,
         },
 };