i2c/gpio: add DT support

To achieve DT support, we need to populate a custom platform_data in a
private struct from DT information. To simplify code, the adapter and
algorithm are also put into the private struct.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: Nicolas Ferre <nicolas.ferre@atmel.com>

1 files changed, 76 insertions, 22 deletions

diff --git a/drivers/i2c/busses/i2c-gpio.c b/drivers/i2c/busses/i2c-gpio.c
index a651779d9ff7..c0330a41db03 100644
--- a/drivers/i2c/busses/i2c-gpio.c
+++ b/drivers/i2c/busses/i2c-gpio.c
@@ -14,8 +14,15 @@
 #include <linux/module.h>
 #include <linux/slab.h>
 #include <linux/platform_device.h>
-
-#include <asm/gpio.h>
+#include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/of_i2c.h>
+
+struct i2c_gpio_private_data {
+        struct i2c_adapter adap;
+        struct i2c_algo_bit_data bit_data;
+        struct i2c_gpio_platform_data pdata;
+};
 
 /* Toggle SDA by changing the direction of the pin */
 static void i2c_gpio_setsda_dir(void *data, int state)
@@ -78,24 +85,62 @@ static int i2c_gpio_getscl(void *data)
         return gpio_get_value(pdata->scl_pin);
 }
 
+static int __devinit of_i2c_gpio_probe(struct device_node *np,
+                             struct i2c_gpio_platform_data *pdata)
+{
+        u32 reg;
+
+        if (of_gpio_count(np) < 2)
+                return -ENODEV;
+
+        pdata->sda_pin = of_get_gpio(np, 0);
+        pdata->scl_pin = of_get_gpio(np, 1);
+
+        if (!gpio_is_valid(pdata->sda_pin) || !gpio_is_valid(pdata->scl_pin)) {
+                pr_err("%s: invalid GPIO pins, sda=%d/scl=%d\n",
+                       np->full_name, pdata->sda_pin, pdata->scl_pin);
+                return -ENODEV;
+        }
+
+        of_property_read_u32(np, "i2c-gpio,delay-us", &pdata->udelay);
+
+        if (!of_property_read_u32(np, "i2c-gpio,timeout-ms", &reg))
+                pdata->timeout = msecs_to_jiffies(reg);
+
+        pdata->sda_is_open_drain =
+                of_property_read_bool(np, "i2c-gpio,sda-open-drain");
+        pdata->scl_is_open_drain =
+                of_property_read_bool(np, "i2c-gpio,scl-open-drain");
+        pdata->scl_is_output_only =
+                of_property_read_bool(np, "i2c-gpio,scl-output-only");
+
+        return 0;
+}
+
 static int __devinit i2c_gpio_probe(struct platform_device *pdev)
 {
+        struct i2c_gpio_private_data *priv;
         struct i2c_gpio_platform_data *pdata;
         struct i2c_algo_bit_data *bit_data;
         struct i2c_adapter *adap;
         int ret;
 
-        pdata = pdev->dev.platform_data;
-        if (!pdata)
-                return -ENXIO;
-
-        ret = -ENOMEM;
-        adap = kzalloc(sizeof(struct i2c_adapter), GFP_KERNEL);
-        if (!adap)
-                goto err_alloc_adap;
-        bit_data = kzalloc(sizeof(struct i2c_algo_bit_data), GFP_KERNEL);
-        if (!bit_data)
-                goto err_alloc_bit_data;
+        priv = devm_kzalloc(&pdev->dev, sizeof(*priv), GFP_KERNEL);
+        if (!priv)
+                return -ENOMEM;
+        adap = &priv->adap;
+        bit_data = &priv->bit_data;
+        pdata = &priv->pdata;
+
+        if (pdev->dev.of_node) {
+                ret = of_i2c_gpio_probe(pdev->dev.of_node, pdata);
+                if (ret)
+                        return ret;
+        } else {
+                if (!pdev->dev.platform_data)
+                        return -ENXIO;
+                memcpy(pdata, pdev->dev.platform_data, sizeof(*pdata));
+        }
 
         ret = gpio_request(pdata->sda_pin, "sda");
         if (ret)
@@ -143,6 +188,7 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
         adap->algo_data = bit_data;
         adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
         adap->dev.parent = &pdev->dev;
+        adap->dev.of_node = pdev->dev.of_node;
 
         /*
          * If "dev->id" is negative we consider it as zero.
@@ -154,7 +200,9 @@ static int __devinit i2c_gpio_probe(struct platform_device *pdev)
         if (ret)
                 goto err_add_bus;
 
-        platform_set_drvdata(pdev, adap);
+        of_i2c_register_devices(adap);
+
+        platform_set_drvdata(pdev, priv);
 
         dev_info(&pdev->dev, "using pins %u (SDA) and %u (SCL%s)\n",
                  pdata->sda_pin, pdata->scl_pin,
@@ -168,34 +216,40 @@ err_add_bus:
 err_request_scl:
         gpio_free(pdata->sda_pin);
 err_request_sda:
-        kfree(bit_data);
-err_alloc_bit_data:
-        kfree(adap);
-err_alloc_adap:
         return ret;
 }
 
 static int __devexit i2c_gpio_remove(struct platform_device *pdev)
 {
+        struct i2c_gpio_private_data *priv;
         struct i2c_gpio_platform_data *pdata;
         struct i2c_adapter *adap;
 
-        adap = platform_get_drvdata(pdev);
-        pdata = pdev->dev.platform_data;
+        priv = platform_get_drvdata(pdev);
+        adap = &priv->adap;
+        pdata = &priv->pdata;
 
         i2c_del_adapter(adap);
         gpio_free(pdata->scl_pin);
         gpio_free(pdata->sda_pin);
-        kfree(adap->algo_data);
-        kfree(adap);
 
         return 0;
 }
 
+#if defined(CONFIG_OF)
+static const struct of_device_id i2c_gpio_dt_ids[] = {
+        { .compatible = "i2c-gpio", },
+        { /* sentinel */ }
+};
+
+MODULE_DEVICE_TABLE(of, i2c_gpio_dt_ids);
+#endif
+
 static struct platform_driver i2c_gpio_driver = {
         .driver         = {
                 .name   = "i2c-gpio",
                 .owner  = THIS_MODULE,
+                .of_match_table = of_match_ptr(i2c_gpio_dt_ids),
         },
         .probe          = i2c_gpio_probe,
         .remove         = __devexit_p(i2c_gpio_remove),