onewire: w1-gpio: add DT bindings

This patch add DT bindings to the w1-gpio driver, along with some
documentation on how to use them.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Acked-by: Ville Syrjälä <syrjala@sci.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/Documentation/devicetree/bindings/w1/w1-gpio.txt b/Documentation/devicetree/bindings/w1/w1-gpio.txt
new file mode 100644 (file)
index 0000000..6e09c35
--- /dev/null
+++ b/Documentation/devicetree/bindings/w1/w1-gpio.txt
@@ -0,0 +1,22 @@
+w1-gpio devicetree bindings
+
+Required properties:
+
+ - compatible: "w1-gpio"
+ - gpios: one or two GPIO specs:
+               - the first one is used as data I/O pin
+               - the second one is optional. If specified, it is used as
+                 enable pin for an external pin pullup.
+
+Optional properties:
+
+ - linux,open-drain: if specified, the data pin is considered in
+                    open-drain mode.
+
+Examples:
+
+       onewire@0 {
+               compatible = "w1-gpio";
+               gpios = <&gpio 126 0>, <&gpio 105 0>;
+       };
+

diff --git a/drivers/w1/masters/w1-gpio.c b/drivers/w1/masters/w1-gpio.c
index df600d1..f01c336 100644 (file)
--- a/drivers/w1/masters/w1-gpio.c
+++ b/drivers/w1/masters/w1-gpio.c
@@ -14,6 +14,8 @@
 #include <linux/slab.h>
 #include <linux/w1-gpio.h>
 #include <linux/gpio.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
 
 #include "../w1.h"
 #include "../w1_int.h"
@@ -42,12 +44,55 @@ static u8 w1_gpio_read_bit(void *data)
        return gpio_get_value(pdata->pin) ? 1 : 0;
 }
 
+#ifdef CONFIG_OF
+static struct of_device_id w1_gpio_dt_ids[] = {
+       { .compatible = "w1-gpio" },
+       {}
+};
+MODULE_DEVICE_TABLE(of, w1_gpio_dt_ids);
+
+static int w1_gpio_probe_dt(struct platform_device *pdev)
+{
+       struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+       struct device_node *np = pdev->dev.of_node;
+       const struct of_device_id *of_id =
+                       of_match_device(w1_gpio_dt_ids, &pdev->dev);
+
+       if (!of_id)
+               return 0;
+
+       pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+       if (!pdata)
+               return -ENOMEM;
+
+       if (of_get_property(np, "linux,open-drain", NULL))
+               pdata->is_open_drain = 1;
+
+       pdata->pin = of_get_gpio(np, 0);
+       pdata->ext_pullup_enable_pin = of_get_gpio(np, 1);
+       pdev->dev.platform_data = pdata;
+
+       return 0;
+}
+#else
+static int w1_gpio_probe_dt(struct platform_device *pdev)
+{
+       return 0;
+}
+#endif
+
 static int __init w1_gpio_probe(struct platform_device *pdev)
 {
        struct w1_bus_master *master;
-       struct w1_gpio_platform_data *pdata = pdev->dev.platform_data;
+       struct w1_gpio_platform_data *pdata;
        int err;
 
+       err = w1_gpio_probe_dt(pdev);
+       if (err < 0)
+               return err;
+
+       pdata = pdev->dev.platform_data;
+
        if (!pdata)
                return -ENXIO;
 
@@ -135,6 +180,7 @@ static struct platform_driver w1_gpio_driver = {
        .driver = {
                .name   = "w1-gpio",
                .owner  = THIS_MODULE,
+               .of_match_table = of_match_ptr(w1_gpio_dt_ids),
        },
        .remove = __exit_p(w1_gpio_remove),
        .suspend = w1_gpio_suspend,