Input: rotary-encoder - add DT bindings

This adds devicetree bindings to the rotary encoder driver and some
documentation about how to use them. Tested on a PXA3xx platform.

Signed-off-by: Daniel Mack <zonque@gmail.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

1 files changed, 80 insertions, 16 deletions

diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
index ea51265d4e04..99a49e4968d2 100644
--- a/drivers/input/misc/rotary_encoder.c
+++ b/drivers/input/misc/rotary_encoder.c
@@ -24,6 +24,8 @@
 #include <linux/gpio.h>
 #include <linux/rotary_encoder.h>
 #include <linux/slab.h>
+#include <linux/of_platform.h>
+#include <linux/of_gpio.h>
 
 #define DRV_NAME "rotary-encoder"
 
@@ -140,6 +142,56 @@ static irqreturn_t rotary_encoder_half_period_irq(int irq, void *dev_id)
         return IRQ_HANDLED;
 }
 
+#ifdef CONFIG_OF
+static struct of_device_id rotary_encoder_of_match[] = {
+        { .compatible = "rotary-encoder", },
+        { },
+};
+MODULE_DEVICE_TABLE(of, rotary_encoder_of_match);
+
+static struct rotary_encoder_platform_data * __devinit
+rotary_encoder_parse_dt(struct device *dev)
+{
+        const struct of_device_id *of_id =
+                                of_match_device(rotary_encoder_of_match, dev);
+        struct device_node *np = dev->of_node;
+        struct rotary_encoder_platform_data *pdata;
+        enum of_gpio_flags flags;
+
+        if (!of_id || !np)
+                return NULL;
+
+        pdata = kzalloc(sizeof(struct rotary_encoder_platform_data),
+                        GFP_KERNEL);
+        if (!pdata)
+                return ERR_PTR(-ENOMEM);
+
+        of_property_read_u32(np, "rotary-encoder,steps", &pdata->steps);
+        of_property_read_u32(np, "linux,axis", &pdata->axis);
+
+        pdata->gpio_a = of_get_gpio_flags(np, 0, &flags);
+        pdata->inverted_a = flags & OF_GPIO_ACTIVE_LOW;
+
+        pdata->gpio_b = of_get_gpio_flags(np, 1, &flags);
+        pdata->inverted_b = flags & OF_GPIO_ACTIVE_LOW;
+
+        pdata->relative_axis = !!of_get_property(np,
+                                        "rotary-encoder,relative-axis", NULL);
+        pdata->rollover = !!of_get_property(np,
+                                        "rotary-encoder,rollover", NULL);
+        pdata->half_period = !!of_get_property(np,
+                                        "rotary-encoder,half-period", NULL);
+
+        return pdata;
+}
+#else
+static inline struct rotary_encoder_platform_data *
+rotary_encoder_parse_dt(struct device *dev)
+{
+        return NULL;
+}
+#endif
+
 static int __devinit rotary_encoder_probe(struct platform_device *pdev)
 {
         struct device *dev = &pdev->dev;
@@ -150,14 +202,19 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
         int err;
 
         if (!pdata) {
-                dev_err(&pdev->dev, "missing platform data\n");
-                return -ENOENT;
+                pdata = rotary_encoder_parse_dt(dev);
+                if (IS_ERR(pdata))
+                        return PTR_ERR(pdata);
+
+                if (!pdata) {
+                        dev_err(dev, "missing platform data\n");
+                        return -EINVAL;
+                }
         }
 
         encoder = kzalloc(sizeof(struct rotary_encoder), GFP_KERNEL);
         input = input_allocate_device();
         if (!encoder || !input) {
-                dev_err(&pdev->dev, "failed to allocate memory for device\n");
                 err = -ENOMEM;
                 goto exit_free_mem;
         }
@@ -165,10 +222,9 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
         encoder->input = input;
         encoder->pdata = pdata;
 
-        /* create and register the input driver */
         input->name = pdev->name;
         input->id.bustype = BUS_HOST;
-        input->dev.parent = &pdev->dev;
+        input->dev.parent = dev;
 
         if (pdata->relative_axis) {
                 input->evbit[0] = BIT_MASK(EV_REL);
@@ -179,17 +235,11 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
                                      pdata->axis, 0, pdata->steps, 0, 1);
         }
 
-        err = input_register_device(input);
-        if (err) {
-                dev_err(dev, "failed to register input device\n");
-                goto exit_free_mem;
-        }
-
         /* request the GPIOs */
         err = gpio_request_one(pdata->gpio_a, GPIOF_IN, dev_name(dev));
         if (err) {
                 dev_err(dev, "unable to request GPIO %d\n", pdata->gpio_a);
-                goto exit_unregister_input;
+                goto exit_free_mem;
         }
 
         err = gpio_request_one(pdata->gpio_b, GPIOF_IN, dev_name(dev));
@@ -225,22 +275,30 @@ static int __devinit rotary_encoder_probe(struct platform_device *pdev)
                 goto exit_free_irq_a;
         }
 
+        err = input_register_device(input);
+        if (err) {
+                dev_err(dev, "failed to register input device\n");
+                goto exit_free_irq_b;
+        }
+
         platform_set_drvdata(pdev, encoder);
 
         return 0;
 
+exit_free_irq_b:
+        free_irq(encoder->irq_b, encoder);
 exit_free_irq_a:
         free_irq(encoder->irq_a, encoder);
 exit_free_gpio_b:
         gpio_free(pdata->gpio_b);
 exit_free_gpio_a:
         gpio_free(pdata->gpio_a);
-exit_unregister_input:
-        input_unregister_device(input);
-        input = NULL; /* so we don't try to free it */
 exit_free_mem:
         input_free_device(input);
         kfree(encoder);
+        if (!dev_get_platdata(&pdev->dev))
+                kfree(pdata);
+
         return err;
 }
 
@@ -253,10 +311,15 @@ static int __devexit rotary_encoder_remove(struct platform_device *pdev)
         free_irq(encoder->irq_b, encoder);
         gpio_free(pdata->gpio_a);
         gpio_free(pdata->gpio_b);
+
         input_unregister_device(encoder->input);
-        platform_set_drvdata(pdev, NULL);
         kfree(encoder);
 
+        if (!dev_get_platdata(&pdev->dev))
+                kfree(pdata);
+
+        platform_set_drvdata(pdev, NULL);
+
         return 0;
 }
 
@@ -266,6 +329,7 @@ static struct platform_driver rotary_encoder_driver = {
         .driver         = {
                 .name   = DRV_NAME,
                 .owner  = THIS_MODULE,
+                .of_match_table = of_match_ptr(rotary_encoder_of_match),
         }
 };
 module_platform_driver(rotary_encoder_driver);