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>

diff --git a/Documentation/devicetree/bindings/input/rotary-encoder.txt b/Documentation/devicetree/bindings/input/rotary-encoder.txt
new file mode 100644 (file)
index 0000000..3315495
--- /dev/null
+++ b/Documentation/devicetree/bindings/input/rotary-encoder.txt
@@ -0,0 +1,36 @@
+Rotary encoder DT bindings
+
+Required properties:
+- gpios: a spec for two GPIOs to be used
+
+Optional properties:
+- linux,axis: the input subsystem axis to map to this rotary encoder.
+  Defaults to 0 (ABS_X / REL_X)
+- rotary-encoder,steps: Number of steps in a full turnaround of the
+  encoder. Only relevant for absolute axis. Defaults to 24 which is a
+  typical value for such devices.
+- rotary-encoder,relative-axis: register a relative axis rather than an
+  absolute one. Relative axis will only generate +1/-1 events on the input
+  device, hence no steps need to be passed.
+- rotary-encoder,rollover: Automatic rollove when the rotary value becomes
+  greater than the specified steps or smaller than 0. For absolute axis only.
+- rotary-encoder,half-period: Makes the driver work on half-period mode.
+
+See Documentation/input/rotary-encoder.txt for more information.
+
+Example:
+
+               rotary@0 {
+                       compatible = "rotary-encoder";
+                       gpios = <&gpio 19 1>, <&gpio 20 0>; /* GPIO19 is inverted */
+                       linux,axis = <0>; /* REL_X */
+                       rotary-encoder,relative-axis;
+               };
+
+               rotary@1 {
+                       compatible = "rotary-encoder";
+                       gpios = <&gpio 21 0>, <&gpio 22 0>;
+                       linux,axis = <1>; /* ABS_Y */
+                       rotary-encoder,steps = <24>;
+                       rotary-encoder,rollover;
+               };

diff --git a/drivers/input/misc/rotary_encoder.c b/drivers/input/misc/rotary_encoder.c
index ea51265..99a49e4 100644 (file)
--- 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);