Commit 80c99bcd authored by Daniel Mack's avatar Daniel Mack Committed by Dmitry Torokhov

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: default avatarDaniel Mack <zonque@gmail.com>
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent ce919537
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;
};
......@@ -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);
......
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