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r: 328512
b: refs/heads/master
c: 80c99bc
h: refs/heads/master
v: v3
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Daniel Mack authored and Dmitry Torokhov committed Aug 22, 2012
1 parent 8ddfb18 commit 370067c
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Showing 3 changed files with 117 additions and 17 deletions.
2 changes: 1 addition & 1 deletion [refs]
Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: ce9195378299ff2f3d703937de46bdd338e780eb
refs/heads/master: 80c99bcd28617bd534b6f9489857235ee613c797
36 changes: 36 additions & 0 deletions trunk/Documentation/devicetree/bindings/input/rotary-encoder.txt
Original file line number Diff line number Diff line change
@@ -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;
};
96 changes: 80 additions & 16 deletions trunk/drivers/input/misc/rotary_encoder.c
Original file line number Diff line number Diff line change
Expand Up @@ -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"

Expand Down Expand Up @@ -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;
Expand All @@ -150,25 +202,29 @@ 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;
}

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);
Expand All @@ -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));
Expand Down Expand Up @@ -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;
}

Expand All @@ -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;
}

Expand All @@ -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);
Expand Down

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