Commit 08541cbc authored by Peter Ujfalusi's avatar Peter Ujfalusi Committed by Bryan Wu

leds: leds-pwm: Add device tree bindings

The DT binding for the pwm-leds devices are similar to the gpio-leds type.
LEDs are represented as sub-nodes of the pwm-leds device.
The code for handling the DT boot is based on the code found in the
leds-gpio driver and adapted to use PWMs instead of GPIOs.
To avoid having custom cleanup code in case of DT boot the newly created
devm_of_pwm_get() API is used to get the correct PWM instance.

For usage see:
Documentation/devicetree/bindings/leds/leds-pwm.txt
Signed-off-by: default avatarPeter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: default avatarGrant Likely <grant.likely@secretlab.ca>
Signed-off-by: default avatarBryan Wu <cooloney@gmail.com>
parent 8a66a579
LED connected to PWM
Required properties:
- compatible : should be "pwm-leds".
Each LED is represented as a sub-node of the pwm-leds device. Each
node's name represents the name of the corresponding LED.
LED sub-node properties:
- pwms : PWM property to point to the PWM device (phandle)/port (id) and to
specify the period time to be used: <&phandle id period_ns>;
- pwm-names : (optional) Name to be used by the PWM subsystem for the PWM device
For the pwms and pwm-names property please refer to:
Documentation/devicetree/bindings/pwm/pwm.txt
- max-brightness : Maximum brightness possible for the LED
- label : (optional)
see Documentation/devicetree/bindings/leds/common.txt
- linux,default-trigger : (optional)
see Documentation/devicetree/bindings/leds/common.txt
Example:
twl_pwm: pwm {
/* provides two PWMs (id 0, 1 for PWM1 and PWM2) */
compatible = "ti,twl6030-pwm";
#pwm-cells = <2>;
};
twl_pwmled: pwmled {
/* provides one PWM (id 0 for Charing indicator LED) */
compatible = "ti,twl6030-pwmled";
#pwm-cells = <2>;
};
pwmleds {
compatible = "pwm-leds";
kpad {
label = "omap4::keypad";
pwms = <&twl_pwm 0 7812500>;
max-brightness = <127>;
};
charging {
label = "omap4:green:chrg";
pwms = <&twl_pwmled 0 7812500>;
max-brightness = <255>;
};
};
......@@ -16,6 +16,7 @@
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/of_platform.h>
#include <linux/fb.h>
#include <linux/leds.h>
#include <linux/err.h>
......@@ -58,16 +59,74 @@ static inline size_t sizeof_pwm_leds_priv(int num_leds)
(sizeof(struct led_pwm_data) * num_leds);
}
static struct led_pwm_priv *led_pwm_create_of(struct platform_device *pdev)
{
struct device_node *node = pdev->dev.of_node;
struct device_node *child;
struct led_pwm_priv *priv;
int count, ret;
/* count LEDs in this device, so we know how much to allocate */
count = of_get_child_count(node);
if (!count)
return NULL;
priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
GFP_KERNEL);
if (!priv)
return NULL;
for_each_child_of_node(node, child) {
struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
led_dat->cdev.name = of_get_property(child, "label",
NULL) ? : child->name;
led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
if (IS_ERR(led_dat->pwm)) {
dev_err(&pdev->dev, "unable to request PWM for %s\n",
led_dat->cdev.name);
goto err;
}
/* Get the period from PWM core when n*/
led_dat->period = pwm_get_period(led_dat->pwm);
led_dat->cdev.default_trigger = of_get_property(child,
"linux,default-trigger", NULL);
of_property_read_u32(child, "max-brightness",
&led_dat->cdev.max_brightness);
led_dat->cdev.brightness_set = led_pwm_set;
led_dat->cdev.brightness = LED_OFF;
led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
if (ret < 0) {
dev_err(&pdev->dev, "failed to register for %s\n",
led_dat->cdev.name);
of_node_put(child);
goto err;
}
priv->num_leds++;
}
return priv;
err:
while (priv->num_leds--)
led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
return NULL;
}
static int led_pwm_probe(struct platform_device *pdev)
{
struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
struct led_pwm_priv *priv;
int i, ret = 0;
if (!pdata)
return -EBUSY;
priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(pdata->num_leds),
if (pdata && pdata->num_leds) {
priv = devm_kzalloc(&pdev->dev,
sizeof_pwm_leds_priv(pdata->num_leds),
GFP_KERNEL);
if (!priv)
return -ENOMEM;
......@@ -79,7 +138,8 @@ static int led_pwm_probe(struct platform_device *pdev)
led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
if (IS_ERR(led_dat->pwm)) {
ret = PTR_ERR(led_dat->pwm);
dev_err(&pdev->dev, "unable to request PWM for %s\n",
dev_err(&pdev->dev,
"unable to request PWM for %s\n",
cur_led->name);
goto err;
}
......@@ -98,6 +158,11 @@ static int led_pwm_probe(struct platform_device *pdev)
goto err;
}
priv->num_leds = pdata->num_leds;
} else {
priv = led_pwm_create_of(pdev);
if (!priv)
return -ENODEV;
}
platform_set_drvdata(pdev, priv);
......@@ -121,12 +186,19 @@ static int led_pwm_remove(struct platform_device *pdev)
return 0;
}
static const struct of_device_id of_pwm_leds_match[] = {
{ .compatible = "pwm-leds", },
{},
};
MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
static struct platform_driver led_pwm_driver = {
.probe = led_pwm_probe,
.remove = led_pwm_remove,
.driver = {
.name = "leds_pwm",
.owner = THIS_MODULE,
.of_match_table = of_match_ptr(of_pwm_leds_match),
},
};
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment