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: Peter Ujfalusi <peter.ujfalusi@ti.com>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Signed-off-by: Bryan Wu <cooloney@gmail.com>
diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
index 46f4e44..a1ea5f6 100644
--- a/drivers/leds/leds-pwm.c
+++ b/drivers/leds/leds-pwm.c
@@ -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>
@@ -58,46 +59,110 @@
(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;
+ if (pdata && pdata->num_leds) {
+ priv = devm_kzalloc(&pdev->dev,
+ sizeof_pwm_leds_priv(pdata->num_leds),
+ GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
- priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(pdata->num_leds),
- GFP_KERNEL);
- if (!priv)
- return -ENOMEM;
+ for (i = 0; i < pdata->num_leds; i++) {
+ struct led_pwm *cur_led = &pdata->leds[i];
+ struct led_pwm_data *led_dat = &priv->leds[i];
- for (i = 0; i < pdata->num_leds; i++) {
- struct led_pwm *cur_led = &pdata->leds[i];
- struct led_pwm_data *led_dat = &priv->leds[i];
+ 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",
+ cur_led->name);
+ goto err;
+ }
- 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",
- cur_led->name);
- goto err;
+ led_dat->cdev.name = cur_led->name;
+ led_dat->cdev.default_trigger = cur_led->default_trigger;
+ led_dat->active_low = cur_led->active_low;
+ led_dat->period = cur_led->pwm_period_ns;
+ led_dat->cdev.brightness_set = led_pwm_set;
+ led_dat->cdev.brightness = LED_OFF;
+ led_dat->cdev.max_brightness = cur_led->max_brightness;
+ led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
+
+ ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
+ if (ret < 0)
+ goto err;
}
-
- led_dat->cdev.name = cur_led->name;
- led_dat->cdev.default_trigger = cur_led->default_trigger;
- led_dat->active_low = cur_led->active_low;
- led_dat->period = cur_led->pwm_period_ns;
- led_dat->cdev.brightness_set = led_pwm_set;
- led_dat->cdev.brightness = LED_OFF;
- led_dat->cdev.max_brightness = cur_led->max_brightness;
- led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
-
- ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
- if (ret < 0)
- goto err;
+ priv->num_leds = pdata->num_leds;
+ } else {
+ priv = led_pwm_create_of(pdev);
+ if (!priv)
+ return -ENODEV;
}
- priv->num_leds = pdata->num_leds;
platform_set_drvdata(pdev, priv);
@@ -121,12 +186,19 @@
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),
},
};