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@xxxxxx>
Acked-by: Grant Likely <grant.likely@xxxxxxxxxxxx>
---
.../devicetree/bindings/leds/leds-pwm.txt | 48 +++++++++
drivers/leds/leds-pwm.c | 112 +++++++++++++++++----
2 files changed, 140 insertions(+), 20 deletions(-)
create mode 100644 Documentation/devicetree/bindings/leds/leds-pwm.txt
diff --git a/Documentation/devicetree/bindings/leds/leds-pwm.txt b/Documentation/devicetree/bindings/leds/leds-pwm.txt
new file mode 100644
index 0000000..7297107
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-pwm.txt
@@ -0,0 +1,48 @@
+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>;
+ };
+};
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 @@ static inline size_t sizeof_pwm_leds_priv(int num_leds)
(sizeof(struct led_pwm_data) * num_leds);
}
-static int led_pwm_probe(struct platform_device *pdev)
+static struct led_pwm_priv *led_pwm_create_of(struct platform_device *pdev)
{
- struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
+ struct device_node *node = pdev->dev.of_node;
+ struct device_node *child;
struct led_pwm_priv *priv;
- int i, ret = 0;
+ int count, ret;
- if (!pdata)
- return -EBUSY;
+ /* 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(pdata->num_leds),
+ priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
GFP_KERNEL);
if (!priv)
- return -ENOMEM;
+ return NULL;
- 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_each_child_of_node(node, child) {
+ struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
- led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
+ 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)) {
- ret = PTR_ERR(led_dat->pwm);
dev_err(&pdev->dev, "unable to request PWM for %s\n",
- cur_led->name);
+ 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.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)
+ 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 && pdata->num_leds) {
+ 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];
+
+ 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;
+ }
+ 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 @@ 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),
},
};
--
1.8.0.2
--
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