[PATCH v2 3/3] leds: leds-pwm: Add device tree bindings
Peter Ujfalusi
peter.ujfalusi at ti.com
Tue Nov 13 01:41:10 EST 2012
Support for device tree booted kernel.
When the kernel is booted with DeviceTree blob we support one led per
leds-pwm device to have cleaner integration with the PWM subsystem.
For usage see:
Documentation/devicetree/bindings/leds/leds-pwm.txt
Signed-off-by: Peter Ujfalusi <peter.ujfalusi at ti.com>
---
.../devicetree/bindings/leds/leds-pwm.txt | 34 ++++++
drivers/leds/leds-pwm.c | 125 +++++++++++++++------
2 files changed, 127 insertions(+), 32 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..9fe3040
--- /dev/null
+++ b/Documentation/devicetree/bindings/leds/leds-pwm.txt
@@ -0,0 +1,34 @@
+LED connected to PWM
+
+Required properties:
+- compatible : should be "pwm-leds".
+- pwms : PWM property, please refer to:
+ Documentation/devicetree/bindings/pwm/pwm.txt
+- pwm-names : (optional) Name to be used by the PWM subsystem for the PWM device
+- label : (optional) The label for this LED. If omitted, the label is
+ taken from the node name (excluding the unit address).
+- max-brightness : Maximum brightness possible for the LED
+- linux,default-trigger : (optional) This parameter, if present, is a
+ string defining the trigger assigned to the LED. Current triggers are:
+ "backlight" - LED will act as a back-light, controlled by the framebuffer
+ system
+ "default-on" - LED will turn on, but see "default-state" below
+ "heartbeat" - LED "double" flashes at a load average based rate
+ "ide-disk" - LED indicates disk activity
+ "timer" - LED flashes at a fixed, configurable rate
+
+Example:
+
+twl_pwm: pwm {
+ compatible = "ti,twl6030-pwm";
+ #pwm-cells = <2>;
+};
+
+pwmled_keypad {
+ compatible = "pwm-leds";
+ pwms = <&twl_pwm 0 7812500>;
+ pwm-names = "Keypad LED";
+
+ label = "omap4::keypad";
+ max-brightness = <127>;
+};
diff --git a/drivers/leds/leds-pwm.c b/drivers/leds/leds-pwm.c
index b219ea9..333c942 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 +59,98 @@ static inline int 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 led_pwm_priv *priv;
+ struct led_pwm_data *led_dat;
+ int ret;
+
+ /* With DT boot we support one LED per leds-pwm device */
+ priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(1),
+ GFP_KERNEL);
+ if (!priv)
+ return NULL;
+
+ led_dat = &priv->leds[priv->num_leds];
+ led_dat->cdev.name = of_get_property(node, "label", NULL) ? : node->name;
+ led_dat->pwm = devm_pwm_get(&pdev->dev, NULL);
+ if (IS_ERR(led_dat->pwm)) {
+ dev_err(&pdev->dev, "unable to request PWM for %s\n",
+ led_dat->cdev.name);
+ return NULL;
+ }
+ /* 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(node,
+ "linux,default-trigger",
+ NULL);
+ of_property_read_u32(node, "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(node);
+ return NULL;
+ }
+
+ priv->num_leds = 1;
+
+ return priv;
+}
+
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),
- 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;
+ 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;
}
-
- 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);
@@ -123,12 +176,20 @@ static int __devexit 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 = __devexit_p(led_pwm_remove),
.driver = {
.name = "leds_pwm",
.owner = THIS_MODULE,
+ .of_match_table = of_match_ptr(of_pwm_leds_match),
},
};
--
1.8.0
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