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/Documentation/devicetree/bindings/leds/leds-pwm.txt b/Documentation/devicetree/bindings/leds/leds-pwm.txt
new file mode 100644 (file)
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 46f4e44c6c6d3b2e445622c98cca2bed25f8f57f..a1ea5f6a8d39c6c948f6545e48d1aee82b4130f3 100644 (file)
--- 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),
        },
 };