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    Subject[PATCH v3 4/4] leds: leds-pwm: Add device tree bindings
    Date
    Support for device tree booted kernel.

    For usage see:
    Documentation/devicetree/bindings/leds/leds-pwm.txt

    Signed-off-by: Peter Ujfalusi <peter.ujfalusi@ti.com>
    ---
    .../devicetree/bindings/leds/leds-pwm.txt | 46 ++++++++
    drivers/leds/leds-pwm.c | 124 +++++++++++++++++----
    2 files changed, 149 insertions(+), 21 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..abdff60
    --- /dev/null
    +++ b/Documentation/devicetree/bindings/leds/leds-pwm.txt
    @@ -0,0 +1,46 @@
    +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, please refer to:
    + Documentation/devicetree/bindings/pwm/pwm.txt
    +- pwm-names : (optional) Name to be used by the PWM subsystem for the PWM device
    +- 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 02f0c0c..a57ac27 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 +59,115 @@ static inline int 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_each_child_of_node(node, child) {
    + struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];

    - 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->cdev.name = of_get_property(child, "label",
    + NULL) ? : child->name;

    - led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
    + led_dat->pwm = of_pwm_request(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);
    + pwm_put(led_dat->pwm);
    goto err;
    + }
    + priv->num_leds++;
    + }
    +
    + return priv;
    +err:
    + if (priv->num_leds > 0) {
    + for (count = priv->num_leds - 1; count >= 0; count--) {
    + led_classdev_unregister(&priv->leds[count].cdev);
    + pwm_put(priv->leds[count].pwm);
    + }
    + }
    +
    + 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);

    @@ -114,21 +184,33 @@ err:

    static int led_pwm_remove(struct platform_device *pdev)
    {
    + struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
    struct led_pwm_priv *priv = platform_get_drvdata(pdev);
    int i;

    - for (i = 0; i < priv->num_leds; i++)
    + for (i = 0; i < priv->num_leds; i++) {
    led_classdev_unregister(&priv->leds[i].cdev);
    + if (!pdata)
    + pwm_put(priv->leds[i].pwm);
    + }

    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


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