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>hifive-unleashed-5.1
Peter Ujfalusi
Bryan Wu
parent
8a66a57908
commit
08541cbcc7
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@ -0,0 +1,48 @@
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LED connected to PWM
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Required properties:
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- compatible : should be "pwm-leds".
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Each LED is represented as a sub-node of the pwm-leds device. Each
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node's name represents the name of the corresponding LED.
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LED sub-node properties:
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- pwms : PWM property to point to the PWM device (phandle)/port (id) and to
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specify the period time to be used: <&phandle id period_ns>;
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- pwm-names : (optional) Name to be used by the PWM subsystem for the PWM device
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For the pwms and pwm-names property please refer to:
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Documentation/devicetree/bindings/pwm/pwm.txt
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- max-brightness : Maximum brightness possible for the LED
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- label : (optional)
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see Documentation/devicetree/bindings/leds/common.txt
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- linux,default-trigger : (optional)
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see Documentation/devicetree/bindings/leds/common.txt
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Example:
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twl_pwm: pwm {
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/* provides two PWMs (id 0, 1 for PWM1 and PWM2) */
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compatible = "ti,twl6030-pwm";
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#pwm-cells = <2>;
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};
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twl_pwmled: pwmled {
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/* provides one PWM (id 0 for Charing indicator LED) */
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compatible = "ti,twl6030-pwmled";
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#pwm-cells = <2>;
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};
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pwmleds {
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compatible = "pwm-leds";
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kpad {
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label = "omap4::keypad";
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pwms = <&twl_pwm 0 7812500>;
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max-brightness = <127>;
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};
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charging {
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label = "omap4:green:chrg";
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pwms = <&twl_pwmled 0 7812500>;
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max-brightness = <255>;
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};
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};
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@ -16,6 +16,7 @@
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/of_platform.h>
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#include <linux/fb.h>
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#include <linux/leds.h>
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#include <linux/err.h>
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@ -58,46 +59,110 @@ static inline size_t sizeof_pwm_leds_priv(int num_leds)
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(sizeof(struct led_pwm_data) * num_leds);
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}
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static struct led_pwm_priv *led_pwm_create_of(struct platform_device *pdev)
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{
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struct device_node *node = pdev->dev.of_node;
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struct device_node *child;
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struct led_pwm_priv *priv;
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int count, ret;
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/* count LEDs in this device, so we know how much to allocate */
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count = of_get_child_count(node);
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if (!count)
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return NULL;
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priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
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GFP_KERNEL);
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if (!priv)
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return NULL;
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for_each_child_of_node(node, child) {
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struct led_pwm_data *led_dat = &priv->leds[priv->num_leds];
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led_dat->cdev.name = of_get_property(child, "label",
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NULL) ? : child->name;
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led_dat->pwm = devm_of_pwm_get(&pdev->dev, child, NULL);
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if (IS_ERR(led_dat->pwm)) {
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dev_err(&pdev->dev, "unable to request PWM for %s\n",
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led_dat->cdev.name);
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goto err;
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}
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/* Get the period from PWM core when n*/
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led_dat->period = pwm_get_period(led_dat->pwm);
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led_dat->cdev.default_trigger = of_get_property(child,
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"linux,default-trigger", NULL);
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of_property_read_u32(child, "max-brightness",
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&led_dat->cdev.max_brightness);
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led_dat->cdev.brightness_set = led_pwm_set;
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led_dat->cdev.brightness = LED_OFF;
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led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
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ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
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if (ret < 0) {
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dev_err(&pdev->dev, "failed to register for %s\n",
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led_dat->cdev.name);
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of_node_put(child);
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goto err;
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}
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priv->num_leds++;
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}
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return priv;
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err:
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while (priv->num_leds--)
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led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
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return NULL;
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}
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static int led_pwm_probe(struct platform_device *pdev)
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{
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struct led_pwm_platform_data *pdata = pdev->dev.platform_data;
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struct led_pwm_priv *priv;
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int i, ret = 0;
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if (!pdata)
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return -EBUSY;
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if (pdata && pdata->num_leds) {
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priv = devm_kzalloc(&pdev->dev,
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sizeof_pwm_leds_priv(pdata->num_leds),
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GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(pdata->num_leds),
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GFP_KERNEL);
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if (!priv)
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return -ENOMEM;
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for (i = 0; i < pdata->num_leds; i++) {
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struct led_pwm *cur_led = &pdata->leds[i];
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struct led_pwm_data *led_dat = &priv->leds[i];
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for (i = 0; i < pdata->num_leds; i++) {
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struct led_pwm *cur_led = &pdata->leds[i];
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struct led_pwm_data *led_dat = &priv->leds[i];
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led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
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if (IS_ERR(led_dat->pwm)) {
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ret = PTR_ERR(led_dat->pwm);
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dev_err(&pdev->dev,
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"unable to request PWM for %s\n",
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cur_led->name);
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goto err;
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}
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led_dat->pwm = devm_pwm_get(&pdev->dev, cur_led->name);
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if (IS_ERR(led_dat->pwm)) {
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ret = PTR_ERR(led_dat->pwm);
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dev_err(&pdev->dev, "unable to request PWM for %s\n",
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cur_led->name);
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goto err;
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led_dat->cdev.name = cur_led->name;
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led_dat->cdev.default_trigger = cur_led->default_trigger;
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led_dat->active_low = cur_led->active_low;
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led_dat->period = cur_led->pwm_period_ns;
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led_dat->cdev.brightness_set = led_pwm_set;
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led_dat->cdev.brightness = LED_OFF;
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led_dat->cdev.max_brightness = cur_led->max_brightness;
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led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
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ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
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if (ret < 0)
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goto err;
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}
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led_dat->cdev.name = cur_led->name;
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led_dat->cdev.default_trigger = cur_led->default_trigger;
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led_dat->active_low = cur_led->active_low;
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led_dat->period = cur_led->pwm_period_ns;
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led_dat->cdev.brightness_set = led_pwm_set;
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led_dat->cdev.brightness = LED_OFF;
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led_dat->cdev.max_brightness = cur_led->max_brightness;
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led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME;
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ret = led_classdev_register(&pdev->dev, &led_dat->cdev);
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if (ret < 0)
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goto err;
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priv->num_leds = pdata->num_leds;
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} else {
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priv = led_pwm_create_of(pdev);
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if (!priv)
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return -ENODEV;
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}
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priv->num_leds = pdata->num_leds;
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platform_set_drvdata(pdev, priv);
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@ -121,12 +186,19 @@ static int led_pwm_remove(struct platform_device *pdev)
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return 0;
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}
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static const struct of_device_id of_pwm_leds_match[] = {
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{ .compatible = "pwm-leds", },
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{},
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};
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MODULE_DEVICE_TABLE(of, of_pwm_leds_match);
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static struct platform_driver led_pwm_driver = {
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.probe = led_pwm_probe,
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.remove = led_pwm_remove,
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.driver = {
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.name = "leds_pwm",
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.owner = THIS_MODULE,
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.of_match_table = of_match_ptr(of_pwm_leds_match),
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},
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};
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