--- /dev/null
+/*
+ * linux/drivers/leds-pwm.c
+ *
+ * simple PWM based LED control
+ *
+ * Copyright 2009 Luotao Fu @ Pengutronix (l.fu@pengutronix.de)
+ *
+ * based on leds-gpio.c by Raphael Assenat <raph@8d.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/of_platform.h>
+#include <linux/fb.h>
+#include <linux/leds.h>
+#include <linux/err.h>
+#include <linux/pwm.h>
+#include <linux/leds_pwm.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+struct led_pwm_data {
+ struct led_classdev cdev;
+ struct pwm_device *pwm;
+ struct work_struct work;
+ unsigned int active_low;
+ unsigned int period;
+ int duty;
+ bool can_sleep;
+};
+
+struct led_pwm_priv {
+ int num_leds;
+ struct led_pwm_data leds[0];
+};
+
+static void __led_pwm_set(struct led_pwm_data *led_dat)
+{
+ int new_duty = led_dat->duty;
+
+ pwm_config(led_dat->pwm, new_duty, led_dat->period);
+
+ if (new_duty == 0)
+ pwm_disable(led_dat->pwm);
+ else
+ pwm_enable(led_dat->pwm);
+}
+
+static void led_pwm_work(struct work_struct *work)
+{
+ struct led_pwm_data *led_dat =
+ container_of(work, struct led_pwm_data, work);
+
+ __led_pwm_set(led_dat);
+}
+
+static void led_pwm_set(struct led_classdev *led_cdev,
+ enum led_brightness brightness)
+{
+ struct led_pwm_data *led_dat =
+ container_of(led_cdev, struct led_pwm_data, cdev);
+ unsigned int max = led_dat->cdev.max_brightness;
+ unsigned long long duty = led_dat->period;
+
+ duty *= brightness;
+ do_div(duty, max);
+
+ if (led_dat->active_low)
+ duty = led_dat->period - duty;
+
+ led_dat->duty = duty;
+
+ if (led_dat->can_sleep)
+ schedule_work(&led_dat->work);
+ else
+ __led_pwm_set(led_dat);
+}
+
+static inline size_t sizeof_pwm_leds_priv(int num_leds)
+{
+ return sizeof(struct led_pwm_priv) +
+ (sizeof(struct led_pwm_data) * num_leds);
+}
+
+static void led_pwm_cleanup(struct led_pwm_priv *priv)
+{
+ while (priv->num_leds--) {
+ led_classdev_unregister(&priv->leds[priv->num_leds].cdev);
+ if (priv->leds[priv->num_leds].can_sleep)
+ cancel_work_sync(&priv->leds[priv->num_leds].work);
+ }
+}
+
+static int led_pwm_add(struct device *dev, struct led_pwm_priv *priv,
+ struct led_pwm *led, struct device_node *child)
+{
+ struct led_pwm_data *led_data = &priv->leds[priv->num_leds];
+ int ret;
+
+ led_data->active_low = led->active_low;
+ led_data->cdev.name = led->name;
+ led_data->cdev.default_trigger = led->default_trigger;
+ led_data->cdev.brightness_set = led_pwm_set;
+ led_data->cdev.brightness = LED_OFF;
+ led_data->cdev.max_brightness = led->max_brightness;
+ led_data->cdev.flags = LED_CORE_SUSPENDRESUME;
+
+ if (child)
+ led_data->pwm = devm_of_pwm_get(dev, child, NULL);
+ else
+ led_data->pwm = devm_pwm_get(dev, led->name);
+ if (IS_ERR(led_data->pwm)) {
+ ret = PTR_ERR(led_data->pwm);
+ dev_err(dev, "unable to request PWM for %s: %d\n",
+ led->name, ret);
+ return ret;
+ }
+
+ led_data->can_sleep = pwm_can_sleep(led_data->pwm);
+ if (led_data->can_sleep)
+ INIT_WORK(&led_data->work, led_pwm_work);
+
+ led_data->period = pwm_get_period(led_data->pwm);
+ if (!led_data->period && (led->pwm_period_ns > 0))
+ led_data->period = led->pwm_period_ns;
+
+ ret = led_classdev_register(dev, &led_data->cdev);
+ if (ret == 0) {
+ priv->num_leds++;
+ } else {
+ dev_err(dev, "failed to register PWM led for %s: %d\n",
+ led->name, ret);
+ }
+
+ return ret;
+}
+
+static int led_pwm_create_of(struct device *dev, struct led_pwm_priv *priv)
+{
+ struct device_node *child;
+ struct led_pwm led;
+ int ret = 0;
+
+ memset(&led, 0, sizeof(led));
+
+ for_each_child_of_node(dev->of_node, child) {
+ led.name = of_get_property(child, "label", NULL) ? :
+ child->name;
+
+ led.default_trigger = of_get_property(child,
+ "linux,default-trigger", NULL);
+ led.active_low = of_property_read_bool(child, "active-low");
+ of_property_read_u32(child, "max-brightness",
+ &led.max_brightness);
+
+ ret = led_pwm_add(dev, priv, &led, child);
+ if (ret) {
+ of_node_put(child);
+ break;
+ }
+ }
+
+ return ret;
+}
+
+static int led_pwm_probe(struct platform_device *pdev)
+{
+ struct led_pwm_platform_data *pdata = dev_get_platdata(&pdev->dev);
+ struct led_pwm_priv *priv;
+ int count, i;
+ int ret = 0;
+
+ if (pdata)
+ count = pdata->num_leds;
+ else
+ count = of_get_child_count(pdev->dev.of_node);
+
+ if (!count)
+ return -EINVAL;
+
+ priv = devm_kzalloc(&pdev->dev, sizeof_pwm_leds_priv(count),
+ GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+
+ if (pdata) {
+ for (i = 0; i < count; i++) {
+ ret = led_pwm_add(&pdev->dev, priv, &pdata->leds[i],
+ NULL);
+ if (ret)
+ break;
+ }
+ } else {
+ ret = led_pwm_create_of(&pdev->dev, priv);
+ }
+
+ if (ret) {
+ led_pwm_cleanup(priv);
+ return ret;
+ }
+
+ platform_set_drvdata(pdev, priv);
+
+ return 0;
+}
+
+static int led_pwm_remove(struct platform_device *pdev)
+{
+ struct led_pwm_priv *priv = platform_get_drvdata(pdev);
+
+ led_pwm_cleanup(priv);
+
+ 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",
+ .of_match_table = of_pwm_leds_match,
+ },
+};
+
+module_platform_driver(led_pwm_driver);
+
+MODULE_AUTHOR("Luotao Fu <l.fu@pengutronix.de>");
+MODULE_DESCRIPTION("PWM LED driver for PXA");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:leds-pwm");
Code Review / kvmfornfv.git / blobdiff