/* * 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/init.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 int period = led_dat->period; led_dat->duty = brightness * period / max; 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 struct led_pwm_priv *led_pwm_create_of(struct platform_device *pdev) { struct device_node *node = pdev->dev.of_node; struct device_node *child; struct led_pwm_priv *priv; int count, ret; /* 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(count), GFP_KERNEL); if (!priv) return NULL; for_each_child_of_node(node, child) { struct led_pwm_data *led_dat = &priv->leds[priv->num_leds]; 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)) { dev_err(&pdev->dev, "unable to request PWM for %s\n", 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.brightness_set = led_pwm_set; led_dat->cdev.brightness = LED_OFF; led_dat->cdev.flags |= LED_CORE_SUSPENDRESUME; led_dat->can_sleep = pwm_can_sleep(led_dat->pwm); if (led_dat->can_sleep) INIT_WORK(&led_dat->work, led_pwm_work); 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(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; led_dat->can_sleep = pwm_can_sleep(led_dat->pwm); if (led_dat->can_sleep) INIT_WORK(&led_dat->work, led_pwm_work); 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; } platform_set_drvdata(pdev, priv); return 0; err: while (i--) led_classdev_unregister(&priv->leds[i].cdev); return ret; } static int led_pwm_remove(struct platform_device *pdev) { struct led_pwm_priv *priv = platform_get_drvdata(pdev); int i; for (i = 0; i < priv->num_leds; i++) { led_classdev_unregister(&priv->leds[i].cdev); if (priv->leds[i].can_sleep) cancel_work_sync(&priv->leds[i].work); } 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), }, }; 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");