/* * leds-regulator.c - LED class driver for regulator driven LEDs. * * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it> * * Inspired by leds-wm8350 driver. * * 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/err.h> #include <linux/slab.h> #include <linux/workqueue.h> #include <linux/leds.h> #include <linux/leds-regulator.h> #include <linux/platform_device.h> #include <linux/regulator/consumer.h> #define to_regulator_led(led_cdev) \ container_of(led_cdev, struct regulator_led, cdev) struct regulator_led { struct led_classdev cdev; enum led_brightness value; int enabled; struct mutex mutex; struct work_struct work; struct regulator *vcc; }; static inline int led_regulator_get_max_brightness(struct regulator *supply) { int ret; int voltage = regulator_list_voltage(supply, 0); if (voltage <= 0) return 1; /* even if regulator can't change voltages, * we still assume it can change status * and the LED can be turned on and off. */ ret = regulator_set_voltage(supply, voltage, voltage); if (ret < 0) return 1; return regulator_count_voltages(supply); } static int led_regulator_get_voltage(struct regulator *supply, enum led_brightness brightness) { if (brightness == 0) return -EINVAL; return regulator_list_voltage(supply, brightness - 1); } static void regulator_led_enable(struct regulator_led *led) { int ret; if (led->enabled) return; ret = regulator_enable(led->vcc); if (ret != 0) { dev_err(led->cdev.dev, "Failed to enable vcc: %d\n", ret); return; } led->enabled = 1; } static void regulator_led_disable(struct regulator_led *led) { int ret; if (!led->enabled) return; ret = regulator_disable(led->vcc); if (ret != 0) { dev_err(led->cdev.dev, "Failed to disable vcc: %d\n", ret); return; } led->enabled = 0; } static void regulator_led_set_value(struct regulator_led *led) { int voltage; int ret; mutex_lock(&led->mutex); if (led->value == LED_OFF) { regulator_led_disable(led); goto out; } if (led->cdev.max_brightness > 1) { voltage = led_regulator_get_voltage(led->vcc, led->value); dev_dbg(led->cdev.dev, "brightness: %d voltage: %d\n", led->value, voltage); ret = regulator_set_voltage(led->vcc, voltage, voltage); if (ret != 0) dev_err(led->cdev.dev, "Failed to set voltage %d: %d\n", voltage, ret); } regulator_led_enable(led); out: mutex_unlock(&led->mutex); } static void led_work(struct work_struct *work) { struct regulator_led *led; led = container_of(work, struct regulator_led, work); regulator_led_set_value(led); } static void regulator_led_brightness_set(struct led_classdev *led_cdev, enum led_brightness value) { struct regulator_led *led = to_regulator_led(led_cdev); led->value = value; schedule_work(&led->work); } static int __devinit regulator_led_probe(struct platform_device *pdev) { struct led_regulator_platform_data *pdata = pdev->dev.platform_data; struct regulator_led *led; struct regulator *vcc; int ret = 0; if (pdata == NULL) { dev_err(&pdev->dev, "no platform data\n"); return -ENODEV; } vcc = regulator_get_exclusive(&pdev->dev, "vled"); if (IS_ERR(vcc)) { dev_err(&pdev->dev, "Cannot get vcc for %s\n", pdata->name); return PTR_ERR(vcc); } led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL); if (led == NULL) { ret = -ENOMEM; goto err_vcc; } led->cdev.max_brightness = led_regulator_get_max_brightness(vcc); if (pdata->brightness > led->cdev.max_brightness) { dev_err(&pdev->dev, "Invalid default brightness %d\n", pdata->brightness); ret = -EINVAL; goto err_vcc; } led->value = pdata->brightness; led->cdev.brightness_set = regulator_led_brightness_set; led->cdev.name = pdata->name; led->cdev.flags |= LED_CORE_SUSPENDRESUME; led->vcc = vcc; /* to handle correctly an already enabled regulator */ if (regulator_is_enabled(led->vcc)) led->enabled = 1; mutex_init(&led->mutex); INIT_WORK(&led->work, led_work); platform_set_drvdata(pdev, led); ret = led_classdev_register(&pdev->dev, &led->cdev); if (ret < 0) { cancel_work_sync(&led->work); goto err_vcc; } /* to expose the default value to userspace */ led->cdev.brightness = led->value; /* Set the default led status */ regulator_led_set_value(led); return 0; err_vcc: regulator_put(vcc); return ret; } static int __devexit regulator_led_remove(struct platform_device *pdev) { struct regulator_led *led = platform_get_drvdata(pdev); led_classdev_unregister(&led->cdev); cancel_work_sync(&led->work); regulator_led_disable(led); regulator_put(led->vcc); return 0; } static struct platform_driver regulator_led_driver = { .driver = { .name = "leds-regulator", .owner = THIS_MODULE, }, .probe = regulator_led_probe, .remove = __devexit_p(regulator_led_remove), }; module_platform_driver(regulator_led_driver); MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); MODULE_DESCRIPTION("Regulator driven LED driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:leds-regulator");