1/* 2 * leds-regulator.c - LED class driver for regulator driven LEDs. 3 * 4 * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it> 5 * 6 * Inspired by leds-wm8350 driver. 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 * 12 */ 13 14#include <linux/module.h> 15#include <linux/err.h> 16#include <linux/slab.h> 17#include <linux/workqueue.h> 18#include <linux/leds.h> 19#include <linux/leds-regulator.h> 20#include <linux/platform_device.h> 21#include <linux/regulator/consumer.h> 22 23#define to_regulator_led(led_cdev) \ 24 container_of(led_cdev, struct regulator_led, cdev) 25 26struct regulator_led { 27 struct led_classdev cdev; 28 enum led_brightness value; 29 int enabled; 30 struct mutex mutex; 31 struct work_struct work; 32 33 struct regulator *vcc; 34}; 35 36static inline int led_regulator_get_max_brightness(struct regulator *supply) 37{ 38 int ret; 39 int voltage = regulator_list_voltage(supply, 0); 40 41 if (voltage <= 0) 42 return 1; 43 44 /* even if regulator can't change voltages, 45 * we still assume it can change status 46 * and the LED can be turned on and off. 47 */ 48 ret = regulator_set_voltage(supply, voltage, voltage); 49 if (ret < 0) 50 return 1; 51 52 return regulator_count_voltages(supply); 53} 54 55static int led_regulator_get_voltage(struct regulator *supply, 56 enum led_brightness brightness) 57{ 58 if (brightness == 0) 59 return -EINVAL; 60 61 return regulator_list_voltage(supply, brightness - 1); 62} 63 64 65static void regulator_led_enable(struct regulator_led *led) 66{ 67 int ret; 68 69 if (led->enabled) 70 return; 71 72 ret = regulator_enable(led->vcc); 73 if (ret != 0) { 74 dev_err(led->cdev.dev, "Failed to enable vcc: %d\n", ret); 75 return; 76 } 77 78 led->enabled = 1; 79} 80 81static void regulator_led_disable(struct regulator_led *led) 82{ 83 int ret; 84 85 if (!led->enabled) 86 return; 87 88 ret = regulator_disable(led->vcc); 89 if (ret != 0) { 90 dev_err(led->cdev.dev, "Failed to disable vcc: %d\n", ret); 91 return; 92 } 93 94 led->enabled = 0; 95} 96 97static void regulator_led_set_value(struct regulator_led *led) 98{ 99 int voltage; 100 int ret; 101 102 mutex_lock(&led->mutex); 103 104 if (led->value == LED_OFF) { 105 regulator_led_disable(led); 106 goto out; 107 } 108 109 if (led->cdev.max_brightness > 1) { 110 voltage = led_regulator_get_voltage(led->vcc, led->value); 111 dev_dbg(led->cdev.dev, "brightness: %d voltage: %d\n", 112 led->value, voltage); 113 114 ret = regulator_set_voltage(led->vcc, voltage, voltage); 115 if (ret != 0) 116 dev_err(led->cdev.dev, "Failed to set voltage %d: %d\n", 117 voltage, ret); 118 } 119 120 regulator_led_enable(led); 121 122out: 123 mutex_unlock(&led->mutex); 124} 125 126static void led_work(struct work_struct *work) 127{ 128 struct regulator_led *led; 129 130 led = container_of(work, struct regulator_led, work); 131 regulator_led_set_value(led); 132} 133 134static void regulator_led_brightness_set(struct led_classdev *led_cdev, 135 enum led_brightness value) 136{ 137 struct regulator_led *led = to_regulator_led(led_cdev); 138 139 led->value = value; 140 schedule_work(&led->work); 141} 142 143static int __devinit regulator_led_probe(struct platform_device *pdev) 144{ 145 struct led_regulator_platform_data *pdata = pdev->dev.platform_data; 146 struct regulator_led *led; 147 struct regulator *vcc; 148 int ret = 0; 149 150 if (pdata == NULL) { 151 dev_err(&pdev->dev, "no platform data\n"); 152 return -ENODEV; 153 } 154 155 vcc = regulator_get_exclusive(&pdev->dev, "vled"); 156 if (IS_ERR(vcc)) { 157 dev_err(&pdev->dev, "Cannot get vcc for %s\n", pdata->name); 158 return PTR_ERR(vcc); 159 } 160 161 led = kzalloc(sizeof(*led), GFP_KERNEL); 162 if (led == NULL) { 163 ret = -ENOMEM; 164 goto err_vcc; 165 } 166 167 led->cdev.max_brightness = led_regulator_get_max_brightness(vcc); 168 if (pdata->brightness > led->cdev.max_brightness) { 169 dev_err(&pdev->dev, "Invalid default brightness %d\n", 170 pdata->brightness); 171 ret = -EINVAL; 172 goto err_led; 173 } 174 led->value = pdata->brightness; 175 176 led->cdev.brightness_set = regulator_led_brightness_set; 177 led->cdev.name = pdata->name; 178 led->cdev.flags |= LED_CORE_SUSPENDRESUME; 179 led->vcc = vcc; 180 181 mutex_init(&led->mutex); 182 INIT_WORK(&led->work, led_work); 183 184 platform_set_drvdata(pdev, led); 185 186 ret = led_classdev_register(&pdev->dev, &led->cdev); 187 if (ret < 0) { 188 cancel_work_sync(&led->work); 189 goto err_led; 190 } 191 192 /* to expose the default value to userspace */ 193 led->cdev.brightness = led->value; 194 195 /* Set the default led status */ 196 regulator_led_set_value(led); 197 198 return 0; 199 200err_led: 201 kfree(led); 202err_vcc: 203 regulator_put(vcc); 204 return ret; 205} 206 207static int __devexit regulator_led_remove(struct platform_device *pdev) 208{ 209 struct regulator_led *led = platform_get_drvdata(pdev); 210 211 led_classdev_unregister(&led->cdev); 212 cancel_work_sync(&led->work); 213 regulator_led_disable(led); 214 regulator_put(led->vcc); 215 kfree(led); 216 return 0; 217} 218 219static struct platform_driver regulator_led_driver = { 220 .driver = { 221 .name = "leds-regulator", 222 .owner = THIS_MODULE, 223 }, 224 .probe = regulator_led_probe, 225 .remove = __devexit_p(regulator_led_remove), 226}; 227 228static int __init regulator_led_init(void) 229{ 230 return platform_driver_register(®ulator_led_driver); 231} 232module_init(regulator_led_init); 233 234static void __exit regulator_led_exit(void) 235{ 236 platform_driver_unregister(®ulator_led_driver); 237} 238module_exit(regulator_led_exit); 239 240MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); 241MODULE_DESCRIPTION("Regulator driven LED driver"); 242MODULE_LICENSE("GPL"); 243MODULE_ALIAS("platform:leds-regulator"); 244