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 26 struct 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 36 static 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 55 static 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 65 static 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 81 static 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 97 static 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); 121 122 out: 123 mutex_unlock(&led->mutex); 124 } 125 126 static 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 } 133 134 static 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 } 142 143 static int regulator_led_probe(struct platform_device *pdev) 144 { 145 struct led_regulator_platform_data *pdata = 146 dev_get_platdata(&pdev->dev); 147 struct regulator_led *led; 148 struct regulator *vcc; 149 int ret = 0; 150 151 if (pdata == NULL) { 152 dev_err(&pdev->dev, "no platform data\n"); 153 return -ENODEV; 154 } 155 156 vcc = regulator_get_exclusive(&pdev->dev, "vled"); 157 if (IS_ERR(vcc)) { 158 dev_err(&pdev->dev, "Cannot get vcc for %s\n", pdata->name); 159 return PTR_ERR(vcc); 160 } 161 162 led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL); 163 if (led == NULL) { 164 ret = -ENOMEM; 165 goto err_vcc; 166 } 167 168 led->cdev.max_brightness = led_regulator_get_max_brightness(vcc); 169 if (pdata->brightness > led->cdev.max_brightness) { 170 dev_err(&pdev->dev, "Invalid default brightness %d\n", 171 pdata->brightness); 172 ret = -EINVAL; 173 goto err_vcc; 174 } 175 led->value = pdata->brightness; 176 177 led->cdev.brightness_set = regulator_led_brightness_set; 178 led->cdev.name = pdata->name; 179 led->cdev.flags |= LED_CORE_SUSPENDRESUME; 180 led->vcc = vcc; 181 182 /* to handle correctly an already enabled regulator */ 183 if (regulator_is_enabled(led->vcc)) 184 led->enabled = 1; 185 186 mutex_init(&led->mutex); 187 INIT_WORK(&led->work, led_work); 188 189 platform_set_drvdata(pdev, led); 190 191 ret = led_classdev_register(&pdev->dev, &led->cdev); 192 if (ret < 0) { 193 cancel_work_sync(&led->work); 194 goto err_vcc; 195 } 196 197 /* to expose the default value to userspace */ 198 led->cdev.brightness = led->value; 199 200 /* Set the default led status */ 201 regulator_led_set_value(led); 202 203 return 0; 204 205 err_vcc: 206 regulator_put(vcc); 207 return ret; 208 } 209 210 static int regulator_led_remove(struct platform_device *pdev) 211 { 212 struct regulator_led *led = platform_get_drvdata(pdev); 213 214 led_classdev_unregister(&led->cdev); 215 cancel_work_sync(&led->work); 216 regulator_led_disable(led); 217 regulator_put(led->vcc); 218 return 0; 219 } 220 221 static struct platform_driver regulator_led_driver = { 222 .driver = { 223 .name = "leds-regulator", 224 .owner = THIS_MODULE, 225 }, 226 .probe = regulator_led_probe, 227 .remove = regulator_led_remove, 228 }; 229 230 module_platform_driver(regulator_led_driver); 231 232 MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); 233 MODULE_DESCRIPTION("Regulator driven LED driver"); 234 MODULE_LICENSE("GPL"); 235 MODULE_ALIAS("platform:leds-regulator"); 236