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| 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 = 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 = devm_kzalloc(&pdev->dev, 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_vcc; |
| 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 | /* to handle correctly an already enabled regulator */ |
| 182 | if (regulator_is_enabled(led->vcc)) |
| 183 | led->enabled = 1; |
| 184 | |
| 185 | mutex_init(&led->mutex); |
| 186 | INIT_WORK(&led->work, led_work); |
| 187 | |
| 188 | platform_set_drvdata(pdev, led); |
| 189 | |
| 190 | ret = led_classdev_register(&pdev->dev, &led->cdev); |
| 191 | if (ret < 0) { |
| 192 | cancel_work_sync(&led->work); |
| 193 | goto err_vcc; |
| 194 | } |
| 195 | |
| 196 | /* to expose the default value to userspace */ |
| 197 | led->cdev.brightness = led->value; |
| 198 | |
| 199 | /* Set the default led status */ |
| 200 | regulator_led_set_value(led); |
| 201 | |
| 202 | return 0; |
| 203 | |
| 204 | err_vcc: |
| 205 | regulator_put(vcc); |
| 206 | return ret; |
| 207 | } |
| 208 | |
| 209 | static int regulator_led_remove(struct platform_device *pdev) |
| 210 | { |
| 211 | struct regulator_led *led = platform_get_drvdata(pdev); |
| 212 | |
| 213 | led_classdev_unregister(&led->cdev); |
| 214 | cancel_work_sync(&led->work); |
| 215 | regulator_led_disable(led); |
| 216 | regulator_put(led->vcc); |
| 217 | return 0; |
| 218 | } |
| 219 | |
| 220 | static struct platform_driver regulator_led_driver = { |
| 221 | .driver = { |
| 222 | .name = "leds-regulator", |
| 223 | .owner = THIS_MODULE, |
| 224 | }, |
| 225 | .probe = regulator_led_probe, |
| 226 | .remove = regulator_led_remove, |
| 227 | }; |
| 228 | |
| 229 | module_platform_driver(regulator_led_driver); |
| 230 | |
| 231 | MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>"); |
| 232 | MODULE_DESCRIPTION("Regulator driven LED driver"); |
| 233 | MODULE_LICENSE("GPL"); |
| 234 | MODULE_ALIAS("platform:leds-regulator"); |
| 235 |
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Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9
