drivers/leds/leds-wm8350.c

   1 /*
   2  * LED driver for WM8350 driven LEDS.
   3  *
   4  * Copyright(C) 2007, 2008 Wolfson Microelectronics PLC.
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  */
  11
  12 #include <linux/kernel.h>
  13 #include <linux/init.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/leds.h>
  16 #include <linux/err.h>
  17 #include <linux/mfd/wm8350/pmic.h>
  18 #include <linux/regulator/consumer.h>
  19 #include <linux/slab.h>
  20 #include <linux/module.h>
  21
  22 /* Microamps */
  23 static const int isink_cur[] = {
  24         4,
  25         5,
  26         6,
  27         7,
  28         8,
  29         10,
  30         11,
  31         14,
  32         16,
  33         19,
  34         23,
  35         27,
  36         32,
  37         39,
  38         46,
  39         54,
  40         65,
  41         77,
  42         92,
  43         109,
  44         130,
  45         154,
  46         183,
  47         218,
  48         259,
  49         308,
  50         367,
  51         436,
  52         518,
  53         616,
  54         733,
  55         872,
  56         1037,
  57         1233,
  58         1466,
  59         1744,
  60         2073,
  61         2466,
  62         2933,
  63         3487,
  64         4147,
  65         4932,
  66         5865,
  67         6975,
  68         8294,
  69         9864,
  70         11730,
  71         13949,
  72         16589,
  73         19728,
  74         23460,
  75         27899,
  76         33178,
  77         39455,
  78         46920,
  79         55798,
  80         66355,
  81         78910,
  82         93840,
  83         111596,
  84         132710,
  85         157820,
  86         187681,
  87         223191
  88 };
  89
  90 #define to_wm8350_led(led_cdev) \
  91         container_of(led_cdev, struct wm8350_led, cdev)
  92
  93 static void wm8350_led_enable(struct wm8350_led *led)
  94 {
  95         int ret;
  96
  97         if (led->enabled)
  98                 return;
  99
 100         ret = regulator_enable(led->isink);
 101         if (ret != 0) {
 102                 dev_err(led->cdev.dev, "Failed to enable ISINK: %d\n", ret);
 103                 return;
 104         }
 105
 106         ret = regulator_enable(led->dcdc);
 107         if (ret != 0) {
 108                 dev_err(led->cdev.dev, "Failed to enable DCDC: %d\n", ret);
 109                 regulator_disable(led->isink);
 110                 return;
 111         }
 112
 113         led->enabled = 1;
 114 }
 115
 116 static void wm8350_led_disable(struct wm8350_led *led)
 117 {
 118         int ret;
 119
 120         if (!led->enabled)
 121                 return;
 122
 123         ret = regulator_disable(led->dcdc);
 124         if (ret != 0) {
 125                 dev_err(led->cdev.dev, "Failed to disable DCDC: %d\n", ret);
 126                 return;
 127         }
 128
 129         ret = regulator_disable(led->isink);
 130         if (ret != 0) {
 131                 dev_err(led->cdev.dev, "Failed to disable ISINK: %d\n", ret);
 132                 ret = regulator_enable(led->dcdc);
 133                 if (ret != 0)
 134                         dev_err(led->cdev.dev, "Failed to reenable DCDC: %d\n",
 135                                 ret);
 136                 return;
 137         }
 138
 139         led->enabled = 0;
 140 }
 141
 142 static void led_work(struct work_struct *work)
 143 {
 144         struct wm8350_led *led = container_of(work, struct wm8350_led, work);
 145         int ret;
 146         int uA;
 147         unsigned long flags;
 148
 149         mutex_lock(&led->mutex);
 150
 151         spin_lock_irqsave(&led->value_lock, flags);
 152
 153         if (led->value == LED_OFF) {
 154                 spin_unlock_irqrestore(&led->value_lock, flags);
 155                 wm8350_led_disable(led);
 156                 goto out;
 157         }
 158
 159         /* This scales linearly into the index of valid current
 160          * settings which results in a linear scaling of perceived
 161          * brightness due to the non-linear current settings provided
 162          * by the hardware.
 163          */
 164         uA = (led->max_uA_index * led->value) / LED_FULL;
 165         spin_unlock_irqrestore(&led->value_lock, flags);
 166         BUG_ON(uA >= ARRAY_SIZE(isink_cur));
 167
 168         ret = regulator_set_current_limit(led->isink, isink_cur[uA],
 169                                           isink_cur[uA]);
 170         if (ret != 0)
 171                 dev_err(led->cdev.dev, "Failed to set %duA: %d\n",
 172                         isink_cur[uA], ret);
 173
 174         wm8350_led_enable(led);
 175
 176 out:
 177         mutex_unlock(&led->mutex);
 178 }
 179
 180 static void wm8350_led_set(struct led_classdev *led_cdev,
 181                            enum led_brightness value)
 182 {
 183         struct wm8350_led *led = to_wm8350_led(led_cdev);
 184         unsigned long flags;
 185
 186         spin_lock_irqsave(&led->value_lock, flags);
 187         led->value = value;
 188         schedule_work(&led->work);
 189         spin_unlock_irqrestore(&led->value_lock, flags);
 190 }
 191
 192 static void wm8350_led_shutdown(struct platform_device *pdev)
 193 {
 194         struct wm8350_led *led = platform_get_drvdata(pdev);
 195
 196         mutex_lock(&led->mutex);
 197         led->value = LED_OFF;
 198         wm8350_led_disable(led);
 199         mutex_unlock(&led->mutex);
 200 }
 201
 202 static int wm8350_led_probe(struct platform_device *pdev)
 203 {
 204         struct regulator *isink, *dcdc;
 205         struct wm8350_led *led;
 206         struct wm8350_led_platform_data *pdata = pdev->dev.platform_data;
 207         int i;
 208
 209         if (pdata == NULL) {
 210                 dev_err(&pdev->dev, "no platform data\n");
 211                 return -ENODEV;
 212         }
 213
 214         if (pdata->max_uA < isink_cur[0]) {
 215                 dev_err(&pdev->dev, "Invalid maximum current %duA\n",
 216                         pdata->max_uA);
 217                 return -EINVAL;
 218         }
 219
 220         isink = devm_regulator_get(&pdev->dev, "led_isink");
 221         if (IS_ERR(isink)) {
 222                 dev_err(&pdev->dev, "%s: can't get ISINK\n", __func__);
 223                 return PTR_ERR(isink);
 224         }
 225
 226         dcdc = devm_regulator_get(&pdev->dev, "led_vcc");
 227         if (IS_ERR(dcdc)) {
 228                 dev_err(&pdev->dev, "%s: can't get DCDC\n", __func__);
 229                 return PTR_ERR(dcdc);
 230         }
 231
 232         led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
 233         if (led == NULL)
 234                 return -ENOMEM;
 235
 236         led->cdev.brightness_set = wm8350_led_set;
 237         led->cdev.default_trigger = pdata->default_trigger;
 238         led->cdev.name = pdata->name;
 239         led->cdev.flags |= LED_CORE_SUSPENDRESUME;
 240         led->enabled = regulator_is_enabled(isink);
 241         led->isink = isink;
 242         led->dcdc = dcdc;
 243
 244         for (i = 0; i < ARRAY_SIZE(isink_cur) - 1; i++)
 245                 if (isink_cur[i] >= pdata->max_uA)
 246                         break;
 247         led->max_uA_index = i;
 248         if (pdata->max_uA != isink_cur[i])
 249                 dev_warn(&pdev->dev,
 250                          "Maximum current %duA is not directly supported,"
 251                          " check platform data\n",
 252                          pdata->max_uA);
 253
 254         spin_lock_init(&led->value_lock);
 255         mutex_init(&led->mutex);
 256         INIT_WORK(&led->work, led_work);
 257         led->value = LED_OFF;
 258         platform_set_drvdata(pdev, led);
 259
 260         return led_classdev_register(&pdev->dev, &led->cdev);
 261 }
 262
 263 static int wm8350_led_remove(struct platform_device *pdev)
 264 {
 265         struct wm8350_led *led = platform_get_drvdata(pdev);
 266
 267         led_classdev_unregister(&led->cdev);
 268         flush_work(&led->work);
 269         wm8350_led_disable(led);
 270         return 0;
 271 }
 272
 273 static struct platform_driver wm8350_led_driver = {
 274         .driver = {
 275                    .name = "wm8350-led",
 276                    .owner = THIS_MODULE,
 277                    },
 278         .probe = wm8350_led_probe,
 279         .remove = wm8350_led_remove,
 280         .shutdown = wm8350_led_shutdown,
 281 };
 282
 283 module_platform_driver(wm8350_led_driver);
 284
 285 MODULE_AUTHOR("Mark Brown");
 286 MODULE_DESCRIPTION("WM8350 LED driver");
 287 MODULE_LICENSE("GPL");
 288 MODULE_ALIAS("platform:wm8350-led");