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