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
  20 /* Microamps */
  21 static const int isink_cur[] = {
  22         4,
  23         5,
  24         6,
  25         7,
  26         8,
  27         10,
  28         11,
  29         14,
  30         16,
  31         19,
  32         23,
  33         27,
  34         32,
  35         39,
  36         46,
  37         54,
  38         65,
  39         77,
  40         92,
  41         109,
  42         130,
  43         154,
  44         183,
  45         218,
  46         259,
  47         308,
  48         367,
  49         436,
  50         518,
  51         616,
  52         733,
  53         872,
  54         1037,
  55         1233,
  56         1466,
  57         1744,
  58         2073,
  59         2466,
  60         2933,
  61         3487,
  62         4147,
  63         4932,
  64         5865,
  65         6975,
  66         8294,
  67         9864,
  68         11730,
  69         13949,
  70         16589,
  71         19728,
  72         23460,
  73         27899,
  74         33178,
  75         39455,
  76         46920,
  77         55798,
  78         66355,
  79         78910,
  80         93840,
  81         111596,
  82         132710,
  83         157820,
  84         187681,
  85         223191
  86 };
  87
  88 #define to_wm8350_led(led_cdev) \
  89         container_of(led_cdev, struct wm8350_led, cdev)
  90
  91 static void wm8350_led_enable(struct wm8350_led *led)
  92 {
  93         int ret;
  94
  95         if (led->enabled)
  96                 return;
  97
  98         ret = regulator_enable(led->isink);
  99         if (ret != 0) {
 100                 dev_err(led->cdev.dev, "Failed to enable ISINK: %d\n", ret);
 101                 return;
 102         }
 103
 104         ret = regulator_enable(led->dcdc);
 105         if (ret != 0) {
 106                 dev_err(led->cdev.dev, "Failed to enable DCDC: %d\n", ret);
 107                 regulator_disable(led->isink);
 108                 return;
 109         }
 110
 111         led->enabled = 1;
 112 }
 113
 114 static void wm8350_led_disable(struct wm8350_led *led)
 115 {
 116         int ret;
 117
 118         if (!led->enabled)
 119                 return;
 120
 121         ret = regulator_disable(led->dcdc);
 122         if (ret != 0) {
 123                 dev_err(led->cdev.dev, "Failed to disable DCDC: %d\n", ret);
 124                 return;
 125         }
 126
 127         ret = regulator_disable(led->isink);
 128         if (ret != 0) {
 129                 dev_err(led->cdev.dev, "Failed to disable ISINK: %d\n", ret);
 130                 regulator_enable(led->dcdc);
 131                 return;
 132         }
 133
 134         led->enabled = 0;
 135 }
 136
 137 static void led_work(struct work_struct *work)
 138 {
 139         struct wm8350_led *led = container_of(work, struct wm8350_led, work);
 140         int ret;
 141         int uA;
 142         unsigned long flags;
 143
 144         mutex_lock(&led->mutex);
 145
 146         spin_lock_irqsave(&led->value_lock, flags);
 147
 148         if (led->value == LED_OFF) {
 149                 spin_unlock_irqrestore(&led->value_lock, flags);
 150                 wm8350_led_disable(led);
 151                 goto out;
 152         }
 153
 154         /* This scales linearly into the index of valid current
 155          * settings which results in a linear scaling of perceived
 156          * brightness due to the non-linear current settings provided
 157          * by the hardware.
 158          */
 159         uA = (led->max_uA_index * led->value) / LED_FULL;
 160         spin_unlock_irqrestore(&led->value_lock, flags);
 161         BUG_ON(uA >= ARRAY_SIZE(isink_cur));
 162
 163         ret = regulator_set_current_limit(led->isink, isink_cur[uA],
 164                                           isink_cur[uA]);
 165         if (ret != 0)
 166                 dev_err(led->cdev.dev, "Failed to set %duA: %d\n",
 167                         isink_cur[uA], ret);
 168
 169         wm8350_led_enable(led);
 170
 171 out:
 172         mutex_unlock(&led->mutex);
 173 }
 174
 175 static void wm8350_led_set(struct led_classdev *led_cdev,
 176                            enum led_brightness value)
 177 {
 178         struct wm8350_led *led = to_wm8350_led(led_cdev);
 179         unsigned long flags;
 180
 181         spin_lock_irqsave(&led->value_lock, flags);
 182         led->value = value;
 183         schedule_work(&led->work);
 184         spin_unlock_irqrestore(&led->value_lock, flags);
 185 }
 186
 187 static void wm8350_led_shutdown(struct platform_device *pdev)
 188 {
 189         struct wm8350_led *led = platform_get_drvdata(pdev);
 190
 191         mutex_lock(&led->mutex);
 192         led->value = LED_OFF;
 193         wm8350_led_disable(led);
 194         mutex_unlock(&led->mutex);
 195 }
 196
 197 static int wm8350_led_probe(struct platform_device *pdev)
 198 {
 199         struct regulator *isink, *dcdc;
 200         struct wm8350_led *led;
 201         struct wm8350_led_platform_data *pdata = pdev->dev.platform_data;
 202         int ret, i;
 203
 204         if (pdata == NULL) {
 205                 dev_err(&pdev->dev, "no platform data\n");
 206                 return -ENODEV;
 207         }
 208
 209         if (pdata->max_uA < isink_cur[0]) {
 210                 dev_err(&pdev->dev, "Invalid maximum current %duA\n",
 211                         pdata->max_uA);
 212                 return -EINVAL;
 213         }
 214
 215         isink = regulator_get(&pdev->dev, "led_isink");
 216         if (IS_ERR(isink)) {
 217                 printk(KERN_ERR "%s: cant get ISINK\n", __func__);
 218                 return PTR_ERR(isink);
 219         }
 220
 221         dcdc = regulator_get(&pdev->dev, "led_vcc");
 222         if (IS_ERR(dcdc)) {
 223                 printk(KERN_ERR "%s: cant get DCDC\n", __func__);
 224                 ret = PTR_ERR(dcdc);
 225                 goto err_isink;
 226         }
 227
 228         led = kzalloc(sizeof(*led), GFP_KERNEL);
 229         if (led == NULL) {
 230                 ret = -ENOMEM;
 231                 goto err_dcdc;
 232         }
 233
 234         led->cdev.brightness_set = wm8350_led_set;
 235         led->cdev.default_trigger = pdata->default_trigger;
 236         led->cdev.name = pdata->name;
 237         led->cdev.flags |= LED_CORE_SUSPENDRESUME;
 238         led->enabled = regulator_is_enabled(isink);
 239         led->isink = isink;
 240         led->dcdc = dcdc;
 241
 242         for (i = 0; i < ARRAY_SIZE(isink_cur) - 1; i++)
 243                 if (isink_cur[i] >= pdata->max_uA)
 244                         break;
 245         led->max_uA_index = i;
 246         if (pdata->max_uA != isink_cur[i])
 247                 dev_warn(&pdev->dev,
 248                          "Maximum current %duA is not directly supported,"
 249                          " check platform data\n",
 250                          pdata->max_uA);
 251
 252         spin_lock_init(&led->value_lock);
 253         mutex_init(&led->mutex);
 254         INIT_WORK(&led->work, led_work);
 255         led->value = LED_OFF;
 256         platform_set_drvdata(pdev, led);
 257
 258         ret = led_classdev_register(&pdev->dev, &led->cdev);
 259         if (ret < 0)
 260                 goto err_led;
 261
 262         return 0;
 263
 264  err_led:
 265         kfree(led);
 266  err_dcdc:
 267         regulator_put(dcdc);
 268  err_isink:
 269         regulator_put(isink);
 270         return ret;
 271 }
 272
 273 static int wm8350_led_remove(struct platform_device *pdev)
 274 {
 275         struct wm8350_led *led = platform_get_drvdata(pdev);
 276
 277         led_classdev_unregister(&led->cdev);
 278         flush_scheduled_work();
 279         wm8350_led_disable(led);
 280         regulator_put(led->dcdc);
 281         regulator_put(led->isink);
 282         kfree(led);
 283         return 0;
 284 }
 285
 286 static struct platform_driver wm8350_led_driver = {
 287         .driver = {
 288                    .name = "wm8350-led",
 289                    .owner = THIS_MODULE,
 290                    },
 291         .probe = wm8350_led_probe,
 292         .remove = wm8350_led_remove,
 293         .shutdown = wm8350_led_shutdown,
 294 };
 295
 296 static int __devinit wm8350_led_init(void)
 297 {
 298         return platform_driver_register(&wm8350_led_driver);
 299 }
 300 module_init(wm8350_led_init);
 301
 302 static void wm8350_led_exit(void)
 303 {
 304         platform_driver_unregister(&wm8350_led_driver);
 305 }
 306 module_exit(wm8350_led_exit);
 307
 308 MODULE_AUTHOR("Mark Brown");
 309 MODULE_DESCRIPTION("WM8350 LED driver");
 310 MODULE_LICENSE("GPL");
 311 MODULE_ALIAS("platform:wm8350-led");