drivers/leds/leds-wm831x-status.c

   1 /*
   2  * LED driver for WM831x status LEDs
   3  *
   4  * Copyright(C) 2009 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/slab.h>
  16 #include <linux/leds.h>
  17 #include <linux/err.h>
  18 #include <linux/mfd/wm831x/core.h>
  19 #include <linux/mfd/wm831x/pdata.h>
  20 #include <linux/mfd/wm831x/status.h>
  21 #include <linux/module.h>
  22
  23
  24 struct wm831x_status {
  25         struct led_classdev cdev;
  26         struct wm831x *wm831x;
  27         struct work_struct work;
  28         struct mutex mutex;
  29
  30         spinlock_t value_lock;
  31         int reg;     /* Control register */
  32         int reg_val; /* Control register value */
  33
  34         int blink;
  35         int blink_time;
  36         int blink_cyc;
  37         int src;
  38         enum led_brightness brightness;
  39 };
  40
  41 #define to_wm831x_status(led_cdev) \
  42         container_of(led_cdev, struct wm831x_status, cdev)
  43
  44 static void wm831x_status_work(struct work_struct *work)
  45 {
  46         struct wm831x_status *led = container_of(work, struct wm831x_status,
  47                                                  work);
  48         unsigned long flags;
  49
  50         mutex_lock(&led->mutex);
  51
  52         led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
  53                           WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
  54
  55         spin_lock_irqsave(&led->value_lock, flags);
  56
  57         led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
  58         if (led->blink) {
  59                 led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
  60                 led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
  61                 led->reg_val |= led->blink_cyc;
  62         } else {
  63                 if (led->brightness != LED_OFF)
  64                         led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
  65         }
  66
  67         spin_unlock_irqrestore(&led->value_lock, flags);
  68
  69         wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
  70
  71         mutex_unlock(&led->mutex);
  72 }
  73
  74 static void wm831x_status_set(struct led_classdev *led_cdev,
  75                            enum led_brightness value)
  76 {
  77         struct wm831x_status *led = to_wm831x_status(led_cdev);
  78         unsigned long flags;
  79
  80         spin_lock_irqsave(&led->value_lock, flags);
  81         led->brightness = value;
  82         if (value == LED_OFF)
  83                 led->blink = 0;
  84         schedule_work(&led->work);
  85         spin_unlock_irqrestore(&led->value_lock, flags);
  86 }
  87
  88 static int wm831x_status_blink_set(struct led_classdev *led_cdev,
  89                                    unsigned long *delay_on,
  90                                    unsigned long *delay_off)
  91 {
  92         struct wm831x_status *led = to_wm831x_status(led_cdev);
  93         unsigned long flags;
  94         int ret = 0;
  95
  96         /* Pick some defaults if we've not been given times */
  97         if (*delay_on == 0 && *delay_off == 0) {
  98                 *delay_on = 250;
  99                 *delay_off = 250;
 100         }
 101
 102         spin_lock_irqsave(&led->value_lock, flags);
 103
 104         /* We only have a limited selection of settings, see if we can
 105          * support the configuration we're being given */
 106         switch (*delay_on) {
 107         case 1000:
 108                 led->blink_time = 0;
 109                 break;
 110         case 250:
 111                 led->blink_time = 1;
 112                 break;
 113         case 125:
 114                 led->blink_time = 2;
 115                 break;
 116         case 62:
 117         case 63:
 118                 /* Actually 62.5ms */
 119                 led->blink_time = 3;
 120                 break;
 121         default:
 122                 ret = -EINVAL;
 123                 break;
 124         }
 125
 126         if (ret == 0) {
 127                 switch (*delay_off / *delay_on) {
 128                 case 1:
 129                         led->blink_cyc = 0;
 130                         break;
 131                 case 3:
 132                         led->blink_cyc = 1;
 133                         break;
 134                 case 4:
 135                         led->blink_cyc = 2;
 136                         break;
 137                 case 8:
 138                         led->blink_cyc = 3;
 139                         break;
 140                 default:
 141                         ret = -EINVAL;
 142                         break;
 143                 }
 144         }
 145
 146         if (ret == 0)
 147                 led->blink = 1;
 148         else
 149                 led->blink = 0;
 150
 151         /* Always update; if we fail turn off blinking since we expect
 152          * a software fallback. */
 153         schedule_work(&led->work);
 154
 155         spin_unlock_irqrestore(&led->value_lock, flags);
 156
 157         return ret;
 158 }
 159
 160 static const char *led_src_texts[] = {
 161         "otp",
 162         "power",
 163         "charger",
 164         "soft",
 165 };
 166
 167 static ssize_t wm831x_status_src_show(struct device *dev,
 168                                       struct device_attribute *attr, char *buf)
 169 {
 170         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 171         struct wm831x_status *led = to_wm831x_status(led_cdev);
 172         int i;
 173         ssize_t ret = 0;
 174
 175         mutex_lock(&led->mutex);
 176
 177         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
 178                 if (i == led->src)
 179                         ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
 180                 else
 181                         ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
 182
 183         mutex_unlock(&led->mutex);
 184
 185         ret += sprintf(&buf[ret], "\n");
 186
 187         return ret;
 188 }
 189
 190 static ssize_t wm831x_status_src_store(struct device *dev,
 191                                        struct device_attribute *attr,
 192                                        const char *buf, size_t size)
 193 {
 194         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 195         struct wm831x_status *led = to_wm831x_status(led_cdev);
 196         char name[20];
 197         int i;
 198         size_t len;
 199
 200         name[sizeof(name) - 1] = '\0';
 201         strncpy(name, buf, sizeof(name) - 1);
 202         len = strlen(name);
 203
 204         if (len && name[len - 1] == '\n')
 205                 name[len - 1] = '\0';
 206
 207         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
 208                 if (!strcmp(name, led_src_texts[i])) {
 209                         mutex_lock(&led->mutex);
 210
 211                         led->src = i;
 212                         schedule_work(&led->work);
 213
 214                         mutex_unlock(&led->mutex);
 215                 }
 216         }
 217
 218         return size;
 219 }
 220
 221 static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
 222
 223 static int wm831x_status_probe(struct platform_device *pdev)
 224 {
 225         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 226         struct wm831x_pdata *chip_pdata;
 227         struct wm831x_status_pdata pdata;
 228         struct wm831x_status *drvdata;
 229         struct resource *res;
 230         int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
 231         int ret;
 232
 233         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 234         if (res == NULL) {
 235                 dev_err(&pdev->dev, "No I/O resource\n");
 236                 ret = -EINVAL;
 237                 goto err;
 238         }
 239
 240         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
 241                                GFP_KERNEL);
 242         if (!drvdata)
 243                 return -ENOMEM;
 244         dev_set_drvdata(&pdev->dev, drvdata);
 245
 246         drvdata->wm831x = wm831x;
 247         drvdata->reg = res->start;
 248
 249         if (wm831x->dev->platform_data)
 250                 chip_pdata = wm831x->dev->platform_data;
 251         else
 252                 chip_pdata = NULL;
 253
 254         memset(&pdata, 0, sizeof(pdata));
 255         if (chip_pdata && chip_pdata->status[id])
 256                 memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
 257         else
 258                 pdata.name = dev_name(&pdev->dev);
 259
 260         mutex_init(&drvdata->mutex);
 261         INIT_WORK(&drvdata->work, wm831x_status_work);
 262         spin_lock_init(&drvdata->value_lock);
 263
 264         /* We cache the configuration register and read startup values
 265          * from it. */
 266         drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
 267
 268         if (drvdata->reg_val & WM831X_LED_MODE_MASK)
 269                 drvdata->brightness = LED_FULL;
 270         else
 271                 drvdata->brightness = LED_OFF;
 272
 273         /* Set a default source if configured, otherwise leave the
 274          * current hardware setting.
 275          */
 276         if (pdata.default_src == WM831X_STATUS_PRESERVE) {
 277                 drvdata->src = drvdata->reg_val;
 278                 drvdata->src &= WM831X_LED_SRC_MASK;
 279                 drvdata->src >>= WM831X_LED_SRC_SHIFT;
 280         } else {
 281                 drvdata->src = pdata.default_src - 1;
 282         }
 283
 284         drvdata->cdev.name = pdata.name;
 285         drvdata->cdev.default_trigger = pdata.default_trigger;
 286         drvdata->cdev.brightness_set = wm831x_status_set;
 287         drvdata->cdev.blink_set = wm831x_status_blink_set;
 288
 289         ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
 290         if (ret < 0) {
 291                 dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
 292                 goto err_led;
 293         }
 294
 295         ret = device_create_file(drvdata->cdev.dev, &dev_attr_src);
 296         if (ret != 0)
 297                 dev_err(&pdev->dev,
 298                         "No source control for LED: %d\n", ret);
 299
 300         return 0;
 301
 302 err_led:
 303         led_classdev_unregister(&drvdata->cdev);
 304 err:
 305         return ret;
 306 }
 307
 308 static int wm831x_status_remove(struct platform_device *pdev)
 309 {
 310         struct wm831x_status *drvdata = platform_get_drvdata(pdev);
 311
 312         device_remove_file(drvdata->cdev.dev, &dev_attr_src);
 313         led_classdev_unregister(&drvdata->cdev);
 314
 315         return 0;
 316 }
 317
 318 static struct platform_driver wm831x_status_driver = {
 319         .driver = {
 320                    .name = "wm831x-status",
 321                    .owner = THIS_MODULE,
 322                    },
 323         .probe = wm831x_status_probe,
 324         .remove = wm831x_status_remove,
 325 };
 326
 327 module_platform_driver(wm831x_status_driver);
 328
 329 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 330 MODULE_DESCRIPTION("WM831x status LED driver");
 331 MODULE_LICENSE("GPL");
 332 MODULE_ALIAS("platform:wm831x-status");