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/platform_device.h>
  14 #include <linux/slab.h>
  15 #include <linux/leds.h>
  16 #include <linux/err.h>
  17 #include <linux/mfd/wm831x/core.h>
  18 #include <linux/mfd/wm831x/pdata.h>
  19 #include <linux/mfd/wm831x/status.h>
  20 #include <linux/module.h>
  21
  22
  23 struct wm831x_status {
  24         struct led_classdev cdev;
  25         struct wm831x *wm831x;
  26         struct mutex mutex;
  27
  28         spinlock_t value_lock;
  29         int reg;     /* Control register */
  30         int reg_val; /* Control register value */
  31
  32         int blink;
  33         int blink_time;
  34         int blink_cyc;
  35         int src;
  36         enum led_brightness brightness;
  37 };
  38
  39 #define to_wm831x_status(led_cdev) \
  40         container_of(led_cdev, struct wm831x_status, cdev)
  41
  42 static void wm831x_status_set(struct wm831x_status *led)
  43 {
  44         unsigned long flags;
  45
  46         mutex_lock(&led->mutex);
  47
  48         led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
  49                           WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
  50
  51         spin_lock_irqsave(&led->value_lock, flags);
  52
  53         led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
  54         if (led->blink) {
  55                 led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
  56                 led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
  57                 led->reg_val |= led->blink_cyc;
  58         } else {
  59                 if (led->brightness != LED_OFF)
  60                         led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
  61         }
  62
  63         spin_unlock_irqrestore(&led->value_lock, flags);
  64
  65         wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
  66
  67         mutex_unlock(&led->mutex);
  68 }
  69
  70 static int wm831x_status_brightness_set(struct led_classdev *led_cdev,
  71                                          enum led_brightness value)
  72 {
  73         struct wm831x_status *led = to_wm831x_status(led_cdev);
  74         unsigned long flags;
  75
  76         spin_lock_irqsave(&led->value_lock, flags);
  77         led->brightness = value;
  78         if (value == LED_OFF)
  79                 led->blink = 0;
  80         spin_unlock_irqrestore(&led->value_lock, flags);
  81         wm831x_status_set(led);
  82
  83         return 0;
  84 }
  85
  86 static int wm831x_status_blink_set(struct led_classdev *led_cdev,
  87                                    unsigned long *delay_on,
  88                                    unsigned long *delay_off)
  89 {
  90         struct wm831x_status *led = to_wm831x_status(led_cdev);
  91         unsigned long flags;
  92         int ret = 0;
  93
  94         /* Pick some defaults if we've not been given times */
  95         if (*delay_on == 0 && *delay_off == 0) {
  96                 *delay_on = 250;
  97                 *delay_off = 250;
  98         }
  99
 100         spin_lock_irqsave(&led->value_lock, flags);
 101
 102         /* We only have a limited selection of settings, see if we can
 103          * support the configuration we're being given */
 104         switch (*delay_on) {
 105         case 1000:
 106                 led->blink_time = 0;
 107                 break;
 108         case 250:
 109                 led->blink_time = 1;
 110                 break;
 111         case 125:
 112                 led->blink_time = 2;
 113                 break;
 114         case 62:
 115         case 63:
 116                 /* Actually 62.5ms */
 117                 led->blink_time = 3;
 118                 break;
 119         default:
 120                 ret = -EINVAL;
 121                 break;
 122         }
 123
 124         if (ret == 0) {
 125                 switch (*delay_off / *delay_on) {
 126                 case 1:
 127                         led->blink_cyc = 0;
 128                         break;
 129                 case 3:
 130                         led->blink_cyc = 1;
 131                         break;
 132                 case 4:
 133                         led->blink_cyc = 2;
 134                         break;
 135                 case 8:
 136                         led->blink_cyc = 3;
 137                         break;
 138                 default:
 139                         ret = -EINVAL;
 140                         break;
 141                 }
 142         }
 143
 144         if (ret == 0)
 145                 led->blink = 1;
 146         else
 147                 led->blink = 0;
 148
 149         spin_unlock_irqrestore(&led->value_lock, flags);
 150         wm831x_status_set(led);
 151
 152         return ret;
 153 }
 154
 155 static const char * const led_src_texts[] = {
 156         "otp",
 157         "power",
 158         "charger",
 159         "soft",
 160 };
 161
 162 static ssize_t wm831x_status_src_show(struct device *dev,
 163                                       struct device_attribute *attr, char *buf)
 164 {
 165         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 166         struct wm831x_status *led = to_wm831x_status(led_cdev);
 167         int i;
 168         ssize_t ret = 0;
 169
 170         mutex_lock(&led->mutex);
 171
 172         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
 173                 if (i == led->src)
 174                         ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
 175                 else
 176                         ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
 177
 178         mutex_unlock(&led->mutex);
 179
 180         ret += sprintf(&buf[ret], "\n");
 181
 182         return ret;
 183 }
 184
 185 static ssize_t wm831x_status_src_store(struct device *dev,
 186                                        struct device_attribute *attr,
 187                                        const char *buf, size_t size)
 188 {
 189         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 190         struct wm831x_status *led = to_wm831x_status(led_cdev);
 191         char name[20];
 192         int i;
 193         size_t len;
 194
 195         name[sizeof(name) - 1] = '\0';
 196         strncpy(name, buf, sizeof(name) - 1);
 197         len = strlen(name);
 198
 199         if (len && name[len - 1] == '\n')
 200                 name[len - 1] = '\0';
 201
 202         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
 203                 if (!strcmp(name, led_src_texts[i])) {
 204                         mutex_lock(&led->mutex);
 205                         led->src = i;
 206                         mutex_unlock(&led->mutex);
 207                         wm831x_status_set(led);
 208                 }
 209         }
 210
 211         return size;
 212 }
 213
 214 static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
 215
 216 static struct attribute *wm831x_status_attrs[] = {
 217         &dev_attr_src.attr,
 218         NULL
 219 };
 220 ATTRIBUTE_GROUPS(wm831x_status);
 221
 222 static int wm831x_status_probe(struct platform_device *pdev)
 223 {
 224         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 225         struct wm831x_pdata *chip_pdata;
 226         struct wm831x_status_pdata pdata;
 227         struct wm831x_status *drvdata;
 228         struct resource *res;
 229         int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
 230         int ret;
 231
 232         res = platform_get_resource(pdev, IORESOURCE_REG, 0);
 233         if (res == NULL) {
 234                 dev_err(&pdev->dev, "No register resource\n");
 235                 return -EINVAL;
 236         }
 237
 238         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
 239                                GFP_KERNEL);
 240         if (!drvdata)
 241                 return -ENOMEM;
 242
 243         drvdata->wm831x = wm831x;
 244         drvdata->reg = res->start;
 245
 246         if (dev_get_platdata(wm831x->dev))
 247                 chip_pdata = dev_get_platdata(wm831x->dev);
 248         else
 249                 chip_pdata = NULL;
 250
 251         memset(&pdata, 0, sizeof(pdata));
 252         if (chip_pdata && chip_pdata->status[id])
 253                 memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
 254         else
 255                 pdata.name = dev_name(&pdev->dev);
 256
 257         mutex_init(&drvdata->mutex);
 258         spin_lock_init(&drvdata->value_lock);
 259
 260         /* We cache the configuration register and read startup values
 261          * from it. */
 262         drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
 263
 264         if (drvdata->reg_val & WM831X_LED_MODE_MASK)
 265                 drvdata->brightness = LED_FULL;
 266         else
 267                 drvdata->brightness = LED_OFF;
 268
 269         /* Set a default source if configured, otherwise leave the
 270          * current hardware setting.
 271          */
 272         if (pdata.default_src == WM831X_STATUS_PRESERVE) {
 273                 drvdata->src = drvdata->reg_val;
 274                 drvdata->src &= WM831X_LED_SRC_MASK;
 275                 drvdata->src >>= WM831X_LED_SRC_SHIFT;
 276         } else {
 277                 drvdata->src = pdata.default_src - 1;
 278         }
 279
 280         drvdata->cdev.name = pdata.name;
 281         drvdata->cdev.default_trigger = pdata.default_trigger;
 282         drvdata->cdev.brightness_set_blocking = wm831x_status_brightness_set;
 283         drvdata->cdev.blink_set = wm831x_status_blink_set;
 284         drvdata->cdev.groups = wm831x_status_groups;
 285
 286         ret = devm_led_classdev_register(wm831x->dev, &drvdata->cdev);
 287         if (ret < 0) {
 288                 dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
 289                 return ret;
 290         }
 291
 292         return 0;
 293 }
 294
 295 static struct platform_driver wm831x_status_driver = {
 296         .driver = {
 297                    .name = "wm831x-status",
 298                    },
 299         .probe = wm831x_status_probe,
 300 };
 301
 302 module_platform_driver(wm831x_status_driver);
 303
 304 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 305 MODULE_DESCRIPTION("WM831x status LED driver");
 306 MODULE_LICENSE("GPL");
 307 MODULE_ALIAS("platform:wm831x-status");