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 work_struct work;
  27         struct mutex mutex;
  28
  29         spinlock_t value_lock;
  30         int reg;     /* Control register */
  31         int reg_val; /* Control register value */
  32
  33         int blink;
  34         int blink_time;
  35         int blink_cyc;
  36         int src;
  37         enum led_brightness brightness;
  38 };
  39
  40 #define to_wm831x_status(led_cdev) \
  41         container_of(led_cdev, struct wm831x_status, cdev)
  42
  43 static void wm831x_status_work(struct work_struct *work)
  44 {
  45         struct wm831x_status *led = container_of(work, struct wm831x_status,
  46                                                  work);
  47         unsigned long flags;
  48
  49         mutex_lock(&led->mutex);
  50
  51         led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
  52                           WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
  53
  54         spin_lock_irqsave(&led->value_lock, flags);
  55
  56         led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
  57         if (led->blink) {
  58                 led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
  59                 led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
  60                 led->reg_val |= led->blink_cyc;
  61         } else {
  62                 if (led->brightness != LED_OFF)
  63                         led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
  64         }
  65
  66         spin_unlock_irqrestore(&led->value_lock, flags);
  67
  68         wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
  69
  70         mutex_unlock(&led->mutex);
  71 }
  72
  73 static void wm831x_status_set(struct led_classdev *led_cdev,
  74                            enum led_brightness value)
  75 {
  76         struct wm831x_status *led = to_wm831x_status(led_cdev);
  77         unsigned long flags;
  78
  79         spin_lock_irqsave(&led->value_lock, flags);
  80         led->brightness = value;
  81         if (value == LED_OFF)
  82                 led->blink = 0;
  83         schedule_work(&led->work);
  84         spin_unlock_irqrestore(&led->value_lock, flags);
  85 }
  86
  87 static int wm831x_status_blink_set(struct led_classdev *led_cdev,
  88                                    unsigned long *delay_on,
  89                                    unsigned long *delay_off)
  90 {
  91         struct wm831x_status *led = to_wm831x_status(led_cdev);
  92         unsigned long flags;
  93         int ret = 0;
  94
  95         /* Pick some defaults if we've not been given times */
  96         if (*delay_on == 0 && *delay_off == 0) {
  97                 *delay_on = 250;
  98                 *delay_off = 250;
  99         }
 100
 101         spin_lock_irqsave(&led->value_lock, flags);
 102
 103         /* We only have a limited selection of settings, see if we can
 104          * support the configuration we're being given */
 105         switch (*delay_on) {
 106         case 1000:
 107                 led->blink_time = 0;
 108                 break;
 109         case 250:
 110                 led->blink_time = 1;
 111                 break;
 112         case 125:
 113                 led->blink_time = 2;
 114                 break;
 115         case 62:
 116         case 63:
 117                 /* Actually 62.5ms */
 118                 led->blink_time = 3;
 119                 break;
 120         default:
 121                 ret = -EINVAL;
 122                 break;
 123         }
 124
 125         if (ret == 0) {
 126                 switch (*delay_off / *delay_on) {
 127                 case 1:
 128                         led->blink_cyc = 0;
 129                         break;
 130                 case 3:
 131                         led->blink_cyc = 1;
 132                         break;
 133                 case 4:
 134                         led->blink_cyc = 2;
 135                         break;
 136                 case 8:
 137                         led->blink_cyc = 3;
 138                         break;
 139                 default:
 140                         ret = -EINVAL;
 141                         break;
 142                 }
 143         }
 144
 145         if (ret == 0)
 146                 led->blink = 1;
 147         else
 148                 led->blink = 0;
 149
 150         /* Always update; if we fail turn off blinking since we expect
 151          * a software fallback. */
 152         schedule_work(&led->work);
 153
 154         spin_unlock_irqrestore(&led->value_lock, flags);
 155
 156         return ret;
 157 }
 158
 159 static const char * const led_src_texts[] = {
 160         "otp",
 161         "power",
 162         "charger",
 163         "soft",
 164 };
 165
 166 static ssize_t wm831x_status_src_show(struct device *dev,
 167                                       struct device_attribute *attr, char *buf)
 168 {
 169         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 170         struct wm831x_status *led = to_wm831x_status(led_cdev);
 171         int i;
 172         ssize_t ret = 0;
 173
 174         mutex_lock(&led->mutex);
 175
 176         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
 177                 if (i == led->src)
 178                         ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
 179                 else
 180                         ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
 181
 182         mutex_unlock(&led->mutex);
 183
 184         ret += sprintf(&buf[ret], "\n");
 185
 186         return ret;
 187 }
 188
 189 static ssize_t wm831x_status_src_store(struct device *dev,
 190                                        struct device_attribute *attr,
 191                                        const char *buf, size_t size)
 192 {
 193         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 194         struct wm831x_status *led = to_wm831x_status(led_cdev);
 195         char name[20];
 196         int i;
 197         size_t len;
 198
 199         name[sizeof(name) - 1] = '\0';
 200         strncpy(name, buf, sizeof(name) - 1);
 201         len = strlen(name);
 202
 203         if (len && name[len - 1] == '\n')
 204                 name[len - 1] = '\0';
 205
 206         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
 207                 if (!strcmp(name, led_src_texts[i])) {
 208                         mutex_lock(&led->mutex);
 209
 210                         led->src = i;
 211                         schedule_work(&led->work);
 212
 213                         mutex_unlock(&led->mutex);
 214                 }
 215         }
 216
 217         return size;
 218 }
 219
 220 static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
 221
 222 static struct attribute *wm831x_status_attrs[] = {
 223         &dev_attr_src.attr,
 224         NULL
 225 };
 226 ATTRIBUTE_GROUPS(wm831x_status);
 227
 228 static int wm831x_status_probe(struct platform_device *pdev)
 229 {
 230         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 231         struct wm831x_pdata *chip_pdata;
 232         struct wm831x_status_pdata pdata;
 233         struct wm831x_status *drvdata;
 234         struct resource *res;
 235         int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
 236         int ret;
 237
 238         res = platform_get_resource(pdev, IORESOURCE_REG, 0);
 239         if (res == NULL) {
 240                 dev_err(&pdev->dev, "No register resource\n");
 241                 return -EINVAL;
 242         }
 243
 244         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
 245                                GFP_KERNEL);
 246         if (!drvdata)
 247                 return -ENOMEM;
 248         platform_set_drvdata(pdev, drvdata);
 249
 250         drvdata->wm831x = wm831x;
 251         drvdata->reg = res->start;
 252
 253         if (dev_get_platdata(wm831x->dev))
 254                 chip_pdata = dev_get_platdata(wm831x->dev);
 255         else
 256                 chip_pdata = NULL;
 257
 258         memset(&pdata, 0, sizeof(pdata));
 259         if (chip_pdata && chip_pdata->status[id])
 260                 memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
 261         else
 262                 pdata.name = dev_name(&pdev->dev);
 263
 264         mutex_init(&drvdata->mutex);
 265         INIT_WORK(&drvdata->work, wm831x_status_work);
 266         spin_lock_init(&drvdata->value_lock);
 267
 268         /* We cache the configuration register and read startup values
 269          * from it. */
 270         drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
 271
 272         if (drvdata->reg_val & WM831X_LED_MODE_MASK)
 273                 drvdata->brightness = LED_FULL;
 274         else
 275                 drvdata->brightness = LED_OFF;
 276
 277         /* Set a default source if configured, otherwise leave the
 278          * current hardware setting.
 279          */
 280         if (pdata.default_src == WM831X_STATUS_PRESERVE) {
 281                 drvdata->src = drvdata->reg_val;
 282                 drvdata->src &= WM831X_LED_SRC_MASK;
 283                 drvdata->src >>= WM831X_LED_SRC_SHIFT;
 284         } else {
 285                 drvdata->src = pdata.default_src - 1;
 286         }
 287
 288         drvdata->cdev.name = pdata.name;
 289         drvdata->cdev.default_trigger = pdata.default_trigger;
 290         drvdata->cdev.brightness_set = wm831x_status_set;
 291         drvdata->cdev.blink_set = wm831x_status_blink_set;
 292         drvdata->cdev.groups = wm831x_status_groups;
 293
 294         ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
 295         if (ret < 0) {
 296                 dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
 297                 return ret;
 298         }
 299
 300         return 0;
 301 }
 302
 303 static int wm831x_status_remove(struct platform_device *pdev)
 304 {
 305         struct wm831x_status *drvdata = platform_get_drvdata(pdev);
 306
 307         led_classdev_unregister(&drvdata->cdev);
 308
 309         return 0;
 310 }
 311
 312 static struct platform_driver wm831x_status_driver = {
 313         .driver = {
 314                    .name = "wm831x-status",
 315                    },
 316         .probe = wm831x_status_probe,
 317         .remove = wm831x_status_remove,
 318 };
 319
 320 module_platform_driver(wm831x_status_driver);
 321
 322 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 323 MODULE_DESCRIPTION("WM831x status LED driver");
 324 MODULE_LICENSE("GPL");
 325 MODULE_ALIAS("platform:wm831x-status");