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/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
  21
  22 struct wm831x_status {
  23         struct led_classdev cdev;
  24         struct wm831x *wm831x;
  25         struct work_struct work;
  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_work(struct work_struct *work)
  43 {
  44         struct wm831x_status *led = container_of(work, struct wm831x_status,
  45                                                  work);
  46         unsigned long flags;
  47
  48         mutex_lock(&led->mutex);
  49
  50         led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
  51                           WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
  52
  53         spin_lock_irqsave(&led->value_lock, flags);
  54
  55         led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
  56         if (led->blink) {
  57                 led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
  58                 led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
  59                 led->reg_val |= led->blink_cyc;
  60         } else {
  61                 if (led->brightness != LED_OFF)
  62                         led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
  63         }
  64
  65         spin_unlock_irqrestore(&led->value_lock, flags);
  66
  67         wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
  68
  69         mutex_unlock(&led->mutex);
  70 }
  71
  72 static void wm831x_status_set(struct led_classdev *led_cdev,
  73                            enum led_brightness value)
  74 {
  75         struct wm831x_status *led = to_wm831x_status(led_cdev);
  76         unsigned long flags;
  77
  78         spin_lock_irqsave(&led->value_lock, flags);
  79         led->brightness = value;
  80         if (value == LED_OFF)
  81                 led->blink = 0;
  82         schedule_work(&led->work);
  83         spin_unlock_irqrestore(&led->value_lock, flags);
  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         /* Always update; if we fail turn off blinking since we expect
 150          * a software fallback. */
 151         schedule_work(&led->work);
 152
 153         spin_unlock_irqrestore(&led->value_lock, flags);
 154
 155         return ret;
 156 }
 157
 158 static const char *led_src_texts[] = {
 159         "otp",
 160         "power",
 161         "charger",
 162         "soft",
 163 };
 164
 165 static ssize_t wm831x_status_src_show(struct device *dev,
 166                                       struct device_attribute *attr, char *buf)
 167 {
 168         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 169         struct wm831x_status *led = to_wm831x_status(led_cdev);
 170         int i;
 171         ssize_t ret = 0;
 172
 173         mutex_lock(&led->mutex);
 174
 175         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
 176                 if (i == led->src)
 177                         ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
 178                 else
 179                         ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
 180
 181         mutex_unlock(&led->mutex);
 182
 183         ret += sprintf(&buf[ret], "\n");
 184
 185         return ret;
 186 }
 187
 188 static ssize_t wm831x_status_src_store(struct device *dev,
 189                                        struct device_attribute *attr,
 190                                        const char *buf, size_t size)
 191 {
 192         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 193         struct wm831x_status *led = to_wm831x_status(led_cdev);
 194         char name[20];
 195         int i;
 196         size_t len;
 197
 198         name[sizeof(name) - 1] = '\0';
 199         strncpy(name, buf, sizeof(name) - 1);
 200         len = strlen(name);
 201
 202         if (len && name[len - 1] == '\n')
 203                 name[len - 1] = '\0';
 204
 205         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
 206                 if (!strcmp(name, led_src_texts[i])) {
 207                         mutex_lock(&led->mutex);
 208
 209                         led->src = i;
 210                         schedule_work(&led->work);
 211
 212                         mutex_unlock(&led->mutex);
 213                 }
 214         }
 215
 216         return size;
 217 }
 218
 219 static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
 220
 221 static int wm831x_status_probe(struct platform_device *pdev)
 222 {
 223         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 224         struct wm831x_pdata *chip_pdata;
 225         struct wm831x_status_pdata pdata;
 226         struct wm831x_status *drvdata;
 227         struct resource *res;
 228         int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
 229         int ret;
 230
 231         res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 232         if (res == NULL) {
 233                 dev_err(&pdev->dev, "No I/O resource\n");
 234                 ret = -EINVAL;
 235                 goto err;
 236         }
 237
 238         drvdata = kzalloc(sizeof(struct wm831x_status), GFP_KERNEL);
 239         if (!drvdata)
 240                 return -ENOMEM;
 241         dev_set_drvdata(&pdev->dev, drvdata);
 242
 243         drvdata->wm831x = wm831x;
 244         drvdata->reg = res->start;
 245
 246         if (wm831x->dev->platform_data)
 247                 chip_pdata = wm831x->dev->platform_data;
 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         INIT_WORK(&drvdata->work, wm831x_status_work);
 259         spin_lock_init(&drvdata->value_lock);
 260
 261         /* We cache the configuration register and read startup values
 262          * from it. */
 263         drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
 264
 265         if (drvdata->reg_val & WM831X_LED_MODE_MASK)
 266                 drvdata->brightness = LED_FULL;
 267         else
 268                 drvdata->brightness = LED_OFF;
 269
 270         /* Set a default source if configured, otherwise leave the
 271          * current hardware setting.
 272          */
 273         if (pdata.default_src == WM831X_STATUS_PRESERVE) {
 274                 drvdata->src = drvdata->reg_val;
 275                 drvdata->src &= WM831X_LED_SRC_MASK;
 276                 drvdata->src >>= WM831X_LED_SRC_SHIFT;
 277         } else {
 278                 drvdata->src = pdata.default_src - 1;
 279         }
 280
 281         drvdata->cdev.name = pdata.name;
 282         drvdata->cdev.default_trigger = pdata.default_trigger;
 283         drvdata->cdev.brightness_set = wm831x_status_set;
 284         drvdata->cdev.blink_set = wm831x_status_blink_set;
 285
 286         ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
 287         if (ret < 0) {
 288                 dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
 289                 goto err_led;
 290         }
 291
 292         ret = device_create_file(drvdata->cdev.dev, &dev_attr_src);
 293         if (ret != 0)
 294                 dev_err(&pdev->dev,
 295                         "No source control for LED: %d\n", ret);
 296
 297         return 0;
 298
 299 err_led:
 300         led_classdev_unregister(&drvdata->cdev);
 301         kfree(drvdata);
 302 err:
 303         return ret;
 304 }
 305
 306 static int wm831x_status_remove(struct platform_device *pdev)
 307 {
 308         struct wm831x_status *drvdata = platform_get_drvdata(pdev);
 309
 310         device_remove_file(drvdata->cdev.dev, &dev_attr_src);
 311         led_classdev_unregister(&drvdata->cdev);
 312         kfree(drvdata);
 313
 314         return 0;
 315 }
 316
 317 static struct platform_driver wm831x_status_driver = {
 318         .driver = {
 319                    .name = "wm831x-status",
 320                    .owner = THIS_MODULE,
 321                    },
 322         .probe = wm831x_status_probe,
 323         .remove = wm831x_status_remove,
 324 };
 325
 326 static int __devinit wm831x_status_init(void)
 327 {
 328         return platform_driver_register(&wm831x_status_driver);
 329 }
 330 module_init(wm831x_status_init);
 331
 332 static void wm831x_status_exit(void)
 333 {
 334         platform_driver_unregister(&wm831x_status_driver);
 335 }
 336 module_exit(wm831x_status_exit);
 337
 338 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 339 MODULE_DESCRIPTION("WM831x status LED driver");
 340 MODULE_LICENSE("GPL");
 341 MODULE_ALIAS("platform:wm831x-status");