drivers/leds/leds-wm831x-status.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * LED driver for WM831x status LEDs
   4  *
   5  * Copyright(C) 2009 Wolfson Microelectronics PLC.
   6  */
   7
   8 #include <linux/kernel.h>
   9 #include <linux/platform_device.h>
  10 #include <linux/slab.h>
  11 #include <linux/leds.h>
  12 #include <linux/err.h>
  13 #include <linux/mfd/wm831x/core.h>
  14 #include <linux/mfd/wm831x/pdata.h>
  15 #include <linux/mfd/wm831x/status.h>
  16 #include <linux/module.h>
  17
  18
  19 struct wm831x_status {
  20         struct led_classdev cdev;
  21         struct wm831x *wm831x;
  22         struct mutex mutex;
  23
  24         spinlock_t value_lock;
  25         int reg;     /* Control register */
  26         int reg_val; /* Control register value */
  27
  28         int blink;
  29         int blink_time;
  30         int blink_cyc;
  31         int src;
  32         enum led_brightness brightness;
  33 };
  34
  35 #define to_wm831x_status(led_cdev) \
  36         container_of(led_cdev, struct wm831x_status, cdev)
  37
  38 static void wm831x_status_set(struct wm831x_status *led)
  39 {
  40         unsigned long flags;
  41
  42         mutex_lock(&led->mutex);
  43
  44         led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
  45                           WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
  46
  47         spin_lock_irqsave(&led->value_lock, flags);
  48
  49         led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
  50         if (led->blink) {
  51                 led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
  52                 led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
  53                 led->reg_val |= led->blink_cyc;
  54         } else {
  55                 if (led->brightness != LED_OFF)
  56                         led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
  57         }
  58
  59         spin_unlock_irqrestore(&led->value_lock, flags);
  60
  61         wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
  62
  63         mutex_unlock(&led->mutex);
  64 }
  65
  66 static int wm831x_status_brightness_set(struct led_classdev *led_cdev,
  67                                          enum led_brightness value)
  68 {
  69         struct wm831x_status *led = to_wm831x_status(led_cdev);
  70         unsigned long flags;
  71
  72         spin_lock_irqsave(&led->value_lock, flags);
  73         led->brightness = value;
  74         if (value == LED_OFF)
  75                 led->blink = 0;
  76         spin_unlock_irqrestore(&led->value_lock, flags);
  77         wm831x_status_set(led);
  78
  79         return 0;
  80 }
  81
  82 static int wm831x_status_blink_set(struct led_classdev *led_cdev,
  83                                    unsigned long *delay_on,
  84                                    unsigned long *delay_off)
  85 {
  86         struct wm831x_status *led = to_wm831x_status(led_cdev);
  87         unsigned long flags;
  88         int ret = 0;
  89
  90         /* Pick some defaults if we've not been given times */
  91         if (*delay_on == 0 && *delay_off == 0) {
  92                 *delay_on = 250;
  93                 *delay_off = 250;
  94         }
  95
  96         spin_lock_irqsave(&led->value_lock, flags);
  97
  98         /* We only have a limited selection of settings, see if we can
  99          * support the configuration we're being given */
 100         switch (*delay_on) {
 101         case 1000:
 102                 led->blink_time = 0;
 103                 break;
 104         case 250:
 105                 led->blink_time = 1;
 106                 break;
 107         case 125:
 108                 led->blink_time = 2;
 109                 break;
 110         case 62:
 111         case 63:
 112                 /* Actually 62.5ms */
 113                 led->blink_time = 3;
 114                 break;
 115         default:
 116                 ret = -EINVAL;
 117                 break;
 118         }
 119
 120         if (ret == 0) {
 121                 switch (*delay_off / *delay_on) {
 122                 case 1:
 123                         led->blink_cyc = 0;
 124                         break;
 125                 case 3:
 126                         led->blink_cyc = 1;
 127                         break;
 128                 case 4:
 129                         led->blink_cyc = 2;
 130                         break;
 131                 case 8:
 132                         led->blink_cyc = 3;
 133                         break;
 134                 default:
 135                         ret = -EINVAL;
 136                         break;
 137                 }
 138         }
 139
 140         if (ret == 0)
 141                 led->blink = 1;
 142         else
 143                 led->blink = 0;
 144
 145         spin_unlock_irqrestore(&led->value_lock, flags);
 146         wm831x_status_set(led);
 147
 148         return ret;
 149 }
 150
 151 static const char * const led_src_texts[] = {
 152         "otp",
 153         "power",
 154         "charger",
 155         "soft",
 156 };
 157
 158 static ssize_t src_show(struct device *dev,
 159                         struct device_attribute *attr, char *buf)
 160 {
 161         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 162         struct wm831x_status *led = to_wm831x_status(led_cdev);
 163         int i;
 164         ssize_t ret = 0;
 165
 166         mutex_lock(&led->mutex);
 167
 168         for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
 169                 if (i == led->src)
 170                         ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
 171                 else
 172                         ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
 173
 174         mutex_unlock(&led->mutex);
 175
 176         ret += sprintf(&buf[ret], "\n");
 177
 178         return ret;
 179 }
 180
 181 static ssize_t src_store(struct device *dev,
 182                          struct device_attribute *attr,
 183                          const char *buf, size_t size)
 184 {
 185         struct led_classdev *led_cdev = dev_get_drvdata(dev);
 186         struct wm831x_status *led = to_wm831x_status(led_cdev);
 187         int i;
 188
 189         i = sysfs_match_string(led_src_texts, buf);
 190         if (i >= 0) {
 191                 mutex_lock(&led->mutex);
 192                 led->src = i;
 193                 mutex_unlock(&led->mutex);
 194                 wm831x_status_set(led);
 195         }
 196
 197         return size;
 198 }
 199
 200 static DEVICE_ATTR_RW(src);
 201
 202 static struct attribute *wm831x_status_attrs[] = {
 203         &dev_attr_src.attr,
 204         NULL
 205 };
 206 ATTRIBUTE_GROUPS(wm831x_status);
 207
 208 static int wm831x_status_probe(struct platform_device *pdev)
 209 {
 210         struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 211         struct wm831x_pdata *chip_pdata;
 212         struct wm831x_status_pdata pdata;
 213         struct wm831x_status *drvdata;
 214         struct resource *res;
 215         int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
 216         int ret;
 217
 218         res = platform_get_resource(pdev, IORESOURCE_REG, 0);
 219         if (res == NULL) {
 220                 dev_err(&pdev->dev, "No register resource\n");
 221                 return -EINVAL;
 222         }
 223
 224         drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
 225                                GFP_KERNEL);
 226         if (!drvdata)
 227                 return -ENOMEM;
 228
 229         drvdata->wm831x = wm831x;
 230         drvdata->reg = res->start;
 231
 232         if (dev_get_platdata(wm831x->dev))
 233                 chip_pdata = dev_get_platdata(wm831x->dev);
 234         else
 235                 chip_pdata = NULL;
 236
 237         memset(&pdata, 0, sizeof(pdata));
 238         if (chip_pdata && chip_pdata->status[id])
 239                 memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
 240         else
 241                 pdata.name = dev_name(&pdev->dev);
 242
 243         mutex_init(&drvdata->mutex);
 244         spin_lock_init(&drvdata->value_lock);
 245
 246         /* We cache the configuration register and read startup values
 247          * from it. */
 248         drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
 249
 250         if (drvdata->reg_val & WM831X_LED_MODE_MASK)
 251                 drvdata->brightness = LED_FULL;
 252         else
 253                 drvdata->brightness = LED_OFF;
 254
 255         /* Set a default source if configured, otherwise leave the
 256          * current hardware setting.
 257          */
 258         if (pdata.default_src == WM831X_STATUS_PRESERVE) {
 259                 drvdata->src = drvdata->reg_val;
 260                 drvdata->src &= WM831X_LED_SRC_MASK;
 261                 drvdata->src >>= WM831X_LED_SRC_SHIFT;
 262         } else {
 263                 drvdata->src = pdata.default_src - 1;
 264         }
 265
 266         drvdata->cdev.name = pdata.name;
 267         drvdata->cdev.default_trigger = pdata.default_trigger;
 268         drvdata->cdev.brightness_set_blocking = wm831x_status_brightness_set;
 269         drvdata->cdev.blink_set = wm831x_status_blink_set;
 270         drvdata->cdev.groups = wm831x_status_groups;
 271
 272         ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
 273         if (ret < 0) {
 274                 dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
 275                 return ret;
 276         }
 277
 278         platform_set_drvdata(pdev, drvdata);
 279
 280         return 0;
 281 }
 282
 283 static void wm831x_status_remove(struct platform_device *pdev)
 284 {
 285         struct wm831x_status *drvdata = platform_get_drvdata(pdev);
 286
 287         led_classdev_unregister(&drvdata->cdev);
 288 }
 289
 290 static struct platform_driver wm831x_status_driver = {
 291         .driver = {
 292                    .name = "wm831x-status",
 293                    },
 294         .probe = wm831x_status_probe,
 295         .remove = wm831x_status_remove,
 296 };
 297
 298 module_platform_driver(wm831x_status_driver);
 299
 300 MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 301 MODULE_DESCRIPTION("WM831x status LED driver");
 302 MODULE_LICENSE("GPL");
 303 MODULE_ALIAS("platform:wm831x-status");