LXR linux/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
  19struct 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
  38static 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
  66static 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
  82static 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
 151static const char * const led_src_texts[] = {
 152        "otp",
 153        "power",
 154        "charger",
 155        "soft",
 156};
 157
 158static 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
 181static 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
 200static DEVICE_ATTR_RW(src);
 201
 202static struct attribute *wm831x_status_attrs[] = {
 203        &dev_attr_src.attr,
 204        NULL
 205};
 206ATTRIBUTE_GROUPS(wm831x_status);
 207
 208static 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
 283static int 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        return 0;
 290}
 291
 292static struct platform_driver wm831x_status_driver = {
 293        .driver = {
 294                   .name = "wm831x-status",
 295                   },
 296        .probe = wm831x_status_probe,
 297        .remove = wm831x_status_remove,
 298};
 299
 300module_platform_driver(wm831x_status_driver);
 301
 302MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 303MODULE_DESCRIPTION("WM831x status LED driver");
 304MODULE_LICENSE("GPL");
 305MODULE_ALIAS("platform:wm831x-status");
 306