linux/drivers/leds/leds-wm831x-status.c
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   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
  23struct 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
  42static 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
  70static 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
  86static 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
 155static const char * const led_src_texts[] = {
 156        "otp",
 157        "power",
 158        "charger",
 159        "soft",
 160};
 161
 162static 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
 185static 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
 214static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
 215
 216static struct attribute *wm831x_status_attrs[] = {
 217        &dev_attr_src.attr,
 218        NULL
 219};
 220ATTRIBUTE_GROUPS(wm831x_status);
 221
 222static 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
 295static struct platform_driver wm831x_status_driver = {
 296        .driver = {
 297                   .name = "wm831x-status",
 298                   },
 299        .probe = wm831x_status_probe,
 300};
 301
 302module_platform_driver(wm831x_status_driver);
 303
 304MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 305MODULE_DESCRIPTION("WM831x status LED driver");
 306MODULE_LICENSE("GPL");
 307MODULE_ALIAS("platform:wm831x-status");
 308