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/init.h>
  14#include <linux/platform_device.h>
  15#include <linux/slab.h>
  16#include <linux/leds.h>
  17#include <linux/err.h>
  18#include <linux/mfd/wm831x/core.h>
  19#include <linux/mfd/wm831x/pdata.h>
  20#include <linux/mfd/wm831x/status.h>
  21#include <linux/module.h>
  22
  23
  24struct wm831x_status {
  25        struct led_classdev cdev;
  26        struct wm831x *wm831x;
  27        struct work_struct work;
  28        struct mutex mutex;
  29
  30        spinlock_t value_lock;
  31        int reg;     /* Control register */
  32        int reg_val; /* Control register value */
  33
  34        int blink;
  35        int blink_time;
  36        int blink_cyc;
  37        int src;
  38        enum led_brightness brightness;
  39};
  40
  41#define to_wm831x_status(led_cdev) \
  42        container_of(led_cdev, struct wm831x_status, cdev)
  43
  44static void wm831x_status_work(struct work_struct *work)
  45{
  46        struct wm831x_status *led = container_of(work, struct wm831x_status,
  47                                                 work);
  48        unsigned long flags;
  49
  50        mutex_lock(&led->mutex);
  51
  52        led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
  53                          WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);
  54
  55        spin_lock_irqsave(&led->value_lock, flags);
  56
  57        led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
  58        if (led->blink) {
  59                led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
  60                led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
  61                led->reg_val |= led->blink_cyc;
  62        } else {
  63                if (led->brightness != LED_OFF)
  64                        led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
  65        }
  66
  67        spin_unlock_irqrestore(&led->value_lock, flags);
  68
  69        wm831x_reg_write(led->wm831x, led->reg, led->reg_val);
  70
  71        mutex_unlock(&led->mutex);
  72}
  73
  74static void wm831x_status_set(struct led_classdev *led_cdev,
  75                           enum led_brightness value)
  76{
  77        struct wm831x_status *led = to_wm831x_status(led_cdev);
  78        unsigned long flags;
  79
  80        spin_lock_irqsave(&led->value_lock, flags);
  81        led->brightness = value;
  82        if (value == LED_OFF)
  83                led->blink = 0;
  84        schedule_work(&led->work);
  85        spin_unlock_irqrestore(&led->value_lock, flags);
  86}
  87
  88static int wm831x_status_blink_set(struct led_classdev *led_cdev,
  89                                   unsigned long *delay_on,
  90                                   unsigned long *delay_off)
  91{
  92        struct wm831x_status *led = to_wm831x_status(led_cdev);
  93        unsigned long flags;
  94        int ret = 0;
  95
  96        /* Pick some defaults if we've not been given times */
  97        if (*delay_on == 0 && *delay_off == 0) {
  98                *delay_on = 250;
  99                *delay_off = 250;
 100        }
 101
 102        spin_lock_irqsave(&led->value_lock, flags);
 103
 104        /* We only have a limited selection of settings, see if we can
 105         * support the configuration we're being given */
 106        switch (*delay_on) {
 107        case 1000:
 108                led->blink_time = 0;
 109                break;
 110        case 250:
 111                led->blink_time = 1;
 112                break;
 113        case 125:
 114                led->blink_time = 2;
 115                break;
 116        case 62:
 117        case 63:
 118                /* Actually 62.5ms */
 119                led->blink_time = 3;
 120                break;
 121        default:
 122                ret = -EINVAL;
 123                break;
 124        }
 125
 126        if (ret == 0) {
 127                switch (*delay_off / *delay_on) {
 128                case 1:
 129                        led->blink_cyc = 0;
 130                        break;
 131                case 3:
 132                        led->blink_cyc = 1;
 133                        break;
 134                case 4:
 135                        led->blink_cyc = 2;
 136                        break;
 137                case 8:
 138                        led->blink_cyc = 3;
 139                        break;
 140                default:
 141                        ret = -EINVAL;
 142                        break;
 143                }
 144        }
 145
 146        if (ret == 0)
 147                led->blink = 1;
 148        else
 149                led->blink = 0;
 150
 151        /* Always update; if we fail turn off blinking since we expect
 152         * a software fallback. */
 153        schedule_work(&led->work);
 154
 155        spin_unlock_irqrestore(&led->value_lock, flags);
 156
 157        return ret;
 158}
 159
 160static const char * const led_src_texts[] = {
 161        "otp",
 162        "power",
 163        "charger",
 164        "soft",
 165};
 166
 167static ssize_t wm831x_status_src_show(struct device *dev,
 168                                      struct device_attribute *attr, char *buf)
 169{
 170        struct led_classdev *led_cdev = dev_get_drvdata(dev);
 171        struct wm831x_status *led = to_wm831x_status(led_cdev);
 172        int i;
 173        ssize_t ret = 0;
 174
 175        mutex_lock(&led->mutex);
 176
 177        for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
 178                if (i == led->src)
 179                        ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
 180                else
 181                        ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);
 182
 183        mutex_unlock(&led->mutex);
 184
 185        ret += sprintf(&buf[ret], "\n");
 186
 187        return ret;
 188}
 189
 190static ssize_t wm831x_status_src_store(struct device *dev,
 191                                       struct device_attribute *attr,
 192                                       const char *buf, size_t size)
 193{
 194        struct led_classdev *led_cdev = dev_get_drvdata(dev);
 195        struct wm831x_status *led = to_wm831x_status(led_cdev);
 196        char name[20];
 197        int i;
 198        size_t len;
 199
 200        name[sizeof(name) - 1] = '\0';
 201        strncpy(name, buf, sizeof(name) - 1);
 202        len = strlen(name);
 203
 204        if (len && name[len - 1] == '\n')
 205                name[len - 1] = '\0';
 206
 207        for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
 208                if (!strcmp(name, led_src_texts[i])) {
 209                        mutex_lock(&led->mutex);
 210
 211                        led->src = i;
 212                        schedule_work(&led->work);
 213
 214                        mutex_unlock(&led->mutex);
 215                }
 216        }
 217
 218        return size;
 219}
 220
 221static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);
 222
 223static int wm831x_status_probe(struct platform_device *pdev)
 224{
 225        struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
 226        struct wm831x_pdata *chip_pdata;
 227        struct wm831x_status_pdata pdata;
 228        struct wm831x_status *drvdata;
 229        struct resource *res;
 230        int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
 231        int ret;
 232
 233        res = platform_get_resource(pdev, IORESOURCE_IO, 0);
 234        if (res == NULL) {
 235                dev_err(&pdev->dev, "No I/O resource\n");
 236                ret = -EINVAL;
 237                goto err;
 238        }
 239
 240        drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
 241                               GFP_KERNEL);
 242        if (!drvdata)
 243                return -ENOMEM;
 244        dev_set_drvdata(&pdev->dev, drvdata);
 245
 246        drvdata->wm831x = wm831x;
 247        drvdata->reg = res->start;
 248
 249        if (wm831x->dev->platform_data)
 250                chip_pdata = wm831x->dev->platform_data;
 251        else
 252                chip_pdata = NULL;
 253
 254        memset(&pdata, 0, sizeof(pdata));
 255        if (chip_pdata && chip_pdata->status[id])
 256                memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
 257        else
 258                pdata.name = dev_name(&pdev->dev);
 259
 260        mutex_init(&drvdata->mutex);
 261        INIT_WORK(&drvdata->work, wm831x_status_work);
 262        spin_lock_init(&drvdata->value_lock);
 263
 264        /* We cache the configuration register and read startup values
 265         * from it. */
 266        drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);
 267
 268        if (drvdata->reg_val & WM831X_LED_MODE_MASK)
 269                drvdata->brightness = LED_FULL;
 270        else
 271                drvdata->brightness = LED_OFF;
 272
 273        /* Set a default source if configured, otherwise leave the
 274         * current hardware setting.
 275         */
 276        if (pdata.default_src == WM831X_STATUS_PRESERVE) {
 277                drvdata->src = drvdata->reg_val;
 278                drvdata->src &= WM831X_LED_SRC_MASK;
 279                drvdata->src >>= WM831X_LED_SRC_SHIFT;
 280        } else {
 281                drvdata->src = pdata.default_src - 1;
 282        }
 283
 284        drvdata->cdev.name = pdata.name;
 285        drvdata->cdev.default_trigger = pdata.default_trigger;
 286        drvdata->cdev.brightness_set = wm831x_status_set;
 287        drvdata->cdev.blink_set = wm831x_status_blink_set;
 288
 289        ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
 290        if (ret < 0) {
 291                dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
 292                goto err_led;
 293        }
 294
 295        ret = device_create_file(drvdata->cdev.dev, &dev_attr_src);
 296        if (ret != 0)
 297                dev_err(&pdev->dev,
 298                        "No source control for LED: %d\n", ret);
 299
 300        return 0;
 301
 302err_led:
 303        led_classdev_unregister(&drvdata->cdev);
 304err:
 305        return ret;
 306}
 307
 308static int wm831x_status_remove(struct platform_device *pdev)
 309{
 310        struct wm831x_status *drvdata = platform_get_drvdata(pdev);
 311
 312        device_remove_file(drvdata->cdev.dev, &dev_attr_src);
 313        led_classdev_unregister(&drvdata->cdev);
 314
 315        return 0;
 316}
 317
 318static struct platform_driver wm831x_status_driver = {
 319        .driver = {
 320                   .name = "wm831x-status",
 321                   .owner = THIS_MODULE,
 322                   },
 323        .probe = wm831x_status_probe,
 324        .remove = wm831x_status_remove,
 325};
 326
 327module_platform_driver(wm831x_status_driver);
 328
 329MODULE_AUTHOR("Mark Brown <broonie@opensource.wolfsonmicro.com>");
 330MODULE_DESCRIPTION("WM831x status LED driver");
 331MODULE_LICENSE("GPL");
 332MODULE_ALIAS("platform:wm831x-status");
 333
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