leds-wm831x-status.c

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/*
 * LED driver for WM831x status LEDs
 *
 * Copyright(C) 2009 Wolfson Microelectronics PLC.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 */

#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/leds.h>
#include <linux/err.h>
#include <linux/mfd/wm831x/core.h>
#include <linux/mfd/wm831x/pdata.h>
#include <linux/mfd/wm831x/status.h>
#include <linux/module.h>


struct wm831x_status {
    struct led_classdev cdev;
    struct wm831x *wm831x;
    struct work_struct work;
    struct mutex mutex;

    spinlock_t value_lock;
    int reg;     /* Control register */
    int reg_val; /* Control register value */

    int blink;
    int blink_time;
    int blink_cyc;
    int src;
    enum led_brightness brightness;
};

#define to_wm831x_status(led_cdev) \
    container_of(led_cdev, struct wm831x_status, cdev)

static void wm831x_status_work(struct work_struct *work)
{
    struct wm831x_status *led = container_of(work, struct wm831x_status,
                         work);
    unsigned long flags;

    mutex_lock(&led->mutex);

    led->reg_val &= ~(WM831X_LED_SRC_MASK | WM831X_LED_MODE_MASK |
              WM831X_LED_DUTY_CYC_MASK | WM831X_LED_DUR_MASK);

    spin_lock_irqsave(&led->value_lock, flags);

    led->reg_val |= led->src << WM831X_LED_SRC_SHIFT;
    if (led->blink) {
        led->reg_val |= 2 << WM831X_LED_MODE_SHIFT;
        led->reg_val |= led->blink_time << WM831X_LED_DUR_SHIFT;
        led->reg_val |= led->blink_cyc;
    } else {
        if (led->brightness != LED_OFF)
            led->reg_val |= 1 << WM831X_LED_MODE_SHIFT;
    }

    spin_unlock_irqrestore(&led->value_lock, flags);

    wm831x_reg_write(led->wm831x, led->reg, led->reg_val);

    mutex_unlock(&led->mutex);
}

static void wm831x_status_set(struct led_classdev *led_cdev,
               enum led_brightness value)
{
    struct wm831x_status *led = to_wm831x_status(led_cdev);
    unsigned long flags;

    spin_lock_irqsave(&led->value_lock, flags);
    led->brightness = value;
    if (value == LED_OFF)
        led->blink = 0;
    schedule_work(&led->work);
    spin_unlock_irqrestore(&led->value_lock, flags);
}

static int wm831x_status_blink_set(struct led_classdev *led_cdev,
                   unsigned long *delay_on,
                   unsigned long *delay_off)
{
    struct wm831x_status *led = to_wm831x_status(led_cdev);
    unsigned long flags;
    int ret = 0;

    /* Pick some defaults if we've not been given times */
    if (*delay_on == 0 && *delay_off == 0) {
        *delay_on = 250;
        *delay_off = 250;
    }

    spin_lock_irqsave(&led->value_lock, flags);

    /* We only have a limited selection of settings, see if we can
     * support the configuration we're being given */
    switch (*delay_on) {
    case 1000:
        led->blink_time = 0;
        break;
    case 250:
        led->blink_time = 1;
        break;
    case 125:
        led->blink_time = 2;
        break;
    case 62:
    case 63:
        /* Actually 62.5ms */
        led->blink_time = 3;
        break;
    default:
        ret = -EINVAL;
        break;
    }

    if (ret == 0) {
        switch (*delay_off / *delay_on) {
        case 1:
            led->blink_cyc = 0;
            break;
        case 3:
            led->blink_cyc = 1;
            break;
        case 4:
            led->blink_cyc = 2;
            break;
        case 8:
            led->blink_cyc = 3;
            break;
        default:
            ret = -EINVAL;
            break;
        }
    }

    if (ret == 0)
        led->blink = 1;
    else
        led->blink = 0;

    /* Always update; if we fail turn off blinking since we expect
     * a software fallback. */
    schedule_work(&led->work);

    spin_unlock_irqrestore(&led->value_lock, flags);

    return ret;
}

static const char *led_src_texts[] = {
    "otp",
    "power",
    "charger",
    "soft",
};

static ssize_t wm831x_status_src_show(struct device *dev,
                      struct device_attribute *attr, char *buf)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);
    struct wm831x_status *led = to_wm831x_status(led_cdev);
    int i;
    ssize_t ret = 0;

    mutex_lock(&led->mutex);

    for (i = 0; i < ARRAY_SIZE(led_src_texts); i++)
        if (i == led->src)
            ret += sprintf(&buf[ret], "[%s] ", led_src_texts[i]);
        else
            ret += sprintf(&buf[ret], "%s ", led_src_texts[i]);

    mutex_unlock(&led->mutex);

    ret += sprintf(&buf[ret], "\n");

    return ret;
}

static ssize_t wm831x_status_src_store(struct device *dev,
                       struct device_attribute *attr,
                       const char *buf, size_t size)
{
    struct led_classdev *led_cdev = dev_get_drvdata(dev);
    struct wm831x_status *led = to_wm831x_status(led_cdev);
    char name[20];
    int i;
    size_t len;

    name[sizeof(name) - 1] = '\0';
    strncpy(name, buf, sizeof(name) - 1);
    len = strlen(name);

    if (len && name[len - 1] == '\n')
        name[len - 1] = '\0';

    for (i = 0; i < ARRAY_SIZE(led_src_texts); i++) {
        if (!strcmp(name, led_src_texts[i])) {
            mutex_lock(&led->mutex);

            led->src = i;
            schedule_work(&led->work);

            mutex_unlock(&led->mutex);
        }
    }

    return size;
}

static DEVICE_ATTR(src, 0644, wm831x_status_src_show, wm831x_status_src_store);

static int wm831x_status_probe(struct platform_device *pdev)
{
    struct wm831x *wm831x = dev_get_drvdata(pdev->dev.parent);
    struct wm831x_pdata *chip_pdata;
    struct wm831x_status_pdata pdata;
    struct wm831x_status *drvdata;
    struct resource *res;
    int id = pdev->id % ARRAY_SIZE(chip_pdata->status);
    int ret;

    res = platform_get_resource(pdev, IORESOURCE_IO, 0);
    if (res == NULL) {
        dev_err(&pdev->dev, "No I/O resource\n");
        ret = -EINVAL;
        goto err;
    }

    drvdata = devm_kzalloc(&pdev->dev, sizeof(struct wm831x_status),
                   GFP_KERNEL);
    if (!drvdata)
        return -ENOMEM;
    dev_set_drvdata(&pdev->dev, drvdata);

    drvdata->wm831x = wm831x;
    drvdata->reg = res->start;

    if (wm831x->dev->platform_data)
        chip_pdata = wm831x->dev->platform_data;
    else
        chip_pdata = NULL;

    memset(&pdata, 0, sizeof(pdata));
    if (chip_pdata && chip_pdata->status[id])
        memcpy(&pdata, chip_pdata->status[id], sizeof(pdata));
    else
        pdata.name = dev_name(&pdev->dev);

    mutex_init(&drvdata->mutex);
    INIT_WORK(&drvdata->work, wm831x_status_work);
    spin_lock_init(&drvdata->value_lock);

    /* We cache the configuration register and read startup values
     * from it. */
    drvdata->reg_val = wm831x_reg_read(wm831x, drvdata->reg);

    if (drvdata->reg_val & WM831X_LED_MODE_MASK)
        drvdata->brightness = LED_FULL;
    else
        drvdata->brightness = LED_OFF;

    /* Set a default source if configured, otherwise leave the
     * current hardware setting.
     */
    if (pdata.default_src == WM831X_STATUS_PRESERVE) {
        drvdata->src = drvdata->reg_val;
        drvdata->src &= WM831X_LED_SRC_MASK;
        drvdata->src >>= WM831X_LED_SRC_SHIFT;
    } else {
        drvdata->src = pdata.default_src - 1;
    }

    drvdata->cdev.name = pdata.name;
    drvdata->cdev.default_trigger = pdata.default_trigger;
    drvdata->cdev.brightness_set = wm831x_status_set;
    drvdata->cdev.blink_set = wm831x_status_blink_set;

    ret = led_classdev_register(wm831x->dev, &drvdata->cdev);
    if (ret < 0) {
        dev_err(&pdev->dev, "Failed to register LED: %d\n", ret);
        goto err_led;
    }

    ret = device_create_file(drvdata->cdev.dev, &dev_attr_src);
    if (ret != 0)
        dev_err(&pdev->dev,
            "No source control for LED: %d\n", ret);

    return 0;

err_led:
    led_classdev_unregister(&drvdata->cdev);
err:
    return ret;
}

static int wm831x_status_remove(struct platform_device *pdev)
{
    struct wm831x_status *drvdata = platform_get_drvdata(pdev);

    device_remove_file(drvdata->cdev.dev, &dev_attr_src);
    led_classdev_unregister(&drvdata->cdev);

    return 0;
}

static struct platform_driver wm831x_status_driver = {
    .driver = {
           .name = "wm831x-status",
           .owner = THIS_MODULE,
           },
    .probe = wm831x_status_probe,
    .remove = wm831x_status_remove,
};

module_platform_driver(wm831x_status_driver);

MODULE_AUTHOR("Mark Brown <[email protected]>");
MODULE_DESCRIPTION("WM831x status LED driver");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:wm831x-status");