/*
 * Backlight driver for Analog Devices ADP8870 Backlight Devices
 *
 * Copyright 2009-2011 Analog Devices Inc.
 *
 * Licensed under the GPL-2 or later.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/pm.h>
#include <linux/platform_device.h>
#include <linux/i2c.h>
#include <linux/fb.h>
#include <linux/backlight.h>
#include <linux/leds.h>
#include <linux/workqueue.h>
#include <linux/slab.h>

#include <linux/i2c/adp8870.h>
#define ADP8870_EXT_FEATURES
#define ADP8870_USE_LEDS


#define ADP8870_MFDVID  0x00  /* Manufacturer and device ID */
#define ADP8870_MDCR    0x01  /* Device mode and status */
#define ADP8870_INT_STAT 0x02  /* Interrupts status */
#define ADP8870_INT_EN  0x03  /* Interrupts enable */
#define ADP8870_CFGR    0x04  /* Configuration register */
#define ADP8870_BLSEL   0x05  /* Sink enable backlight or independent */
#define ADP8870_PWMLED  0x06  /* PWM Enable Selection Register */
#define ADP8870_BLOFF   0x07  /* Backlight off timeout */
#define ADP8870_BLDIM   0x08  /* Backlight dim timeout */
#define ADP8870_BLFR    0x09  /* Backlight fade in and out rates */
#define ADP8870_BLMX1   0x0A  /* Backlight (Brightness Level 1-daylight) maximum current */
#define ADP8870_BLDM1   0x0B  /* Backlight (Brightness Level 1-daylight) dim current */
#define ADP8870_BLMX2   0x0C  /* Backlight (Brightness Level 2-bright) maximum current */
#define ADP8870_BLDM2   0x0D  /* Backlight (Brightness Level 2-bright) dim current */
#define ADP8870_BLMX3   0x0E  /* Backlight (Brightness Level 3-office) maximum current */
#define ADP8870_BLDM3   0x0F  /* Backlight (Brightness Level 3-office) dim current */
#define ADP8870_BLMX4   0x10  /* Backlight (Brightness Level 4-indoor) maximum current */
#define ADP8870_BLDM4   0x11  /* Backlight (Brightness Level 4-indoor) dim current */
#define ADP8870_BLMX5   0x12  /* Backlight (Brightness Level 5-dark) maximum current */
#define ADP8870_BLDM5   0x13  /* Backlight (Brightness Level 5-dark) dim current */
#define ADP8870_ISCLAW  0x1A  /* Independent sink current fade law register */
#define ADP8870_ISCC    0x1B  /* Independent sink current control register */
#define ADP8870_ISCT1   0x1C  /* Independent Sink Current Timer Register LED[7:5] */
#define ADP8870_ISCT2   0x1D  /* Independent Sink Current Timer Register LED[4:1] */
#define ADP8870_ISCF    0x1E  /* Independent sink current fade register */
#define ADP8870_ISC1    0x1F  /* Independent Sink Current LED1 */
#define ADP8870_ISC2    0x20  /* Independent Sink Current LED2 */
#define ADP8870_ISC3    0x21  /* Independent Sink Current LED3 */
#define ADP8870_ISC4    0x22  /* Independent Sink Current LED4 */
#define ADP8870_ISC5    0x23  /* Independent Sink Current LED5 */
#define ADP8870_ISC6    0x24  /* Independent Sink Current LED6 */
#define ADP8870_ISC7    0x25  /* Independent Sink Current LED7 (Brightness Level 1-daylight) */
#define ADP8870_ISC7_L2 0x26  /* Independent Sink Current LED7 (Brightness Level 2-bright) */
#define ADP8870_ISC7_L3 0x27  /* Independent Sink Current LED7 (Brightness Level 3-office) */
#define ADP8870_ISC7_L4 0x28  /* Independent Sink Current LED7 (Brightness Level 4-indoor) */
#define ADP8870_ISC7_L5 0x29  /* Independent Sink Current LED7 (Brightness Level 5-dark) */
#define ADP8870_CMP_CTL 0x2D  /* ALS Comparator Control Register */
#define ADP8870_ALS1_EN 0x2E  /* Main ALS comparator level enable */
#define ADP8870_ALS2_EN 0x2F  /* Second ALS comparator level enable */
#define ADP8870_ALS1_STAT 0x30  /* Main ALS Comparator Status Register */
#define ADP8870_ALS2_STAT 0x31  /* Second ALS Comparator Status Register */
#define ADP8870_L2TRP   0x32  /* L2 comparator reference */
#define ADP8870_L2HYS   0x33  /* L2 hysteresis */
#define ADP8870_L3TRP   0x34  /* L3 comparator reference */
#define ADP8870_L3HYS   0x35  /* L3 hysteresis */
#define ADP8870_L4TRP   0x36  /* L4 comparator reference */
#define ADP8870_L4HYS   0x37  /* L4 hysteresis */
#define ADP8870_L5TRP   0x38  /* L5 comparator reference */
#define ADP8870_L5HYS   0x39  /* L5 hysteresis */
#define ADP8870_PH1LEVL 0x40  /* First phototransistor ambient light level-low byte register */
#define ADP8870_PH1LEVH 0x41  /* First phototransistor ambient light level-high byte register */
#define ADP8870_PH2LEVL 0x42  /* Second phototransistor ambient light level-low byte register */
#define ADP8870_PH2LEVH 0x43  /* Second phototransistor ambient light level-high byte register */

#define ADP8870_MANUFID         0x3  /* Analog Devices AD8870 Manufacturer and device ID */
#define ADP8870_DEVID(x)        ((x) & 0xF)
#define ADP8870_MANID(x)        ((x) >> 4)

/* MDCR Device mode and status */
#define D7ALSEN                 (1 << 7)
#define INT_CFG                 (1 << 6)
#define NSTBY                   (1 << 5)
#define DIM_EN                  (1 << 4)
#define GDWN_DIS                (1 << 3)
#define SIS_EN                  (1 << 2)
#define CMP_AUTOEN              (1 << 1)
#define BLEN                    (1 << 0)

/* ADP8870_ALS1_EN Main ALS comparator level enable */
#define L5_EN                   (1 << 3)
#define L4_EN                   (1 << 2)
#define L3_EN                   (1 << 1)
#define L2_EN                   (1 << 0)

#define CFGR_BLV_SHIFT          3
#define CFGR_BLV_MASK           0x7
#define ADP8870_FLAG_LED_MASK   0xFF

#define FADE_VAL(in, out)       ((0xF & (in)) | ((0xF & (out)) << 4))
#define BL_CFGR_VAL(law, blv)   ((((blv) & CFGR_BLV_MASK) << CFGR_BLV_SHIFT) | ((0x3 & (law)) << 1))
#define ALS_CMPR_CFG_VAL(filt)  ((0x7 & (filt)) << 1)

struct adp8870_bl {
        struct i2c_client *client;
        struct backlight_device *bl;
        struct adp8870_led *led;
        struct adp8870_backlight_platform_data *pdata;
        struct mutex lock;
        unsigned long cached_daylight_max;
        int id;
        int revid;
        int current_brightness;
};

struct adp8870_led {
        struct led_classdev     cdev;
        struct work_struct      work;
        struct i2c_client       *client;
        enum led_brightness     new_brightness;
        int                     id;
        int                     flags;
};

static int adp8870_read(struct i2c_client *client, int reg, uint8_t *val)
{
        int ret;

        ret = i2c_smbus_read_byte_data(client, reg);
        if (ret < 0) {
                dev_err(&client->dev, "failed reading at 0x%02x\n", reg);
                return ret;
        }

        *val = ret;
        return 0;
}


static int adp8870_write(struct i2c_client *client, u8 reg, u8 val)
{
        int ret = i2c_smbus_write_byte_data(client, reg, val);
        if (ret)
                dev_err(&client->dev, "failed to write\n");

        return ret;
}

static int adp8870_set_bits(struct i2c_client *client, int reg, uint8_t bit_mask)
{
        struct adp8870_bl *data = i2c_get_clientdata(client);
        uint8_t reg_val;
        int ret;

        mutex_lock(&data->lock);

        ret = adp8870_read(client, reg, &reg_val);

        if (!ret && ((reg_val & bit_mask) != bit_mask)) {
                reg_val |= bit_mask;
                ret = adp8870_write(client, reg, reg_val);
        }

        mutex_unlock(&data->lock);
        return ret;
}

static int adp8870_clr_bits(struct i2c_client *client, int reg, uint8_t bit_mask)
{
        struct adp8870_bl *data = i2c_get_clientdata(client);
        uint8_t reg_val;
        int ret;

        mutex_lock(&data->lock);

        ret = adp8870_read(client, reg, &reg_val);

        if (!ret && (reg_val & bit_mask)) {
                reg_val &= ~bit_mask;
                ret = adp8870_write(client, reg, reg_val);
        }

        mutex_unlock(&data->lock);
        return ret;
}

/*
 * Independent sink / LED
 */
#if defined(ADP8870_USE_LEDS)
static void adp8870_led_work(struct work_struct *work)
{
        struct adp8870_led *led = container_of(work, struct adp8870_led, work);
        adp8870_write(led->client, ADP8870_ISC1 + led->id - 1,
                         led->new_brightness >> 1);
}

static void adp8870_led_set(struct led_classdev *led_cdev,
                           enum led_brightness value)
{
        struct adp8870_led *led;

        led = container_of(led_cdev, struct adp8870_led, cdev);
        led->new_brightness = value;
        /*
         * Use workqueue for IO since I2C operations can sleep.
         */
        schedule_work(&led->work);
}

static int adp8870_led_setup(struct adp8870_led *led)
{
        struct i2c_client *client = led->client;
        int ret = 0;

        ret = adp8870_write(client, ADP8870_ISC1 + led->id - 1, 0);
        if (ret)
                return ret;

        ret = adp8870_set_bits(client, ADP8870_ISCC, 1 << (led->id - 1));
        if (ret)
                return ret;

        if (led->id > 4)
                ret = adp8870_set_bits(client, ADP8870_ISCT1,
                                (led->flags & 0x3) << ((led->id - 5) * 2));
        else
                ret = adp8870_set_bits(client, ADP8870_ISCT2,
                                (led->flags & 0x3) << ((led->id - 1) * 2));

        return ret;
}

static int __devinit adp8870_led_probe(struct i2c_client *client)
{
        struct adp8870_backlight_platform_data *pdata =
                client->dev.platform_data;
        struct adp8870_bl *data = i2c_get_clientdata(client);
        struct adp8870_led *led, *led_dat;
        struct led_info *cur_led;
        int ret, i;


        led = kcalloc(pdata->num_leds, sizeof(*led), GFP_KERNEL);
        if (led == NULL) {
                dev_err(&client->dev, "failed to alloc memory\n");
                return -ENOMEM;
        }

        ret = adp8870_write(client, ADP8870_ISCLAW, pdata->led_fade_law);
        if (ret)
                goto err_free;

        ret = adp8870_write(client, ADP8870_ISCT1,
                        (pdata->led_on_time & 0x3) << 6);
        if (ret)
                goto err_free;

        ret = adp8870_write(client, ADP8870_ISCF,
                        FADE_VAL(pdata->led_fade_in, pdata->led_fade_out));
        if (ret)
                goto err_free;

        for (i = 0; i < pdata->num_leds; ++i) {
                cur_led = &pdata->leds[i];
                led_dat = &led[i];

                led_dat->id = cur_led->flags & ADP8870_FLAG_LED_MASK;

                if (led_dat->id > 7 || led_dat->id < 1) {
                        dev_err(&client->dev, "Invalid LED ID %d\n",
                                led_dat->id);
                        goto err;
                }

                if (pdata->bl_led_assign & (1 << (led_dat->id - 1))) {
                        dev_err(&client->dev, "LED %d used by Backlight\n",
                                led_dat->id);
                        goto err;
                }

                led_dat->cdev.name = cur_led->name;
                led_dat->cdev.default_trigger = cur_led->default_trigger;
                led_dat->cdev.brightness_set = adp8870_led_set;
                led_dat->cdev.brightness = LED_OFF;
                led_dat->flags = cur_led->flags >> FLAG_OFFT_SHIFT;
                led_dat->client = client;
                led_dat->new_brightness = LED_OFF;
                INIT_WORK(&led_dat->work, adp8870_led_work);

                ret = led_classdev_register(&client->dev, &led_dat->cdev);
                if (ret) {
                        dev_err(&client->dev, "failed to register LED %d\n",
                                led_dat->id);
                        goto err;
                }

                ret = adp8870_led_setup(led_dat);
                if (ret) {
                        dev_err(&client->dev, "failed to write\n");
                        i++;
                        goto err;
                }
        }

        data->led = led;

        return 0;

 err:
        for (i = i - 1; i >= 0; --i) {
                led_classdev_unregister(&led[i].cdev);
                cancel_work_sync(&led[i].work);
        }

 err_free:
        kfree(led);

        return ret;
}

static int __devexit adp8870_led_remove(struct i2c_client *client)
{
        struct adp8870_backlight_platform_data *pdata =
                client->dev.platform_data;
        struct adp8870_bl *data = i2c_get_clientdata(client);
        int i;

        for (i = 0; i < pdata->num_leds; i++) {
                led_classdev_unregister(&data->led[i].cdev);
                cancel_work_sync(&data->led[i].work);
        }

        kfree(data->led);
        return 0;
}
#else
static int __devinit adp8870_led_probe(struct i2c_client *client)
{
        return 0;
}

static int __devexit adp8870_led_remove(struct i2c_client *client)
{
        return 0;
}
#endif

static int adp8870_bl_set(struct backlight_device *bl, int brightness)
{
        struct adp8870_bl *data = bl_get_data(bl);
        struct i2c_client *client = data->client;
        int ret = 0;

        if (data->pdata->en_ambl_sens) {
                if ((brightness > 0) && (brightness < ADP8870_MAX_BRIGHTNESS)) {
                        /* Disable Ambient Light auto adjust */
                        ret = adp8870_clr_bits(client, ADP8870_MDCR,
                                        CMP_AUTOEN);
                        if (ret)
                                return ret;
                        ret = adp8870_write(client, ADP8870_BLMX1, brightness);
                        if (ret)
                                return ret;
                } else {
                        /*
                         * MAX_BRIGHTNESS -> Enable Ambient Light auto adjust
                         * restore daylight l1 sysfs brightness
                         */
                        ret = adp8870_write(client, ADP8870_BLMX1,
                                         data->cached_daylight_max);
                        if (ret)
                                return ret;

                        ret = adp8870_set_bits(client, ADP8870_MDCR,
                                         CMP_AUTOEN);
                        if (ret)
                                return ret;
                }
        } else {
                ret = adp8870_write(client, ADP8870_BLMX1, brightness);
                if (ret)
                        return ret;
        }

        if (data->current_brightness && brightness == 0)
                ret = adp8870_set_bits(client,
                                ADP8870_MDCR, DIM_EN);
        else if (data->current_brightness == 0 && brightness)
                ret = adp8870_clr_bits(client,
                                ADP8870_MDCR, DIM_EN);

        if (!ret)
                data->current_brightness = brightness;

        return ret;
}

static int adp8870_bl_update_status(struct backlight_device *bl)
{
        int brightness = bl->props.brightness;
        if (bl->props.power != FB_BLANK_UNBLANK)
                brightness = 0;

        if (bl->props.fb_blank != FB_BLANK_UNBLANK)
                brightness = 0;

        return adp8870_bl_set(bl, brightness);
}

static int adp8870_bl_get_brightness(struct backlight_device *bl)
{
        struct adp8870_bl *data = bl_get_data(bl);

        return data->current_brightness;
}

static const struct backlight_ops adp8870_bl_ops = {
        .update_status  = adp8870_bl_update_status,
        .get_brightness = adp8870_bl_get_brightness,
};

static int adp8870_bl_setup(struct backlight_device *bl)
{
        struct adp8870_bl *data = bl_get_data(bl);
        struct i2c_client *client = data->client;
        struct adp8870_backlight_platform_data *pdata = data->pdata;
        int ret = 0;

        ret = adp8870_write(client, ADP8870_BLSEL, ~pdata->bl_led_assign);
        if (ret)
                return ret;

        ret = adp8870_write(client, ADP8870_PWMLED, pdata->pwm_assign);
        if (ret)
                return ret;

        ret = adp8870_write(client, ADP8870_BLMX1, pdata->l1_daylight_max);
        if (ret)
                return ret;

        ret = adp8870_write(client, ADP8870_BLDM1, pdata->l1_daylight_dim);
        if (ret)
                return ret;

        if (pdata->en_ambl_sens) {
                data->cached_daylight_max = pdata->l1_daylight_max;
                ret = adp8870_write(client, ADP8870_BLMX2,
                                                pdata->l2_bright_max);
                if (ret)
                        return ret;
                ret = adp8870_write(client, ADP8870_BLDM2,
                                                pdata->l2_bright_dim);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_BLMX3,
                                                pdata->l3_office_max);
                if (ret)
                        return ret;
                ret = adp8870_write(client, ADP8870_BLDM3,
                                                pdata->l3_office_dim);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_BLMX4,
                                                pdata->l4_indoor_max);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_BLDM4,
                                                pdata->l4_indor_dim);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_BLMX5,
                                                pdata->l5_dark_max);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_BLDM5,
                                                pdata->l5_dark_dim);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_L2TRP, pdata->l2_trip);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_L2HYS, pdata->l2_hyst);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_L3TRP, pdata->l3_trip);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_L3HYS, pdata->l3_hyst);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_L4TRP, pdata->l4_trip);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_L4HYS, pdata->l4_hyst);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_L5TRP, pdata->l5_trip);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_L5HYS, pdata->l5_hyst);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_ALS1_EN, L5_EN | L4_EN |
                                                L3_EN | L2_EN);
                if (ret)
                        return ret;

                ret = adp8870_write(client, ADP8870_CMP_CTL,
                        ALS_CMPR_CFG_VAL(pdata->abml_filt));
                if (ret)
                        return ret;
        }

        ret = adp8870_write(client, ADP8870_CFGR,
                        BL_CFGR_VAL(pdata->bl_fade_law, 0));
        if (ret)
                return ret;

        ret = adp8870_write(client, ADP8870_BLFR, FADE_VAL(pdata->bl_fade_in,
                        pdata->bl_fade_out));
        if (ret)
                return ret;
        /*
         * ADP8870 Rev0 requires GDWN_DIS bit set
         */

        ret = adp8870_set_bits(client, ADP8870_MDCR, BLEN | DIM_EN | NSTBY |
                        (data->revid == 0 ? GDWN_DIS : 0));

        return ret;
}

static ssize_t adp8870_show(struct device *dev, char *buf, int reg)
{
        struct adp8870_bl *data = dev_get_drvdata(dev);
        int error;
        uint8_t reg_val;

        mutex_lock(&data->lock);
        error = adp8870_read(data->client, reg, &reg_val);
        mutex_unlock(&data->lock);

        if (error < 0)
                return error;

        return sprintf(buf, "%u\n", reg_val);
}

static ssize_t adp8870_store(struct device *dev, const char *buf,
                         size_t count, int reg)
{
        struct adp8870_bl *data = dev_get_drvdata(dev);
        unsigned long val;
        int ret;

        ret = strict_strtoul(buf, 10, &val);
        if (ret)
                return ret;

        mutex_lock(&data->lock);
        adp8870_write(data->client, reg, val);
        mutex_unlock(&data->lock);

        return count;
}

static ssize_t adp8870_bl_l5_dark_max_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        return adp8870_show(dev, buf, ADP8870_BLMX5);
}

static ssize_t adp8870_bl_l5_dark_max_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        return adp8870_store(dev, buf, count, ADP8870_BLMX5);
}
static DEVICE_ATTR(l5_dark_max, 0664, adp8870_bl_l5_dark_max_show,
                        adp8870_bl_l5_dark_max_store);


static ssize_t adp8870_bl_l4_indoor_max_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        return adp8870_show(dev, buf, ADP8870_BLMX4);
}

static ssize_t adp8870_bl_l4_indoor_max_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        return adp8870_store(dev, buf, count, ADP8870_BLMX4);
}
static DEVICE_ATTR(l4_indoor_max, 0664, adp8870_bl_l4_indoor_max_show,
                        adp8870_bl_l4_indoor_max_store);


static ssize_t adp8870_bl_l3_office_max_show(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        return adp8870_show(dev, buf, ADP8870_BLMX3);
}

static ssize_t adp8870_bl_l3_office_max_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        return adp8870_store(dev, buf, count, ADP8870_BLMX3);
}

static DEVICE_ATTR(l3_office_max, 0664, adp8870_bl_l3_office_max_show,
                        adp8870_bl_l3_office_max_store);

static ssize_t adp8870_bl_l2_bright_max_show(struct device *dev,
                struct device_attribute *attr, char *buf)
{
        return adp8870_show(dev, buf, ADP8870_BLMX2);
}

static ssize_t adp8870_bl_l2_bright_max_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        return adp8870_store(dev, buf, count, ADP8870_BLMX2);
}
static DEVICE_ATTR(l2_bright_max, 0664, adp8870_bl_l2_bright_max_show,
                        adp8870_bl_l2_bright_max_store);

static ssize_t adp8870_bl_l1_daylight_max_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        return adp8870_show(dev, buf, ADP8870_BLMX1);
}

static ssize_t adp8870_bl_l1_daylight_max_store(struct device *dev,
                struct device_attribute *attr, const char *buf, size_t count)
{
        struct adp8870_bl *data = dev_get_drvdata(dev);
        int ret = strict_strtoul(buf, 10, &data->cached_daylight_max);
        if (ret)
                return ret;

        return adp8870_store(dev, buf, count, ADP8870_BLMX1);
}
static DEVICE_ATTR(l1_daylight_max, 0664, adp8870_bl_l1_daylight_max_show,
                        adp8870_bl_l1_daylight_max_store);

static ssize_t adp8870_bl_l5_dark_dim_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        return adp8870_show(dev, buf, ADP8870_BLDM5);
}

static ssize_t adp8870_bl_l5_dark_dim_store(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
{
        return adp8870_store(dev, buf, count, ADP8870_BLDM5);
}
static DEVICE_ATTR(l5_dark_dim, 0664, adp8870_bl_l5_dark_dim_show,
                        adp8870_bl_l5_dark_dim_store);

static ssize_t adp8870_bl_l4_indoor_dim_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        return adp8870_show(dev, buf, ADP8870_BLDM4);
}

static ssize_t adp8870_bl_l4_indoor_dim_store(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
{
        return adp8870_store(dev, buf, count, ADP8870_BLDM4);
}
static DEVICE_ATTR(l4_indoor_dim, 0664, adp8870_bl_l4_indoor_dim_show,
                        adp8870_bl_l4_indoor_dim_store);


static ssize_t adp8870_bl_l3_office_dim_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        return adp8870_show(dev, buf, ADP8870_BLDM3);
}

static ssize_t adp8870_bl_l3_office_dim_store(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
{
        return adp8870_store(dev, buf, count, ADP8870_BLDM3);
}
static DEVICE_ATTR(l3_office_dim, 0664, adp8870_bl_l3_office_dim_show,
                        adp8870_bl_l3_office_dim_store);

static ssize_t adp8870_bl_l2_bright_dim_show(struct device *dev,
                        struct device_attribute *attr, char *buf)
{
        return adp8870_show(dev, buf, ADP8870_BLDM2);
}

static ssize_t adp8870_bl_l2_bright_dim_store(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
{
        return adp8870_store(dev, buf, count, ADP8870_BLDM2);
}
static DEVICE_ATTR(l2_bright_dim, 0664, adp8870_bl_l2_bright_dim_show,
                        adp8870_bl_l2_bright_dim_store);

static ssize_t adp8870_bl_l1_daylight_dim_show(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        return adp8870_show(dev, buf, ADP8870_BLDM1);
}

static ssize_t adp8870_bl_l1_daylight_dim_store(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
{
        return adp8870_store(dev, buf, count, ADP8870_BLDM1);
}
static DEVICE_ATTR(l1_daylight_dim, 0664, adp8870_bl_l1_daylight_dim_show,
                        adp8870_bl_l1_daylight_dim_store);

#ifdef ADP8870_EXT_FEATURES
static ssize_t adp8870_bl_ambient_light_level_show(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        struct adp8870_bl *data = dev_get_drvdata(dev);
        int error;
        uint8_t reg_val;
        uint16_t ret_val;

        mutex_lock(&data->lock);
        error = adp8870_read(data->client, ADP8870_PH1LEVL, &reg_val);
        if (error < 0) {
                mutex_unlock(&data->lock);
                return error;
        }
        ret_val = reg_val;
        error = adp8870_read(data->client, ADP8870_PH1LEVH, &reg_val);
        mutex_unlock(&data->lock);

        if (error < 0)
                return error;

        /* Return 13-bit conversion value for the first light sensor */
        ret_val += (reg_val & 0x1F) << 8;

        return sprintf(buf, "%u\n", ret_val);
}
static DEVICE_ATTR(ambient_light_level, 0444,
                adp8870_bl_ambient_light_level_show, NULL);

static ssize_t adp8870_bl_ambient_light_zone_show(struct device *dev,
                                     struct device_attribute *attr, char *buf)
{
        struct adp8870_bl *data = dev_get_drvdata(dev);
        int error;
        uint8_t reg_val;

        mutex_lock(&data->lock);
        error = adp8870_read(data->client, ADP8870_CFGR, &reg_val);
        mutex_unlock(&data->lock);

        if (error < 0)
                return error;

        return sprintf(buf, "%u\n",
                ((reg_val >> CFGR_BLV_SHIFT) & CFGR_BLV_MASK) + 1);
}

static ssize_t adp8870_bl_ambient_light_zone_store(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t count)
{
        struct adp8870_bl *data = dev_get_drvdata(dev);
        unsigned long val;
        uint8_t reg_val;
        int ret;

        ret = strict_strtoul(buf, 10, &val);
        if (ret)
                return ret;

        if (val == 0) {
                /* Enable automatic ambient light sensing */
                adp8870_set_bits(data->client, ADP8870_MDCR, CMP_AUTOEN);
        } else if ((val > 0) && (val < 6)) {
                /* Disable automatic ambient light sensing */
                adp8870_clr_bits(data->client, ADP8870_MDCR, CMP_AUTOEN);

                /* Set user supplied ambient light zone */
                mutex_lock(&data->lock);
                adp8870_read(data->client, ADP8870_CFGR, &reg_val);
                reg_val &= ~(CFGR_BLV_MASK << CFGR_BLV_SHIFT);
                reg_val |= (val - 1) << CFGR_BLV_SHIFT;
                adp8870_write(data->client, ADP8870_CFGR, reg_val);
                mutex_unlock(&data->lock);
        }

        return count;
}
static DEVICE_ATTR(ambient_light_zone, 0664,
                adp8870_bl_ambient_light_zone_show,
                adp8870_bl_ambient_light_zone_store);
#endif

static struct attribute *adp8870_bl_attributes[] = {
        &dev_attr_l5_dark_max.attr,
        &dev_attr_l5_dark_dim.attr,
        &dev_attr_l4_indoor_max.attr,
        &dev_attr_l4_indoor_dim.attr,
        &dev_attr_l3_office_max.attr,
        &dev_attr_l3_office_dim.attr,
        &dev_attr_l2_bright_max.attr,
        &dev_attr_l2_bright_dim.attr,
        &dev_attr_l1_daylight_max.attr,
        &dev_attr_l1_daylight_dim.attr,
#ifdef ADP8870_EXT_FEATURES
        &dev_attr_ambient_light_level.attr,
        &dev_attr_ambient_light_zone.attr,
#endif
        NULL
};

static const struct attribute_group adp8870_bl_attr_group = {
        .attrs = adp8870_bl_attributes,
};

static int __devinit adp8870_probe(struct i2c_client *client,
                                        const struct i2c_device_id *id)
{
        struct backlight_properties props;
        struct backlight_device *bl;
        struct adp8870_bl *data;
        struct adp8870_backlight_platform_data *pdata =
                client->dev.platform_data;
        uint8_t reg_val;
        int ret;

        if (!i2c_check_functionality(client->adapter,
                                        I2C_FUNC_SMBUS_BYTE_DATA)) {
                dev_err(&client->dev, "SMBUS Byte Data not Supported\n");
                return -EIO;
        }

        if (!pdata) {
                dev_err(&client->dev, "no platform data?\n");
                return -EINVAL;
        }

        ret = adp8870_read(client, ADP8870_MFDVID, &reg_val);
        if (ret < 0)
                return -EIO;

        if (ADP8870_MANID(reg_val) != ADP8870_MANUFID) {
                dev_err(&client->dev, "failed to probe\n");
                return -ENODEV;
        }

        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (data == NULL)
                return -ENOMEM;

        data->revid = ADP8870_DEVID(reg_val);
        data->client = client;
        data->pdata = pdata;
        data->id = id->driver_data;
        data->current_brightness = 0;
        i2c_set_clientdata(client, data);

        mutex_init(&data->lock);

        memset(&props, 0, sizeof(props));
        props.type = BACKLIGHT_RAW;
        props.max_brightness = props.brightness = ADP8870_MAX_BRIGHTNESS;
        bl = backlight_device_register(dev_driver_string(&client->dev),
                        &client->dev, data, &adp8870_bl_ops, &props);
        if (IS_ERR(bl)) {
                dev_err(&client->dev, "failed to register backlight\n");
                ret = PTR_ERR(bl);
                goto out2;
        }

        data->bl = bl;

        if (pdata->en_ambl_sens)
                ret = sysfs_create_group(&bl->dev.kobj,
                        &adp8870_bl_attr_group);

        if (ret) {
                dev_err(&client->dev, "failed to register sysfs\n");
                goto out1;
        }

        ret = adp8870_bl_setup(bl);
        if (ret) {
                ret = -EIO;
                goto out;
        }

        backlight_update_status(bl);

        dev_info(&client->dev, "Rev.%d Backlight\n", data->revid);

        if (pdata->num_leds)
                adp8870_led_probe(client);

        return 0;

out:
        if (data->pdata->en_ambl_sens)
                sysfs_remove_group(&data->bl->dev.kobj,
                        &adp8870_bl_attr_group);
out1:
        backlight_device_unregister(bl);
out2:
        kfree(data);

        return ret;
}

static int __devexit adp8870_remove(struct i2c_client *client)
{
        struct adp8870_bl *data = i2c_get_clientdata(client);

        adp8870_clr_bits(client, ADP8870_MDCR, NSTBY);

        if (data->led)
                adp8870_led_remove(client);

        if (data->pdata->en_ambl_sens)
                sysfs_remove_group(&data->bl->dev.kobj,
                        &adp8870_bl_attr_group);

        backlight_device_unregister(data->bl);
        kfree(data);

        return 0;
}

#ifdef CONFIG_PM
static int adp8870_i2c_suspend(struct i2c_client *client, pm_message_t message)
{
        adp8870_clr_bits(client, ADP8870_MDCR, NSTBY);

        return 0;
}

static int adp8870_i2c_resume(struct i2c_client *client)
{
        adp8870_set_bits(client, ADP8870_MDCR, NSTBY);

        return 0;
}
#else
#define adp8870_i2c_suspend NULL
#define adp8870_i2c_resume NULL
#endif

static const struct i2c_device_id adp8870_id[] = {
        { "adp8870", 0 },
        { }
};
MODULE_DEVICE_TABLE(i2c, adp8870_id);

static struct i2c_driver adp8870_driver = {
        .driver = {
                .name = KBUILD_MODNAME,
        },
        .probe    = adp8870_probe,
        .remove   = __devexit_p(adp8870_remove),
        .suspend = adp8870_i2c_suspend,
        .resume  = adp8870_i2c_resume,
        .id_table = adp8870_id,
};

static int __init adp8870_init(void)
{
        return i2c_add_driver(&adp8870_driver);
}
module_init(adp8870_init);

static void __exit adp8870_exit(void)

{
        i2c_del_driver(&adp8870_driver);
}
module_exit(adp8870_exit);

MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
MODULE_DESCRIPTION("ADP8870 Backlight driver");
MODULE_ALIAS("i2c:adp8870-backlight");