/*
 * lp5523.c - LP5523 LED Driver
 *
 * Copyright (C) 2010 Nokia Corporation
 *
 * Contact: Samu Onkalo <samu.p.onkalo@nokia.com>
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/i2c.h>
#include <linux/mutex.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/delay.h>
#include <linux/ctype.h>
#include <linux/spinlock.h>
#include <linux/wait.h>
#include <linux/leds.h>
#include <linux/leds-lp5523.h>
#include <linux/workqueue.h>
#include <linux/slab.h>

#define LP5523_REG_ENABLE               0x00
#define LP5523_REG_OP_MODE              0x01
#define LP5523_REG_RATIOMETRIC_MSB      0x02
#define LP5523_REG_RATIOMETRIC_LSB      0x03
#define LP5523_REG_ENABLE_LEDS_MSB      0x04
#define LP5523_REG_ENABLE_LEDS_LSB      0x05
#define LP5523_REG_LED_CNTRL_BASE       0x06
#define LP5523_REG_LED_PWM_BASE         0x16
#define LP5523_REG_LED_CURRENT_BASE     0x26
#define LP5523_REG_CONFIG               0x36
#define LP5523_REG_CHANNEL1_PC          0x37
#define LP5523_REG_CHANNEL2_PC          0x38
#define LP5523_REG_CHANNEL3_PC          0x39
#define LP5523_REG_STATUS               0x3a
#define LP5523_REG_GPO                  0x3b
#define LP5523_REG_VARIABLE             0x3c
#define LP5523_REG_RESET                0x3d
#define LP5523_REG_TEMP_CTRL            0x3e
#define LP5523_REG_TEMP_READ            0x3f
#define LP5523_REG_TEMP_WRITE           0x40
#define LP5523_REG_LED_TEST_CTRL        0x41
#define LP5523_REG_LED_TEST_ADC         0x42
#define LP5523_REG_ENG1_VARIABLE        0x45
#define LP5523_REG_ENG2_VARIABLE        0x46
#define LP5523_REG_ENG3_VARIABLE        0x47
#define LP5523_REG_MASTER_FADER1        0x48
#define LP5523_REG_MASTER_FADER2        0x49
#define LP5523_REG_MASTER_FADER3        0x4a
#define LP5523_REG_CH1_PROG_START       0x4c
#define LP5523_REG_CH2_PROG_START       0x4d
#define LP5523_REG_CH3_PROG_START       0x4e
#define LP5523_REG_PROG_PAGE_SEL        0x4f
#define LP5523_REG_PROG_MEM             0x50

#define LP5523_CMD_LOAD                 0x15 /* 00010101 */
#define LP5523_CMD_RUN                  0x2a /* 00101010 */
#define LP5523_CMD_DISABLED             0x00 /* 00000000 */

#define LP5523_ENABLE                   0x40
#define LP5523_AUTO_INC                 0x40
#define LP5523_PWR_SAVE                 0x20
#define LP5523_PWM_PWR_SAVE             0x04
#define LP5523_CP_1                     0x08
#define LP5523_CP_1_5                   0x10
#define LP5523_CP_AUTO                  0x18
#define LP5523_INT_CLK                  0x01
#define LP5523_AUTO_CLK                 0x02
#define LP5523_EN_LEDTEST               0x80
#define LP5523_LEDTEST_DONE             0x80

#define LP5523_DEFAULT_CURRENT          50 /* microAmps */
#define LP5523_PROGRAM_LENGTH           32 /* in bytes */
#define LP5523_PROGRAM_PAGES            6
#define LP5523_ADC_SHORTCIRC_LIM        80

#define LP5523_LEDS                     9
#define LP5523_ENGINES                  3

#define LP5523_ENG_MASK_BASE            0x30 /* 00110000 */

#define LP5523_ENG_STATUS_MASK          0x07 /* 00000111 */

#define LP5523_IRQ_FLAGS                IRQF_TRIGGER_FALLING

#define LP5523_EXT_CLK_USED             0x08

#define LED_ACTIVE(mux, led)            (!!(mux & (0x0001 << led)))
#define SHIFT_MASK(id)                  (((id) - 1) * 2)

struct lp5523_engine {
        int             id;
        u8              mode;
        u8              prog_page;
        u8              mux_page;
        u16             led_mux;
        u8              engine_mask;
};

struct lp5523_led {
        int                     id;
        u8                      chan_nr;
        u8                      led_current;
        u8                      max_current;
        struct led_classdev     cdev;
        struct work_struct      brightness_work;
        u8                      brightness;
};

struct lp5523_chip {
        struct mutex            lock; /* Serialize control */
        struct i2c_client       *client;
        struct lp5523_engine    engines[LP5523_ENGINES];
        struct lp5523_led       leds[LP5523_LEDS];
        struct lp5523_platform_data *pdata;
        u8                      num_channels;
        u8                      num_leds;
};

static inline struct lp5523_led *cdev_to_led(struct led_classdev *cdev)
{
        return container_of(cdev, struct lp5523_led, cdev);
}

static inline struct lp5523_chip *engine_to_lp5523(struct lp5523_engine *engine)
{
        return container_of(engine, struct lp5523_chip,
                            engines[engine->id - 1]);
}

static inline struct lp5523_chip *led_to_lp5523(struct lp5523_led *led)
{
        return container_of(led, struct lp5523_chip,
                            leds[led->id]);
}

static int lp5523_set_mode(struct lp5523_engine *engine, u8 mode);
static int lp5523_set_engine_mode(struct lp5523_engine *engine, u8 mode);
static int lp5523_load_program(struct lp5523_engine *engine, const u8 *pattern);

static void lp5523_led_brightness_work(struct work_struct *work);

static int lp5523_write(struct i2c_client *client, u8 reg, u8 value)
{
        return i2c_smbus_write_byte_data(client, reg, value);
}

static int lp5523_read(struct i2c_client *client, u8 reg, u8 *buf)
{
        s32 ret = i2c_smbus_read_byte_data(client, reg);

        if (ret < 0)
                return -EIO;

        *buf = ret;
        return 0;
}

static int lp5523_detect(struct i2c_client *client)
{
        int ret;
        u8 buf;

        ret = lp5523_write(client, LP5523_REG_ENABLE, 0x40);
        if (ret)
                return ret;
        ret = lp5523_read(client, LP5523_REG_ENABLE, &buf);
        if (ret)
                return ret;
        if (buf == 0x40)
                return 0;
        else
                return -ENODEV;
}

static int lp5523_configure(struct i2c_client *client)
{
        struct lp5523_chip *chip = i2c_get_clientdata(client);
        int ret = 0;
        u8 status;

        /* one pattern per engine setting led mux start and stop addresses */
        static const u8 pattern[][LP5523_PROGRAM_LENGTH] =  {
                { 0x9c, 0x30, 0x9c, 0xb0, 0x9d, 0x80, 0xd8, 0x00, 0},
                { 0x9c, 0x40, 0x9c, 0xc0, 0x9d, 0x80, 0xd8, 0x00, 0},
                { 0x9c, 0x50, 0x9c, 0xd0, 0x9d, 0x80, 0xd8, 0x00, 0},
        };

        ret |= lp5523_write(client, LP5523_REG_ENABLE, LP5523_ENABLE);
        /* Chip startup time is 500 us, 1 - 2 ms gives some margin */
        usleep_range(1000, 2000);

        ret |= lp5523_write(client, LP5523_REG_CONFIG,
                            LP5523_AUTO_INC | LP5523_PWR_SAVE |
                            LP5523_CP_AUTO | LP5523_AUTO_CLK |
                            LP5523_PWM_PWR_SAVE);

        /* turn on all leds */
        ret |= lp5523_write(client, LP5523_REG_ENABLE_LEDS_MSB, 0x01);
        ret |= lp5523_write(client, LP5523_REG_ENABLE_LEDS_LSB, 0xff);

        /* hardcode 32 bytes of memory for each engine from program memory */
        ret |= lp5523_write(client, LP5523_REG_CH1_PROG_START, 0x00);
        ret |= lp5523_write(client, LP5523_REG_CH2_PROG_START, 0x10);
        ret |= lp5523_write(client, LP5523_REG_CH3_PROG_START, 0x20);

        /* write led mux address space for each channel */
        ret |= lp5523_load_program(&chip->engines[0], pattern[0]);
        ret |= lp5523_load_program(&chip->engines[1], pattern[1]);
        ret |= lp5523_load_program(&chip->engines[2], pattern[2]);

        if (ret) {
                dev_err(&client->dev, "could not load mux programs\n");
                return -1;
        }

        /* set all engines exec state and mode to run 00101010 */
        ret |= lp5523_write(client, LP5523_REG_ENABLE,
                            (LP5523_CMD_RUN | LP5523_ENABLE));

        ret |= lp5523_write(client, LP5523_REG_OP_MODE, LP5523_CMD_RUN);

        if (ret) {
                dev_err(&client->dev, "could not start mux programs\n");
                return -1;
        }

        /* Let the programs run for couple of ms and check the engine status */
        usleep_range(3000, 6000);
        lp5523_read(client, LP5523_REG_STATUS, &status);
        status &= LP5523_ENG_STATUS_MASK;

        if (status == LP5523_ENG_STATUS_MASK) {
                dev_dbg(&client->dev, "all engines configured\n");
        } else {
                dev_info(&client->dev, "status == %x\n", status);
                dev_err(&client->dev, "cound not configure LED engine\n");
                return -1;
        }

        dev_info(&client->dev, "disabling engines\n");

        ret |= lp5523_write(client, LP5523_REG_OP_MODE, LP5523_CMD_DISABLED);

        return ret;
}

static int lp5523_set_engine_mode(struct lp5523_engine *engine, u8 mode)
{
        struct lp5523_chip *chip = engine_to_lp5523(engine);
        struct i2c_client *client = chip->client;
        int ret;
        u8 engine_state;

        ret = lp5523_read(client, LP5523_REG_OP_MODE, &engine_state);
        if (ret)
                goto fail;

        engine_state &= ~(engine->engine_mask);

        /* set mode only for this engine */
        mode &= engine->engine_mask;

        engine_state |= mode;

        ret |= lp5523_write(client, LP5523_REG_OP_MODE, engine_state);
fail:
        return ret;
}

static int lp5523_load_mux(struct lp5523_engine *engine, u16 mux)
{
        struct lp5523_chip *chip = engine_to_lp5523(engine);
        struct i2c_client *client = chip->client;
        int ret = 0;

        ret |= lp5523_set_engine_mode(engine, LP5523_CMD_LOAD);

        ret |= lp5523_write(client, LP5523_REG_PROG_PAGE_SEL, engine->mux_page);
        ret |= lp5523_write(client, LP5523_REG_PROG_MEM,
                            (u8)(mux >> 8));
        ret |= lp5523_write(client, LP5523_REG_PROG_MEM + 1, (u8)(mux));
        engine->led_mux = mux;

        return ret;
}

static int lp5523_load_program(struct lp5523_engine *engine, const u8 *pattern)
{
        struct lp5523_chip *chip = engine_to_lp5523(engine);
        struct i2c_client *client = chip->client;

        int ret = 0;

        ret |= lp5523_set_engine_mode(engine, LP5523_CMD_LOAD);

        ret |= lp5523_write(client, LP5523_REG_PROG_PAGE_SEL,
                            engine->prog_page);
        ret |= i2c_smbus_write_i2c_block_data(client, LP5523_REG_PROG_MEM,
                                              LP5523_PROGRAM_LENGTH, pattern);

        return ret;
}

static int lp5523_run_program(struct lp5523_engine *engine)
{
        struct lp5523_chip *chip = engine_to_lp5523(engine);
        struct i2c_client *client = chip->client;
        int ret;

        ret = lp5523_write(client, LP5523_REG_ENABLE,
                                        LP5523_CMD_RUN | LP5523_ENABLE);
        if (ret)
                goto fail;

        ret = lp5523_set_engine_mode(engine, LP5523_CMD_RUN);
fail:
        return ret;
}

static int lp5523_mux_parse(const char *buf, u16 *mux, size_t len)
{
        int i;
        u16 tmp_mux = 0;
        len = len < LP5523_LEDS ? len : LP5523_LEDS;
        for (i = 0; i < len; i++) {
                switch (buf[i]) {
                case '1':
                        tmp_mux |= (1 << i);
                        break;
                case '0':
                        break;
                case '\n':
                        i = len;
                        break;
                default:
                        return -1;
                }
        }
        *mux = tmp_mux;

        return 0;
}

static void lp5523_mux_to_array(u16 led_mux, char *array)
{
        int i, pos = 0;
        for (i = 0; i < LP5523_LEDS; i++)
                pos += sprintf(array + pos, "%x", LED_ACTIVE(led_mux, i));

        array[pos] = '\0';
}

/*--------------------------------------------------------------*/
/*                      Sysfs interface                         */
/*--------------------------------------------------------------*/

static ssize_t show_engine_leds(struct device *dev,
                            struct device_attribute *attr,
                            char *buf, int nr)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct lp5523_chip *chip = i2c_get_clientdata(client);
        char mux[LP5523_LEDS + 1];

        lp5523_mux_to_array(chip->engines[nr - 1].led_mux, mux);

        return sprintf(buf, "%s\n", mux);
}

#define show_leds(nr)                                                   \
static ssize_t show_engine##nr##_leds(struct device *dev,               \
                            struct device_attribute *attr,              \
                            char *buf)                                  \
{                                                                       \
        return show_engine_leds(dev, attr, buf, nr);                    \
}
show_leds(1)
show_leds(2)
show_leds(3)

static ssize_t store_engine_leds(struct device *dev,
                             struct device_attribute *attr,
                             const char *buf, size_t len, int nr)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct lp5523_chip *chip = i2c_get_clientdata(client);
        u16 mux = 0;
        ssize_t ret;

        if (lp5523_mux_parse(buf, &mux, len))
                return -EINVAL;

        mutex_lock(&chip->lock);
        ret = -EINVAL;
        if (chip->engines[nr - 1].mode != LP5523_CMD_LOAD)
                goto leave;

        if (lp5523_load_mux(&chip->engines[nr - 1], mux))
                goto leave;

        ret = len;
leave:
        mutex_unlock(&chip->lock);
        return ret;
}

#define store_leds(nr)                                          \
static ssize_t store_engine##nr##_leds(struct device *dev,      \
                             struct device_attribute *attr,     \
                             const char *buf, size_t len)       \
{                                                               \
        return store_engine_leds(dev, attr, buf, len, nr);      \
}
store_leds(1)
store_leds(2)
store_leds(3)

static ssize_t lp5523_selftest(struct device *dev,
                               struct device_attribute *attr,
                               char *buf)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct lp5523_chip *chip = i2c_get_clientdata(client);
        int i, ret, pos = 0;
        int led = 0;
        u8 status, adc, vdd;

        mutex_lock(&chip->lock);

        ret = lp5523_read(chip->client, LP5523_REG_STATUS, &status);
        if (ret < 0)
                goto fail;

        /* Check that ext clock is really in use if requested */
        if ((chip->pdata) && (chip->pdata->clock_mode == LP5523_CLOCK_EXT))
                if  ((status & LP5523_EXT_CLK_USED) == 0)
                        goto fail;

        /* Measure VDD (i.e. VBAT) first (channel 16 corresponds to VDD) */
        lp5523_write(chip->client, LP5523_REG_LED_TEST_CTRL,
                                    LP5523_EN_LEDTEST | 16);
        usleep_range(3000, 6000); /* ADC conversion time is typically 2.7 ms */
        ret = lp5523_read(chip->client, LP5523_REG_STATUS, &status);
        if (!(status & LP5523_LEDTEST_DONE))
                usleep_range(3000, 6000); /* Was not ready. Wait little bit */

        ret |= lp5523_read(chip->client, LP5523_REG_LED_TEST_ADC, &vdd);
        vdd--;  /* There may be some fluctuation in measurement */

        for (i = 0; i < LP5523_LEDS; i++) {
                /* Skip non-existing channels */
                if (chip->pdata->led_config[i].led_current == 0)
                        continue;

                /* Set default current */
                lp5523_write(chip->client,
                        LP5523_REG_LED_CURRENT_BASE + i,
                        chip->pdata->led_config[i].led_current);

                lp5523_write(chip->client, LP5523_REG_LED_PWM_BASE + i, 0xff);
                /* let current stabilize 2 - 4ms before measurements start */
                usleep_range(2000, 4000);
                lp5523_write(chip->client,
                             LP5523_REG_LED_TEST_CTRL,
                             LP5523_EN_LEDTEST | i);
                /* ADC conversion time is 2.7 ms typically */
                usleep_range(3000, 6000);
                ret = lp5523_read(chip->client, LP5523_REG_STATUS, &status);
                if (!(status & LP5523_LEDTEST_DONE))
                        usleep_range(3000, 6000);/* Was not ready. Wait. */
                ret |= lp5523_read(chip->client, LP5523_REG_LED_TEST_ADC, &adc);

                if (adc >= vdd || adc < LP5523_ADC_SHORTCIRC_LIM)
                        pos += sprintf(buf + pos, "LED %d FAIL\n", i);

                lp5523_write(chip->client, LP5523_REG_LED_PWM_BASE + i, 0x00);

                /* Restore current */
                lp5523_write(chip->client,
                        LP5523_REG_LED_CURRENT_BASE + i,
                        chip->leds[led].led_current);
                led++;
        }
        if (pos == 0)
                pos = sprintf(buf, "OK\n");
        goto release_lock;
fail:
        pos = sprintf(buf, "FAIL\n");

release_lock:
        mutex_unlock(&chip->lock);

        return pos;
}

static void lp5523_set_brightness(struct led_classdev *cdev,
                             enum led_brightness brightness)
{
        struct lp5523_led *led = cdev_to_led(cdev);

        led->brightness = (u8)brightness;

        schedule_work(&led->brightness_work);
}

static void lp5523_led_brightness_work(struct work_struct *work)
{
        struct lp5523_led *led = container_of(work,
                                              struct lp5523_led,
                                              brightness_work);
        struct lp5523_chip *chip = led_to_lp5523(led);
        struct i2c_client *client = chip->client;

        mutex_lock(&chip->lock);

        lp5523_write(client, LP5523_REG_LED_PWM_BASE + led->chan_nr,
                     led->brightness);

        mutex_unlock(&chip->lock);
}

static int lp5523_do_store_load(struct lp5523_engine *engine,
                                const char *buf, size_t len)
{
        struct lp5523_chip *chip = engine_to_lp5523(engine);
        struct i2c_client *client = chip->client;
        int  ret, nrchars, offset = 0, i = 0;
        char c[3];
        unsigned cmd;
        u8 pattern[LP5523_PROGRAM_LENGTH] = {0};

        while ((offset < len - 1) && (i < LP5523_PROGRAM_LENGTH)) {
                /* separate sscanfs because length is working only for %s */
                ret = sscanf(buf + offset, "%2s%n ", c, &nrchars);
                ret = sscanf(c, "%2x", &cmd);
                if (ret != 1)
                        goto fail;
                pattern[i] = (u8)cmd;

                offset += nrchars;
                i++;
        }

        /* Each instruction is 16bit long. Check that length is even */
        if (i % 2)
                goto fail;

        mutex_lock(&chip->lock);

        if (engine->mode == LP5523_CMD_LOAD)
                ret = lp5523_load_program(engine, pattern);
        else
                ret = -EINVAL;

        mutex_unlock(&chip->lock);

        if (ret) {
                dev_err(&client->dev, "failed loading pattern\n");
                return ret;
        }

        return len;
fail:
        dev_err(&client->dev, "wrong pattern format\n");
        return -EINVAL;
}

static ssize_t store_engine_load(struct device *dev,
                                     struct device_attribute *attr,
                                     const char *buf, size_t len, int nr)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct lp5523_chip *chip = i2c_get_clientdata(client);
        return lp5523_do_store_load(&chip->engines[nr - 1], buf, len);
}

#define store_load(nr)                                                  \
static ssize_t store_engine##nr##_load(struct device *dev,              \
                                     struct device_attribute *attr,     \
                                     const char *buf, size_t len)       \
{                                                                       \
        return store_engine_load(dev, attr, buf, len, nr);              \
}
store_load(1)
store_load(2)
store_load(3)

static ssize_t show_engine_mode(struct device *dev,
                                struct device_attribute *attr,
                                char *buf, int nr)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct lp5523_chip *chip = i2c_get_clientdata(client);
        switch (chip->engines[nr - 1].mode) {
        case LP5523_CMD_RUN:
                return sprintf(buf, "run\n");
        case LP5523_CMD_LOAD:
                return sprintf(buf, "load\n");
        case LP5523_CMD_DISABLED:
                return sprintf(buf, "disabled\n");
        default:
                return sprintf(buf, "disabled\n");
        }
}

#define show_mode(nr)                                                   \
static ssize_t show_engine##nr##_mode(struct device *dev,               \
                                    struct device_attribute *attr,      \
                                    char *buf)                          \
{                                                                       \
        return show_engine_mode(dev, attr, buf, nr);                    \
}
show_mode(1)
show_mode(2)
show_mode(3)

static ssize_t store_engine_mode(struct device *dev,
                                 struct device_attribute *attr,
                                 const char *buf, size_t len, int nr)
{
        struct i2c_client *client = to_i2c_client(dev);
        struct lp5523_chip *chip = i2c_get_clientdata(client);
        struct lp5523_engine *engine = &chip->engines[nr - 1];
        mutex_lock(&chip->lock);

        if (!strncmp(buf, "run", 3))
                lp5523_set_mode(engine, LP5523_CMD_RUN);
        else if (!strncmp(buf, "load", 4))
                lp5523_set_mode(engine, LP5523_CMD_LOAD);
        else if (!strncmp(buf, "disabled", 8))
                lp5523_set_mode(engine, LP5523_CMD_DISABLED);

        mutex_unlock(&chip->lock);
        return len;
}

#define store_mode(nr)                                                  \
static ssize_t store_engine##nr##_mode(struct device *dev,              \
                                     struct device_attribute *attr,     \
                                     const char *buf, size_t len)       \
{                                                                       \
        return store_engine_mode(dev, attr, buf, len, nr);              \
}
store_mode(1)
store_mode(2)
store_mode(3)

static ssize_t show_max_current(struct device *dev,
                            struct device_attribute *attr,
                            char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct lp5523_led *led = cdev_to_led(led_cdev);

        return sprintf(buf, "%d\n", led->max_current);
}

static ssize_t show_current(struct device *dev,
                            struct device_attribute *attr,
                            char *buf)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct lp5523_led *led = cdev_to_led(led_cdev);

        return sprintf(buf, "%d\n", led->led_current);
}

static ssize_t store_current(struct device *dev,
                             struct device_attribute *attr,
                             const char *buf, size_t len)
{
        struct led_classdev *led_cdev = dev_get_drvdata(dev);
        struct lp5523_led *led = cdev_to_led(led_cdev);
        struct lp5523_chip *chip = led_to_lp5523(led);
        ssize_t ret;
        unsigned long curr;

        if (strict_strtoul(buf, 0, &curr))
                return -EINVAL;

        if (curr > led->max_current)
                return -EINVAL;

        mutex_lock(&chip->lock);
        ret = lp5523_write(chip->client,
                        LP5523_REG_LED_CURRENT_BASE + led->chan_nr,
                        (u8)curr);
        mutex_unlock(&chip->lock);

        if (ret < 0)
                return ret;

        led->led_current = (u8)curr;

        return len;
}

/* led class device attributes */
static DEVICE_ATTR(led_current, S_IRUGO | S_IWUSR, show_current, store_current);
static DEVICE_ATTR(max_current, S_IRUGO , show_max_current, NULL);

static struct attribute *lp5523_led_attributes[] = {
        &dev_attr_led_current.attr,
        &dev_attr_max_current.attr,
        NULL,
};

static struct attribute_group lp5523_led_attribute_group = {
        .attrs = lp5523_led_attributes
};

/* device attributes */
static DEVICE_ATTR(engine1_mode, S_IRUGO | S_IWUSR,
                   show_engine1_mode, store_engine1_mode);
static DEVICE_ATTR(engine2_mode, S_IRUGO | S_IWUSR,
                   show_engine2_mode, store_engine2_mode);
static DEVICE_ATTR(engine3_mode, S_IRUGO | S_IWUSR,
                   show_engine3_mode, store_engine3_mode);
static DEVICE_ATTR(engine1_leds, S_IRUGO | S_IWUSR,
                   show_engine1_leds, store_engine1_leds);
static DEVICE_ATTR(engine2_leds, S_IRUGO | S_IWUSR,
                   show_engine2_leds, store_engine2_leds);
static DEVICE_ATTR(engine3_leds, S_IRUGO | S_IWUSR,
                   show_engine3_leds, store_engine3_leds);
static DEVICE_ATTR(engine1_load, S_IWUSR, NULL, store_engine1_load);
static DEVICE_ATTR(engine2_load, S_IWUSR, NULL, store_engine2_load);
static DEVICE_ATTR(engine3_load, S_IWUSR, NULL, store_engine3_load);
static DEVICE_ATTR(selftest, S_IRUGO, lp5523_selftest, NULL);

static struct attribute *lp5523_attributes[] = {
        &dev_attr_engine1_mode.attr,
        &dev_attr_engine2_mode.attr,
        &dev_attr_engine3_mode.attr,
        &dev_attr_selftest.attr,
        &dev_attr_engine1_load.attr,
        &dev_attr_engine1_leds.attr,
        &dev_attr_engine2_load.attr,
        &dev_attr_engine2_leds.attr,
        &dev_attr_engine3_load.attr,
        &dev_attr_engine3_leds.attr,
};

static const struct attribute_group lp5523_group = {
        .attrs = lp5523_attributes,
};

static int lp5523_register_sysfs(struct i2c_client *client)
{
        struct device *dev = &client->dev;
        int ret;

        ret = sysfs_create_group(&dev->kobj, &lp5523_group);
        if (ret < 0)
                return ret;

        return 0;
}

static void lp5523_unregister_sysfs(struct i2c_client *client)
{
        struct lp5523_chip *chip = i2c_get_clientdata(client);
        struct device *dev = &client->dev;
        int i;

        sysfs_remove_group(&dev->kobj, &lp5523_group);

        for (i = 0; i < chip->num_leds; i++)
                sysfs_remove_group(&chip->leds[i].cdev.dev->kobj,
                                &lp5523_led_attribute_group);
}

/*--------------------------------------------------------------*/
/*                      Set chip operating mode                 */
/*--------------------------------------------------------------*/
static int lp5523_set_mode(struct lp5523_engine *engine, u8 mode)
{
        int ret = 0;

        /* if in that mode already do nothing, except for run */
        if (mode == engine->mode && mode != LP5523_CMD_RUN)
                return 0;

        if (mode == LP5523_CMD_RUN) {
                ret = lp5523_run_program(engine);
        } else if (mode == LP5523_CMD_LOAD) {
                lp5523_set_engine_mode(engine, LP5523_CMD_DISABLED);
                lp5523_set_engine_mode(engine, LP5523_CMD_LOAD);
        } else if (mode == LP5523_CMD_DISABLED) {
                lp5523_set_engine_mode(engine, LP5523_CMD_DISABLED);
        }

        engine->mode = mode;

        return ret;
}

/*--------------------------------------------------------------*/
/*                      Probe, Attach, Remove                   */
/*--------------------------------------------------------------*/
static int __init lp5523_init_engine(struct lp5523_engine *engine, int id)
{
        if (id < 1 || id > LP5523_ENGINES)
                return -1;
        engine->id = id;
        engine->engine_mask = LP5523_ENG_MASK_BASE >> SHIFT_MASK(id);
        engine->prog_page = id - 1;
        engine->mux_page = id + 2;

        return 0;
}

static int __devinit lp5523_init_led(struct lp5523_led *led, struct device *dev,
                           int chan, struct lp5523_platform_data *pdata)
{
        char name[32];
        int res;

        if (chan >= LP5523_LEDS)
                return -EINVAL;

        if (pdata->led_config[chan].led_current) {
                led->led_current = pdata->led_config[chan].led_current;
                led->max_current = pdata->led_config[chan].max_current;
                led->chan_nr = pdata->led_config[chan].chan_nr;

                if (led->chan_nr >= LP5523_LEDS) {
                        dev_err(dev, "Use channel numbers between 0 and %d\n",
                                LP5523_LEDS - 1);
                        return -EINVAL;
                }

                snprintf(name, sizeof(name), "%s:channel%d",
                        pdata->label ?: "lp5523", chan);

                led->cdev.name = name;
                led->cdev.brightness_set = lp5523_set_brightness;
                res = led_classdev_register(dev, &led->cdev);
                if (res < 0) {
                        dev_err(dev, "couldn't register led on channel %d\n",
                                chan);
                        return res;
                }
                res = sysfs_create_group(&led->cdev.dev->kobj,
                                &lp5523_led_attribute_group);
                if (res < 0) {
                        dev_err(dev, "couldn't register current attribute\n");
                        led_classdev_unregister(&led->cdev);
                        return res;
                }
        } else {
                led->led_current = 0;
        }
        return 0;
}

static int __devinit lp5523_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        struct lp5523_chip              *chip;
        struct lp5523_platform_data     *pdata;
        int ret, i, led;

        chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
        if (!chip)
                return -ENOMEM;

        i2c_set_clientdata(client, chip);
        chip->client = client;

        pdata = client->dev.platform_data;

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

        mutex_init(&chip->lock);

        chip->pdata   = pdata;

        if (pdata->setup_resources) {
                ret = pdata->setup_resources();
                if (ret < 0)
                        return ret;
        }

        if (pdata->enable) {
                pdata->enable(0);
                usleep_range(1000, 2000); /* Keep enable down at least 1ms */
                pdata->enable(1);
                usleep_range(1000, 2000); /* 500us abs min. */
        }

        lp5523_write(client, LP5523_REG_RESET, 0xff);
        usleep_range(10000, 20000); /*
                                     * Exact value is not available. 10 - 20ms
                                     * appears to be enough for reset.
                                     */
        ret = lp5523_detect(client);
        if (ret)
                goto fail1;

        dev_info(&client->dev, "LP5523 Programmable led chip found\n");

        /* Initialize engines */
        for (i = 0; i < ARRAY_SIZE(chip->engines); i++) {
                ret = lp5523_init_engine(&chip->engines[i], i + 1);
                if (ret) {
                        dev_err(&client->dev, "error initializing engine\n");
                        goto fail1;
                }
        }
        ret = lp5523_configure(client);
        if (ret < 0) {
                dev_err(&client->dev, "error configuring chip\n");
                goto fail1;
        }

        /* Initialize leds */
        chip->num_channels = pdata->num_channels;
        chip->num_leds = 0;
        led = 0;
        for (i = 0; i < pdata->num_channels; i++) {
                /* Do not initialize channels that are not connected */
                if (pdata->led_config[i].led_current == 0)
                        continue;

                INIT_WORK(&chip->leds[led].brightness_work,
                        lp5523_led_brightness_work);

                ret = lp5523_init_led(&chip->leds[led], &client->dev, i, pdata);
                if (ret) {
                        dev_err(&client->dev, "error initializing leds\n");
                        goto fail2;
                }
                chip->num_leds++;

                chip->leds[led].id = led;
                /* Set LED current */
                lp5523_write(client,
                          LP5523_REG_LED_CURRENT_BASE + chip->leds[led].chan_nr,
                          chip->leds[led].led_current);

                led++;
        }

        ret = lp5523_register_sysfs(client);
        if (ret) {
                dev_err(&client->dev, "registering sysfs failed\n");
                goto fail2;
        }
        return ret;
fail2:
        for (i = 0; i < chip->num_leds; i++) {
                led_classdev_unregister(&chip->leds[i].cdev);
                cancel_work_sync(&chip->leds[i].brightness_work);
        }
fail1:
        if (pdata->enable)
                pdata->enable(0);
        if (pdata->release_resources)
                pdata->release_resources();
        return ret;
}

static int lp5523_remove(struct i2c_client *client)
{
        struct lp5523_chip *chip = i2c_get_clientdata(client);
        int i;

        lp5523_unregister_sysfs(client);

        for (i = 0; i < chip->num_leds; i++) {
                led_classdev_unregister(&chip->leds[i].cdev);
                cancel_work_sync(&chip->leds[i].brightness_work);
        }

        if (chip->pdata->enable)
                chip->pdata->enable(0);
        if (chip->pdata->release_resources)
                chip->pdata->release_resources();
        return 0;
}

static const struct i2c_device_id lp5523_id[] = {
        { "lp5523", 0 },
        { }
};

MODULE_DEVICE_TABLE(i2c, lp5523_id);

static struct i2c_driver lp5523_driver = {
        .driver = {
                .name   = "lp5523",
        },
        .probe          = lp5523_probe,
        .remove         = lp5523_remove,
        .id_table       = lp5523_id,
};

module_i2c_driver(lp5523_driver);

MODULE_AUTHOR("Mathias Nyman <mathias.nyman@nokia.com>");
MODULE_DESCRIPTION("LP5523 LED engine");
MODULE_LICENSE("GPL");