/*
 *  leds-blinkm.c
 *  (c) Jan-Simon Möller (dl9pf@gmx.de)
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/slab.h>
#include <linux/jiffies.h>
#include <linux/i2c.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/sysfs.h>
#include <linux/printk.h>
#include <linux/pm_runtime.h>
#include <linux/leds.h>
#include <linux/delay.h>

/* Addresses to scan - BlinkM is on 0x09 by default*/
static const unsigned short normal_i2c[] = { 0x09, I2C_CLIENT_END };

static int blinkm_transfer_hw(struct i2c_client *client, int cmd);
static int blinkm_test_run(struct i2c_client *client);

struct blinkm_led {
        struct i2c_client *i2c_client;
        struct led_classdev led_cdev;
        int id;
};

#define cdev_to_blmled(c)          container_of(c, struct blinkm_led, led_cdev)

struct blinkm_data {
        struct i2c_client *i2c_client;
        struct mutex update_lock;
        /* used for led class interface */
        struct blinkm_led blinkm_leds[3];
        /* used for "blinkm" sysfs interface */
        u8 red;                 /* color red */
        u8 green;               /* color green */
        u8 blue;                /* color blue */
        /* next values to use for transfer */
        u8 next_red;                    /* color red */
        u8 next_green;          /* color green */
        u8 next_blue;           /* color blue */
        /* internal use */
        u8 args[7];             /* set of args for transmission */
        u8 i2c_addr;            /* i2c addr */
        u8 fw_ver;              /* firmware version */
        /* used, but not from userspace */
        u8 hue;                 /* HSB  hue */
        u8 saturation;          /* HSB  saturation */
        u8 brightness;          /* HSB  brightness */
        u8 next_hue;                    /* HSB  hue */
        u8 next_saturation;             /* HSB  saturation */
        u8 next_brightness;             /* HSB  brightness */
        /* currently unused / todo */
        u8 fade_speed;          /* fade speed     1 - 255 */
        s8 time_adjust;         /* time adjust -128 - 127 */
        u8 fade:1;              /* fade on = 1, off = 0 */
        u8 rand:1;              /* rand fade mode on = 1 */
        u8 script_id;           /* script ID */
        u8 script_repeats;      /* repeats of script */
        u8 script_startline;    /* line to start */
};

/* Colors */
#define RED   0
#define GREEN 1
#define BLUE  2

/* mapping command names to cmd chars - see datasheet */
#define BLM_GO_RGB            0
#define BLM_FADE_RGB          1
#define BLM_FADE_HSB          2
#define BLM_FADE_RAND_RGB     3
#define BLM_FADE_RAND_HSB     4
#define BLM_PLAY_SCRIPT       5
#define BLM_STOP_SCRIPT       6
#define BLM_SET_FADE_SPEED    7
#define BLM_SET_TIME_ADJ      8
#define BLM_GET_CUR_RGB       9
#define BLM_WRITE_SCRIPT_LINE 10
#define BLM_READ_SCRIPT_LINE  11
#define BLM_SET_SCRIPT_LR     12        /* Length & Repeats */
#define BLM_SET_ADDR          13
#define BLM_GET_ADDR          14
#define BLM_GET_FW_VER        15
#define BLM_SET_STARTUP_PARAM 16

/* BlinkM Commands
 *  as extracted out of the datasheet:
 *
 *  cmdchar = command (ascii)
 *  cmdbyte = command in hex
 *  nr_args = number of arguments (to send)
 *  nr_ret  = number of return values (to read)
 *  dir = direction (0 = read, 1 = write, 2 = both)
 *
 */
static const struct {
        char cmdchar;
        u8 cmdbyte;
        u8 nr_args;
        u8 nr_ret;
        u8 dir:2;
} blinkm_cmds[17] = {
  /* cmdchar, cmdbyte, nr_args, nr_ret,  dir */
        { 'n', 0x6e, 3, 0, 1},
        { 'c', 0x63, 3, 0, 1},
        { 'h', 0x68, 3, 0, 1},
        { 'C', 0x43, 3, 0, 1},
        { 'H', 0x48, 3, 0, 1},
        { 'p', 0x70, 3, 0, 1},
        { 'o', 0x6f, 0, 0, 1},
        { 'f', 0x66, 1, 0, 1},
        { 't', 0x74, 1, 0, 1},
        { 'g', 0x67, 0, 3, 0},
        { 'W', 0x57, 7, 0, 1},
        { 'R', 0x52, 2, 5, 2},
        { 'L', 0x4c, 3, 0, 1},
        { 'A', 0x41, 4, 0, 1},
        { 'a', 0x61, 0, 1, 0},
        { 'Z', 0x5a, 0, 1, 0},
        { 'B', 0x42, 5, 0, 1},
};

static ssize_t show_color_common(struct device *dev, char *buf, int color)
{
        struct i2c_client *client;
        struct blinkm_data *data;
        int ret;

        client = to_i2c_client(dev);
        data = i2c_get_clientdata(client);

        ret = blinkm_transfer_hw(client, BLM_GET_CUR_RGB);
        if (ret < 0)
                return ret;
        switch (color) {
        case RED:
                return scnprintf(buf, PAGE_SIZE, "%02X\n", data->red);
        case GREEN:
                return scnprintf(buf, PAGE_SIZE, "%02X\n", data->green);
        case BLUE:
                return scnprintf(buf, PAGE_SIZE, "%02X\n", data->blue);
        default:
                return -EINVAL;
        }
        return -EINVAL;
}

static int store_color_common(struct device *dev, const char *buf, int color)
{
        struct i2c_client *client;
        struct blinkm_data *data;
        int ret;
        u8 value;

        client = to_i2c_client(dev);
        data = i2c_get_clientdata(client);

        ret = kstrtou8(buf, 10, &value);
        if (ret < 0) {
                dev_err(dev, "BlinkM: value too large!\n");
                return ret;
        }

        switch (color) {
        case RED:
                data->next_red = value;
                break;
        case GREEN:
                data->next_green = value;
                break;
        case BLUE:
                data->next_blue = value;
                break;
        default:
                return -EINVAL;
        }

        dev_dbg(dev, "next_red = %d, next_green = %d, next_blue = %d\n",
                        data->next_red, data->next_green, data->next_blue);

        /* if mode ... */
        ret = blinkm_transfer_hw(client, BLM_GO_RGB);
        if (ret < 0) {
                dev_err(dev, "BlinkM: can't set RGB\n");
                return ret;
        }
        return 0;
}

static ssize_t show_red(struct device *dev, struct device_attribute *attr,
                        char *buf)
{
        return show_color_common(dev, buf, RED);
}

static ssize_t store_red(struct device *dev, struct device_attribute *attr,
                         const char *buf, size_t count)
{
        int ret;

        ret = store_color_common(dev, buf, RED);
        if (ret < 0)
                return ret;
        return count;
}

static DEVICE_ATTR(red, S_IRUGO | S_IWUSR, show_red, store_red);

static ssize_t show_green(struct device *dev, struct device_attribute *attr,
                          char *buf)
{
        return show_color_common(dev, buf, GREEN);
}

static ssize_t store_green(struct device *dev, struct device_attribute *attr,
                           const char *buf, size_t count)
{

        int ret;

        ret = store_color_common(dev, buf, GREEN);
        if (ret < 0)
                return ret;
        return count;
}

static DEVICE_ATTR(green, S_IRUGO | S_IWUSR, show_green, store_green);

static ssize_t show_blue(struct device *dev, struct device_attribute *attr,
                         char *buf)
{
        return show_color_common(dev, buf, BLUE);
}

static ssize_t store_blue(struct device *dev, struct device_attribute *attr,
                          const char *buf, size_t count)
{
        int ret;

        ret = store_color_common(dev, buf, BLUE);
        if (ret < 0)
                return ret;
        return count;
}

static DEVICE_ATTR(blue, S_IRUGO | S_IWUSR, show_blue, store_blue);

static ssize_t show_test(struct device *dev, struct device_attribute *attr,
                         char *buf)
{
        return scnprintf(buf, PAGE_SIZE,
                         "#Write into test to start test sequence!#\n");
}

static ssize_t store_test(struct device *dev, struct device_attribute *attr,
                          const char *buf, size_t count)
{

        struct i2c_client *client;
        int ret;
        client = to_i2c_client(dev);

        /*test */
        ret = blinkm_test_run(client);
        if (ret < 0)
                return ret;

        return count;
}

static DEVICE_ATTR(test, S_IRUGO | S_IWUSR, show_test, store_test);

/* TODO: HSB, fade, timeadj, script ... */

static struct attribute *blinkm_attrs[] = {
        &dev_attr_red.attr,
        &dev_attr_green.attr,
        &dev_attr_blue.attr,
        &dev_attr_test.attr,
        NULL,
};

static const struct attribute_group blinkm_group = {
        .name = "blinkm",
        .attrs = blinkm_attrs,
};

static int blinkm_write(struct i2c_client *client, int cmd, u8 *arg)
{
        int result;
        int i;
        int arglen = blinkm_cmds[cmd].nr_args;
        /* write out cmd to blinkm - always / default step */
        result = i2c_smbus_write_byte(client, blinkm_cmds[cmd].cmdbyte);
        if (result < 0)
                return result;
        /* no args to write out */
        if (arglen == 0)
                return 0;

        for (i = 0; i < arglen; i++) {
                /* repeat for arglen */
                result = i2c_smbus_write_byte(client, arg[i]);
                if (result < 0)
                        return result;
        }
        return 0;
}

static int blinkm_read(struct i2c_client *client, int cmd, u8 *arg)
{
        int result;
        int i;
        int retlen = blinkm_cmds[cmd].nr_ret;
        for (i = 0; i < retlen; i++) {
                /* repeat for retlen */
                result = i2c_smbus_read_byte(client);
                if (result < 0)
                        return result;
                arg[i] = result;
        }

        return 0;
}

static int blinkm_transfer_hw(struct i2c_client *client, int cmd)
{
        /* the protocol is simple but non-standard:
         * e.g.  cmd 'g' (= 0x67) for "get device address"
         * - which defaults to 0x09 - would be the sequence:
         *   a) write 0x67 to the device (byte write)
         *   b) read the value (0x09) back right after (byte read)
         *
         * Watch out for "unfinished" sequences (i.e. not enough reads
         * or writes after a command. It will make the blinkM misbehave.
         * Sequence is key here.
         */

        /* args / return are in private data struct */
        struct blinkm_data *data = i2c_get_clientdata(client);

        /* We start hardware transfers which are not to be
         * mixed with other commands. Aquire a lock now. */
        if (mutex_lock_interruptible(&data->update_lock) < 0)
                return -EAGAIN;

        /* switch cmd - usually write before reads */
        switch (cmd) {
        case BLM_FADE_RAND_RGB:
        case BLM_GO_RGB:
        case BLM_FADE_RGB:
                data->args[0] = data->next_red;
                data->args[1] = data->next_green;
                data->args[2] = data->next_blue;
                blinkm_write(client, cmd, data->args);
                data->red = data->args[0];
                data->green = data->args[1];
                data->blue = data->args[2];
                break;
        case BLM_FADE_HSB:
        case BLM_FADE_RAND_HSB:
                data->args[0] = data->next_hue;
                data->args[1] = data->next_saturation;
                data->args[2] = data->next_brightness;
                blinkm_write(client, cmd, data->args);
                data->hue = data->next_hue;
                data->saturation = data->next_saturation;
                data->brightness = data->next_brightness;
                break;
        case BLM_PLAY_SCRIPT:
                data->args[0] = data->script_id;
                data->args[1] = data->script_repeats;
                data->args[2] = data->script_startline;
                blinkm_write(client, cmd, data->args);
                break;
        case BLM_STOP_SCRIPT:
                blinkm_write(client, cmd, NULL);
                break;
        case BLM_GET_CUR_RGB:
                data->args[0] = data->red;
                data->args[1] = data->green;
                data->args[2] = data->blue;
                blinkm_write(client, cmd, NULL);
                blinkm_read(client, cmd, data->args);
                data->red = data->args[0];
                data->green = data->args[1];
                data->blue = data->args[2];
                break;
        case BLM_GET_ADDR:
                data->args[0] = data->i2c_addr;
                blinkm_write(client, cmd, NULL);
                blinkm_read(client, cmd, data->args);
                data->i2c_addr = data->args[0];
                break;
        case BLM_SET_TIME_ADJ:
        case BLM_SET_FADE_SPEED:
        case BLM_READ_SCRIPT_LINE:
        case BLM_WRITE_SCRIPT_LINE:
        case BLM_SET_SCRIPT_LR:
        case BLM_SET_ADDR:
        case BLM_GET_FW_VER:
        case BLM_SET_STARTUP_PARAM:
                dev_err(&client->dev,
                                "BlinkM: cmd %d not implemented yet.\n", cmd);
                break;
        default:
                dev_err(&client->dev, "BlinkM: unknown command %d\n", cmd);
                mutex_unlock(&data->update_lock);
                return -EINVAL;
        }                       /* end switch(cmd) */

        /* transfers done, unlock */
        mutex_unlock(&data->update_lock);
        return 0;
}

static int blinkm_led_common_set(struct led_classdev *led_cdev,
                                 enum led_brightness value, int color)
{
        /* led_brightness is 0, 127 or 255 - we just use it here as-is */
        struct blinkm_led *led = cdev_to_blmled(led_cdev);
        struct blinkm_data *data = i2c_get_clientdata(led->i2c_client);

        switch (color) {
        case RED:
                /* bail out if there's no change */
                if (data->next_red == (u8) value)
                        return 0;
                data->next_red = (u8) value;
                break;
        case GREEN:
                /* bail out if there's no change */
                if (data->next_green == (u8) value)
                        return 0;
                data->next_green = (u8) value;
                break;
        case BLUE:
                /* bail out if there's no change */
                if (data->next_blue == (u8) value)
                        return 0;
                data->next_blue = (u8) value;
                break;

        default:
                dev_err(&led->i2c_client->dev, "BlinkM: unknown color.\n");
                return -EINVAL;
        }

        blinkm_transfer_hw(led->i2c_client, BLM_GO_RGB);
        dev_dbg(&led->i2c_client->dev,
                        "# DONE # next_red = %d, next_green = %d,"
                        " next_blue = %d\n",
                        data->next_red, data->next_green,
                        data->next_blue);
        return 0;
}

static int blinkm_led_red_set(struct led_classdev *led_cdev,
                               enum led_brightness value)
{
        return blinkm_led_common_set(led_cdev, value, RED);
}

static int blinkm_led_green_set(struct led_classdev *led_cdev,
                                 enum led_brightness value)
{
        return blinkm_led_common_set(led_cdev, value, GREEN);
}

static int blinkm_led_blue_set(struct led_classdev *led_cdev,
                                enum led_brightness value)
{
        return blinkm_led_common_set(led_cdev, value, BLUE);
}

static void blinkm_init_hw(struct i2c_client *client)
{
        int ret;
        ret = blinkm_transfer_hw(client, BLM_STOP_SCRIPT);
        ret = blinkm_transfer_hw(client, BLM_GO_RGB);
}

static int blinkm_test_run(struct i2c_client *client)
{
        int ret;
        struct blinkm_data *data = i2c_get_clientdata(client);

        data->next_red = 0x01;
        data->next_green = 0x05;
        data->next_blue = 0x10;
        ret = blinkm_transfer_hw(client, BLM_GO_RGB);
        if (ret < 0)
                return ret;
        msleep(2000);

        data->next_red = 0x25;
        data->next_green = 0x10;
        data->next_blue = 0x31;
        ret = blinkm_transfer_hw(client, BLM_FADE_RGB);
        if (ret < 0)
                return ret;
        msleep(2000);

        data->next_hue = 0x50;
        data->next_saturation = 0x10;
        data->next_brightness = 0x20;
        ret = blinkm_transfer_hw(client, BLM_FADE_HSB);
        if (ret < 0)
                return ret;
        msleep(2000);

        return 0;
}

/* Return 0 if detection is successful, -ENODEV otherwise */
static int blinkm_detect(struct i2c_client *client, struct i2c_board_info *info)
{
        struct i2c_adapter *adapter = client->adapter;
        int ret;
        int count = 99;
        u8 tmpargs[7];

        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA
                                     | I2C_FUNC_SMBUS_WORD_DATA
                                     | I2C_FUNC_SMBUS_WRITE_BYTE))
                return -ENODEV;

        /* Now, we do the remaining detection. Simple for now. */
        /* We might need more guards to protect other i2c slaves */

        /* make sure the blinkM is balanced (read/writes) */
        while (count > 0) {
                ret = blinkm_write(client, BLM_GET_ADDR, NULL);
                usleep_range(5000, 10000);
                ret = blinkm_read(client, BLM_GET_ADDR, tmpargs);
                usleep_range(5000, 10000);
                if (tmpargs[0] == 0x09)
                        count = 0;
                count--;
        }

        /* Step 1: Read BlinkM address back  -  cmd_char 'a' */
        ret = blinkm_write(client, BLM_GET_ADDR, NULL);
        if (ret < 0)
                return ret;
        usleep_range(20000, 30000);     /* allow a small delay */
        ret = blinkm_read(client, BLM_GET_ADDR, tmpargs);
        if (ret < 0)
                return ret;

        if (tmpargs[0] != 0x09) {
                dev_err(&client->dev, "enodev DEV ADDR = 0x%02X\n", tmpargs[0]);
                return -ENODEV;
        }

        strlcpy(info->type, "blinkm", I2C_NAME_SIZE);
        return 0;
}

static int blinkm_probe(struct i2c_client *client,
                        const struct i2c_device_id *id)
{
        struct blinkm_data *data;
        struct blinkm_led *led[3];
        int err, i;
        char blinkm_led_name[28];

        data = devm_kzalloc(&client->dev,
                        sizeof(struct blinkm_data), GFP_KERNEL);
        if (!data) {
                err = -ENOMEM;
                goto exit;
        }

        data->i2c_addr = 0x09;
        data->i2c_addr = 0x08;
        /* i2c addr  - use fake addr of 0x08 initially (real is 0x09) */
        data->fw_ver = 0xfe;
        /* firmware version - use fake until we read real value
         * (currently broken - BlinkM confused!) */
        data->script_id = 0x01;
        data->i2c_client = client;

        i2c_set_clientdata(client, data);
        mutex_init(&data->update_lock);

        /* Register sysfs hooks */
        err = sysfs_create_group(&client->dev.kobj, &blinkm_group);
        if (err < 0) {
                dev_err(&client->dev, "couldn't register sysfs group\n");
                goto exit;
        }

        for (i = 0; i < 3; i++) {
                /* RED = 0, GREEN = 1, BLUE = 2 */
                led[i] = &data->blinkm_leds[i];
                led[i]->i2c_client = client;
                led[i]->id = i;
                led[i]->led_cdev.max_brightness = 255;
                led[i]->led_cdev.flags = LED_CORE_SUSPENDRESUME;
                switch (i) {
                case RED:
                        snprintf(blinkm_led_name, sizeof(blinkm_led_name),
                                         "blinkm-%d-%d-red",
                                         client->adapter->nr,
                                         client->addr);
                        led[i]->led_cdev.name = blinkm_led_name;
                        led[i]->led_cdev.brightness_set_blocking =
                                                        blinkm_led_red_set;
                        err = led_classdev_register(&client->dev,
                                                    &led[i]->led_cdev);
                        if (err < 0) {
                                dev_err(&client->dev,
                                        "couldn't register LED %s\n",
                                        led[i]->led_cdev.name);
                                goto failred;
                        }
                        break;
                case GREEN:
                        snprintf(blinkm_led_name, sizeof(blinkm_led_name),
                                         "blinkm-%d-%d-green",
                                         client->adapter->nr,
                                         client->addr);
                        led[i]->led_cdev.name = blinkm_led_name;
                        led[i]->led_cdev.brightness_set_blocking =
                                                        blinkm_led_green_set;
                        err = led_classdev_register(&client->dev,
                                                    &led[i]->led_cdev);
                        if (err < 0) {
                                dev_err(&client->dev,
                                        "couldn't register LED %s\n",
                                        led[i]->led_cdev.name);
                                goto failgreen;
                        }
                        break;
                case BLUE:
                        snprintf(blinkm_led_name, sizeof(blinkm_led_name),
                                         "blinkm-%d-%d-blue",
                                         client->adapter->nr,
                                         client->addr);
                        led[i]->led_cdev.name = blinkm_led_name;
                        led[i]->led_cdev.brightness_set_blocking =
                                                        blinkm_led_blue_set;
                        err = led_classdev_register(&client->dev,
                                                    &led[i]->led_cdev);
                        if (err < 0) {
                                dev_err(&client->dev,
                                        "couldn't register LED %s\n",
                                        led[i]->led_cdev.name);
                                goto failblue;
                        }
                        break;
                }               /* end switch */
        }                       /* end for */

        /* Initialize the blinkm */
        blinkm_init_hw(client);

        return 0;

failblue:
        led_classdev_unregister(&led[GREEN]->led_cdev);

failgreen:
        led_classdev_unregister(&led[RED]->led_cdev);

failred:
        sysfs_remove_group(&client->dev.kobj, &blinkm_group);
exit:
        return err;
}

static int blinkm_remove(struct i2c_client *client)
{
        struct blinkm_data *data = i2c_get_clientdata(client);
        int ret = 0;
        int i;

        /* make sure no workqueue entries are pending */
        for (i = 0; i < 3; i++)
                led_classdev_unregister(&data->blinkm_leds[i].led_cdev);

        /* reset rgb */
        data->next_red = 0x00;
        data->next_green = 0x00;
        data->next_blue = 0x00;
        ret = blinkm_transfer_hw(client, BLM_FADE_RGB);
        if (ret < 0)
                dev_err(&client->dev, "Failure in blinkm_remove ignored. Continuing.\n");

        /* reset hsb */
        data->next_hue = 0x00;
        data->next_saturation = 0x00;
        data->next_brightness = 0x00;
        ret = blinkm_transfer_hw(client, BLM_FADE_HSB);
        if (ret < 0)
                dev_err(&client->dev, "Failure in blinkm_remove ignored. Continuing.\n");

        /* red fade to off */
        data->next_red = 0xff;
        ret = blinkm_transfer_hw(client, BLM_GO_RGB);
        if (ret < 0)
                dev_err(&client->dev, "Failure in blinkm_remove ignored. Continuing.\n");

        /* off */
        data->next_red = 0x00;
        ret = blinkm_transfer_hw(client, BLM_FADE_RGB);
        if (ret < 0)
                dev_err(&client->dev, "Failure in blinkm_remove ignored. Continuing.\n");

        sysfs_remove_group(&client->dev.kobj, &blinkm_group);
        return 0;
}

static const struct i2c_device_id blinkm_id[] = {
        {"blinkm", 0},
        {}
};

MODULE_DEVICE_TABLE(i2c, blinkm_id);

  /* This is the driver that will be inserted */
static struct i2c_driver blinkm_driver = {
        .class = I2C_CLASS_HWMON,
        .driver = {
                   .name = "blinkm",
                   },
        .probe = blinkm_probe,
        .remove = blinkm_remove,
        .id_table = blinkm_id,
        .detect = blinkm_detect,
        .address_list = normal_i2c,
};

module_i2c_driver(blinkm_driver);

MODULE_AUTHOR("Jan-Simon Moeller <dl9pf@gmx.de>");
MODULE_DESCRIPTION("BlinkM RGB LED driver");
MODULE_LICENSE("GPL");