text: /*
   *  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/init.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;
  	atomic_t active;
  };
  
  struct blinkm_work {
  	struct blinkm_led *blinkm_led;
  	struct work_struct work;
  };
  
  #define cdev_to_blmled(c)          container_of(c, struct blinkm_led, led_cdev)
  #define work_to_blmwork(c)         container_of(c, struct blinkm_work, work)
  
  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 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 void led_work(struct work_struct *work)
  {
  	int ret;
  	struct blinkm_led *led;
  	struct blinkm_data *data ;
  	struct blinkm_work *blm_work = work_to_blmwork(work);
  
  	led = blm_work->blinkm_led;
  	data = i2c_get_clientdata(led->i2c_client);
  	ret = blinkm_transfer_hw(led->i2c_client, BLM_GO_RGB);
  	atomic_dec(&led->active);
  	dev_dbg(&led->i2c_client->dev,
  			"# DONE # next_red = %d, next_green = %d,"
  			" next_blue = %d, active = %d\n",
  			data->next_red, data->next_green,
  			data->next_blue, atomic_read(&led->active));
  	kfree(blm_work);
  }
  
  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);
  	struct blinkm_work *bl_work;
  
  	switch (color) {
  	case RED:
  		/* bail out if there's no change */
  		if (data->next_red == (u8) value)
  			return 0;
  		/* we assume a quite fast sequence here ([off]->on->off)
  		 * think of network led trigger - we cannot blink that fast, so
  		 * in case we already have a off->on->off transition queued up,
  		 * we refuse to queue up more.
  		 * Revisit: fast-changing brightness. */
  		if (atomic_read(&led->active) > 1)
  			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;
  		/* we assume a quite fast sequence here ([off]->on->off)
  		 * Revisit: fast-changing brightness. */
  		if (atomic_read(&led->active) > 1)
  			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;
  		/* we assume a quite fast sequence here ([off]->on->off)
  		 * Revisit: fast-changing brightness. */
  		if (atomic_read(&led->active) > 1)
  			return 0;
  		data->next_blue = (u8) value;
  		break;
  
  	default:
  		dev_err(&led->i2c_client->dev, "BlinkM: unknown color.\n");
  		return -EINVAL;
  	}
  
  	bl_work = kzalloc(sizeof(*bl_work), GFP_ATOMIC);
  	if (!bl_work)
  		return -ENOMEM;
  
  	atomic_inc(&led->active);
  	dev_dbg(&led->i2c_client->dev,
  			"#TO_SCHED# next_red = %d, next_green = %d,"
  			" next_blue = %d, active = %d\n",
  			data->next_red, data->next_green,
  			data->next_blue, atomic_read(&led->active));
  
  	/* a fresh work _item_ for each change */
  	bl_work->blinkm_led = led;
  	INIT_WORK(&bl_work->work, led_work);
  	/* queue work in own queue for easy sync on exit*/
  	schedule_work(&bl_work->work);
  
  	return 0;
  }
  
  static void blinkm_led_red_set(struct led_classdev *led_cdev,
  			       enum led_brightness value)
  {
  	blinkm_led_common_set(led_cdev, value, RED);
  }
  
  static void blinkm_led_green_set(struct led_classdev *led_cdev,
  				 enum led_brightness value)
  {
  	blinkm_led_common_set(led_cdev, value, GREEN);
  }
  
  static void blinkm_led_blue_set(struct led_classdev *led_cdev,
  				enum led_brightness value)
  {
  	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;
  		atomic_set(&led[i]->active, 0);
  		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 = 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 = 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 = 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++) {
  		flush_scheduled_work();
  		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");
  
  