/*
   * LP5521 LED chip driver.
   *
   * Copyright (C) 2010 Nokia Corporation
   * Copyright (C) 2012 Texas Instruments
   *
   * Contact: Samu Onkalo <samu.p.onkalo@nokia.com>
   *          Milo(Woogyom) Kim <milo.kim@ti.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/delay.h>
  #include <linux/firmware.h>
  #include <linux/i2c.h>
  #include <linux/leds.h>
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include <linux/platform_data/leds-lp55xx.h>
  #include <linux/slab.h>
  #include <linux/of.h>
  
  #include "leds-lp55xx-common.h"
  
  #define LP5521_PROGRAM_LENGTH		32
  #define LP5521_MAX_LEDS			3
  #define LP5521_CMD_DIRECT		0x3F
  
  /* Registers */
  #define LP5521_REG_ENABLE		0x00
  #define LP5521_REG_OP_MODE		0x01
  #define LP5521_REG_R_PWM		0x02
  #define LP5521_REG_G_PWM		0x03
  #define LP5521_REG_B_PWM		0x04
  #define LP5521_REG_R_CURRENT		0x05
  #define LP5521_REG_G_CURRENT		0x06
  #define LP5521_REG_B_CURRENT		0x07
  #define LP5521_REG_CONFIG		0x08
  #define LP5521_REG_STATUS		0x0C
  #define LP5521_REG_RESET		0x0D
  #define LP5521_REG_R_PROG_MEM		0x10
  #define LP5521_REG_G_PROG_MEM		0x30
  #define LP5521_REG_B_PROG_MEM		0x50
  
  /* Base register to set LED current */
  #define LP5521_REG_LED_CURRENT_BASE	LP5521_REG_R_CURRENT
  /* Base register to set the brightness */
  #define LP5521_REG_LED_PWM_BASE		LP5521_REG_R_PWM
  
  /* Bits in ENABLE register */
  #define LP5521_MASTER_ENABLE		0x40	/* Chip master enable */
  #define LP5521_LOGARITHMIC_PWM		0x80	/* Logarithmic PWM adjustment */
  #define LP5521_EXEC_RUN			0x2A
  #define LP5521_ENABLE_DEFAULT	\
  	(LP5521_MASTER_ENABLE | LP5521_LOGARITHMIC_PWM)
  #define LP5521_ENABLE_RUN_PROGRAM	\
  	(LP5521_ENABLE_DEFAULT | LP5521_EXEC_RUN)
  
  /* CONFIG register */
  #define LP5521_PWM_HF			0x40	/* PWM: 0 = 256Hz, 1 = 558Hz */
  #define LP5521_PWRSAVE_EN		0x20	/* 1 = Power save mode */
  #define LP5521_CP_MODE_OFF		0	/* Charge pump (CP) off */
  #define LP5521_CP_MODE_BYPASS		8	/* CP forced to bypass mode */
  #define LP5521_CP_MODE_1X5		0x10	/* CP forced to 1.5x mode */
  #define LP5521_CP_MODE_AUTO		0x18	/* Automatic mode selection */
  #define LP5521_R_TO_BATT		0x04	/* R out: 0 = CP, 1 = Vbat */
  #define LP5521_CLK_INT			0x01	/* Internal clock */
  #define LP5521_DEFAULT_CFG		\
  	(LP5521_PWM_HF | LP5521_PWRSAVE_EN | LP5521_CP_MODE_AUTO)
  
  /* Status */
  #define LP5521_EXT_CLK_USED		0x08
  
  /* default R channel current register value */
  #define LP5521_REG_R_CURR_DEFAULT	0xAF
  
  /* Reset register value */
  #define LP5521_RESET			0xFF
  
  /* Program Memory Operations */
  #define LP5521_MODE_R_M			0x30	/* Operation Mode Register */
  #define LP5521_MODE_G_M			0x0C
  #define LP5521_MODE_B_M			0x03
  #define LP5521_LOAD_R			0x10
  #define LP5521_LOAD_G			0x04
  #define LP5521_LOAD_B			0x01
  
  #define LP5521_R_IS_LOADING(mode)	\
  	((mode & LP5521_MODE_R_M) == LP5521_LOAD_R)
  #define LP5521_G_IS_LOADING(mode)	\
  	((mode & LP5521_MODE_G_M) == LP5521_LOAD_G)
  #define LP5521_B_IS_LOADING(mode)	\
  	((mode & LP5521_MODE_B_M) == LP5521_LOAD_B)
  
  #define LP5521_EXEC_R_M			0x30	/* Enable Register */
  #define LP5521_EXEC_G_M			0x0C
  #define LP5521_EXEC_B_M			0x03
  #define LP5521_EXEC_M			0x3F
  #define LP5521_RUN_R			0x20
  #define LP5521_RUN_G			0x08
  #define LP5521_RUN_B			0x02
  
  static inline void lp5521_wait_opmode_done(void)
  {
  	/* operation mode change needs to be longer than 153 us */
  	usleep_range(200, 300);
  }
  
  static inline void lp5521_wait_enable_done(void)
  {
  	/* it takes more 488 us to update ENABLE register */
  	usleep_range(500, 600);
  }
  
  static void lp5521_set_led_current(struct lp55xx_led *led, u8 led_current)
  {
  	led->led_current = led_current;
  	lp55xx_write(led->chip, LP5521_REG_LED_CURRENT_BASE + led->chan_nr,
  		led_current);
  }
  
  static void lp5521_load_engine(struct lp55xx_chip *chip)
  {
  	enum lp55xx_engine_index idx = chip->engine_idx;
  	u8 mask[] = {
  		[LP55XX_ENGINE_1] = LP5521_MODE_R_M,
  		[LP55XX_ENGINE_2] = LP5521_MODE_G_M,
  		[LP55XX_ENGINE_3] = LP5521_MODE_B_M,
  	};
  
  	u8 val[] = {
  		[LP55XX_ENGINE_1] = LP5521_LOAD_R,
  		[LP55XX_ENGINE_2] = LP5521_LOAD_G,
  		[LP55XX_ENGINE_3] = LP5521_LOAD_B,
  	};
  
  	lp55xx_update_bits(chip, LP5521_REG_OP_MODE, mask[idx], val[idx]);
  
  	lp5521_wait_opmode_done();
  }
  
  static void lp5521_stop_all_engines(struct lp55xx_chip *chip)
  {
  	lp55xx_write(chip, LP5521_REG_OP_MODE, 0);
  	lp5521_wait_opmode_done();
  }
  
  static void lp5521_stop_engine(struct lp55xx_chip *chip)
  {
  	enum lp55xx_engine_index idx = chip->engine_idx;
  	u8 mask[] = {
  		[LP55XX_ENGINE_1] = LP5521_MODE_R_M,
  		[LP55XX_ENGINE_2] = LP5521_MODE_G_M,
  		[LP55XX_ENGINE_3] = LP5521_MODE_B_M,
  	};
  
  	lp55xx_update_bits(chip, LP5521_REG_OP_MODE, mask[idx], 0);
  
  	lp5521_wait_opmode_done();
  }
  
  static void lp5521_run_engine(struct lp55xx_chip *chip, bool start)
  {
  	int ret;
  	u8 mode;
  	u8 exec;
  
  	/* stop engine */
  	if (!start) {
  		lp5521_stop_engine(chip);
  		lp55xx_write(chip, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);
  		lp5521_wait_opmode_done();
  		return;
  	}
  
  	/*
  	 * To run the engine,
  	 * operation mode and enable register should updated at the same time
  	 */
  
  	ret = lp55xx_read(chip, LP5521_REG_OP_MODE, &mode);
  	if (ret)
  		return;
  
  	ret = lp55xx_read(chip, LP5521_REG_ENABLE, &exec);
  	if (ret)
  		return;
  
  	/* change operation mode to RUN only when each engine is loading */
  	if (LP5521_R_IS_LOADING(mode)) {
  		mode = (mode & ~LP5521_MODE_R_M) | LP5521_RUN_R;
  		exec = (exec & ~LP5521_EXEC_R_M) | LP5521_RUN_R;
  	}
  
  	if (LP5521_G_IS_LOADING(mode)) {
  		mode = (mode & ~LP5521_MODE_G_M) | LP5521_RUN_G;
  		exec = (exec & ~LP5521_EXEC_G_M) | LP5521_RUN_G;
  	}
  
  	if (LP5521_B_IS_LOADING(mode)) {
  		mode = (mode & ~LP5521_MODE_B_M) | LP5521_RUN_B;
  		exec = (exec & ~LP5521_EXEC_B_M) | LP5521_RUN_B;
  	}
  
  	lp55xx_write(chip, LP5521_REG_OP_MODE, mode);
  	lp5521_wait_opmode_done();
  
  	lp55xx_update_bits(chip, LP5521_REG_ENABLE, LP5521_EXEC_M, exec);
  	lp5521_wait_enable_done();
  }
  
  static int lp5521_update_program_memory(struct lp55xx_chip *chip,
  					const u8 *data, size_t size)
  {
  	enum lp55xx_engine_index idx = chip->engine_idx;
  	u8 pattern[LP5521_PROGRAM_LENGTH] = {0};
  	u8 addr[] = {
  		[LP55XX_ENGINE_1] = LP5521_REG_R_PROG_MEM,
  		[LP55XX_ENGINE_2] = LP5521_REG_G_PROG_MEM,
  		[LP55XX_ENGINE_3] = LP5521_REG_B_PROG_MEM,
  	};
  	unsigned cmd;
  	char c[3];
  	int nrchars;
  	int ret;
  	int offset = 0;
  	int i = 0;
  
  	while ((offset < size - 1) && (i < LP5521_PROGRAM_LENGTH)) {
  		/* separate sscanfs because length is working only for %s */
  		ret = sscanf(data + offset, "%2s%n ", c, &nrchars);
  		if (ret != 1)
  			goto err;
  
  		ret = sscanf(c, "%2x", &cmd);
  		if (ret != 1)
  			goto err;
  
  		pattern[i] = (u8)cmd;
  		offset += nrchars;
  		i++;
  	}
  
  	/* Each instruction is 16bit long. Check that length is even */
  	if (i % 2)
  		goto err;
  
  	for (i = 0; i < LP5521_PROGRAM_LENGTH; i++) {
  		ret = lp55xx_write(chip, addr[idx] + i, pattern[i]);
  		if (ret)
  			return -EINVAL;
  	}
  
  	return size;
  
  err:
  	dev_err(&chip->cl->dev, "wrong pattern format
  ");
  	return -EINVAL;
  }
  
  static void lp5521_firmware_loaded(struct lp55xx_chip *chip)
  {
  	const struct firmware *fw = chip->fw;
  
  	if (fw->size > LP5521_PROGRAM_LENGTH) {
  		dev_err(&chip->cl->dev, "firmware data size overflow: %zu
  ",
  			fw->size);
  		return;
  	}
  
  	/*
  	 * Program momery sequence
  	 *  1) set engine mode to "LOAD"
  	 *  2) write firmware data into program memory
  	 */
  
  	lp5521_load_engine(chip);
  	lp5521_update_program_memory(chip, fw->data, fw->size);
  }
  
  static int lp5521_post_init_device(struct lp55xx_chip *chip)
  {
  	int ret;
  	u8 val;
  
  	/*
  	 * Make sure that the chip is reset by reading back the r channel
  	 * current reg. This is dummy read is required on some platforms -
  	 * otherwise further access to the R G B channels in the
  	 * LP5521_REG_ENABLE register will not have any effect - strange!
  	 */
  	ret = lp55xx_read(chip, LP5521_REG_R_CURRENT, &val);
  	if (ret) {
  		dev_err(&chip->cl->dev, "error in resetting chip
  ");
  		return ret;
  	}
  	if (val != LP5521_REG_R_CURR_DEFAULT) {
  		dev_err(&chip->cl->dev,
  			"unexpected data in register (expected 0x%x got 0x%x)
  ",
  			LP5521_REG_R_CURR_DEFAULT, val);
  		ret = -EINVAL;
  		return ret;
  	}
  	usleep_range(10000, 20000);
  
  	/* Set all PWMs to direct control mode */
  	ret = lp55xx_write(chip, LP5521_REG_OP_MODE, LP5521_CMD_DIRECT);
  
  	/* Update configuration for the clock setting */
  	val = LP5521_DEFAULT_CFG;
  	if (!lp55xx_is_extclk_used(chip))
  		val |= LP5521_CLK_INT;
  
  	ret = lp55xx_write(chip, LP5521_REG_CONFIG, val);
  	if (ret)
  		return ret;
  
  	/* Initialize all channels PWM to zero -> leds off */
  	lp55xx_write(chip, LP5521_REG_R_PWM, 0);
  	lp55xx_write(chip, LP5521_REG_G_PWM, 0);
  	lp55xx_write(chip, LP5521_REG_B_PWM, 0);
  
  	/* Set engines are set to run state when OP_MODE enables engines */
  	ret = lp55xx_write(chip, LP5521_REG_ENABLE, LP5521_ENABLE_RUN_PROGRAM);
  	if (ret)
  		return ret;
  
  	lp5521_wait_enable_done();
  
  	return 0;
  }
  
  static int lp5521_run_selftest(struct lp55xx_chip *chip, char *buf)
  {
  	struct lp55xx_platform_data *pdata = chip->pdata;
  	int ret;
  	u8 status;
  
  	ret = lp55xx_read(chip, LP5521_REG_STATUS, &status);
  	if (ret < 0)
  		return ret;
  
  	if (pdata->clock_mode != LP55XX_CLOCK_EXT)
  		return 0;
  
  	/* Check that ext clock is really in use if requested */
  	if  ((status & LP5521_EXT_CLK_USED) == 0)
  		return -EIO;
  
  	return 0;
  }
  
  static void lp5521_led_brightness_work(struct work_struct *work)
  {
  	struct lp55xx_led *led = container_of(work, struct lp55xx_led,
  					      brightness_work);
  	struct lp55xx_chip *chip = led->chip;
  
  	mutex_lock(&chip->lock);
  	lp55xx_write(chip, LP5521_REG_LED_PWM_BASE + led->chan_nr,
  		led->brightness);
  	mutex_unlock(&chip->lock);
  }
  
  static ssize_t show_engine_mode(struct device *dev,
  				struct device_attribute *attr,
  				char *buf, int nr)
  {
  	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
  	struct lp55xx_chip *chip = led->chip;
  	enum lp55xx_engine_mode mode = chip->engines[nr - 1].mode;
  
  	switch (mode) {
  	case LP55XX_ENGINE_RUN:
  		return sprintf(buf, "run
  ");
  	case LP55XX_ENGINE_LOAD:
  		return sprintf(buf, "load
  ");
  	case LP55XX_ENGINE_DISABLED:
  	default:
  		return sprintf(buf, "disabled
  ");
  	}
  }
  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 lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
  	struct lp55xx_chip *chip = led->chip;
  	struct lp55xx_engine *engine = &chip->engines[nr - 1];
  
  	mutex_lock(&chip->lock);
  
  	chip->engine_idx = nr;
  
  	if (!strncmp(buf, "run", 3)) {
  		lp5521_run_engine(chip, true);
  		engine->mode = LP55XX_ENGINE_RUN;
  	} else if (!strncmp(buf, "load", 4)) {
  		lp5521_stop_engine(chip);
  		lp5521_load_engine(chip);
  		engine->mode = LP55XX_ENGINE_LOAD;
  	} else if (!strncmp(buf, "disabled", 8)) {
  		lp5521_stop_engine(chip);
  		engine->mode = LP55XX_ENGINE_DISABLED;
  	}
  
  	mutex_unlock(&chip->lock);
  
  	return len;
  }
  store_mode(1)
  store_mode(2)
  store_mode(3)
  
  static ssize_t store_engine_load(struct device *dev,
  			     struct device_attribute *attr,
  			     const char *buf, size_t len, int nr)
  {
  	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
  	struct lp55xx_chip *chip = led->chip;
  	int ret;
  
  	mutex_lock(&chip->lock);
  
  	chip->engine_idx = nr;
  	lp5521_load_engine(chip);
  	ret = lp5521_update_program_memory(chip, buf, len);
  
  	mutex_unlock(&chip->lock);
  
  	return ret;
  }
  store_load(1)
  store_load(2)
  store_load(3)
  
  static ssize_t lp5521_selftest(struct device *dev,
  			       struct device_attribute *attr,
  			       char *buf)
  {
  	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
  	struct lp55xx_chip *chip = led->chip;
  	int ret;
  
  	mutex_lock(&chip->lock);
  	ret = lp5521_run_selftest(chip, buf);
  	mutex_unlock(&chip->lock);
  
  	return scnprintf(buf, PAGE_SIZE, "%s
  ", ret ? "FAIL" : "OK");
  }
  
  /* device attributes */
  static LP55XX_DEV_ATTR_RW(engine1_mode, show_engine1_mode, store_engine1_mode);
  static LP55XX_DEV_ATTR_RW(engine2_mode, show_engine2_mode, store_engine2_mode);
  static LP55XX_DEV_ATTR_RW(engine3_mode, show_engine3_mode, store_engine3_mode);
  static LP55XX_DEV_ATTR_WO(engine1_load, store_engine1_load);
  static LP55XX_DEV_ATTR_WO(engine2_load, store_engine2_load);
  static LP55XX_DEV_ATTR_WO(engine3_load, store_engine3_load);
  static LP55XX_DEV_ATTR_RO(selftest, lp5521_selftest);
  
  static struct attribute *lp5521_attributes[] = {
  	&dev_attr_engine1_mode.attr,
  	&dev_attr_engine2_mode.attr,
  	&dev_attr_engine3_mode.attr,
  	&dev_attr_engine1_load.attr,
  	&dev_attr_engine2_load.attr,
  	&dev_attr_engine3_load.attr,
  	&dev_attr_selftest.attr,
  	NULL
  };
  
  static const struct attribute_group lp5521_group = {
  	.attrs = lp5521_attributes,
  };
  
  /* Chip specific configurations */
  static struct lp55xx_device_config lp5521_cfg = {
  	.reset = {
  		.addr = LP5521_REG_RESET,
  		.val  = LP5521_RESET,
  	},
  	.enable = {
  		.addr = LP5521_REG_ENABLE,
  		.val  = LP5521_ENABLE_DEFAULT,
  	},
  	.max_channel  = LP5521_MAX_LEDS,
  	.post_init_device   = lp5521_post_init_device,
  	.brightness_work_fn = lp5521_led_brightness_work,
  	.set_led_current    = lp5521_set_led_current,
  	.firmware_cb        = lp5521_firmware_loaded,
  	.run_engine         = lp5521_run_engine,
  	.dev_attr_group     = &lp5521_group,
  };
  
  static int lp5521_probe(struct i2c_client *client,
  			const struct i2c_device_id *id)
  {
  	int ret;
  	struct lp55xx_chip *chip;
  	struct lp55xx_led *led;
  	struct lp55xx_platform_data *pdata = dev_get_platdata(&client->dev);
  	struct device_node *np = client->dev.of_node;
  
  	if (!pdata) {
  		if (np) {
  			pdata = lp55xx_of_populate_pdata(&client->dev, np);
  			if (IS_ERR(pdata))
  				return PTR_ERR(pdata);
  		} else {
  			dev_err(&client->dev, "no platform data
  ");
  			return -EINVAL;
  		}
  	}
  
  	chip = devm_kzalloc(&client->dev, sizeof(*chip), GFP_KERNEL);
  	if (!chip)
  		return -ENOMEM;
  
  	led = devm_kzalloc(&client->dev,
  			sizeof(*led) * pdata->num_channels, GFP_KERNEL);
  	if (!led)
  		return -ENOMEM;
  
  	chip->cl = client;
  	chip->pdata = pdata;
  	chip->cfg = &lp5521_cfg;
  
  	mutex_init(&chip->lock);
  
  	i2c_set_clientdata(client, led);
  
  	ret = lp55xx_init_device(chip);
  	if (ret)
  		goto err_init;
  
  	dev_info(&client->dev, "%s programmable led chip found
  ", id->name);
  
  	ret = lp55xx_register_leds(led, chip);
  	if (ret)
  		goto err_register_leds;
  
  	ret = lp55xx_register_sysfs(chip);
  	if (ret) {
  		dev_err(&client->dev, "registering sysfs failed
  ");
  		goto err_register_sysfs;
  	}
  
  	return 0;
  
  err_register_sysfs:
  	lp55xx_unregister_leds(led, chip);
  err_register_leds:
  	lp55xx_deinit_device(chip);
  err_init:
  	return ret;
  }
  
  static int lp5521_remove(struct i2c_client *client)
  {
  	struct lp55xx_led *led = i2c_get_clientdata(client);
  	struct lp55xx_chip *chip = led->chip;
  
  	lp5521_stop_all_engines(chip);
  	lp55xx_unregister_sysfs(chip);
  	lp55xx_unregister_leds(led, chip);
  	lp55xx_deinit_device(chip);
  
  	return 0;
  }
  
  static const struct i2c_device_id lp5521_id[] = {
  	{ "lp5521", 0 }, /* Three channel chip */
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, lp5521_id);
  
  #ifdef CONFIG_OF
  static const struct of_device_id of_lp5521_leds_match[] = {
  	{ .compatible = "national,lp5521", },
  	{},
  };
  
  MODULE_DEVICE_TABLE(of, of_lp5521_leds_match);
  #endif
  static struct i2c_driver lp5521_driver = {
  	.driver = {
  		.name	= "lp5521",
  		.of_match_table = of_match_ptr(of_lp5521_leds_match),
  	},
  	.probe		= lp5521_probe,
  	.remove		= lp5521_remove,
  	.id_table	= lp5521_id,
  };
  
  module_i2c_driver(lp5521_driver);
  
  MODULE_AUTHOR("Mathias Nyman, Yuri Zaporozhets, Samu Onkalo");
  MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
  MODULE_DESCRIPTION("LP5521 LED engine");
  MODULE_LICENSE("GPL v2");