/*
   * LP5521/LP5523/LP55231/LP5562 Common Driver
   *
   * Copyright 2012 Texas Instruments
   *
   * Author: 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.
   *
   * Derived from leds-lp5521.c, leds-lp5523.c
   */
  
  #include <linux/clk.h>
  #include <linux/delay.h>
  #include <linux/firmware.h>
  #include <linux/i2c.h>
  #include <linux/leds.h>
  #include <linux/module.h>
  #include <linux/platform_data/leds-lp55xx.h>
  #include <linux/slab.h>
  #include <linux/gpio.h>
  #include <linux/of_gpio.h>
  
  #include "leds-lp55xx-common.h"
  
  /* External clock rate */
  #define LP55XX_CLK_32K			32768
  
  static struct lp55xx_led *cdev_to_lp55xx_led(struct led_classdev *cdev)
  {
  	return container_of(cdev, struct lp55xx_led, cdev);
  }
  
  static struct lp55xx_led *dev_to_lp55xx_led(struct device *dev)
  {
  	return cdev_to_lp55xx_led(dev_get_drvdata(dev));
  }
  
  static void lp55xx_reset_device(struct lp55xx_chip *chip)
  {
  	struct lp55xx_device_config *cfg = chip->cfg;
  	u8 addr = cfg->reset.addr;
  	u8 val  = cfg->reset.val;
  
  	/* no error checking here because no ACK from the device after reset */
  	lp55xx_write(chip, addr, val);
  }
  
  static int lp55xx_detect_device(struct lp55xx_chip *chip)
  {
  	struct lp55xx_device_config *cfg = chip->cfg;
  	u8 addr = cfg->enable.addr;
  	u8 val  = cfg->enable.val;
  	int ret;
  
  	ret = lp55xx_write(chip, addr, val);
  	if (ret)
  		return ret;
  
  	usleep_range(1000, 2000);
  
  	ret = lp55xx_read(chip, addr, &val);
  	if (ret)
  		return ret;
  
  	if (val != cfg->enable.val)
  		return -ENODEV;
  
  	return 0;
  }
  
  static int lp55xx_post_init_device(struct lp55xx_chip *chip)
  {
  	struct lp55xx_device_config *cfg = chip->cfg;
  
  	if (!cfg->post_init_device)
  		return 0;
  
  	return cfg->post_init_device(chip);
  }
  
  static ssize_t lp55xx_show_current(struct device *dev,
  			    struct device_attribute *attr,
  			    char *buf)
  {
  	struct lp55xx_led *led = dev_to_lp55xx_led(dev);
  
  	return scnprintf(buf, PAGE_SIZE, "%d
  ", led->led_current);
  }
  
  static ssize_t lp55xx_store_current(struct device *dev,
  			     struct device_attribute *attr,
  			     const char *buf, size_t len)
  {
  	struct lp55xx_led *led = dev_to_lp55xx_led(dev);
  	struct lp55xx_chip *chip = led->chip;
  	unsigned long curr;
  
  	if (kstrtoul(buf, 0, &curr))
  		return -EINVAL;
  
  	if (curr > led->max_current)
  		return -EINVAL;
  
  	if (!chip->cfg->set_led_current)
  		return len;
  
  	mutex_lock(&chip->lock);
  	chip->cfg->set_led_current(led, (u8)curr);
  	mutex_unlock(&chip->lock);
  
  	return len;
  }
  
  static ssize_t lp55xx_show_max_current(struct device *dev,
  			    struct device_attribute *attr,
  			    char *buf)
  {
  	struct lp55xx_led *led = dev_to_lp55xx_led(dev);
  
  	return scnprintf(buf, PAGE_SIZE, "%d
  ", led->max_current);
  }
  
  static DEVICE_ATTR(led_current, S_IRUGO | S_IWUSR, lp55xx_show_current,
  		lp55xx_store_current);
  static DEVICE_ATTR(max_current, S_IRUGO , lp55xx_show_max_current, NULL);
  
  static struct attribute *lp55xx_led_attributes[] = {
  	&dev_attr_led_current.attr,
  	&dev_attr_max_current.attr,
  	NULL,
  };
  
  static struct attribute_group lp55xx_led_attr_group = {
  	.attrs = lp55xx_led_attributes
  };
  
  static void lp55xx_set_brightness(struct led_classdev *cdev,
  			     enum led_brightness brightness)
  {
  	struct lp55xx_led *led = cdev_to_lp55xx_led(cdev);
  
  	led->brightness = (u8)brightness;
  	schedule_work(&led->brightness_work);
  }
  
  static int lp55xx_init_led(struct lp55xx_led *led,
  			struct lp55xx_chip *chip, int chan)
  {
  	struct lp55xx_platform_data *pdata = chip->pdata;
  	struct lp55xx_device_config *cfg = chip->cfg;
  	struct device *dev = &chip->cl->dev;
  	char name[32];
  	int ret;
  	int max_channel = cfg->max_channel;
  
  	if (chan >= max_channel) {
  		dev_err(dev, "invalid channel: %d / %d
  ", chan, max_channel);
  		return -EINVAL;
  	}
  
  	if (pdata->led_config[chan].led_current == 0)
  		return 0;
  
  	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;
  	led->cdev.default_trigger = pdata->led_config[chan].default_trigger;
  
  	if (led->chan_nr >= max_channel) {
  		dev_err(dev, "Use channel numbers between 0 and %d
  ",
  			max_channel - 1);
  		return -EINVAL;
  	}
  
  	led->cdev.brightness_set = lp55xx_set_brightness;
  
  	if (pdata->led_config[chan].name) {
  		led->cdev.name = pdata->led_config[chan].name;
  	} else {
  		snprintf(name, sizeof(name), "%s:channel%d",
  			pdata->label ? : chip->cl->name, chan);
  		led->cdev.name = name;
  	}
  
  	/*
  	 * register led class device for each channel and
  	 * add device attributes
  	 */
  
  	ret = led_classdev_register(dev, &led->cdev);
  	if (ret) {
  		dev_err(dev, "led register err: %d
  ", ret);
  		return ret;
  	}
  
  	ret = sysfs_create_group(&led->cdev.dev->kobj, &lp55xx_led_attr_group);
  	if (ret) {
  		dev_err(dev, "led sysfs err: %d
  ", ret);
  		led_classdev_unregister(&led->cdev);
  		return ret;
  	}
  
  	return 0;
  }
  
  static void lp55xx_firmware_loaded(const struct firmware *fw, void *context)
  {
  	struct lp55xx_chip *chip = context;
  	struct device *dev = &chip->cl->dev;
  	enum lp55xx_engine_index idx = chip->engine_idx;
  
  	if (!fw) {
  		dev_err(dev, "firmware request failed
  ");
  		goto out;
  	}
  
  	/* handling firmware data is chip dependent */
  	mutex_lock(&chip->lock);
  
  	chip->engines[idx - 1].mode = LP55XX_ENGINE_LOAD;
  	chip->fw = fw;
  	if (chip->cfg->firmware_cb)
  		chip->cfg->firmware_cb(chip);
  
  	mutex_unlock(&chip->lock);
  
  out:
  	/* firmware should be released for other channel use */
  	release_firmware(chip->fw);
  }
  
  static int lp55xx_request_firmware(struct lp55xx_chip *chip)
  {
  	const char *name = chip->cl->name;
  	struct device *dev = &chip->cl->dev;
  
  	return request_firmware_nowait(THIS_MODULE, true, name, dev,
  				GFP_KERNEL, chip, lp55xx_firmware_loaded);
  }
  
  static ssize_t lp55xx_show_engine_select(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;
  
  	return sprintf(buf, "%d
  ", chip->engine_idx);
  }
  
  static ssize_t lp55xx_store_engine_select(struct device *dev,
  			     struct device_attribute *attr,
  			     const char *buf, size_t len)
  {
  	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
  	struct lp55xx_chip *chip = led->chip;
  	unsigned long val;
  	int ret;
  
  	if (kstrtoul(buf, 0, &val))
  		return -EINVAL;
  
  	/* select the engine to be run */
  
  	switch (val) {
  	case LP55XX_ENGINE_1:
  	case LP55XX_ENGINE_2:
  	case LP55XX_ENGINE_3:
  		mutex_lock(&chip->lock);
  		chip->engine_idx = val;
  		ret = lp55xx_request_firmware(chip);
  		mutex_unlock(&chip->lock);
  		break;
  	default:
  		dev_err(dev, "%lu: invalid engine index. (1, 2, 3)
  ", val);
  		return -EINVAL;
  	}
  
  	if (ret) {
  		dev_err(dev, "request firmware err: %d
  ", ret);
  		return ret;
  	}
  
  	return len;
  }
  
  static inline void lp55xx_run_engine(struct lp55xx_chip *chip, bool start)
  {
  	if (chip->cfg->run_engine)
  		chip->cfg->run_engine(chip, start);
  }
  
  static ssize_t lp55xx_store_engine_run(struct device *dev,
  			     struct device_attribute *attr,
  			     const char *buf, size_t len)
  {
  	struct lp55xx_led *led = i2c_get_clientdata(to_i2c_client(dev));
  	struct lp55xx_chip *chip = led->chip;
  	unsigned long val;
  
  	if (kstrtoul(buf, 0, &val))
  		return -EINVAL;
  
  	/* run or stop the selected engine */
  
  	if (val <= 0) {
  		lp55xx_run_engine(chip, false);
  		return len;
  	}
  
  	mutex_lock(&chip->lock);
  	lp55xx_run_engine(chip, true);
  	mutex_unlock(&chip->lock);
  
  	return len;
  }
  
  static DEVICE_ATTR(select_engine, S_IRUGO | S_IWUSR,
  		   lp55xx_show_engine_select, lp55xx_store_engine_select);
  static DEVICE_ATTR(run_engine, S_IWUSR, NULL, lp55xx_store_engine_run);
  
  static struct attribute *lp55xx_engine_attributes[] = {
  	&dev_attr_select_engine.attr,
  	&dev_attr_run_engine.attr,
  	NULL,
  };
  
  static const struct attribute_group lp55xx_engine_attr_group = {
  	.attrs = lp55xx_engine_attributes,
  };
  
  int lp55xx_write(struct lp55xx_chip *chip, u8 reg, u8 val)
  {
  	return i2c_smbus_write_byte_data(chip->cl, reg, val);
  }
  EXPORT_SYMBOL_GPL(lp55xx_write);
  
  int lp55xx_read(struct lp55xx_chip *chip, u8 reg, u8 *val)
  {
  	s32 ret;
  
  	ret = i2c_smbus_read_byte_data(chip->cl, reg);
  	if (ret < 0)
  		return ret;
  
  	*val = ret;
  	return 0;
  }
  EXPORT_SYMBOL_GPL(lp55xx_read);
  
  int lp55xx_update_bits(struct lp55xx_chip *chip, u8 reg, u8 mask, u8 val)
  {
  	int ret;
  	u8 tmp;
  
  	ret = lp55xx_read(chip, reg, &tmp);
  	if (ret)
  		return ret;
  
  	tmp &= ~mask;
  	tmp |= val & mask;
  
  	return lp55xx_write(chip, reg, tmp);
  }
  EXPORT_SYMBOL_GPL(lp55xx_update_bits);
  
  bool lp55xx_is_extclk_used(struct lp55xx_chip *chip)
  {
  	struct clk *clk;
  	int err;
  
  	clk = devm_clk_get(&chip->cl->dev, "32k_clk");
  	if (IS_ERR(clk))
  		goto use_internal_clk;
  
  	err = clk_prepare_enable(clk);
  	if (err)
  		goto use_internal_clk;
  
  	if (clk_get_rate(clk) != LP55XX_CLK_32K) {
  		clk_disable_unprepare(clk);
  		goto use_internal_clk;
  	}
  
  	dev_info(&chip->cl->dev, "%dHz external clock used
  ",	LP55XX_CLK_32K);
  
  	chip->clk = clk;
  	return true;
  
  use_internal_clk:
  	dev_info(&chip->cl->dev, "internal clock used
  ");
  	return false;
  }
  EXPORT_SYMBOL_GPL(lp55xx_is_extclk_used);
  
  int lp55xx_init_device(struct lp55xx_chip *chip)
  {
  	struct lp55xx_platform_data *pdata;
  	struct lp55xx_device_config *cfg;
  	struct device *dev = &chip->cl->dev;
  	int ret = 0;
  
  	WARN_ON(!chip);
  
  	pdata = chip->pdata;
  	cfg = chip->cfg;
  
  	if (!pdata || !cfg)
  		return -EINVAL;
  
  	if (gpio_is_valid(pdata->enable_gpio)) {
  		ret = devm_gpio_request_one(dev, pdata->enable_gpio,
  					    GPIOF_DIR_OUT, "lp5523_enable");
  		if (ret < 0) {
  			dev_err(dev, "could not acquire enable gpio (err=%d)
  ",
  				ret);
  			goto err;
  		}
  
  		gpio_set_value(pdata->enable_gpio, 0);
  		usleep_range(1000, 2000); /* Keep enable down at least 1ms */
  		gpio_set_value(pdata->enable_gpio, 1);
  		usleep_range(1000, 2000); /* 500us abs min. */
  	}
  
  	lp55xx_reset_device(chip);
  
  	/*
  	 * Exact value is not available. 10 - 20ms
  	 * appears to be enough for reset.
  	 */
  	usleep_range(10000, 20000);
  
  	ret = lp55xx_detect_device(chip);
  	if (ret) {
  		dev_err(dev, "device detection err: %d
  ", ret);
  		goto err;
  	}
  
  	/* chip specific initialization */
  	ret = lp55xx_post_init_device(chip);
  	if (ret) {
  		dev_err(dev, "post init device err: %d
  ", ret);
  		goto err_post_init;
  	}
  
  	return 0;
  
  err_post_init:
  	lp55xx_deinit_device(chip);
  err:
  	return ret;
  }
  EXPORT_SYMBOL_GPL(lp55xx_init_device);
  
  void lp55xx_deinit_device(struct lp55xx_chip *chip)
  {
  	struct lp55xx_platform_data *pdata = chip->pdata;
  
  	if (chip->clk)
  		clk_disable_unprepare(chip->clk);
  
  	if (gpio_is_valid(pdata->enable_gpio))
  		gpio_set_value(pdata->enable_gpio, 0);
  }
  EXPORT_SYMBOL_GPL(lp55xx_deinit_device);
  
  int lp55xx_register_leds(struct lp55xx_led *led, struct lp55xx_chip *chip)
  {
  	struct lp55xx_platform_data *pdata = chip->pdata;
  	struct lp55xx_device_config *cfg = chip->cfg;
  	int num_channels = pdata->num_channels;
  	struct lp55xx_led *each;
  	u8 led_current;
  	int ret;
  	int i;
  
  	if (!cfg->brightness_work_fn) {
  		dev_err(&chip->cl->dev, "empty brightness configuration
  ");
  		return -EINVAL;
  	}
  
  	for (i = 0; i < num_channels; i++) {
  
  		/* do not initialize channels that are not connected */
  		if (pdata->led_config[i].led_current == 0)
  			continue;
  
  		led_current = pdata->led_config[i].led_current;
  		each = led + i;
  		ret = lp55xx_init_led(each, chip, i);
  		if (ret)
  			goto err_init_led;
  
  		INIT_WORK(&each->brightness_work, cfg->brightness_work_fn);
  
  		chip->num_leds++;
  		each->chip = chip;
  
  		/* setting led current at each channel */
  		if (cfg->set_led_current)
  			cfg->set_led_current(each, led_current);
  	}
  
  	return 0;
  
  err_init_led:
  	lp55xx_unregister_leds(led, chip);
  	return ret;
  }
  EXPORT_SYMBOL_GPL(lp55xx_register_leds);
  
  void lp55xx_unregister_leds(struct lp55xx_led *led, struct lp55xx_chip *chip)
  {
  	int i;
  	struct lp55xx_led *each;
  
  	for (i = 0; i < chip->num_leds; i++) {
  		each = led + i;
  		led_classdev_unregister(&each->cdev);
  		flush_work(&each->brightness_work);
  	}
  }
  EXPORT_SYMBOL_GPL(lp55xx_unregister_leds);
  
  int lp55xx_register_sysfs(struct lp55xx_chip *chip)
  {
  	struct device *dev = &chip->cl->dev;
  	struct lp55xx_device_config *cfg = chip->cfg;
  	int ret;
  
  	if (!cfg->run_engine || !cfg->firmware_cb)
  		goto dev_specific_attrs;
  
  	ret = sysfs_create_group(&dev->kobj, &lp55xx_engine_attr_group);
  	if (ret)
  		return ret;
  
  dev_specific_attrs:
  	return cfg->dev_attr_group ?
  		sysfs_create_group(&dev->kobj, cfg->dev_attr_group) : 0;
  }
  EXPORT_SYMBOL_GPL(lp55xx_register_sysfs);
  
  void lp55xx_unregister_sysfs(struct lp55xx_chip *chip)
  {
  	struct device *dev = &chip->cl->dev;
  	struct lp55xx_device_config *cfg = chip->cfg;
  
  	if (cfg->dev_attr_group)
  		sysfs_remove_group(&dev->kobj, cfg->dev_attr_group);
  
  	sysfs_remove_group(&dev->kobj, &lp55xx_engine_attr_group);
  }
  EXPORT_SYMBOL_GPL(lp55xx_unregister_sysfs);
  
  int lp55xx_of_populate_pdata(struct device *dev, struct device_node *np)
  {
  	struct device_node *child;
  	struct lp55xx_platform_data *pdata;
  	struct lp55xx_led_config *cfg;
  	int num_channels;
  	int i = 0;
  
  	pdata = devm_kzalloc(dev, sizeof(*pdata), GFP_KERNEL);
  	if (!pdata)
  		return -ENOMEM;
  
  	num_channels = of_get_child_count(np);
  	if (num_channels == 0) {
  		dev_err(dev, "no LED channels
  ");
  		return -EINVAL;
  	}
  
  	cfg = devm_kzalloc(dev, sizeof(*cfg) * num_channels, GFP_KERNEL);
  	if (!cfg)
  		return -ENOMEM;
  
  	pdata->led_config = &cfg[0];
  	pdata->num_channels = num_channels;
  
  	for_each_child_of_node(np, child) {
  		cfg[i].chan_nr = i;
  
  		of_property_read_string(child, "chan-name", &cfg[i].name);
  		of_property_read_u8(child, "led-cur", &cfg[i].led_current);
  		of_property_read_u8(child, "max-cur", &cfg[i].max_current);
  		cfg[i].default_trigger =
  			of_get_property(child, "linux,default-trigger", NULL);
  
  		i++;
  	}
  
  	of_property_read_string(np, "label", &pdata->label);
  	of_property_read_u8(np, "clock-mode", &pdata->clock_mode);
  
  	pdata->enable_gpio = of_get_named_gpio(np, "enable-gpio", 0);
  
  	/* LP8501 specific */
  	of_property_read_u8(np, "pwr-sel", (u8 *)&pdata->pwr_sel);
  
  	dev->platform_data = pdata;
  
  	return 0;
  }
  EXPORT_SYMBOL_GPL(lp55xx_of_populate_pdata);
  
  MODULE_AUTHOR("Milo Kim <milo.kim@ti.com>");
  MODULE_DESCRIPTION("LP55xx Common Driver");
  MODULE_LICENSE("GPL");