/*
   * drivers/media/i2c/as3645a.c - AS3645A and LM3555 flash controllers driver
   *
   * Copyright (C) 2008-2011 Nokia Corporation
   * Copyright (c) 2011, Intel Corporation.
   *
   * Contact: Laurent Pinchart <laurent.pinchart@ideasonboard.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
   *
   * TODO:
   * - Check hardware FSTROBE control when sensor driver add support for this
   *
   */
  
  #include <linux/delay.h>
  #include <linux/i2c.h>
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include <linux/slab.h>
  
  #include <media/as3645a.h>
  #include <media/v4l2-ctrls.h>
  #include <media/v4l2-device.h>
  
  #define AS_TIMER_MS_TO_CODE(t)			(((t) - 100) / 50)
  #define AS_TIMER_CODE_TO_MS(c)			(50 * (c) + 100)
  
  /* Register definitions */
  
  /* Read-only Design info register: Reset state: xxxx 0001 */
  #define AS_DESIGN_INFO_REG			0x00
  #define AS_DESIGN_INFO_FACTORY(x)		(((x) >> 4))
  #define AS_DESIGN_INFO_MODEL(x)			((x) & 0x0f)
  
  /* Read-only Version control register: Reset state: 0000 0000
   * for first engineering samples
   */
  #define AS_VERSION_CONTROL_REG			0x01
  #define AS_VERSION_CONTROL_RFU(x)		(((x) >> 4))
  #define AS_VERSION_CONTROL_VERSION(x)		((x) & 0x0f)
  
  /* Read / Write	(Indicator and timer register): Reset state: 0000 1111 */
  #define AS_INDICATOR_AND_TIMER_REG		0x02
  #define AS_INDICATOR_AND_TIMER_TIMEOUT_SHIFT	0
  #define AS_INDICATOR_AND_TIMER_VREF_SHIFT	4
  #define AS_INDICATOR_AND_TIMER_INDICATOR_SHIFT	6
  
  /* Read / Write	(Current set register): Reset state: 0110 1001 */
  #define AS_CURRENT_SET_REG			0x03
  #define AS_CURRENT_ASSIST_LIGHT_SHIFT		0
  #define AS_CURRENT_LED_DET_ON			(1 << 3)
  #define AS_CURRENT_FLASH_CURRENT_SHIFT		4
  
  /* Read / Write	(Control register): Reset state: 1011 0100 */
  #define AS_CONTROL_REG				0x04
  #define AS_CONTROL_MODE_SETTING_SHIFT		0
  #define AS_CONTROL_STROBE_ON			(1 << 2)
  #define AS_CONTROL_OUT_ON			(1 << 3)
  #define AS_CONTROL_EXT_TORCH_ON			(1 << 4)
  #define AS_CONTROL_STROBE_TYPE_EDGE		(0 << 5)
  #define AS_CONTROL_STROBE_TYPE_LEVEL		(1 << 5)
  #define AS_CONTROL_COIL_PEAK_SHIFT		6
  
  /* Read only (D3 is read / write) (Fault and info): Reset state: 0000 x000 */
  #define AS_FAULT_INFO_REG			0x05
  #define AS_FAULT_INFO_INDUCTOR_PEAK_LIMIT	(1 << 1)
  #define AS_FAULT_INFO_INDICATOR_LED		(1 << 2)
  #define AS_FAULT_INFO_LED_AMOUNT		(1 << 3)
  #define AS_FAULT_INFO_TIMEOUT			(1 << 4)
  #define AS_FAULT_INFO_OVER_TEMPERATURE		(1 << 5)
  #define AS_FAULT_INFO_SHORT_CIRCUIT		(1 << 6)
  #define AS_FAULT_INFO_OVER_VOLTAGE		(1 << 7)
  
  /* Boost register */
  #define AS_BOOST_REG				0x0d
  #define AS_BOOST_CURRENT_DISABLE		(0 << 0)
  #define AS_BOOST_CURRENT_ENABLE			(1 << 0)
  
  /* Password register is used to unlock boost register writing */
  #define AS_PASSWORD_REG				0x0f
  #define AS_PASSWORD_UNLOCK_VALUE		0x55
  
  enum as_mode {
  	AS_MODE_EXT_TORCH = 0 << AS_CONTROL_MODE_SETTING_SHIFT,
  	AS_MODE_INDICATOR = 1 << AS_CONTROL_MODE_SETTING_SHIFT,
  	AS_MODE_ASSIST = 2 << AS_CONTROL_MODE_SETTING_SHIFT,
  	AS_MODE_FLASH = 3 << AS_CONTROL_MODE_SETTING_SHIFT,
  };
  
  /*
   * struct as3645a
   *
   * @subdev:		V4L2 subdev
   * @pdata:		Flash platform data
   * @power_lock:		Protects power_count
   * @power_count:	Power reference count
   * @led_mode:		V4L2 flash LED mode
   * @timeout:		Flash timeout in microseconds
   * @flash_current:	Flash current (0=200mA ... 15=500mA). Maximum
   *			values are 400mA for two LEDs and 500mA for one LED.
   * @assist_current:	Torch/Assist light current (0=20mA, 1=40mA ... 7=160mA)
   * @indicator_current:	Indicator LED current (0=0mA, 1=2.5mA ... 4=10mA)
   * @strobe_source:	Flash strobe source (software or external)
   */
  struct as3645a {
  	struct v4l2_subdev subdev;
  	const struct as3645a_platform_data *pdata;
  
  	struct mutex power_lock;
  	int power_count;
  
  	/* Controls */
  	struct v4l2_ctrl_handler ctrls;
  
  	enum v4l2_flash_led_mode led_mode;
  	unsigned int timeout;
  	u8 flash_current;
  	u8 assist_current;
  	u8 indicator_current;
  	enum v4l2_flash_strobe_source strobe_source;
  };
  
  #define to_as3645a(sd) container_of(sd, struct as3645a, subdev)
  
  /* Return negative errno else zero on success */
  static int as3645a_write(struct as3645a *flash, u8 addr, u8 val)
  {
  	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
  	int rval;
  
  	rval = i2c_smbus_write_byte_data(client, addr, val);
  
  	dev_dbg(&client->dev, "Write Addr:%02X Val:%02X %s
  ", addr, val,
  		rval < 0 ? "fail" : "ok");
  
  	return rval;
  }
  
  /* Return negative errno else a data byte received from the device. */
  static int as3645a_read(struct as3645a *flash, u8 addr)
  {
  	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
  	int rval;
  
  	rval = i2c_smbus_read_byte_data(client, addr);
  
  	dev_dbg(&client->dev, "Read Addr:%02X Val:%02X %s
  ", addr, rval,
  		rval < 0 ? "fail" : "ok");
  
  	return rval;
  }
  
  /* -----------------------------------------------------------------------------
   * Hardware configuration and trigger
   */
  
  /*
   * as3645a_set_config - Set flash configuration registers
   * @flash: The flash
   *
   * Configure the hardware with flash, assist and indicator currents, as well as
   * flash timeout.
   *
   * Return 0 on success, or a negative error code if an I2C communication error
   * occurred.
   */
  static int as3645a_set_config(struct as3645a *flash)
  {
  	int ret;
  	u8 val;
  
  	val = (flash->flash_current << AS_CURRENT_FLASH_CURRENT_SHIFT)
  	    | (flash->assist_current << AS_CURRENT_ASSIST_LIGHT_SHIFT)
  	    | AS_CURRENT_LED_DET_ON;
  
  	ret = as3645a_write(flash, AS_CURRENT_SET_REG, val);
  	if (ret < 0)
  		return ret;
  
  	val = AS_TIMER_MS_TO_CODE(flash->timeout / 1000)
  		    << AS_INDICATOR_AND_TIMER_TIMEOUT_SHIFT;
  
  	val |= (flash->pdata->vref << AS_INDICATOR_AND_TIMER_VREF_SHIFT)
  	    |  ((flash->indicator_current ? flash->indicator_current - 1 : 0)
  		 << AS_INDICATOR_AND_TIMER_INDICATOR_SHIFT);
  
  	return as3645a_write(flash, AS_INDICATOR_AND_TIMER_REG, val);
  }
  
  /*
   * as3645a_set_control - Set flash control register
   * @flash: The flash
   * @mode: Desired output mode
   * @on: Desired output state
   *
   * Configure the hardware with output mode and state.
   *
   * Return 0 on success, or a negative error code if an I2C communication error
   * occurred.
   */
  static int
  as3645a_set_control(struct as3645a *flash, enum as_mode mode, bool on)
  {
  	u8 reg;
  
  	/* Configure output parameters and operation mode. */
  	reg = (flash->pdata->peak << AS_CONTROL_COIL_PEAK_SHIFT)
  	    | (on ? AS_CONTROL_OUT_ON : 0)
  	    | mode;
  
  	if (flash->led_mode == V4L2_FLASH_LED_MODE_FLASH &&
  	    flash->strobe_source == V4L2_FLASH_STROBE_SOURCE_EXTERNAL) {
  		reg |= AS_CONTROL_STROBE_TYPE_LEVEL
  		    |  AS_CONTROL_STROBE_ON;
  	}
  
  	return as3645a_write(flash, AS_CONTROL_REG, reg);
  }
  
  /*
   * as3645a_set_output - Configure output and operation mode
   * @flash: Flash controller
   * @strobe: Strobe the flash (only valid in flash mode)
   *
   * Turn the LEDs output on/off and set the operation mode based on the current
   * parameters.
   *
   * The AS3645A can't control the indicator LED independently of the flash/torch
   * LED. If the flash controller is in V4L2_FLASH_LED_MODE_NONE mode, set the
   * chip to indicator mode. Otherwise set it to assist light (torch) or flash
   * mode.
   *
   * In indicator and assist modes, turn the output on/off based on the indicator
   * and torch currents. In software strobe flash mode, turn the output on/off
   * based on the strobe parameter.
   */
  static int as3645a_set_output(struct as3645a *flash, bool strobe)
  {
  	enum as_mode mode;
  	bool on;
  
  	switch (flash->led_mode) {
  	case V4L2_FLASH_LED_MODE_NONE:
  		on = flash->indicator_current != 0;
  		mode = AS_MODE_INDICATOR;
  		break;
  	case V4L2_FLASH_LED_MODE_TORCH:
  		on = true;
  		mode = AS_MODE_ASSIST;
  		break;
  	case V4L2_FLASH_LED_MODE_FLASH:
  		on = strobe;
  		mode = AS_MODE_FLASH;
  		break;
  	default:
  		BUG();
  	}
  
  	/* Configure output parameters and operation mode. */
  	return as3645a_set_control(flash, mode, on);
  }
  
  /* -----------------------------------------------------------------------------
   * V4L2 controls
   */
  
  static int as3645a_is_active(struct as3645a *flash)
  {
  	int ret;
  
  	ret = as3645a_read(flash, AS_CONTROL_REG);
  	return ret < 0 ? ret : !!(ret & AS_CONTROL_OUT_ON);
  }
  
  static int as3645a_read_fault(struct as3645a *flash)
  {
  	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
  	int rval;
  
  	/* NOTE: reading register clear fault status */
  	rval = as3645a_read(flash, AS_FAULT_INFO_REG);
  	if (rval < 0)
  		return rval;
  
  	if (rval & AS_FAULT_INFO_INDUCTOR_PEAK_LIMIT)
  		dev_dbg(&client->dev, "Inductor Peak limit fault
  ");
  
  	if (rval & AS_FAULT_INFO_INDICATOR_LED)
  		dev_dbg(&client->dev, "Indicator LED fault: "
  			"Short circuit or open loop
  ");
  
  	dev_dbg(&client->dev, "%u connected LEDs
  ",
  		rval & AS_FAULT_INFO_LED_AMOUNT ? 2 : 1);
  
  	if (rval & AS_FAULT_INFO_TIMEOUT)
  		dev_dbg(&client->dev, "Timeout fault
  ");
  
  	if (rval & AS_FAULT_INFO_OVER_TEMPERATURE)
  		dev_dbg(&client->dev, "Over temperature fault
  ");
  
  	if (rval & AS_FAULT_INFO_SHORT_CIRCUIT)
  		dev_dbg(&client->dev, "Short circuit fault
  ");
  
  	if (rval & AS_FAULT_INFO_OVER_VOLTAGE)
  		dev_dbg(&client->dev, "Over voltage fault: "
  			"Indicates missing capacitor or open connection
  ");
  
  	return rval;
  }
  
  static int as3645a_get_ctrl(struct v4l2_ctrl *ctrl)
  {
  	struct as3645a *flash =
  		container_of(ctrl->handler, struct as3645a, ctrls);
  	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
  	int value;
  
  	switch (ctrl->id) {
  	case V4L2_CID_FLASH_FAULT:
  		value = as3645a_read_fault(flash);
  		if (value < 0)
  			return value;
  
  		ctrl->cur.val = 0;
  		if (value & AS_FAULT_INFO_SHORT_CIRCUIT)
  			ctrl->cur.val |= V4L2_FLASH_FAULT_SHORT_CIRCUIT;
  		if (value & AS_FAULT_INFO_OVER_TEMPERATURE)
  			ctrl->cur.val |= V4L2_FLASH_FAULT_OVER_TEMPERATURE;
  		if (value & AS_FAULT_INFO_TIMEOUT)
  			ctrl->cur.val |= V4L2_FLASH_FAULT_TIMEOUT;
  		if (value & AS_FAULT_INFO_OVER_VOLTAGE)
  			ctrl->cur.val |= V4L2_FLASH_FAULT_OVER_VOLTAGE;
  		if (value & AS_FAULT_INFO_INDUCTOR_PEAK_LIMIT)
  			ctrl->cur.val |= V4L2_FLASH_FAULT_OVER_CURRENT;
  		if (value & AS_FAULT_INFO_INDICATOR_LED)
  			ctrl->cur.val |= V4L2_FLASH_FAULT_INDICATOR;
  		break;
  
  	case V4L2_CID_FLASH_STROBE_STATUS:
  		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH) {
  			ctrl->cur.val = 0;
  			break;
  		}
  
  		value = as3645a_is_active(flash);
  		if (value < 0)
  			return value;
  
  		ctrl->cur.val = value;
  		break;
  	}
  
  	dev_dbg(&client->dev, "G_CTRL %08x:%d
  ", ctrl->id, ctrl->cur.val);
  
  	return 0;
  }
  
  static int as3645a_set_ctrl(struct v4l2_ctrl *ctrl)
  {
  	struct as3645a *flash =
  		container_of(ctrl->handler, struct as3645a, ctrls);
  	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
  	int ret;
  
  	dev_dbg(&client->dev, "S_CTRL %08x:%d
  ", ctrl->id, ctrl->val);
  
  	/* If a control that doesn't apply to the current mode is modified,
  	 * we store the value and return immediately. The setting will be
  	 * applied when the LED mode is changed. Otherwise we apply the setting
  	 * immediately.
  	 */
  
  	switch (ctrl->id) {
  	case V4L2_CID_FLASH_LED_MODE:
  		if (flash->indicator_current)
  			return -EBUSY;
  
  		ret = as3645a_set_config(flash);
  		if (ret < 0)
  			return ret;
  
  		flash->led_mode = ctrl->val;
  		return as3645a_set_output(flash, false);
  
  	case V4L2_CID_FLASH_STROBE_SOURCE:
  		flash->strobe_source = ctrl->val;
  
  		/* Applies to flash mode only. */
  		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH)
  			break;
  
  		return as3645a_set_output(flash, false);
  
  	case V4L2_CID_FLASH_STROBE:
  		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH)
  			return -EBUSY;
  
  		return as3645a_set_output(flash, true);
  
  	case V4L2_CID_FLASH_STROBE_STOP:
  		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH)
  			return -EBUSY;
  
  		return as3645a_set_output(flash, false);
  
  	case V4L2_CID_FLASH_TIMEOUT:
  		flash->timeout = ctrl->val;
  
  		/* Applies to flash mode only. */
  		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH)
  			break;
  
  		return as3645a_set_config(flash);
  
  	case V4L2_CID_FLASH_INTENSITY:
  		flash->flash_current = (ctrl->val - AS3645A_FLASH_INTENSITY_MIN)
  				     / AS3645A_FLASH_INTENSITY_STEP;
  
  		/* Applies to flash mode only. */
  		if (flash->led_mode != V4L2_FLASH_LED_MODE_FLASH)
  			break;
  
  		return as3645a_set_config(flash);
  
  	case V4L2_CID_FLASH_TORCH_INTENSITY:
  		flash->assist_current =
  			(ctrl->val - AS3645A_TORCH_INTENSITY_MIN)
  			/ AS3645A_TORCH_INTENSITY_STEP;
  
  		/* Applies to torch mode only. */
  		if (flash->led_mode != V4L2_FLASH_LED_MODE_TORCH)
  			break;
  
  		return as3645a_set_config(flash);
  
  	case V4L2_CID_FLASH_INDICATOR_INTENSITY:
  		if (flash->led_mode != V4L2_FLASH_LED_MODE_NONE)
  			return -EBUSY;
  
  		flash->indicator_current =
  			(ctrl->val - AS3645A_INDICATOR_INTENSITY_MIN)
  			/ AS3645A_INDICATOR_INTENSITY_STEP;
  
  		ret = as3645a_set_config(flash);
  		if (ret < 0)
  			return ret;
  
  		if ((ctrl->val == 0) == (ctrl->cur.val == 0))
  			break;
  
  		return as3645a_set_output(flash, false);
  	}
  
  	return 0;
  }
  
  static const struct v4l2_ctrl_ops as3645a_ctrl_ops = {
  	.g_volatile_ctrl = as3645a_get_ctrl,
  	.s_ctrl = as3645a_set_ctrl,
  };
  
  /* -----------------------------------------------------------------------------
   * V4L2 subdev core operations
   */
  
  /* Put device into know state. */
  static int as3645a_setup(struct as3645a *flash)
  {
  	struct i2c_client *client = v4l2_get_subdevdata(&flash->subdev);
  	int ret;
  
  	/* clear errors */
  	ret = as3645a_read(flash, AS_FAULT_INFO_REG);
  	if (ret < 0)
  		return ret;
  
  	dev_dbg(&client->dev, "Fault info: %02x
  ", ret);
  
  	ret = as3645a_set_config(flash);
  	if (ret < 0)
  		return ret;
  
  	ret = as3645a_set_output(flash, false);
  	if (ret < 0)
  		return ret;
  
  	/* read status */
  	ret = as3645a_read_fault(flash);
  	if (ret < 0)
  		return ret;
  
  	dev_dbg(&client->dev, "AS_INDICATOR_AND_TIMER_REG: %02x
  ",
  		as3645a_read(flash, AS_INDICATOR_AND_TIMER_REG));
  	dev_dbg(&client->dev, "AS_CURRENT_SET_REG: %02x
  ",
  		as3645a_read(flash, AS_CURRENT_SET_REG));
  	dev_dbg(&client->dev, "AS_CONTROL_REG: %02x
  ",
  		as3645a_read(flash, AS_CONTROL_REG));
  
  	return ret & ~AS_FAULT_INFO_LED_AMOUNT ? -EIO : 0;
  }
  
  static int __as3645a_set_power(struct as3645a *flash, int on)
  {
  	int ret;
  
  	if (!on)
  		as3645a_set_control(flash, AS_MODE_EXT_TORCH, false);
  
  	if (flash->pdata->set_power) {
  		ret = flash->pdata->set_power(&flash->subdev, on);
  		if (ret < 0)
  			return ret;
  	}
  
  	if (!on)
  		return 0;
  
  	ret = as3645a_setup(flash);
  	if (ret < 0) {
  		if (flash->pdata->set_power)
  			flash->pdata->set_power(&flash->subdev, 0);
  	}
  
  	return ret;
  }
  
  static int as3645a_set_power(struct v4l2_subdev *sd, int on)
  {
  	struct as3645a *flash = to_as3645a(sd);
  	int ret = 0;
  
  	mutex_lock(&flash->power_lock);
  
  	if (flash->power_count == !on) {
  		ret = __as3645a_set_power(flash, !!on);
  		if (ret < 0)
  			goto done;
  	}
  
  	flash->power_count += on ? 1 : -1;
  	WARN_ON(flash->power_count < 0);
  
  done:
  	mutex_unlock(&flash->power_lock);
  	return ret;
  }
  
  static int as3645a_registered(struct v4l2_subdev *sd)
  {
  	struct as3645a *flash = to_as3645a(sd);
  	struct i2c_client *client = v4l2_get_subdevdata(sd);
  	int rval, man, model, rfu, version;
  	const char *vendor;
  
  	/* Power up the flash driver and read manufacturer ID, model ID, RFU
  	 * and version.
  	 */
  	rval = as3645a_set_power(&flash->subdev, 1);
  	if (rval < 0)
  		return rval;
  
  	rval = as3645a_read(flash, AS_DESIGN_INFO_REG);
  	if (rval < 0)
  		goto power_off;
  
  	man = AS_DESIGN_INFO_FACTORY(rval);
  	model = AS_DESIGN_INFO_MODEL(rval);
  
  	rval = as3645a_read(flash, AS_VERSION_CONTROL_REG);
  	if (rval < 0)
  		goto power_off;
  
  	rfu = AS_VERSION_CONTROL_RFU(rval);
  	version = AS_VERSION_CONTROL_VERSION(rval);
  
  	/* Verify the chip model and version. */
  	if (model != 0x01 || rfu != 0x00) {
  		dev_err(&client->dev, "AS3645A not detected "
  			"(model %d rfu %d)
  ", model, rfu);
  		rval = -ENODEV;
  		goto power_off;
  	}
  
  	switch (man) {
  	case 1:
  		vendor = "AMS, Austria Micro Systems";
  		break;
  	case 2:
  		vendor = "ADI, Analog Devices Inc.";
  		break;
  	case 3:
  		vendor = "NSC, National Semiconductor";
  		break;
  	case 4:
  		vendor = "NXP";
  		break;
  	case 5:
  		vendor = "TI, Texas Instrument";
  		break;
  	default:
  		vendor = "Unknown";
  	}
  
  	dev_info(&client->dev, "Chip vendor: %s (%d) Version: %d
  ", vendor,
  		 man, version);
  
  	rval = as3645a_write(flash, AS_PASSWORD_REG, AS_PASSWORD_UNLOCK_VALUE);
  	if (rval < 0)
  		goto power_off;
  
  	rval = as3645a_write(flash, AS_BOOST_REG, AS_BOOST_CURRENT_DISABLE);
  	if (rval < 0)
  		goto power_off;
  
  	/* Setup default values. This makes sure that the chip is in a known
  	 * state, in case the power rail can't be controlled.
  	 */
  	rval = as3645a_setup(flash);
  
  power_off:
  	as3645a_set_power(&flash->subdev, 0);
  
  	return rval;
  }
  
  static int as3645a_open(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
  {
  	return as3645a_set_power(sd, 1);
  }
  
  static int as3645a_close(struct v4l2_subdev *sd, struct v4l2_subdev_fh *fh)
  {
  	return as3645a_set_power(sd, 0);
  }
  
  static const struct v4l2_subdev_core_ops as3645a_core_ops = {
  	.s_power		= as3645a_set_power,
  };
  
  static const struct v4l2_subdev_ops as3645a_ops = {
  	.core = &as3645a_core_ops,
  };
  
  static const struct v4l2_subdev_internal_ops as3645a_internal_ops = {
  	.registered = as3645a_registered,
  	.open = as3645a_open,
  	.close = as3645a_close,
  };
  
  /* -----------------------------------------------------------------------------
   *  I2C driver
   */
  #ifdef CONFIG_PM
  
  static int as3645a_suspend(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
  	struct as3645a *flash = to_as3645a(subdev);
  	int rval;
  
  	if (flash->power_count == 0)
  		return 0;
  
  	rval = __as3645a_set_power(flash, 0);
  
  	dev_dbg(&client->dev, "Suspend %s
  ", rval < 0 ? "failed" : "ok");
  
  	return rval;
  }
  
  static int as3645a_resume(struct device *dev)
  {
  	struct i2c_client *client = to_i2c_client(dev);
  	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
  	struct as3645a *flash = to_as3645a(subdev);
  	int rval;
  
  	if (flash->power_count == 0)
  		return 0;
  
  	rval = __as3645a_set_power(flash, 1);
  
  	dev_dbg(&client->dev, "Resume %s
  ", rval < 0 ? "fail" : "ok");
  
  	return rval;
  }
  
  #else
  
  #define as3645a_suspend	NULL
  #define as3645a_resume	NULL
  
  #endif /* CONFIG_PM */
  
  /*
   * as3645a_init_controls - Create controls
   * @flash: The flash
   *
   * The number of LEDs reported in platform data is used to compute default
   * limits. Parameters passed through platform data can override those limits.
   */
  static int as3645a_init_controls(struct as3645a *flash)
  {
  	const struct as3645a_platform_data *pdata = flash->pdata;
  	struct v4l2_ctrl *ctrl;
  	int maximum;
  
  	v4l2_ctrl_handler_init(&flash->ctrls, 10);
  
  	/* V4L2_CID_FLASH_LED_MODE */
  	v4l2_ctrl_new_std_menu(&flash->ctrls, &as3645a_ctrl_ops,
  			       V4L2_CID_FLASH_LED_MODE, 2, ~7,
  			       V4L2_FLASH_LED_MODE_NONE);
  
  	/* V4L2_CID_FLASH_STROBE_SOURCE */
  	v4l2_ctrl_new_std_menu(&flash->ctrls, &as3645a_ctrl_ops,
  			       V4L2_CID_FLASH_STROBE_SOURCE,
  			       pdata->ext_strobe ? 1 : 0,
  			       pdata->ext_strobe ? ~3 : ~1,
  			       V4L2_FLASH_STROBE_SOURCE_SOFTWARE);
  
  	flash->strobe_source = V4L2_FLASH_STROBE_SOURCE_SOFTWARE;
  
  	/* V4L2_CID_FLASH_STROBE */
  	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
  			  V4L2_CID_FLASH_STROBE, 0, 0, 0, 0);
  
  	/* V4L2_CID_FLASH_STROBE_STOP */
  	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
  			  V4L2_CID_FLASH_STROBE_STOP, 0, 0, 0, 0);
  
  	/* V4L2_CID_FLASH_STROBE_STATUS */
  	ctrl = v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
  				 V4L2_CID_FLASH_STROBE_STATUS, 0, 1, 1, 1);
  	if (ctrl != NULL)
  		ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
  
  	/* V4L2_CID_FLASH_TIMEOUT */
  	maximum = pdata->timeout_max;
  
  	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
  			  V4L2_CID_FLASH_TIMEOUT, AS3645A_FLASH_TIMEOUT_MIN,
  			  maximum, AS3645A_FLASH_TIMEOUT_STEP, maximum);
  
  	flash->timeout = maximum;
  
  	/* V4L2_CID_FLASH_INTENSITY */
  	maximum = pdata->flash_max_current;
  
  	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
  			  V4L2_CID_FLASH_INTENSITY, AS3645A_FLASH_INTENSITY_MIN,
  			  maximum, AS3645A_FLASH_INTENSITY_STEP, maximum);
  
  	flash->flash_current = (maximum - AS3645A_FLASH_INTENSITY_MIN)
  			     / AS3645A_FLASH_INTENSITY_STEP;
  
  	/* V4L2_CID_FLASH_TORCH_INTENSITY */
  	maximum = pdata->torch_max_current;
  
  	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
  			  V4L2_CID_FLASH_TORCH_INTENSITY,
  			  AS3645A_TORCH_INTENSITY_MIN, maximum,
  			  AS3645A_TORCH_INTENSITY_STEP,
  			  AS3645A_TORCH_INTENSITY_MIN);
  
  	flash->assist_current = 0;
  
  	/* V4L2_CID_FLASH_INDICATOR_INTENSITY */
  	v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
  			  V4L2_CID_FLASH_INDICATOR_INTENSITY,
  			  AS3645A_INDICATOR_INTENSITY_MIN,
  			  AS3645A_INDICATOR_INTENSITY_MAX,
  			  AS3645A_INDICATOR_INTENSITY_STEP,
  			  AS3645A_INDICATOR_INTENSITY_MIN);
  
  	flash->indicator_current = 0;
  
  	/* V4L2_CID_FLASH_FAULT */
  	ctrl = v4l2_ctrl_new_std(&flash->ctrls, &as3645a_ctrl_ops,
  				 V4L2_CID_FLASH_FAULT, 0,
  				 V4L2_FLASH_FAULT_OVER_VOLTAGE |
  				 V4L2_FLASH_FAULT_TIMEOUT |
  				 V4L2_FLASH_FAULT_OVER_TEMPERATURE |
  				 V4L2_FLASH_FAULT_SHORT_CIRCUIT, 0, 0);
  	if (ctrl != NULL)
  		ctrl->flags |= V4L2_CTRL_FLAG_VOLATILE;
  
  	flash->subdev.ctrl_handler = &flash->ctrls;
  
  	return flash->ctrls.error;
  }
  
  static int as3645a_probe(struct i2c_client *client,
  			 const struct i2c_device_id *devid)
  {
  	struct as3645a *flash;
  	int ret;
  
  	if (client->dev.platform_data == NULL)
  		return -ENODEV;
  
  	flash = devm_kzalloc(&client->dev, sizeof(*flash), GFP_KERNEL);
  	if (flash == NULL)
  		return -ENOMEM;
  
  	flash->pdata = client->dev.platform_data;
  
  	v4l2_i2c_subdev_init(&flash->subdev, client, &as3645a_ops);
  	flash->subdev.internal_ops = &as3645a_internal_ops;
  	flash->subdev.flags |= V4L2_SUBDEV_FL_HAS_DEVNODE;
  
  	ret = as3645a_init_controls(flash);
  	if (ret < 0)
  		goto done;
  
  	ret = media_entity_init(&flash->subdev.entity, 0, NULL, 0);
  	if (ret < 0)
  		goto done;
  
  	flash->subdev.entity.type = MEDIA_ENT_T_V4L2_SUBDEV_FLASH;
  
  	mutex_init(&flash->power_lock);
  
  	flash->led_mode = V4L2_FLASH_LED_MODE_NONE;
  
  done:
  	if (ret < 0)
  		v4l2_ctrl_handler_free(&flash->ctrls);
  
  	return ret;
  }
  
  static int as3645a_remove(struct i2c_client *client)
  {
  	struct v4l2_subdev *subdev = i2c_get_clientdata(client);
  	struct as3645a *flash = to_as3645a(subdev);
  
  	v4l2_device_unregister_subdev(subdev);
  	v4l2_ctrl_handler_free(&flash->ctrls);
  	media_entity_cleanup(&flash->subdev.entity);
  	mutex_destroy(&flash->power_lock);
  
  	return 0;
  }
  
  static const struct i2c_device_id as3645a_id_table[] = {
  	{ AS3645A_NAME, 0 },
  	{ },
  };
  MODULE_DEVICE_TABLE(i2c, as3645a_id_table);
  
  static const struct dev_pm_ops as3645a_pm_ops = {
  	.suspend = as3645a_suspend,
  	.resume = as3645a_resume,
  };
  
  static struct i2c_driver as3645a_i2c_driver = {
  	.driver	= {
  		.name = AS3645A_NAME,
  		.pm   = &as3645a_pm_ops,
  	},
  	.probe	= as3645a_probe,
  	.remove	= as3645a_remove,
  	.id_table = as3645a_id_table,
  };
  
  module_i2c_driver(as3645a_i2c_driver);
  
  MODULE_AUTHOR("Laurent Pinchart <laurent.pinchart@ideasonboard.com>");
  MODULE_DESCRIPTION("LED flash driver for AS3645A, LM3555 and their clones");
  MODULE_LICENSE("GPL");