/*
   * Summit Microelectronics SMB347 Battery Charger Driver
   *
   * Copyright (C) 2011, Intel Corporation
   *
   * Authors: Bruce E. Robertson <bruce.e.robertson@intel.com>
   *          Mika Westerberg <mika.westerberg@linux.intel.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.
   */
  
  #include <linux/err.h>
  #include <linux/gpio.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/init.h>
  #include <linux/interrupt.h>
  #include <linux/i2c.h>
  #include <linux/mutex.h>
  #include <linux/power_supply.h>
  #include <linux/power/smb347-charger.h>
  #include <linux/regmap.h>
  
  /*
   * Configuration registers. These are mirrored to volatile RAM and can be
   * written once %CMD_A_ALLOW_WRITE is set in %CMD_A register. They will be
   * reloaded from non-volatile registers after POR.
   */
  #define CFG_CHARGE_CURRENT			0x00
  #define CFG_CHARGE_CURRENT_FCC_MASK		0xe0
  #define CFG_CHARGE_CURRENT_FCC_SHIFT		5
  #define CFG_CHARGE_CURRENT_PCC_MASK		0x18
  #define CFG_CHARGE_CURRENT_PCC_SHIFT		3
  #define CFG_CHARGE_CURRENT_TC_MASK		0x07
  #define CFG_CURRENT_LIMIT			0x01
  #define CFG_CURRENT_LIMIT_DC_MASK		0xf0
  #define CFG_CURRENT_LIMIT_DC_SHIFT		4
  #define CFG_CURRENT_LIMIT_USB_MASK		0x0f
  #define CFG_FLOAT_VOLTAGE			0x03
  #define CFG_FLOAT_VOLTAGE_FLOAT_MASK		0x3f
  #define CFG_FLOAT_VOLTAGE_THRESHOLD_MASK	0xc0
  #define CFG_FLOAT_VOLTAGE_THRESHOLD_SHIFT	6
  #define CFG_STAT				0x05
  #define CFG_STAT_DISABLED			BIT(5)
  #define CFG_STAT_ACTIVE_HIGH			BIT(7)
  #define CFG_PIN					0x06
  #define CFG_PIN_EN_CTRL_MASK			0x60
  #define CFG_PIN_EN_CTRL_ACTIVE_HIGH		0x40
  #define CFG_PIN_EN_CTRL_ACTIVE_LOW		0x60
  #define CFG_PIN_EN_APSD_IRQ			BIT(1)
  #define CFG_PIN_EN_CHARGER_ERROR		BIT(2)
  #define CFG_THERM				0x07
  #define CFG_THERM_SOFT_HOT_COMPENSATION_MASK	0x03
  #define CFG_THERM_SOFT_HOT_COMPENSATION_SHIFT	0
  #define CFG_THERM_SOFT_COLD_COMPENSATION_MASK	0x0c
  #define CFG_THERM_SOFT_COLD_COMPENSATION_SHIFT	2
  #define CFG_THERM_MONITOR_DISABLED		BIT(4)
  #define CFG_SYSOK				0x08
  #define CFG_SYSOK_SUSPEND_HARD_LIMIT_DISABLED	BIT(2)
  #define CFG_OTHER				0x09
  #define CFG_OTHER_RID_MASK			0xc0
  #define CFG_OTHER_RID_ENABLED_AUTO_OTG		0xc0
  #define CFG_OTG					0x0a
  #define CFG_OTG_TEMP_THRESHOLD_MASK		0x30
  #define CFG_OTG_TEMP_THRESHOLD_SHIFT		4
  #define CFG_OTG_CC_COMPENSATION_MASK		0xc0
  #define CFG_OTG_CC_COMPENSATION_SHIFT		6
  #define CFG_TEMP_LIMIT				0x0b
  #define CFG_TEMP_LIMIT_SOFT_HOT_MASK		0x03
  #define CFG_TEMP_LIMIT_SOFT_HOT_SHIFT		0
  #define CFG_TEMP_LIMIT_SOFT_COLD_MASK		0x0c
  #define CFG_TEMP_LIMIT_SOFT_COLD_SHIFT		2
  #define CFG_TEMP_LIMIT_HARD_HOT_MASK		0x30
  #define CFG_TEMP_LIMIT_HARD_HOT_SHIFT		4
  #define CFG_TEMP_LIMIT_HARD_COLD_MASK		0xc0
  #define CFG_TEMP_LIMIT_HARD_COLD_SHIFT		6
  #define CFG_FAULT_IRQ				0x0c
  #define CFG_FAULT_IRQ_DCIN_UV			BIT(2)
  #define CFG_STATUS_IRQ				0x0d
  #define CFG_STATUS_IRQ_TERMINATION_OR_TAPER	BIT(4)
  #define CFG_STATUS_IRQ_CHARGE_TIMEOUT		BIT(7)
  #define CFG_ADDRESS				0x0e
  
  /* Command registers */
  #define CMD_A					0x30
  #define CMD_A_CHG_ENABLED			BIT(1)
  #define CMD_A_SUSPEND_ENABLED			BIT(2)
  #define CMD_A_ALLOW_WRITE			BIT(7)
  #define CMD_B					0x31
  #define CMD_C					0x33
  
  /* Interrupt Status registers */
  #define IRQSTAT_A				0x35
  #define IRQSTAT_C				0x37
  #define IRQSTAT_C_TERMINATION_STAT		BIT(0)
  #define IRQSTAT_C_TERMINATION_IRQ		BIT(1)
  #define IRQSTAT_C_TAPER_IRQ			BIT(3)
  #define IRQSTAT_D				0x38
  #define IRQSTAT_D_CHARGE_TIMEOUT_STAT		BIT(2)
  #define IRQSTAT_D_CHARGE_TIMEOUT_IRQ		BIT(3)
  #define IRQSTAT_E				0x39
  #define IRQSTAT_E_USBIN_UV_STAT			BIT(0)
  #define IRQSTAT_E_USBIN_UV_IRQ			BIT(1)
  #define IRQSTAT_E_DCIN_UV_STAT			BIT(4)
  #define IRQSTAT_E_DCIN_UV_IRQ			BIT(5)
  #define IRQSTAT_F				0x3a
  
  /* Status registers */
  #define STAT_A					0x3b
  #define STAT_A_FLOAT_VOLTAGE_MASK		0x3f
  #define STAT_B					0x3c
  #define STAT_C					0x3d
  #define STAT_C_CHG_ENABLED			BIT(0)
  #define STAT_C_HOLDOFF_STAT			BIT(3)
  #define STAT_C_CHG_MASK				0x06
  #define STAT_C_CHG_SHIFT			1
  #define STAT_C_CHG_TERM				BIT(5)
  #define STAT_C_CHARGER_ERROR			BIT(6)
  #define STAT_E					0x3f
  
  #define SMB347_MAX_REGISTER			0x3f
  
  /**
   * struct smb347_charger - smb347 charger instance
   * @lock: protects concurrent access to online variables
   * @dev: pointer to device
   * @regmap: pointer to driver regmap
   * @mains: power_supply instance for AC/DC power
   * @usb: power_supply instance for USB power
   * @battery: power_supply instance for battery
   * @mains_online: is AC/DC input connected
   * @usb_online: is USB input connected
   * @charging_enabled: is charging enabled
   * @pdata: pointer to platform data
   */
  struct smb347_charger {
  	struct mutex		lock;
  	struct device		*dev;
  	struct regmap		*regmap;
  	struct power_supply	mains;
  	struct power_supply	usb;
  	struct power_supply	battery;
  	bool			mains_online;
  	bool			usb_online;
  	bool			charging_enabled;
  	const struct smb347_charger_platform_data *pdata;
  };
  
  /* Fast charge current in uA */
  static const unsigned int fcc_tbl[] = {
  	700000,
  	900000,
  	1200000,
  	1500000,
  	1800000,
  	2000000,
  	2200000,
  	2500000,
  };
  
  /* Pre-charge current in uA */
  static const unsigned int pcc_tbl[] = {
  	100000,
  	150000,
  	200000,
  	250000,
  };
  
  /* Termination current in uA */
  static const unsigned int tc_tbl[] = {
  	37500,
  	50000,
  	100000,
  	150000,
  	200000,
  	250000,
  	500000,
  	600000,
  };
  
  /* Input current limit in uA */
  static const unsigned int icl_tbl[] = {
  	300000,
  	500000,
  	700000,
  	900000,
  	1200000,
  	1500000,
  	1800000,
  	2000000,
  	2200000,
  	2500000,
  };
  
  /* Charge current compensation in uA */
  static const unsigned int ccc_tbl[] = {
  	250000,
  	700000,
  	900000,
  	1200000,
  };
  
  /* Convert register value to current using lookup table */
  static int hw_to_current(const unsigned int *tbl, size_t size, unsigned int val)
  {
  	if (val >= size)
  		return -EINVAL;
  	return tbl[val];
  }
  
  /* Convert current to register value using lookup table */
  static int current_to_hw(const unsigned int *tbl, size_t size, unsigned int val)
  {
  	size_t i;
  
  	for (i = 0; i < size; i++)
  		if (val < tbl[i])
  			break;
  	return i > 0 ? i - 1 : -EINVAL;
  }
  
  /**
   * smb347_update_ps_status - refreshes the power source status
   * @smb: pointer to smb347 charger instance
   *
   * Function checks whether any power source is connected to the charger and
   * updates internal state accordingly. If there is a change to previous state
   * function returns %1, otherwise %0 and negative errno in case of errror.
   */
  static int smb347_update_ps_status(struct smb347_charger *smb)
  {
  	bool usb = false;
  	bool dc = false;
  	unsigned int val;
  	int ret;
  
  	ret = regmap_read(smb->regmap, IRQSTAT_E, &val);
  	if (ret < 0)
  		return ret;
  
  	/*
  	 * Dc and usb are set depending on whether they are enabled in
  	 * platform data _and_ whether corresponding undervoltage is set.
  	 */
  	if (smb->pdata->use_mains)
  		dc = !(val & IRQSTAT_E_DCIN_UV_STAT);
  	if (smb->pdata->use_usb)
  		usb = !(val & IRQSTAT_E_USBIN_UV_STAT);
  
  	mutex_lock(&smb->lock);
  	ret = smb->mains_online != dc || smb->usb_online != usb;
  	smb->mains_online = dc;
  	smb->usb_online = usb;
  	mutex_unlock(&smb->lock);
  
  	return ret;
  }
  
  /*
   * smb347_is_ps_online - returns whether input power source is connected
   * @smb: pointer to smb347 charger instance
   *
   * Returns %true if input power source is connected. Note that this is
   * dependent on what platform has configured for usable power sources. For
   * example if USB is disabled, this will return %false even if the USB cable
   * is connected.
   */
  static bool smb347_is_ps_online(struct smb347_charger *smb)
  {
  	bool ret;
  
  	mutex_lock(&smb->lock);
  	ret = smb->usb_online || smb->mains_online;
  	mutex_unlock(&smb->lock);
  
  	return ret;
  }
  
  /**
   * smb347_charging_status - returns status of charging
   * @smb: pointer to smb347 charger instance
   *
   * Function returns charging status. %0 means no charging is in progress,
   * %1 means pre-charging, %2 fast-charging and %3 taper-charging.
   */
  static int smb347_charging_status(struct smb347_charger *smb)
  {
  	unsigned int val;
  	int ret;
  
  	if (!smb347_is_ps_online(smb))
  		return 0;
  
  	ret = regmap_read(smb->regmap, STAT_C, &val);
  	if (ret < 0)
  		return 0;
  
  	return (val & STAT_C_CHG_MASK) >> STAT_C_CHG_SHIFT;
  }
  
  static int smb347_charging_set(struct smb347_charger *smb, bool enable)
  {
  	int ret = 0;
  
  	if (smb->pdata->enable_control != SMB347_CHG_ENABLE_SW) {
  		dev_dbg(smb->dev, "charging enable/disable in SW disabled
  ");
  		return 0;
  	}
  
  	mutex_lock(&smb->lock);
  	if (smb->charging_enabled != enable) {
  		ret = regmap_update_bits(smb->regmap, CMD_A, CMD_A_CHG_ENABLED,
  					 enable ? CMD_A_CHG_ENABLED : 0);
  		if (!ret)
  			smb->charging_enabled = enable;
  	}
  	mutex_unlock(&smb->lock);
  	return ret;
  }
  
  static inline int smb347_charging_enable(struct smb347_charger *smb)
  {
  	return smb347_charging_set(smb, true);
  }
  
  static inline int smb347_charging_disable(struct smb347_charger *smb)
  {
  	return smb347_charging_set(smb, false);
  }
  
  static int smb347_start_stop_charging(struct smb347_charger *smb)
  {
  	int ret;
  
  	/*
  	 * Depending on whether valid power source is connected or not, we
  	 * disable or enable the charging. We do it manually because it
  	 * depends on how the platform has configured the valid inputs.
  	 */
  	if (smb347_is_ps_online(smb)) {
  		ret = smb347_charging_enable(smb);
  		if (ret < 0)
  			dev_err(smb->dev, "failed to enable charging
  ");
  	} else {
  		ret = smb347_charging_disable(smb);
  		if (ret < 0)
  			dev_err(smb->dev, "failed to disable charging
  ");
  	}
  
  	return ret;
  }
  
  static int smb347_set_charge_current(struct smb347_charger *smb)
  {
  	int ret;
  
  	if (smb->pdata->max_charge_current) {
  		ret = current_to_hw(fcc_tbl, ARRAY_SIZE(fcc_tbl),
  				    smb->pdata->max_charge_current);
  		if (ret < 0)
  			return ret;
  
  		ret = regmap_update_bits(smb->regmap, CFG_CHARGE_CURRENT,
  					 CFG_CHARGE_CURRENT_FCC_MASK,
  					 ret << CFG_CHARGE_CURRENT_FCC_SHIFT);
  		if (ret < 0)
  			return ret;
  	}
  
  	if (smb->pdata->pre_charge_current) {
  		ret = current_to_hw(pcc_tbl, ARRAY_SIZE(pcc_tbl),
  				    smb->pdata->pre_charge_current);
  		if (ret < 0)
  			return ret;
  
  		ret = regmap_update_bits(smb->regmap, CFG_CHARGE_CURRENT,
  					 CFG_CHARGE_CURRENT_PCC_MASK,
  					 ret << CFG_CHARGE_CURRENT_PCC_SHIFT);
  		if (ret < 0)
  			return ret;
  	}
  
  	if (smb->pdata->termination_current) {
  		ret = current_to_hw(tc_tbl, ARRAY_SIZE(tc_tbl),
  				    smb->pdata->termination_current);
  		if (ret < 0)
  			return ret;
  
  		ret = regmap_update_bits(smb->regmap, CFG_CHARGE_CURRENT,
  					 CFG_CHARGE_CURRENT_TC_MASK, ret);
  		if (ret < 0)
  			return ret;
  	}
  
  	return 0;
  }
  
  static int smb347_set_current_limits(struct smb347_charger *smb)
  {
  	int ret;
  
  	if (smb->pdata->mains_current_limit) {
  		ret = current_to_hw(icl_tbl, ARRAY_SIZE(icl_tbl),
  				    smb->pdata->mains_current_limit);
  		if (ret < 0)
  			return ret;
  
  		ret = regmap_update_bits(smb->regmap, CFG_CURRENT_LIMIT,
  					 CFG_CURRENT_LIMIT_DC_MASK,
  					 ret << CFG_CURRENT_LIMIT_DC_SHIFT);
  		if (ret < 0)
  			return ret;
  	}
  
  	if (smb->pdata->usb_hc_current_limit) {
  		ret = current_to_hw(icl_tbl, ARRAY_SIZE(icl_tbl),
  				    smb->pdata->usb_hc_current_limit);
  		if (ret < 0)
  			return ret;
  
  		ret = regmap_update_bits(smb->regmap, CFG_CURRENT_LIMIT,
  					 CFG_CURRENT_LIMIT_USB_MASK, ret);
  		if (ret < 0)
  			return ret;
  	}
  
  	return 0;
  }
  
  static int smb347_set_voltage_limits(struct smb347_charger *smb)
  {
  	int ret;
  
  	if (smb->pdata->pre_to_fast_voltage) {
  		ret = smb->pdata->pre_to_fast_voltage;
  
  		/* uV */
  		ret = clamp_val(ret, 2400000, 3000000) - 2400000;
  		ret /= 200000;
  
  		ret = regmap_update_bits(smb->regmap, CFG_FLOAT_VOLTAGE,
  				CFG_FLOAT_VOLTAGE_THRESHOLD_MASK,
  				ret << CFG_FLOAT_VOLTAGE_THRESHOLD_SHIFT);
  		if (ret < 0)
  			return ret;
  	}
  
  	if (smb->pdata->max_charge_voltage) {
  		ret = smb->pdata->max_charge_voltage;
  
  		/* uV */
  		ret = clamp_val(ret, 3500000, 4500000) - 3500000;
  		ret /= 20000;
  
  		ret = regmap_update_bits(smb->regmap, CFG_FLOAT_VOLTAGE,
  					 CFG_FLOAT_VOLTAGE_FLOAT_MASK, ret);
  		if (ret < 0)
  			return ret;
  	}
  
  	return 0;
  }
  
  static int smb347_set_temp_limits(struct smb347_charger *smb)
  {
  	bool enable_therm_monitor = false;
  	int ret = 0;
  	int val;
  
  	if (smb->pdata->chip_temp_threshold) {
  		val = smb->pdata->chip_temp_threshold;
  
  		/* degree C */
  		val = clamp_val(val, 100, 130) - 100;
  		val /= 10;
  
  		ret = regmap_update_bits(smb->regmap, CFG_OTG,
  					 CFG_OTG_TEMP_THRESHOLD_MASK,
  					 val << CFG_OTG_TEMP_THRESHOLD_SHIFT);
  		if (ret < 0)
  			return ret;
  	}
  
  	if (smb->pdata->soft_cold_temp_limit != SMB347_TEMP_USE_DEFAULT) {
  		val = smb->pdata->soft_cold_temp_limit;
  
  		val = clamp_val(val, 0, 15);
  		val /= 5;
  		/* this goes from higher to lower so invert the value */
  		val = ~val & 0x3;
  
  		ret = regmap_update_bits(smb->regmap, CFG_TEMP_LIMIT,
  					 CFG_TEMP_LIMIT_SOFT_COLD_MASK,
  					 val << CFG_TEMP_LIMIT_SOFT_COLD_SHIFT);
  		if (ret < 0)
  			return ret;
  
  		enable_therm_monitor = true;
  	}
  
  	if (smb->pdata->soft_hot_temp_limit != SMB347_TEMP_USE_DEFAULT) {
  		val = smb->pdata->soft_hot_temp_limit;
  
  		val = clamp_val(val, 40, 55) - 40;
  		val /= 5;
  
  		ret = regmap_update_bits(smb->regmap, CFG_TEMP_LIMIT,
  					 CFG_TEMP_LIMIT_SOFT_HOT_MASK,
  					 val << CFG_TEMP_LIMIT_SOFT_HOT_SHIFT);
  		if (ret < 0)
  			return ret;
  
  		enable_therm_monitor = true;
  	}
  
  	if (smb->pdata->hard_cold_temp_limit != SMB347_TEMP_USE_DEFAULT) {
  		val = smb->pdata->hard_cold_temp_limit;
  
  		val = clamp_val(val, -5, 10) + 5;
  		val /= 5;
  		/* this goes from higher to lower so invert the value */
  		val = ~val & 0x3;
  
  		ret = regmap_update_bits(smb->regmap, CFG_TEMP_LIMIT,
  					 CFG_TEMP_LIMIT_HARD_COLD_MASK,
  					 val << CFG_TEMP_LIMIT_HARD_COLD_SHIFT);
  		if (ret < 0)
  			return ret;
  
  		enable_therm_monitor = true;
  	}
  
  	if (smb->pdata->hard_hot_temp_limit != SMB347_TEMP_USE_DEFAULT) {
  		val = smb->pdata->hard_hot_temp_limit;
  
  		val = clamp_val(val, 50, 65) - 50;
  		val /= 5;
  
  		ret = regmap_update_bits(smb->regmap, CFG_TEMP_LIMIT,
  					 CFG_TEMP_LIMIT_HARD_HOT_MASK,
  					 val << CFG_TEMP_LIMIT_HARD_HOT_SHIFT);
  		if (ret < 0)
  			return ret;
  
  		enable_therm_monitor = true;
  	}
  
  	/*
  	 * If any of the temperature limits are set, we also enable the
  	 * thermistor monitoring.
  	 *
  	 * When soft limits are hit, the device will start to compensate
  	 * current and/or voltage depending on the configuration.
  	 *
  	 * When hard limit is hit, the device will suspend charging
  	 * depending on the configuration.
  	 */
  	if (enable_therm_monitor) {
  		ret = regmap_update_bits(smb->regmap, CFG_THERM,
  					 CFG_THERM_MONITOR_DISABLED, 0);
  		if (ret < 0)
  			return ret;
  	}
  
  	if (smb->pdata->suspend_on_hard_temp_limit) {
  		ret = regmap_update_bits(smb->regmap, CFG_SYSOK,
  				 CFG_SYSOK_SUSPEND_HARD_LIMIT_DISABLED, 0);
  		if (ret < 0)
  			return ret;
  	}
  
  	if (smb->pdata->soft_temp_limit_compensation !=
  	    SMB347_SOFT_TEMP_COMPENSATE_DEFAULT) {
  		val = smb->pdata->soft_temp_limit_compensation & 0x3;
  
  		ret = regmap_update_bits(smb->regmap, CFG_THERM,
  				 CFG_THERM_SOFT_HOT_COMPENSATION_MASK,
  				 val << CFG_THERM_SOFT_HOT_COMPENSATION_SHIFT);
  		if (ret < 0)
  			return ret;
  
  		ret = regmap_update_bits(smb->regmap, CFG_THERM,
  				 CFG_THERM_SOFT_COLD_COMPENSATION_MASK,
  				 val << CFG_THERM_SOFT_COLD_COMPENSATION_SHIFT);
  		if (ret < 0)
  			return ret;
  	}
  
  	if (smb->pdata->charge_current_compensation) {
  		val = current_to_hw(ccc_tbl, ARRAY_SIZE(ccc_tbl),
  				    smb->pdata->charge_current_compensation);
  		if (val < 0)
  			return val;
  
  		ret = regmap_update_bits(smb->regmap, CFG_OTG,
  				CFG_OTG_CC_COMPENSATION_MASK,
  				(val & 0x3) << CFG_OTG_CC_COMPENSATION_SHIFT);
  		if (ret < 0)
  			return ret;
  	}
  
  	return ret;
  }
  
  /*
   * smb347_set_writable - enables/disables writing to non-volatile registers
   * @smb: pointer to smb347 charger instance
   *
   * You can enable/disable writing to the non-volatile configuration
   * registers by calling this function.
   *
   * Returns %0 on success and negative errno in case of failure.
   */
  static int smb347_set_writable(struct smb347_charger *smb, bool writable)
  {
  	return regmap_update_bits(smb->regmap, CMD_A, CMD_A_ALLOW_WRITE,
  				  writable ? CMD_A_ALLOW_WRITE : 0);
  }
  
  static int smb347_hw_init(struct smb347_charger *smb)
  {
  	unsigned int val;
  	int ret;
  
  	ret = smb347_set_writable(smb, true);
  	if (ret < 0)
  		return ret;
  
  	/*
  	 * Program the platform specific configuration values to the device
  	 * first.
  	 */
  	ret = smb347_set_charge_current(smb);
  	if (ret < 0)
  		goto fail;
  
  	ret = smb347_set_current_limits(smb);
  	if (ret < 0)
  		goto fail;
  
  	ret = smb347_set_voltage_limits(smb);
  	if (ret < 0)
  		goto fail;
  
  	ret = smb347_set_temp_limits(smb);
  	if (ret < 0)
  		goto fail;
  
  	/* If USB charging is disabled we put the USB in suspend mode */
  	if (!smb->pdata->use_usb) {
  		ret = regmap_update_bits(smb->regmap, CMD_A,
  					 CMD_A_SUSPEND_ENABLED,
  					 CMD_A_SUSPEND_ENABLED);
  		if (ret < 0)
  			goto fail;
  	}
  
  	/*
  	 * If configured by platform data, we enable hardware Auto-OTG
  	 * support for driving VBUS. Otherwise we disable it.
  	 */
  	ret = regmap_update_bits(smb->regmap, CFG_OTHER, CFG_OTHER_RID_MASK,
  		smb->pdata->use_usb_otg ? CFG_OTHER_RID_ENABLED_AUTO_OTG : 0);
  	if (ret < 0)
  		goto fail;
  
  	/*
  	 * Make the charging functionality controllable by a write to the
  	 * command register unless pin control is specified in the platform
  	 * data.
  	 */
  	switch (smb->pdata->enable_control) {
  	case SMB347_CHG_ENABLE_PIN_ACTIVE_LOW:
  		val = CFG_PIN_EN_CTRL_ACTIVE_LOW;
  		break;
  	case SMB347_CHG_ENABLE_PIN_ACTIVE_HIGH:
  		val = CFG_PIN_EN_CTRL_ACTIVE_HIGH;
  		break;
  	default:
  		val = 0;
  		break;
  	}
  
  	ret = regmap_update_bits(smb->regmap, CFG_PIN, CFG_PIN_EN_CTRL_MASK,
  				 val);
  	if (ret < 0)
  		goto fail;
  
  	/* Disable Automatic Power Source Detection (APSD) interrupt. */
  	ret = regmap_update_bits(smb->regmap, CFG_PIN, CFG_PIN_EN_APSD_IRQ, 0);
  	if (ret < 0)
  		goto fail;
  
  	ret = smb347_update_ps_status(smb);
  	if (ret < 0)
  		goto fail;
  
  	ret = smb347_start_stop_charging(smb);
  
  fail:
  	smb347_set_writable(smb, false);
  	return ret;
  }
  
  static irqreturn_t smb347_interrupt(int irq, void *data)
  {
  	struct smb347_charger *smb = data;
  	unsigned int stat_c, irqstat_c, irqstat_d, irqstat_e;
  	bool handled = false;
  	int ret;
  
  	ret = regmap_read(smb->regmap, STAT_C, &stat_c);
  	if (ret < 0) {
  		dev_warn(smb->dev, "reading STAT_C failed
  ");
  		return IRQ_NONE;
  	}
  
  	ret = regmap_read(smb->regmap, IRQSTAT_C, &irqstat_c);
  	if (ret < 0) {
  		dev_warn(smb->dev, "reading IRQSTAT_C failed
  ");
  		return IRQ_NONE;
  	}
  
  	ret = regmap_read(smb->regmap, IRQSTAT_D, &irqstat_d);
  	if (ret < 0) {
  		dev_warn(smb->dev, "reading IRQSTAT_D failed
  ");
  		return IRQ_NONE;
  	}
  
  	ret = regmap_read(smb->regmap, IRQSTAT_E, &irqstat_e);
  	if (ret < 0) {
  		dev_warn(smb->dev, "reading IRQSTAT_E failed
  ");
  		return IRQ_NONE;
  	}
  
  	/*
  	 * If we get charger error we report the error back to user.
  	 * If the error is recovered charging will resume again.
  	 */
  	if (stat_c & STAT_C_CHARGER_ERROR) {
  		dev_err(smb->dev, "charging stopped due to charger error
  ");
  		power_supply_changed(&smb->battery);
  		handled = true;
  	}
  
  	/*
  	 * If we reached the termination current the battery is charged and
  	 * we can update the status now. Charging is automatically
  	 * disabled by the hardware.
  	 */
  	if (irqstat_c & (IRQSTAT_C_TERMINATION_IRQ | IRQSTAT_C_TAPER_IRQ)) {
  		if (irqstat_c & IRQSTAT_C_TERMINATION_STAT)
  			power_supply_changed(&smb->battery);
  		dev_dbg(smb->dev, "going to HW maintenance mode
  ");
  		handled = true;
  	}
  
  	/*
  	 * If we got a charger timeout INT that means the charge
  	 * full is not detected with in charge timeout value.
  	 */
  	if (irqstat_d & IRQSTAT_D_CHARGE_TIMEOUT_IRQ) {
  		dev_dbg(smb->dev, "total Charge Timeout INT received
  ");
  
  		if (irqstat_d & IRQSTAT_D_CHARGE_TIMEOUT_STAT)
  			dev_warn(smb->dev, "charging stopped due to timeout
  ");
  		power_supply_changed(&smb->battery);
  		handled = true;
  	}
  
  	/*
  	 * If we got an under voltage interrupt it means that AC/USB input
  	 * was connected or disconnected.
  	 */
  	if (irqstat_e & (IRQSTAT_E_USBIN_UV_IRQ | IRQSTAT_E_DCIN_UV_IRQ)) {
  		if (smb347_update_ps_status(smb) > 0) {
  			smb347_start_stop_charging(smb);
  			if (smb->pdata->use_mains)
  				power_supply_changed(&smb->mains);
  			if (smb->pdata->use_usb)
  				power_supply_changed(&smb->usb);
  		}
  		handled = true;
  	}
  
  	return handled ? IRQ_HANDLED : IRQ_NONE;
  }
  
  static int smb347_irq_set(struct smb347_charger *smb, bool enable)
  {
  	int ret;
  
  	ret = smb347_set_writable(smb, true);
  	if (ret < 0)
  		return ret;
  
  	/*
  	 * Enable/disable interrupts for:
  	 *	- under voltage
  	 *	- termination current reached
  	 *	- charger timeout
  	 *	- charger error
  	 */
  	ret = regmap_update_bits(smb->regmap, CFG_FAULT_IRQ, 0xff,
  				 enable ? CFG_FAULT_IRQ_DCIN_UV : 0);
  	if (ret < 0)
  		goto fail;
  
  	ret = regmap_update_bits(smb->regmap, CFG_STATUS_IRQ, 0xff,
  			enable ? (CFG_STATUS_IRQ_TERMINATION_OR_TAPER |
  					CFG_STATUS_IRQ_CHARGE_TIMEOUT) : 0);
  	if (ret < 0)
  		goto fail;
  
  	ret = regmap_update_bits(smb->regmap, CFG_PIN, CFG_PIN_EN_CHARGER_ERROR,
  				 enable ? CFG_PIN_EN_CHARGER_ERROR : 0);
  fail:
  	smb347_set_writable(smb, false);
  	return ret;
  }
  
  static inline int smb347_irq_enable(struct smb347_charger *smb)
  {
  	return smb347_irq_set(smb, true);
  }
  
  static inline int smb347_irq_disable(struct smb347_charger *smb)
  {
  	return smb347_irq_set(smb, false);
  }
  
  static int smb347_irq_init(struct smb347_charger *smb,
  			   struct i2c_client *client)
  {
  	const struct smb347_charger_platform_data *pdata = smb->pdata;
  	int ret, irq = gpio_to_irq(pdata->irq_gpio);
  
  	ret = gpio_request_one(pdata->irq_gpio, GPIOF_IN, client->name);
  	if (ret < 0)
  		goto fail;
  
  	ret = request_threaded_irq(irq, NULL, smb347_interrupt,
  				   IRQF_TRIGGER_FALLING, client->name, smb);
  	if (ret < 0)
  		goto fail_gpio;
  
  	ret = smb347_set_writable(smb, true);
  	if (ret < 0)
  		goto fail_irq;
  
  	/*
  	 * Configure the STAT output to be suitable for interrupts: disable
  	 * all other output (except interrupts) and make it active low.
  	 */
  	ret = regmap_update_bits(smb->regmap, CFG_STAT,
  				 CFG_STAT_ACTIVE_HIGH | CFG_STAT_DISABLED,
  				 CFG_STAT_DISABLED);
  	if (ret < 0)
  		goto fail_readonly;
  
  	smb347_set_writable(smb, false);
  	client->irq = irq;
  	return 0;
  
  fail_readonly:
  	smb347_set_writable(smb, false);
  fail_irq:
  	free_irq(irq, smb);
  fail_gpio:
  	gpio_free(pdata->irq_gpio);
  fail:
  	client->irq = 0;
  	return ret;
  }
  
  /*
   * Returns the constant charge current programmed
   * into the charger in uA.
   */
  static int get_const_charge_current(struct smb347_charger *smb)
  {
  	int ret, intval;
  	unsigned int v;
  
  	if (!smb347_is_ps_online(smb))
  		return -ENODATA;
  
  	ret = regmap_read(smb->regmap, STAT_B, &v);
  	if (ret < 0)
  		return ret;
  
  	/*
  	 * The current value is composition of FCC and PCC values
  	 * and we can detect which table to use from bit 5.
  	 */
  	if (v & 0x20) {
  		intval = hw_to_current(fcc_tbl, ARRAY_SIZE(fcc_tbl), v & 7);
  	} else {
  		v >>= 3;
  		intval = hw_to_current(pcc_tbl, ARRAY_SIZE(pcc_tbl), v & 7);
  	}
  
  	return intval;
  }
  
  /*
   * Returns the constant charge voltage programmed
   * into the charger in uV.
   */
  static int get_const_charge_voltage(struct smb347_charger *smb)
  {
  	int ret, intval;
  	unsigned int v;
  
  	if (!smb347_is_ps_online(smb))
  		return -ENODATA;
  
  	ret = regmap_read(smb->regmap, STAT_A, &v);
  	if (ret < 0)
  		return ret;
  
  	v &= STAT_A_FLOAT_VOLTAGE_MASK;
  	if (v > 0x3d)
  		v = 0x3d;
  
  	intval = 3500000 + v * 20000;
  
  	return intval;
  }
  
  static int smb347_mains_get_property(struct power_supply *psy,
  				     enum power_supply_property prop,
  				     union power_supply_propval *val)
  {
  	struct smb347_charger *smb =
  		container_of(psy, struct smb347_charger, mains);
  	int ret;
  
  	switch (prop) {
  	case POWER_SUPPLY_PROP_ONLINE:
  		val->intval = smb->mains_online;
  		break;
  
  	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
  		ret = get_const_charge_voltage(smb);
  		if (ret < 0)
  			return ret;
  		else
  			val->intval = ret;
  		break;
  
  	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
  		ret = get_const_charge_current(smb);
  		if (ret < 0)
  			return ret;
  		else
  			val->intval = ret;
  		break;
  
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static enum power_supply_property smb347_mains_properties[] = {
  	POWER_SUPPLY_PROP_ONLINE,
  	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
  	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
  };
  
  static int smb347_usb_get_property(struct power_supply *psy,
  				   enum power_supply_property prop,
  				   union power_supply_propval *val)
  {
  	struct smb347_charger *smb =
  		container_of(psy, struct smb347_charger, usb);
  	int ret;
  
  	switch (prop) {
  	case POWER_SUPPLY_PROP_ONLINE:
  		val->intval = smb->usb_online;
  		break;
  
  	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
  		ret = get_const_charge_voltage(smb);
  		if (ret < 0)
  			return ret;
  		else
  			val->intval = ret;
  		break;
  
  	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
  		ret = get_const_charge_current(smb);
  		if (ret < 0)
  			return ret;
  		else
  			val->intval = ret;
  		break;
  
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static enum power_supply_property smb347_usb_properties[] = {
  	POWER_SUPPLY_PROP_ONLINE,
  	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
  	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
  };
  
  static int smb347_get_charging_status(struct smb347_charger *smb)
  {
  	int ret, status;
  	unsigned int val;
  
  	if (!smb347_is_ps_online(smb))
  		return POWER_SUPPLY_STATUS_DISCHARGING;
  
  	ret = regmap_read(smb->regmap, STAT_C, &val);
  	if (ret < 0)
  		return ret;
  
  	if ((val & STAT_C_CHARGER_ERROR) ||
  			(val & STAT_C_HOLDOFF_STAT)) {
  		/*
  		 * set to NOT CHARGING upon charger error
  		 * or charging has stopped.
  		 */
  		status = POWER_SUPPLY_STATUS_NOT_CHARGING;
  	} else {
  		if ((val & STAT_C_CHG_MASK) >> STAT_C_CHG_SHIFT) {
  			/*
  			 * set to charging if battery is in pre-charge,
  			 * fast charge or taper charging mode.
  			 */
  			status = POWER_SUPPLY_STATUS_CHARGING;
  		} else if (val & STAT_C_CHG_TERM) {
  			/*
  			 * set the status to FULL if battery is not in pre
  			 * charge, fast charge or taper charging mode AND
  			 * charging is terminated at least once.
  			 */
  			status = POWER_SUPPLY_STATUS_FULL;
  		} else {
  			/*
  			 * in this case no charger error or termination
  			 * occured but charging is not in progress!!!
  			 */
  			status = POWER_SUPPLY_STATUS_NOT_CHARGING;
  		}
  	}
  
  	return status;
  }
  
  static int smb347_battery_get_property(struct power_supply *psy,
  				       enum power_supply_property prop,
  				       union power_supply_propval *val)
  {
  	struct smb347_charger *smb =
  			container_of(psy, struct smb347_charger, battery);
  	const struct smb347_charger_platform_data *pdata = smb->pdata;
  	int ret;
  
  	ret = smb347_update_ps_status(smb);
  	if (ret < 0)
  		return ret;
  
  	switch (prop) {
  	case POWER_SUPPLY_PROP_STATUS:
  		ret = smb347_get_charging_status(smb);
  		if (ret < 0)
  			return ret;
  		val->intval = ret;
  		break;
  
  	case POWER_SUPPLY_PROP_CHARGE_TYPE:
  		if (!smb347_is_ps_online(smb))
  			return -ENODATA;
  
  		/*
  		 * We handle trickle and pre-charging the same, and taper
  		 * and none the same.
  		 */
  		switch (smb347_charging_status(smb)) {
  		case 1:
  			val->intval = POWER_SUPPLY_CHARGE_TYPE_TRICKLE;
  			break;
  		case 2:
  			val->intval = POWER_SUPPLY_CHARGE_TYPE_FAST;
  			break;
  		default:
  			val->intval = POWER_SUPPLY_CHARGE_TYPE_NONE;
  			break;
  		}
  		break;
  
  	case POWER_SUPPLY_PROP_TECHNOLOGY:
  		val->intval = pdata->battery_info.technology;
  		break;
  
  	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
  		val->intval = pdata->battery_info.voltage_min_design;
  		break;
  
  	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
  		val->intval = pdata->battery_info.voltage_max_design;
  		break;
  
  	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
  		val->intval = pdata->battery_info.charge_full_design;
  		break;
  
  	case POWER_SUPPLY_PROP_MODEL_NAME:
  		val->strval = pdata->battery_info.name;
  		break;
  
  	default:
  		return -EINVAL;
  	}
  
  	return 0;
  }
  
  static enum power_supply_property smb347_battery_properties[] = {
  	POWER_SUPPLY_PROP_STATUS,
  	POWER_SUPPLY_PROP_CHARGE_TYPE,
  	POWER_SUPPLY_PROP_TECHNOLOGY,
  	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
  	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
  	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
  	POWER_SUPPLY_PROP_MODEL_NAME,
  };
  
  static bool smb347_volatile_reg(struct device *dev, unsigned int reg)
  {
  	switch (reg) {
  	case IRQSTAT_A:
  	case IRQSTAT_C:
  	case IRQSTAT_E:
  	case IRQSTAT_F:
  	case STAT_A:
  	case STAT_B:
  	case STAT_C:
  	case STAT_E:
  		return true;
  	}
  
  	return false;
  }
  
  static bool smb347_readable_reg(struct device *dev, unsigned int reg)
  {
  	switch (reg) {
  	case CFG_CHARGE_CURRENT:
  	case CFG_CURRENT_LIMIT:
  	case CFG_FLOAT_VOLTAGE:
  	case CFG_STAT:
  	case CFG_PIN:
  	case CFG_THERM:
  	case CFG_SYSOK:
  	case CFG_OTHER:
  	case CFG_OTG:
  	case CFG_TEMP_LIMIT:
  	case CFG_FAULT_IRQ:
  	case CFG_STATUS_IRQ:
  	case CFG_ADDRESS:
  	case CMD_A:
  	case CMD_B:
  	case CMD_C:
  		return true;
  	}
  
  	return smb347_volatile_reg(dev, reg);
  }
  
  static const struct regmap_config smb347_regmap = {
  	.reg_bits	= 8,
  	.val_bits	= 8,
  	.max_register	= SMB347_MAX_REGISTER,
  	.volatile_reg	= smb347_volatile_reg,
  	.readable_reg	= smb347_readable_reg,
  };
  
  static int smb347_probe(struct i2c_client *client,
  			const struct i2c_device_id *id)
  {
  	static char *battery[] = { "smb347-battery" };
  	const struct smb347_charger_platform_data *pdata;
  	struct device *dev = &client->dev;
  	struct smb347_charger *smb;
  	int ret;
  
  	pdata = dev->platform_data;
  	if (!pdata)
  		return -EINVAL;
  
  	if (!pdata->use_mains && !pdata->use_usb)
  		return -EINVAL;
  
  	smb = devm_kzalloc(dev, sizeof(*smb), GFP_KERNEL);
  	if (!smb)
  		return -ENOMEM;
  
  	i2c_set_clientdata(client, smb);
  
  	mutex_init(&smb->lock);
  	smb->dev = &client->dev;
  	smb->pdata = pdata;
  
  	smb->regmap = devm_regmap_init_i2c(client, &smb347_regmap);
  	if (IS_ERR(smb->regmap))
  		return PTR_ERR(smb->regmap);
  
  	ret = smb347_hw_init(smb);
  	if (ret < 0)
  		return ret;
  
  	if (smb->pdata->use_mains) {
  		smb->mains.name = "smb347-mains";
  		smb->mains.type = POWER_SUPPLY_TYPE_MAINS;
  		smb->mains.get_property = smb347_mains_get_property;
  		smb->mains.properties = smb347_mains_properties;
  		smb->mains.num_properties = ARRAY_SIZE(smb347_mains_properties);
  		smb->mains.supplied_to = battery;
  		smb->mains.num_supplicants = ARRAY_SIZE(battery);
  		ret = power_supply_register(dev, &smb->mains);
  		if (ret < 0)
  			return ret;
  	}
  
  	if (smb->pdata->use_usb) {
  		smb->usb.name = "smb347-usb";
  		smb->usb.type = POWER_SUPPLY_TYPE_USB;
  		smb->usb.get_property = smb347_usb_get_property;
  		smb->usb.properties = smb347_usb_properties;
  		smb->usb.num_properties = ARRAY_SIZE(smb347_usb_properties);
  		smb->usb.supplied_to = battery;
  		smb->usb.num_supplicants = ARRAY_SIZE(battery);
  		ret = power_supply_register(dev, &smb->usb);
  		if (ret < 0) {
  			if (smb->pdata->use_mains)
  				power_supply_unregister(&smb->mains);
  			return ret;
  		}
  	}
  
  	smb->battery.name = "smb347-battery";
  	smb->battery.type = POWER_SUPPLY_TYPE_BATTERY;
  	smb->battery.get_property = smb347_battery_get_property;
  	smb->battery.properties = smb347_battery_properties;
  	smb->battery.num_properties = ARRAY_SIZE(smb347_battery_properties);
  
  
  	ret = power_supply_register(dev, &smb->battery);
  	if (ret < 0) {
  		if (smb->pdata->use_usb)
  			power_supply_unregister(&smb->usb);
  		if (smb->pdata->use_mains)
  			power_supply_unregister(&smb->mains);
  		return ret;
  	}
  
  	/*
  	 * Interrupt pin is optional. If it is connected, we setup the
  	 * interrupt support here.
  	 */
  	if (pdata->irq_gpio >= 0) {
  		ret = smb347_irq_init(smb, client);
  		if (ret < 0) {
  			dev_warn(dev, "failed to initialize IRQ: %d
  ", ret);
  			dev_warn(dev, "disabling IRQ support
  ");
  		} else {
  			smb347_irq_enable(smb);
  		}
  	}
  
  	return 0;
  }
  
  static int smb347_remove(struct i2c_client *client)
  {
  	struct smb347_charger *smb = i2c_get_clientdata(client);
  
  	if (client->irq) {
  		smb347_irq_disable(smb);
  		free_irq(client->irq, smb);
  		gpio_free(smb->pdata->irq_gpio);
  	}
  
  	power_supply_unregister(&smb->battery);
  	if (smb->pdata->use_usb)
  		power_supply_unregister(&smb->usb);
  	if (smb->pdata->use_mains)
  		power_supply_unregister(&smb->mains);
  	return 0;
  }
  
  static const struct i2c_device_id smb347_id[] = {
  	{ "smb347", 0 },
  	{ }
  };
  MODULE_DEVICE_TABLE(i2c, smb347_id);
  
  static struct i2c_driver smb347_driver = {
  	.driver = {
  		.name = "smb347",
  	},
  	.probe        = smb347_probe,
  	.remove       = smb347_remove,
  	.id_table     = smb347_id,
  };
  
  module_i2c_driver(smb347_driver);
  
  MODULE_AUTHOR("Bruce E. Robertson <bruce.e.robertson@intel.com>");
  MODULE_AUTHOR("Mika Westerberg <mika.westerberg@linux.intel.com>");
  MODULE_DESCRIPTION("SMB347 battery charger driver");
  MODULE_LICENSE("GPL");
  MODULE_ALIAS("i2c:smb347");