power_supply: Add support for TI BQ25890 charger chip

More details about the chip can be found here:
http://www.ti.com/product/bq25890

Signed-off-by: Laurentiu Palcu <[e-mail]>
Reviewed-by: Krzysztof Kozlowski <[e-mail]>
Signed-off-by: Sebastian Reichel <[e-mail]>

drivers/power/Kconfig

···
 	help
 	  Say Y to enable support for the TI BQ24735 battery charger.
 
+config CHARGER_BQ25890
+	tristate "TI BQ25890 battery charger driver"
+	depends on I2C && GPIOLIB
+	select REGMAP_I2C
+	help
+	  Say Y to enable support for the TI BQ25890 battery charger.
+
 config CHARGER_SMB347
 	tristate "Summit Microelectronics SMB347 Battery Charger"
 	depends on I2C

drivers/power/Makefile

···
 obj-$(CONFIG_CHARGER_BQ24190)	+= bq24190_charger.o
 obj-$(CONFIG_CHARGER_BQ24257)	+= bq24257_charger.o
 obj-$(CONFIG_CHARGER_BQ24735)	+= bq24735-charger.o
+obj-$(CONFIG_CHARGER_BQ25890)	+= bq25890_charger.o
 obj-$(CONFIG_POWER_AVS)		+= avs/
 obj-$(CONFIG_CHARGER_SMB347)	+= smb347-charger.o
 obj-$(CONFIG_CHARGER_TPS65090)	+= tps65090-charger.o

drivers/power/bq25890_charger.c

···
+/*
+ * TI BQ25890 charger driver
+ *
+ * Copyright (C) 2015 Intel Corporation
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/i2c.h>
+#include <linux/power_supply.h>
+#include <linux/regmap.h>
+#include <linux/types.h>
+#include <linux/gpio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/delay.h>
+#include <linux/usb/phy.h>
+
+#include <linux/acpi.h>
+#include <linux/of.h>
+
+#define BQ25890_MANUFACTURER		"Texas Instruments"
+#define BQ25890_IRQ_PIN			"bq25890_irq"
+
+#define BQ25890_ID			3
+
+enum bq25890_fields {
+	F_EN_HIZ, F_EN_ILIM, F_IILIM,				     /* Reg00 */
+	F_BHOT, F_BCOLD, F_VINDPM_OFS,				     /* Reg01 */
+	F_CONV_START, F_CONV_RATE, F_BOOSTF, F_ICO_EN,
+	F_HVDCP_EN, F_MAXC_EN, F_FORCE_DPM, F_AUTO_DPDM_EN,	     /* Reg02 */
+	F_BAT_LOAD_EN, F_WD_RST, F_OTG_CFG, F_CHG_CFG, F_SYSVMIN,    /* Reg03 */
+	F_PUMPX_EN, F_ICHG,					     /* Reg04 */
+	F_IPRECHG, F_ITERM,					     /* Reg05 */
+	F_VREG, F_BATLOWV, F_VRECHG,				     /* Reg06 */
+	F_TERM_EN, F_STAT_DIS, F_WD, F_TMR_EN, F_CHG_TMR,
+	F_JEITA_ISET,						     /* Reg07 */
+	F_BATCMP, F_VCLAMP, F_TREG,				     /* Reg08 */
+	F_FORCE_ICO, F_TMR2X_EN, F_BATFET_DIS, F_JEITA_VSET,
+	F_BATFET_DLY, F_BATFET_RST_EN, F_PUMPX_UP, F_PUMPX_DN,	     /* Reg09 */
+	F_BOOSTV, F_BOOSTI,					     /* Reg0A */
+	F_VBUS_STAT, F_CHG_STAT, F_PG_STAT, F_SDP_STAT, F_VSYS_STAT, /* Reg0B */
+	F_WD_FAULT, F_BOOST_FAULT, F_CHG_FAULT, F_BAT_FAULT,
+	F_NTC_FAULT,						     /* Reg0C */
+	F_FORCE_VINDPM, F_VINDPM,				     /* Reg0D */
+	F_THERM_STAT, F_BATV,					     /* Reg0E */
+	F_SYSV,							     /* Reg0F */
+	F_TSPCT,						     /* Reg10 */
+	F_VBUS_GD, F_VBUSV,					     /* Reg11 */
+	F_ICHGR,						     /* Reg12 */
+	F_VDPM_STAT, F_IDPM_STAT, F_IDPM_LIM,			     /* Reg13 */
+	F_REG_RST, F_ICO_OPTIMIZED, F_PN, F_TS_PROFILE, F_DEV_REV,   /* Reg14 */
+
+	F_MAX_FIELDS
+};
+
+/* initial field values, converted to register values */
+struct bq25890_init_data {
+	u8 ichg;	/* charge current		*/
+	u8 vreg;	/* regulation voltage		*/
+	u8 iterm;	/* termination current		*/
+	u8 iprechg;	/* precharge current		*/
+	u8 sysvmin;	/* minimum system voltage limit */
+	u8 boostv;	/* boost regulation voltage	*/
+	u8 boosti;	/* boost current limit		*/
+	u8 boostf;	/* boost frequency		*/
+	u8 ilim_en;	/* enable ILIM pin		*/
+	u8 treg;	/* thermal regulation threshold */
+};
+
+struct bq25890_state {
+	u8 online;
+	u8 chrg_status;
+	u8 chrg_fault;
+	u8 vsys_status;
+	u8 boost_fault;
+	u8 bat_fault;
+};
+
+struct bq25890_device {
+	struct i2c_client *client;
+	struct device *dev;
+	struct power_supply *charger;
+
+	struct usb_phy *usb_phy;
+	struct notifier_block usb_nb;
+	struct work_struct usb_work;
+	unsigned long usb_event;
+
+	struct regmap *rmap;
+	struct regmap_field *rmap_fields[F_MAX_FIELDS];
+
+	u8 chip_id;
+	struct bq25890_init_data init_data;
+	struct bq25890_state state;
+
+	struct mutex lock; /* protect state data */
+};
+
+static const struct regmap_range bq25890_readonly_reg_ranges[] = {
+	regmap_reg_range(0x0b, 0x0c),
+	regmap_reg_range(0x0e, 0x13),
+};
+
+static const struct regmap_access_table bq25890_writeable_regs = {
+	.no_ranges = bq25890_readonly_reg_ranges,
+	.n_no_ranges = ARRAY_SIZE(bq25890_readonly_reg_ranges),
+};
+
+static const struct regmap_range bq25890_volatile_reg_ranges[] = {
+	regmap_reg_range(0x00, 0x00),
+	regmap_reg_range(0x09, 0x09),
+	regmap_reg_range(0x0b, 0x0c),
+	regmap_reg_range(0x0e, 0x14),
+};
+
+static const struct regmap_access_table bq25890_volatile_regs = {
+	.yes_ranges = bq25890_volatile_reg_ranges,
+	.n_yes_ranges = ARRAY_SIZE(bq25890_volatile_reg_ranges),
+};
+
+static const struct regmap_config bq25890_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = 0x14,
+	.cache_type = REGCACHE_RBTREE,
+
+	.wr_table = &bq25890_writeable_regs,
+	.volatile_table = &bq25890_volatile_regs,
+};
+
+static const struct reg_field bq25890_reg_fields[] = {
+	/* REG00 */
+	[F_EN_HIZ]		= REG_FIELD(0x00, 7, 7),
+	[F_EN_ILIM]		= REG_FIELD(0x00, 6, 6),
+	[F_IILIM]		= REG_FIELD(0x00, 0, 5),
+	/* REG01 */
+	[F_BHOT]		= REG_FIELD(0x01, 6, 7),
+	[F_BCOLD]		= REG_FIELD(0x01, 5, 5),
+	[F_VINDPM_OFS]		= REG_FIELD(0x01, 0, 4),
+	/* REG02 */
+	[F_CONV_START]		= REG_FIELD(0x02, 7, 7),
+	[F_CONV_RATE]		= REG_FIELD(0x02, 6, 6),
+	[F_BOOSTF]		= REG_FIELD(0x02, 5, 5),
+	[F_ICO_EN]		= REG_FIELD(0x02, 4, 4),
+	[F_HVDCP_EN]		= REG_FIELD(0x02, 3, 3),
+	[F_MAXC_EN]		= REG_FIELD(0x02, 2, 2),
+	[F_FORCE_DPM]		= REG_FIELD(0x02, 1, 1),
+	[F_AUTO_DPDM_EN]	= REG_FIELD(0x02, 0, 0),
+	/* REG03 */
+	[F_BAT_LOAD_EN]		= REG_FIELD(0x03, 7, 7),
+	[F_WD_RST]		= REG_FIELD(0x03, 6, 6),
+	[F_OTG_CFG]		= REG_FIELD(0x03, 5, 5),
+	[F_CHG_CFG]		= REG_FIELD(0x03, 4, 4),
+	[F_SYSVMIN]		= REG_FIELD(0x03, 1, 3),
+	/* REG04 */
+	[F_PUMPX_EN]		= REG_FIELD(0x04, 7, 7),
+	[F_ICHG]		= REG_FIELD(0x04, 0, 6),
+	/* REG05 */
+	[F_IPRECHG]		= REG_FIELD(0x05, 4, 7),
+	[F_ITERM]		= REG_FIELD(0x05, 0, 3),
+	/* REG06 */
+	[F_VREG]		= REG_FIELD(0x06, 2, 7),
+	[F_BATLOWV]		= REG_FIELD(0x06, 1, 1),
+	[F_VRECHG]		= REG_FIELD(0x06, 0, 0),
+	/* REG07 */
+	[F_TERM_EN]		= REG_FIELD(0x07, 7, 7),
+	[F_STAT_DIS]		= REG_FIELD(0x07, 6, 6),
+	[F_WD]			= REG_FIELD(0x07, 4, 5),
+	[F_TMR_EN]		= REG_FIELD(0x07, 3, 3),
+	[F_CHG_TMR]		= REG_FIELD(0x07, 1, 2),
+	[F_JEITA_ISET]		= REG_FIELD(0x07, 0, 0),
+	/* REG08 */
+	[F_BATCMP]		= REG_FIELD(0x08, 6, 7),
+	[F_VCLAMP]		= REG_FIELD(0x08, 2, 4),
+	[F_TREG]		= REG_FIELD(0x08, 0, 1),
+	/* REG09 */
+	[F_FORCE_ICO]		= REG_FIELD(0x09, 7, 7),
+	[F_TMR2X_EN]		= REG_FIELD(0x09, 6, 6),
+	[F_BATFET_DIS]		= REG_FIELD(0x09, 5, 5),
+	[F_JEITA_VSET]		= REG_FIELD(0x09, 4, 4),
+	[F_BATFET_DLY]		= REG_FIELD(0x09, 3, 3),
+	[F_BATFET_RST_EN]	= REG_FIELD(0x09, 2, 2),
+	[F_PUMPX_UP]		= REG_FIELD(0x09, 1, 1),
+	[F_PUMPX_DN]		= REG_FIELD(0x09, 0, 0),
+	/* REG0A */
+	[F_BOOSTV]		= REG_FIELD(0x0A, 4, 7),
+	[F_BOOSTI]		= REG_FIELD(0x0A, 0, 2),
+	/* REG0B */
+	[F_VBUS_STAT]		= REG_FIELD(0x0B, 5, 7),
+	[F_CHG_STAT]		= REG_FIELD(0x0B, 3, 4),
+	[F_PG_STAT]		= REG_FIELD(0x0B, 2, 2),
+	[F_SDP_STAT]		= REG_FIELD(0x0B, 1, 1),
+	[F_VSYS_STAT]		= REG_FIELD(0x0B, 0, 0),
+	/* REG0C */
+	[F_WD_FAULT]		= REG_FIELD(0x0C, 7, 7),
+	[F_BOOST_FAULT]		= REG_FIELD(0x0C, 6, 6),
+	[F_CHG_FAULT]		= REG_FIELD(0x0C, 4, 5),
+	[F_BAT_FAULT]		= REG_FIELD(0x0C, 3, 3),
+	[F_NTC_FAULT]		= REG_FIELD(0x0C, 0, 2),
+	/* REG0D */
+	[F_FORCE_VINDPM]	= REG_FIELD(0x0D, 7, 7),
+	[F_VINDPM]		= REG_FIELD(0x0D, 0, 6),
+	/* REG0E */
+	[F_THERM_STAT]		= REG_FIELD(0x0E, 7, 7),
+	[F_BATV]		= REG_FIELD(0x0E, 0, 6),
+	/* REG0F */
+	[F_SYSV]		= REG_FIELD(0x0F, 0, 6),
+	/* REG10 */
+	[F_TSPCT]		= REG_FIELD(0x10, 0, 6),
+	/* REG11 */
+	[F_VBUS_GD]		= REG_FIELD(0x11, 7, 7),
+	[F_VBUSV]		= REG_FIELD(0x11, 0, 6),
+	/* REG12 */
+	[F_ICHGR]		= REG_FIELD(0x12, 0, 6),
+	/* REG13 */
+	[F_VDPM_STAT]		= REG_FIELD(0x13, 7, 7),
+	[F_IDPM_STAT]		= REG_FIELD(0x13, 6, 6),
+	[F_IDPM_LIM]		= REG_FIELD(0x13, 0, 5),
+	/* REG14 */
+	[F_REG_RST]		= REG_FIELD(0x14, 7, 7),
+	[F_ICO_OPTIMIZED]	= REG_FIELD(0x14, 6, 6),
+	[F_PN]			= REG_FIELD(0x14, 3, 5),
+	[F_TS_PROFILE]		= REG_FIELD(0x14, 2, 2),
+	[F_DEV_REV]		= REG_FIELD(0x14, 0, 1)
+};
+
+/*
+ * Most of the val -> idx conversions can be computed, given the minimum,
+ * maximum and the step between values. For the rest of conversions, we use
+ * lookup tables.
+ */
+enum bq25890_table_ids {
+	/* range tables */
+	TBL_ICHG,
+	TBL_ITERM,
+	TBL_IPRECHG,
+	TBL_VREG,
+	TBL_BATCMP,
+	TBL_VCLAMP,
+	TBL_BOOSTV,
+	TBL_SYSVMIN,
+
+	/* lookup tables */
+	TBL_TREG,
+	TBL_BOOSTI,
+};
+
+/* Thermal Regulation Threshold lookup table, in degrees Celsius */
+static const u32 bq25890_treg_tbl[] = { 60, 80, 100, 120 };
+
+#define BQ25890_TREG_TBL_SIZE		ARRAY_SIZE(bq25890_treg_tbl)
+
+/* Boost mode current limit lookup table, in uA */
+static const u32 bq25890_boosti_tbl[] = {
+	500000, 700000, 1100000, 1300000, 1600000, 1800000, 2100000, 2400000
+};
+
+#define BQ25890_BOOSTI_TBL_SIZE		ARRAY_SIZE(bq25890_boosti_tbl)
+
+struct bq25890_range {
+	u32 min;
+	u32 max;
+	u32 step;
+};
+
+struct bq25890_lookup {
+	const u32 *tbl;
+	u32 size;
+};
+
+static const union {
+	struct bq25890_range  rt;
+	struct bq25890_lookup lt;
+} bq25890_tables[] = {
+	/* range tables */
+	[TBL_ICHG] =	{ .rt = {0,	  5056000, 64000} },	 /* uA */
+	[TBL_ITERM] =	{ .rt = {64000,   1024000, 64000} },	 /* uA */
+	[TBL_VREG] =	{ .rt = {3840000, 4608000, 16000} },	 /* uV */
+	[TBL_BATCMP] =	{ .rt = {0,	  140,     20} },	 /* mOhm */
+	[TBL_VCLAMP] =	{ .rt = {0,	  224000,  32000} },	 /* uV */
+	[TBL_BOOSTV] =	{ .rt = {4550000, 5510000, 64000} },	 /* uV */
+	[TBL_SYSVMIN] = { .rt = {3000000, 3700000, 100000} },	 /* uV */
+
+	/* lookup tables */
+	[TBL_TREG] =	{ .lt = {bq25890_treg_tbl, BQ25890_TREG_TBL_SIZE} },
+	[TBL_BOOSTI] =	{ .lt = {bq25890_boosti_tbl, BQ25890_BOOSTI_TBL_SIZE} }
+};
+
+static int bq25890_field_read(struct bq25890_device *bq,
+			      enum bq25890_fields field_id)
+{
+	int ret;
+	int val;
+
+	ret = regmap_field_read(bq->rmap_fields[field_id], &val);
+	if (ret < 0)
+		return ret;
+
+	return val;
+}
+
+static int bq25890_field_write(struct bq25890_device *bq,
+			       enum bq25890_fields field_id, u8 val)
+{
+	return regmap_field_write(bq->rmap_fields[field_id], val);
+}
+
+static u8 bq25890_find_idx(u32 value, enum bq25890_table_ids id)
+{
+	u8 idx;
+
+	if (id >= TBL_TREG) {
+		const u32 *tbl = bq25890_tables[id].lt.tbl;
+		u32 tbl_size = bq25890_tables[id].lt.size;
+
+		for (idx = 1; idx < tbl_size && tbl[idx] <= value; idx++)
+			;
+	} else {
+		const struct bq25890_range *rtbl = &bq25890_tables[id].rt;
+		u8 rtbl_size;
+
+		rtbl_size = (rtbl->max - rtbl->min) / rtbl->step + 1;
+
+		for (idx = 1;
+		     idx < rtbl_size && (idx * rtbl->step + rtbl->min <= value);
+		     idx++)
+			;
+	}
+
+	return idx - 1;
+}
+
+static u32 bq25890_find_val(u8 idx, enum bq25890_table_ids id)
+{
+	const struct bq25890_range *rtbl;
+
+	/* lookup table? */
+	if (id >= TBL_TREG)
+		return bq25890_tables[id].lt.tbl[idx];
+
+	/* range table */
+	rtbl = &bq25890_tables[id].rt;
+
+	return (rtbl->min + idx * rtbl->step);
+}
+
+enum bq25890_status {
+	STATUS_NOT_CHARGING,
+	STATUS_PRE_CHARGING,
+	STATUS_FAST_CHARGING,
+	STATUS_TERMINATION_DONE,
+};
+
+enum bq25890_chrg_fault {
+	CHRG_FAULT_NORMAL,
+	CHRG_FAULT_INPUT,
+	CHRG_FAULT_THERMAL_SHUTDOWN,
+	CHRG_FAULT_TIMER_EXPIRED,
+};
+
+static int bq25890_power_supply_get_property(struct power_supply *psy,
+					     enum power_supply_property psp,
+					     union power_supply_propval *val)
+{
+	int ret;
+	struct bq25890_device *bq = power_supply_get_drvdata(psy);
+	struct bq25890_state state;
+
+	mutex_lock(&bq->lock);
+	state = bq->state;
+	mutex_unlock(&bq->lock);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		if (!state.online)
+			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+		else if (state.chrg_status == STATUS_NOT_CHARGING)
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+		else if (state.chrg_status == STATUS_PRE_CHARGING ||
+			 state.chrg_status == STATUS_FAST_CHARGING)
+			val->intval = POWER_SUPPLY_STATUS_CHARGING;
+		else if (state.chrg_status == STATUS_TERMINATION_DONE)
+			val->intval = POWER_SUPPLY_STATUS_FULL;
+		else
+			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+
+		break;
+
+	case POWER_SUPPLY_PROP_MANUFACTURER:
+		val->strval = BQ25890_MANUFACTURER;
+		break;
+
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = state.online;
+		break;
+
+	case POWER_SUPPLY_PROP_HEALTH:
+		if (!state.chrg_fault && !state.bat_fault && !state.boost_fault)
+			val->intval = POWER_SUPPLY_HEALTH_GOOD;
+		else if (state.bat_fault)
+			val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+		else if (state.chrg_fault == CHRG_FAULT_TIMER_EXPIRED)
+			val->intval = POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
+		else if (state.chrg_fault == CHRG_FAULT_THERMAL_SHUTDOWN)
+			val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
+		else
+			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+		ret = bq25890_field_read(bq, F_ICHGR); /* read measured value */
+		if (ret < 0)
+			return ret;
+
+		/* converted_val = ADC_val * 50mA (table 10.3.19) */
+		val->intval = ret * 50000;
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		val->intval = bq25890_tables[TBL_ICHG].rt.max;
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+		if (!state.online) {
+			val->intval = 0;
+			break;
+		}
+
+		ret = bq25890_field_read(bq, F_BATV); /* read measured value */
+		if (ret < 0)
+			return ret;
+
+		/* converted_val = 2.304V + ADC_val * 20mV (table 10.3.15) */
+		val->intval = 2304000 + ret * 20000;
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+		val->intval = bq25890_tables[TBL_VREG].rt.max;
+		break;
+
+	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
+		val->intval = bq25890_find_val(bq->init_data.iterm, TBL_ITERM);
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int bq25890_get_chip_state(struct bq25890_device *bq,
+				  struct bq25890_state *state)
+{
+	int i, ret;
+
+	struct {
+		enum bq25890_fields id;
+		u8 *data;
+	} state_fields[] = {
+		{F_CHG_STAT,	&state->chrg_status},
+		{F_PG_STAT,	&state->online},
+		{F_VSYS_STAT,	&state->vsys_status},
+		{F_BOOST_FAULT, &state->boost_fault},
+		{F_BAT_FAULT,	&state->bat_fault},
+		{F_CHG_FAULT,	&state->chrg_fault}
+	};
+
+	for (i = 0; i < ARRAY_SIZE(state_fields); i++) {
+		ret = bq25890_field_read(bq, state_fields[i].id);
+		if (ret < 0)
+			return ret;
+
+		*state_fields[i].data = ret;
+	}
+
+	dev_dbg(bq->dev, "S:CHG/PG/VSYS=%d/%d/%d, F:CHG/BOOST/BAT=%d/%d/%d\n",
+		state->chrg_status, state->online, state->vsys_status,
+		state->chrg_fault, state->boost_fault, state->bat_fault);
+
+	return 0;
+}
+
+static bool bq25890_state_changed(struct bq25890_device *bq,
+				  struct bq25890_state *new_state)
+{
+	struct bq25890_state old_state;
+
+	mutex_lock(&bq->lock);
+	old_state = bq->state;
+	mutex_unlock(&bq->lock);
+
+	return (old_state.chrg_status != new_state->chrg_status ||
+		old_state.chrg_fault != new_state->chrg_fault	||
+		old_state.online != new_state->online		||
+		old_state.bat_fault != new_state->bat_fault	||
+		old_state.boost_fault != new_state->boost_fault ||
+		old_state.vsys_status != new_state->vsys_status);
+}
+
+static void bq25890_handle_state_change(struct bq25890_device *bq,
+					struct bq25890_state *new_state)
+{
+	int ret;
+	struct bq25890_state old_state;
+
+	mutex_lock(&bq->lock);
+	old_state = bq->state;
+	mutex_unlock(&bq->lock);
+
+	if (!new_state->online) {			     /* power removed */
+		/* disable ADC */
+		ret = bq25890_field_write(bq, F_CONV_START, 0);
+		if (ret < 0)
+			goto error;
+	} else if (!old_state.online) {			    /* power inserted */
+		/* enable ADC, to have control of charge current/voltage */
+		ret = bq25890_field_write(bq, F_CONV_START, 1);
+		if (ret < 0)
+			goto error;
+	}
+
+	return;
+
+error:
+	dev_err(bq->dev, "Error communicating with the chip.\n");
+}
+
+static irqreturn_t bq25890_irq_handler_thread(int irq, void *private)
+{
+	struct bq25890_device *bq = private;
+	int ret;
+	struct bq25890_state state;
+
+	ret = bq25890_get_chip_state(bq, &state);
+	if (ret < 0)
+		goto handled;
+
+	if (!bq25890_state_changed(bq, &state))
+		goto handled;
+
+	bq25890_handle_state_change(bq, &state);
+
+	mutex_lock(&bq->lock);
+	bq->state = state;
+	mutex_unlock(&bq->lock);
+
+	power_supply_changed(bq->charger);
+
+handled:
+	return IRQ_HANDLED;
+}
+
+static int bq25890_chip_reset(struct bq25890_device *bq)
+{
+	int ret;
+	int rst_check_counter = 10;
+
+	ret = bq25890_field_write(bq, F_REG_RST, 1);
+	if (ret < 0)
+		return ret;
+
+	do {
+		ret = bq25890_field_read(bq, F_REG_RST);
+		if (ret < 0)
+			return ret;
+
+		usleep_range(5, 10);
+	} while (ret == 1 && --rst_check_counter);
+
+	if (!rst_check_counter)
+		return -ETIMEDOUT;
+
+	return 0;
+}
+
+static int bq25890_hw_init(struct bq25890_device *bq)
+{
+	int ret;
+	int i;
+	struct bq25890_state state;
+
+	const struct {
+		enum bq25890_fields id;
+		u32 value;
+	} init_data[] = {
+		{F_ICHG,	 bq->init_data.ichg},
+		{F_VREG,	 bq->init_data.vreg},
+		{F_ITERM,	 bq->init_data.iterm},
+		{F_IPRECHG,	 bq->init_data.iprechg},
+		{F_SYSVMIN,	 bq->init_data.sysvmin},
+		{F_BOOSTV,	 bq->init_data.boostv},
+		{F_BOOSTI,	 bq->init_data.boosti},
+		{F_BOOSTF,	 bq->init_data.boostf},
+		{F_EN_ILIM,	 bq->init_data.ilim_en},
+		{F_TREG,	 bq->init_data.treg}
+	};
+
+	ret = bq25890_chip_reset(bq);
+	if (ret < 0)
+		return ret;
+
+	/* disable watchdog */
+	ret = bq25890_field_write(bq, F_WD, 0);
+	if (ret < 0)
+		return ret;
+
+	/* initialize currents/voltages and other parameters */
+	for (i = 0; i < ARRAY_SIZE(init_data); i++) {
+		ret = bq25890_field_write(bq, init_data[i].id,
+					  init_data[i].value);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* Configure ADC for continuous conversions. This does not enable it. */
+	ret = bq25890_field_write(bq, F_CONV_RATE, 1);
+	if (ret < 0)
+		return ret;
+
+	ret = bq25890_get_chip_state(bq, &state);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&bq->lock);
+	bq->state = state;
+	mutex_unlock(&bq->lock);
+
+	return 0;
+}
+
+static enum power_supply_property bq25890_power_supply_props[] = {
+	POWER_SUPPLY_PROP_MANUFACTURER,
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_HEALTH,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX,
+	POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT,
+};
+
+static char *bq25890_charger_supplied_to[] = {
+	"main-battery",
+};
+
+static const struct power_supply_desc bq25890_power_supply_desc = {
+	.name = "bq25890-charger",
+	.type = POWER_SUPPLY_TYPE_USB,
+	.properties = bq25890_power_supply_props,
+	.num_properties = ARRAY_SIZE(bq25890_power_supply_props),
+	.get_property = bq25890_power_supply_get_property,
+};
+
+static int bq25890_power_supply_init(struct bq25890_device *bq)
+{
+	struct power_supply_config psy_cfg = { .drv_data = bq, };
+
+	psy_cfg.supplied_to = bq25890_charger_supplied_to;
+	psy_cfg.num_supplicants = ARRAY_SIZE(bq25890_charger_supplied_to);
+
+	bq->charger = power_supply_register(bq->dev, &bq25890_power_supply_desc,
+					    &psy_cfg);
+
+	return PTR_ERR_OR_ZERO(bq->charger);
+}
+
+static void bq25890_usb_work(struct work_struct *data)
+{
+	int ret;
+	struct bq25890_device *bq =
+			container_of(data, struct bq25890_device, usb_work);
+
+	switch (bq->usb_event) {
+	case USB_EVENT_ID:
+		/* Enable boost mode */
+		ret = bq25890_field_write(bq, F_OTG_CFG, 1);
+		if (ret < 0)
+			goto error;
+		break;
+
+	case USB_EVENT_NONE:
+		/* Disable boost mode */
+		ret = bq25890_field_write(bq, F_OTG_CFG, 0);
+		if (ret < 0)
+			goto error;
+
+		power_supply_changed(bq->charger);
+		break;
+	}
+
+	return;
+
+error:
+	dev_err(bq->dev, "Error switching to boost/charger mode.\n");
+}
+
+static int bq25890_usb_notifier(struct notifier_block *nb, unsigned long val,
+				void *priv)
+{
+	struct bq25890_device *bq =
+			container_of(nb, struct bq25890_device, usb_nb);
+
+	bq->usb_event = val;
+	queue_work(system_power_efficient_wq, &bq->usb_work);
+
+	return NOTIFY_OK;
+}
+
+static int bq25890_irq_probe(struct bq25890_device *bq)
+{
+	int ret;
+	struct gpio_desc *irq;
+
+	irq = devm_gpiod_get_index(bq->dev, BQ25890_IRQ_PIN, 0);
+	if (IS_ERR(irq)) {
+		dev_err(bq->dev, "Could not probe irq pin.\n");
+		return PTR_ERR(irq);
+	}
+
+	ret = gpiod_direction_input(irq);
+	if (ret < 0)
+		return ret;
+
+	return gpiod_to_irq(irq);
+}
+
+static int bq25890_fw_read_u32_props(struct bq25890_device *bq)
+{
+	int ret;
+	u32 property;
+	int i;
+	struct bq25890_init_data *init = &bq->init_data;
+	struct {
+		char *name;
+		bool optional;
+		enum bq25890_table_ids tbl_id;
+		u8 *conv_data; /* holds converted value from given property */
+	} props[] = {
+		/* required properties */
+		{"ti,charge-current", false, TBL_ICHG, &init->ichg},
+		{"ti,battery-regulation-voltage", false, TBL_VREG, &init->vreg},
+		{"ti,termination-current", false, TBL_ITERM, &init->iterm},
+		{"ti,precharge-current", false, TBL_ITERM, &init->iprechg},
+		{"ti,minimum-sys-voltage", false, TBL_SYSVMIN, &init->sysvmin},
+		{"ti,boost-voltage", false, TBL_BOOSTV, &init->boostv},
+		{"ti,boost-max-current", false, TBL_BOOSTI, &init->boosti},
+
+		/* optional properties */
+		{"ti,thermal-regulation-threshold", true, TBL_TREG, &init->treg}
+	};
+
+	/* initialize data for optional properties */
+	init->treg = 3; /* 120 degrees Celsius */
+
+	for (i = 0; i < ARRAY_SIZE(props); i++) {
+		ret = device_property_read_u32(bq->dev, props[i].name,
+					       &property);
+		if (ret < 0) {
+			if (props[i].optional)
+				continue;
+
+			return ret;
+		}
+
+		*props[i].conv_data = bq25890_find_idx(property,
+						       props[i].tbl_id);
+	}
+
+	return 0;
+}
+
+static int bq25890_fw_probe(struct bq25890_device *bq)
+{
+	int ret;
+	struct bq25890_init_data *init = &bq->init_data;
+
+	ret = bq25890_fw_read_u32_props(bq);
+	if (ret < 0)
+		return ret;
+
+	init->ilim_en = device_property_read_bool(bq->dev, "ti,use-ilim-pin");
+	init->boostf = device_property_read_bool(bq->dev, "ti,boost-low-freq");
+
+	return 0;
+}
+
+static int bq25890_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
+	struct device *dev = &client->dev;
+	struct bq25890_device *bq;
+	int ret;
+	int i;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) {
+		dev_err(dev, "No support for SMBUS_BYTE_DATA\n");
+		return -ENODEV;
+	}
+
+	bq = devm_kzalloc(dev, sizeof(*bq), GFP_KERNEL);
+	if (!bq)
+		return -ENOMEM;
+
+	bq->client = client;
+	bq->dev = dev;
+
+	mutex_init(&bq->lock);
+
+	bq->rmap = devm_regmap_init_i2c(client, &bq25890_regmap_config);
+	if (IS_ERR(bq->rmap)) {
+		dev_err(dev, "failed to allocate register map\n");
+		return PTR_ERR(bq->rmap);
+	}
+
+	for (i = 0; i < ARRAY_SIZE(bq25890_reg_fields); i++) {
+		const struct reg_field *reg_fields = bq25890_reg_fields;
+
+		bq->rmap_fields[i] = devm_regmap_field_alloc(dev, bq->rmap,
+							     reg_fields[i]);
+		if (IS_ERR(bq->rmap_fields[i])) {
+			dev_err(dev, "cannot allocate regmap field\n");
+			return PTR_ERR(bq->rmap_fields[i]);
+		}
+	}
+
+	i2c_set_clientdata(client, bq);
+
+	bq->chip_id = bq25890_field_read(bq, F_PN);
+	if (bq->chip_id < 0) {
+		dev_err(dev, "Cannot read chip ID.\n");
+		return ret;
+	}
+
+	if (bq->chip_id != BQ25890_ID) {
+		dev_err(dev, "Chip with ID=%d, not supported!\n", bq->chip_id);
+		return -ENODEV;
+	}
+
+	if (!dev->platform_data) {
+		ret = bq25890_fw_probe(bq);
+		if (ret < 0) {
+			dev_err(dev, "Cannot read device properties.\n");
+			return ret;
+		}
+	} else {
+		return -ENODEV;
+	}
+
+	ret = bq25890_hw_init(bq);
+	if (ret < 0) {
+		dev_err(dev, "Cannot initialize the chip.\n");
+		return ret;
+	}
+
+	if (client->irq <= 0)
+		client->irq = bq25890_irq_probe(bq);
+
+	if (client->irq < 0) {
+		dev_err(dev, "No irq resource found.\n");
+		return client->irq;
+	}
+
+	/* OTG reporting */
+	bq->usb_phy = devm_usb_get_phy(dev, USB_PHY_TYPE_USB2);
+	if (!IS_ERR_OR_NULL(bq->usb_phy)) {
+		INIT_WORK(&bq->usb_work, bq25890_usb_work);
+		bq->usb_nb.notifier_call = bq25890_usb_notifier;
+		usb_register_notifier(bq->usb_phy, &bq->usb_nb);
+	}
+
+	ret = devm_request_threaded_irq(dev, client->irq, NULL,
+					bq25890_irq_handler_thread,
+					IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
+					BQ25890_IRQ_PIN, bq);
+	if (ret)
+		goto irq_fail;
+
+	ret = bq25890_power_supply_init(bq);
+	if (ret < 0) {
+		dev_err(dev, "Failed to register power supply\n");
+		goto irq_fail;
+	}
+
+	return 0;
+
+irq_fail:
+	if (!IS_ERR_OR_NULL(bq->usb_phy))
+		usb_unregister_notifier(bq->usb_phy, &bq->usb_nb);
+
+	return ret;
+}
+
+static int bq25890_remove(struct i2c_client *client)
+{
+	struct bq25890_device *bq = i2c_get_clientdata(client);
+
+	power_supply_unregister(bq->charger);
+
+	if (!IS_ERR_OR_NULL(bq->usb_phy))
+		usb_unregister_notifier(bq->usb_phy, &bq->usb_nb);
+
+	/* reset all registers to default values */
+	bq25890_chip_reset(bq);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int bq25890_suspend(struct device *dev)
+{
+	struct bq25890_device *bq = dev_get_drvdata(dev);
+
+	/*
+	 * If charger is removed, while in suspend, make sure ADC is diabled
+	 * since it consumes slightly more power.
+	 */
+	return bq25890_field_write(bq, F_CONV_START, 0);
+}
+
+static int bq25890_resume(struct device *dev)
+{
+	int ret;
+	struct bq25890_state state;
+	struct bq25890_device *bq = dev_get_drvdata(dev);
+
+	ret = bq25890_get_chip_state(bq, &state);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&bq->lock);
+	bq->state = state;
+	mutex_unlock(&bq->lock);
+
+	/* Re-enable ADC only if charger is plugged in. */
+	if (state.online) {
+		ret = bq25890_field_write(bq, F_CONV_START, 1);
+		if (ret < 0)
+			return ret;
+	}
+
+	/* signal userspace, maybe state changed while suspended */
+	power_supply_changed(bq->charger);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops bq25890_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(bq25890_suspend, bq25890_resume)
+};
+
+static const struct i2c_device_id bq25890_i2c_ids[] = {
+	{ "bq25890", 0 },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, bq25890_i2c_ids);
+
+static const struct of_device_id bq25890_of_match[] = {
+	{ .compatible = "ti,bq25890", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, bq25890_of_match);
+
+static const struct acpi_device_id bq25890_acpi_match[] = {
+	{"BQ258900", 0},
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, bq25890_acpi_match);
+
+static struct i2c_driver bq25890_driver = {
+	.driver = {
+		.name = "bq25890-charger",
+		.of_match_table = of_match_ptr(bq25890_of_match),
+		.acpi_match_table = ACPI_PTR(bq25890_acpi_match),
+		.pm = &bq25890_pm,
+	},
+	.probe = bq25890_probe,
+	.remove = bq25890_remove,
+	.id_table = bq25890_i2c_ids,
+};
+module_i2c_driver(bq25890_driver);
+
+MODULE_AUTHOR("Laurentiu Palcu <[e-mail]>");
+MODULE_DESCRIPTION("bq25890 charger driver");
+MODULE_LICENSE("GPL");