Message-Id: <1428671897-12232-1-git-send-email-laurentiu.palcu@intel.com>
Date:	Fri, 10 Apr 2015 16:18:17 +0300
From:	Laurentiu Palcu <laurentiu.palcu@...el.com>
To:	Sebastian Reichel <sre@...nel.org>,
	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Rob Herring <robh+dt@...nel.org>,
	Pawel Moll <pawel.moll@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>
Cc:	Laurentiu Palcu <laurentiu.palcu@...el.com>,
	devicetree@...r.kernel.org, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] power_supply: Add TI BQ24257 charger driver

Based on the datasheet found here:
http://www.ti.com/lit/ds/symlink/bq24257.pdf

Signed-off-by: Laurentiu Palcu <laurentiu.palcu@...el.com>
---
The driver was tested using an EVM [1], not with a final product.

[1] http://www.ti.com/tool/bq24257evm-150

laurentiu

 .../devicetree/bindings/power/bq24257.txt          |  21 +
 drivers/power/Kconfig                              |   7 +
 drivers/power/Makefile                             |   1 +
 drivers/power/bq24257_charger.c                    | 868 +++++++++++++++++++++
 4 files changed, 897 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/bq24257.txt
 create mode 100644 drivers/power/bq24257_charger.c

diff --git a/Documentation/devicetree/bindings/power/bq24257.txt b/Documentation/devicetree/bindings/power/bq24257.txt
new file mode 100644
index 0000000..5c9d394
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/bq24257.txt
@@ -0,0 +1,21 @@
+Binding for TI bq24257 Li-Ion Charger
+
+Required properties:
+- compatible: Should contain one of the following:
+ * "ti,bq24257"
+- reg:			   integer, i2c address of the device.
+- ti,battery-regulation-voltage: integer, maximum charging voltage in uV.
+- ti,charge-current:	   integer, maximum charging current in uA.
+- ti,termination-current:  integer, charge will be terminated when current in
+			   constant-voltage phase drops below this value (in uA).
+
+Example:
+
+bq24257 {
+	compatible = "ti,bq24257";
+	reg = <0x6a>;
+
+	ti,battery-regulation-voltage = <4200000>;
+	ti,charge-current = <1000000>;
+	ti,termination-current = <50000>;
+};
diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 4091fb0..20352a7 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -388,6 +388,13 @@ config CHARGER_BQ24190
 	help
 	  Say Y to enable support for the TI BQ24190 battery charger.
 
+config CHARGER_BQ24257
+	tristate "TI BQ24257 battery charger driver"
+	depends on I2C && GPIOLIB
+	depends on REGMAP_I2C
+	help
+	  Say Y to enable support for the TI BQ24257 battery charger.
+
 config CHARGER_BQ24735
 	tristate "TI BQ24735 battery charger support"
 	depends on I2C && GPIOLIB
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index b7b0181..19a1f41 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -58,6 +58,7 @@ obj-$(CONFIG_CHARGER_MAX8997)	+= max8997_charger.o
 obj-$(CONFIG_CHARGER_MAX8998)	+= max8998_charger.o
 obj-$(CONFIG_CHARGER_BQ2415X)	+= bq2415x_charger.o
 obj-$(CONFIG_CHARGER_BQ24190)	+= bq24190_charger.o
+obj-$(CONFIG_CHARGER_BQ24257)	+= bq24257_charger.o
 obj-$(CONFIG_CHARGER_BQ24735)	+= bq24735-charger.o
 obj-$(CONFIG_POWER_AVS)		+= avs/
 obj-$(CONFIG_CHARGER_SMB347)	+= smb347-charger.o
diff --git a/drivers/power/bq24257_charger.c b/drivers/power/bq24257_charger.c
new file mode 100644
index 0000000..58b9af1
--- /dev/null
+++ b/drivers/power/bq24257_charger.c
@@ -0,0 +1,868 @@
+/*
+ * TI BQ24257 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/acpi.h>
+#include <linux/of.h>
+
+#define BQ24257_REG_1			0x00
+#define BQ24257_REG_2			0x01
+#define BQ24257_REG_3			0x02
+#define BQ24257_REG_4			0x03
+#define BQ24257_REG_5			0x04
+#define BQ24257_REG_6			0x05
+#define BQ24257_REG_7			0x06
+
+#define BQ24257_MANUFACTURER		"Texas Instruments"
+#define BQ24257_STAT_IRQ		"stat"
+#define BQ24257_PG_GPIO			"pg"
+
+#define BQ24257_ILIM_SET_DELAY		1000	/* msec */
+
+enum bq24257_fields {
+	F_WD_FAULT, F_WD_EN, F_STAT, F_FAULT,			    /* REG 1 */
+	F_RESET, F_IILIMIT, F_EN_STAT, F_EN_TERM, F_CE, F_HZ_MODE,  /* REG 2 */
+	F_VBAT, F_USB_DET,					    /* REG 3 */
+	F_ICHG, F_ITERM,					    /* REG 4 */
+	F_LOOP_STATUS, F_LOW_CHG, F_DPDM_EN, F_CE_STATUS, F_VINDPM, /* REG 5 */
+	F_X2_TMR_EN, F_TMR, F_SYSOFF, F_TS_STAT,		    /* REG 6 */
+	F_VOVP, F_CLR_VDP, F_FORCE_BATDET, F_FORCE_PTM,		    /* REG 7 */
+
+	F_MAX_FIELDS
+};
+
+/* initial field values, converted from uV/uA */
+struct bq24257_init_data {
+	u8 ichg;	/* charge current      */
+	u8 vbat;	/* regulation voltage  */
+	u8 iterm;	/* termination current */
+};
+
+struct bq24257_state {
+	u8 status;
+	u8 fault;
+	bool power_good;
+};
+
+struct bq24257_device {
+	struct i2c_client *client;
+	struct device *dev;
+	struct power_supply *charger;
+	struct power_supply_desc charger_desc;
+
+	struct regmap *rmap;
+	struct regmap_field *rmap_fields[F_MAX_FIELDS];
+
+	struct gpio_desc *pg;
+
+	struct delayed_work iilimit_setup_work;
+
+	struct bq24257_init_data init_data;
+	struct bq24257_state state;
+
+	struct mutex lock; /* protect state data */
+};
+
+static bool bq24257_is_writeable_reg(struct device *dev, unsigned int reg)
+{
+	return true;
+}
+
+static bool bq24257_is_volatile_reg(struct device *dev, unsigned int reg)
+{
+	switch (reg) {
+	case BQ24257_REG_2:
+	case BQ24257_REG_4:
+		return false;
+
+	default:
+		return true;
+	}
+}
+
+static const struct regmap_config bq24257_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 8,
+
+	.max_register = BQ24257_REG_7,
+	.cache_type = REGCACHE_RBTREE,
+
+	.writeable_reg = bq24257_is_writeable_reg,
+	.volatile_reg = bq24257_is_volatile_reg,
+};
+
+static const struct reg_field bq24257_reg_fields[] = {
+	/* REG 1 */
+	[F_WD_FAULT]		= REG_FIELD(BQ24257_REG_1, 7, 7),
+	[F_WD_EN]		= REG_FIELD(BQ24257_REG_1, 6, 6),
+	[F_STAT]		= REG_FIELD(BQ24257_REG_1, 4, 5),
+	[F_FAULT]		= REG_FIELD(BQ24257_REG_1, 0, 3),
+	/* REG 2 */
+	[F_RESET]		= REG_FIELD(BQ24257_REG_2, 7, 7),
+	[F_IILIMIT]		= REG_FIELD(BQ24257_REG_2, 4, 6),
+	[F_EN_STAT]		= REG_FIELD(BQ24257_REG_2, 3, 3),
+	[F_EN_TERM]		= REG_FIELD(BQ24257_REG_2, 2, 2),
+	[F_CE]			= REG_FIELD(BQ24257_REG_2, 1, 1),
+	[F_HZ_MODE]		= REG_FIELD(BQ24257_REG_2, 0, 0),
+	/* REG 3 */
+	[F_VBAT]		= REG_FIELD(BQ24257_REG_3, 2, 7),
+	[F_USB_DET]		= REG_FIELD(BQ24257_REG_3, 0, 1),
+	/* REG 4 */
+	[F_ICHG]		= REG_FIELD(BQ24257_REG_4, 3, 7),
+	[F_ITERM]		= REG_FIELD(BQ24257_REG_4, 0, 2),
+	/* REG 5 */
+	[F_LOOP_STATUS]		= REG_FIELD(BQ24257_REG_5, 6, 7),
+	[F_LOW_CHG]		= REG_FIELD(BQ24257_REG_5, 5, 5),
+	[F_DPDM_EN]		= REG_FIELD(BQ24257_REG_5, 4, 4),
+	[F_CE_STATUS]		= REG_FIELD(BQ24257_REG_5, 3, 3),
+	[F_VINDPM]		= REG_FIELD(BQ24257_REG_5, 0, 2),
+	/* REG 6 */
+	[F_X2_TMR_EN]		= REG_FIELD(BQ24257_REG_6, 7, 7),
+	[F_TMR]			= REG_FIELD(BQ24257_REG_6, 5, 6),
+	[F_SYSOFF]		= REG_FIELD(BQ24257_REG_6, 4, 4),
+	[F_TS_STAT]		= REG_FIELD(BQ24257_REG_6, 0, 2),
+	/* REG 7 */
+	[F_VOVP]		= REG_FIELD(BQ24257_REG_7, 5, 7),
+	[F_CLR_VDP]		= REG_FIELD(BQ24257_REG_7, 4, 4),
+	[F_FORCE_BATDET]	= REG_FIELD(BQ24257_REG_7, 3, 3),
+	[F_FORCE_PTM]		= REG_FIELD(BQ24257_REG_7, 2, 2)
+};
+
+static const u32 bq24257_vbat_map[] = {
+	3500000, 3520000, 3540000, 3560000, 3580000, 3600000, 3620000, 3640000,
+	3660000, 3680000, 3700000, 3720000, 3740000, 3760000, 3780000, 3800000,
+	3820000, 3840000, 3860000, 3880000, 3900000, 3920000, 3940000, 3960000,
+	3980000, 4000000, 4020000, 4040000, 4060000, 4080000, 4100000, 4120000,
+	4140000, 4160000, 4180000, 4200000, 4220000, 4240000, 4260000, 4280000,
+	4300000, 4320000, 4340000, 4360000, 4380000, 4400000, 4420000, 4440000
+};
+
+#define BQ24257_VBAT_MAP_SIZE		ARRAY_SIZE(bq24257_vbat_map)
+
+static const u32 bq24257_ichg_map[] = {
+	500000, 550000, 600000, 650000, 700000, 750000, 800000, 850000, 900000,
+	950000, 1000000, 1050000, 1100000, 1150000, 1200000, 1250000, 1300000,
+	1350000, 1400000, 1450000, 1500000, 1550000, 1600000, 1650000, 1700000,
+	1750000, 1800000, 1850000, 1900000, 1950000, 2000000
+};
+
+#define BQ24257_ICHG_MAP_SIZE		ARRAY_SIZE(bq24257_ichg_map)
+
+static const u32 bq24257_iterm_map[] = {
+	50000, 75000, 100000, 125000, 150000, 175000, 200000, 225000
+};
+
+#define BQ24257_ITERM_MAP_SIZE		ARRAY_SIZE(bq24257_iterm_map)
+
+static int bq24257_field_read(struct bq24257_device *bq,
+			      enum bq24257_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 bq24257_field_write(struct bq24257_device *bq,
+			       enum bq24257_fields field_id, u8 val)
+{
+	return regmap_field_write(bq->rmap_fields[field_id], val);
+}
+
+static u8 bq24257_find_idx(u32 value, const u32 *map, u8 map_size)
+{
+	u8 idx;
+
+	for (idx = 1; idx < map_size; idx++)
+		if (value < map[idx])
+			break;
+
+	return idx - 1;
+}
+
+enum bq24257_status {
+	STATUS_READY,
+	STATUS_CHARGE_IN_PROGRESS,
+	STATUS_CHARGE_DONE,
+	STATUS_FAULT,
+};
+
+enum bq24257_fault {
+	FAULT_NORMAL,
+	FAULT_INPUT_OVP,
+	FAULT_INPUT_UVLO,
+	FAULT_SLEEP,
+	FAULT_BAT_TS,
+	FAULT_BAT_OVP,
+	FAULT_TS,
+	FAULT_TIMER,
+	FAULT_NO_BAT,
+	FAULT_ISET,
+	FAULT_INPUT_LDO_LOW,
+};
+
+static int bq24257_power_supply_get_property(struct power_supply *psy,
+					     enum power_supply_property psp,
+					     union power_supply_propval *val)
+{
+	struct bq24257_device *bq = power_supply_get_drvdata(psy);
+	struct bq24257_state state;
+
+	mutex_lock(&bq->lock);
+	state = bq->state;
+	mutex_unlock(&bq->lock);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		if (!state.power_good)
+			val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+		else if (state.status == STATUS_READY)
+			val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+		else if (state.status == STATUS_CHARGE_IN_PROGRESS)
+			val->intval = POWER_SUPPLY_STATUS_CHARGING;
+		else if (state.status == STATUS_CHARGE_DONE)
+			val->intval = POWER_SUPPLY_STATUS_FULL;
+		else
+			val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+		break;
+
+	case POWER_SUPPLY_PROP_MANUFACTURER:
+		val->strval = BQ24257_MANUFACTURER;
+		break;
+
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = state.power_good;
+		break;
+
+	case POWER_SUPPLY_PROP_HEALTH:
+		switch (state.fault) {
+		case FAULT_NORMAL:
+			val->intval = POWER_SUPPLY_HEALTH_GOOD;
+			break;
+
+		case FAULT_INPUT_OVP:
+		case FAULT_BAT_OVP:
+			val->intval = POWER_SUPPLY_HEALTH_OVERVOLTAGE;
+			break;
+
+		case FAULT_TS:
+		case FAULT_BAT_TS:
+			val->intval = POWER_SUPPLY_HEALTH_OVERHEAT;
+			break;
+
+		case FAULT_TIMER:
+			val->intval = POWER_SUPPLY_HEALTH_SAFETY_TIMER_EXPIRE;
+			break;
+
+		default:
+			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+			break;
+		}
+
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+		val->intval = bq24257_ichg_map[bq->init_data.ichg];
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
+		val->intval = bq24257_ichg_map[BQ24257_ICHG_MAP_SIZE - 1];
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
+		val->intval = bq24257_vbat_map[bq->init_data.vbat];
+		break;
+
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+		val->intval = bq24257_vbat_map[BQ24257_VBAT_MAP_SIZE - 1];
+		break;
+
+	case POWER_SUPPLY_PROP_CHARGE_TERM_CURRENT:
+		val->intval = bq24257_iterm_map[bq->init_data.iterm];
+		break;
+
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int bq24257_get_chip_state(struct bq24257_device *bq,
+				  struct bq24257_state *state)
+{
+	int ret;
+
+	ret = bq24257_field_read(bq, F_STAT);
+	if (ret < 0)
+		return ret;
+
+	state->status = ret;
+
+	ret = bq24257_field_read(bq, F_FAULT);
+	if (ret < 0)
+		return ret;
+
+	state->fault = ret;
+
+	state->power_good = !gpiod_get_value_cansleep(bq->pg);
+
+	return 0;
+}
+
+static bool bq24257_state_changed(struct bq24257_device *bq,
+				  struct bq24257_state *new_state)
+{
+	int ret;
+
+	mutex_lock(&bq->lock);
+	ret = (bq->state.status != new_state->status ||
+	       bq->state.fault != new_state->fault ||
+	       bq->state.power_good != new_state->power_good);
+	mutex_unlock(&bq->lock);
+
+	return ret;
+}
+
+enum bq24257_loop_status {
+	LOOP_STATUS_NONE,
+	LOOP_STATUS_IN_DPM,
+	LOOP_STATUS_IN_CURRENT_LIMIT,
+	LOOP_STATUS_THERMAL,
+};
+
+enum bq24257_in_ilimit {
+	IILIMIT_100,
+	IILIMIT_150,
+	IILIMIT_500,
+	IILIMIT_900,
+	IILIMIT_1500,
+	IILIMIT_2000,
+	IILIMIT_EXT,
+	IILIMIT_NONE,
+};
+
+enum bq24257_port_type {
+	PORT_TYPE_DCP,		/* Dedicated Charging Port */
+	PORT_TYPE_CDP,		/* Charging Downstream Port */
+	PORT_TYPE_SDP,		/* Standard Downstream Port */
+	PORT_TYPE_NON_STANDARD,
+};
+
+enum bq24257_safety_timer {
+	SAFETY_TIMER_45,
+	SAFETY_TIMER_360,
+	SAFETY_TIMER_540,
+	SAFETY_TIMER_NONE,
+};
+
+static int bq24257_iilimit_autoset(struct bq24257_device *bq)
+{
+	int loop_status;
+	int iilimit;
+	int port_type;
+	int ret;
+	const u8 new_iilimit[] = {
+		[PORT_TYPE_DCP] = IILIMIT_2000,
+		[PORT_TYPE_CDP] = IILIMIT_2000,
+		[PORT_TYPE_SDP] = IILIMIT_500,
+		[PORT_TYPE_NON_STANDARD] = IILIMIT_500
+	};
+
+	ret = bq24257_field_read(bq, F_LOOP_STATUS);
+	if (ret < 0)
+		goto error;
+
+	loop_status = ret;
+
+	ret = bq24257_field_read(bq, F_IILIMIT);
+	if (ret < 0)
+		goto error;
+
+	iilimit = ret;
+
+	/*
+	 * All USB ports should be able to handle 500mA. If not, DPM will lower
+	 * the charging current to accommodate the power source. No need to set
+	 * a lower IILIMIT value.
+	 */
+	if (loop_status == LOOP_STATUS_IN_DPM && iilimit == IILIMIT_500)
+		return 0;
+
+	ret = bq24257_field_read(bq, F_USB_DET);
+	if (ret < 0)
+		goto error;
+
+	port_type = ret;
+
+	ret = bq24257_field_write(bq, F_IILIMIT, new_iilimit[port_type]);
+	if (ret < 0)
+		goto error;
+
+	ret = bq24257_field_write(bq, F_TMR, SAFETY_TIMER_360);
+	if (ret < 0)
+		goto error;
+
+	ret = bq24257_field_write(bq, F_CLR_VDP, 1);
+	if (ret < 0)
+		goto error;
+
+	dev_dbg(bq->dev, "port/loop = %d/%d -> iilimit = %d\n",
+		port_type, loop_status, new_iilimit[port_type]);
+
+	return 0;
+
+error:
+	dev_err(bq->dev, "%s: Error communicating with the chip.\n", __func__);
+	return ret;
+}
+
+static void bq24257_iilimit_setup_work(struct work_struct *work)
+{
+	struct bq24257_device *bq = container_of(work, struct bq24257_device,
+						 iilimit_setup_work.work);
+
+	bq24257_iilimit_autoset(bq);
+}
+
+static void bq24257_handle_state_change(struct bq24257_device *bq,
+					struct bq24257_state *new_state)
+{
+	int ret;
+	struct bq24257_state old_state;
+	bool reset_iilimit = false;
+	bool config_iilimit = false;
+
+	mutex_lock(&bq->lock);
+	old_state = bq->state;
+	mutex_unlock(&bq->lock);
+
+	if (!new_state->power_good) {			     /* power removed */
+		cancel_delayed_work_sync(&bq->iilimit_setup_work);
+
+		/* activate D+/D- port detection algorithm */
+		ret = bq24257_field_write(bq, F_DPDM_EN, 1);
+		if (ret < 0)
+			goto error;
+
+		reset_iilimit = true;
+	} else if (!old_state.power_good) {		    /* power inserted */
+		config_iilimit = true;
+	} else if (new_state->fault == FAULT_NO_BAT) {	   /* battery removed */
+		cancel_delayed_work_sync(&bq->iilimit_setup_work);
+
+		reset_iilimit = true;
+	} else if (old_state.fault == FAULT_NO_BAT) {    /* battery connected */
+		config_iilimit = true;
+	} else if (new_state->fault == FAULT_TIMER) { /* safety timer expired */
+		dev_err(bq->dev, "Safety timer expired! Battery dead?\n");
+	}
+
+	if (reset_iilimit) {
+		ret = bq24257_field_write(bq, F_IILIMIT, IILIMIT_500);
+		if (ret < 0)
+			goto error;
+	} else if (config_iilimit) {
+		schedule_delayed_work(&bq->iilimit_setup_work,
+				      msecs_to_jiffies(BQ24257_ILIM_SET_DELAY));
+	}
+
+	return;
+
+error:
+	dev_err(bq->dev, "%s: Error communicating with the chip.\n", __func__);
+}
+
+static irqreturn_t bq24257_irq_handler_thread(int irq, void *private)
+{
+	int ret;
+	struct bq24257_device *bq = private;
+	struct bq24257_state state;
+
+	ret = bq24257_get_chip_state(bq, &state);
+	if (ret < 0)
+		return IRQ_HANDLED;
+
+	if (!bq24257_state_changed(bq, &state))
+		return IRQ_HANDLED;
+
+	dev_dbg(bq->dev, "irq(state changed): status/fault/pg = %d/%d/%d\n",
+		state.status, state.fault, state.power_good);
+
+	bq24257_handle_state_change(bq, &state);
+
+	mutex_lock(&bq->lock);
+	bq->state = state;
+	mutex_unlock(&bq->lock);
+
+	power_supply_changed(bq->charger);
+
+	return IRQ_HANDLED;
+}
+
+static int bq24257_hw_init(struct bq24257_device *bq)
+{
+	int ret;
+	int i;
+	struct bq24257_state state;
+
+	const struct {
+		int field;
+		u32 value;
+	} init_data[] = {
+		{F_ICHG, bq->init_data.ichg},
+		{F_VBAT, bq->init_data.vbat},
+		{F_ITERM, bq->init_data.iterm}
+	};
+
+	/*
+	 * Disable the watchdog timer to prevent the IC from going back to
+	 * default settings after 50 seconds of I2C inactivity.
+	 */
+	ret = bq24257_field_write(bq, F_WD_EN, 0);
+	if (ret < 0)
+		return ret;
+
+	/* configure the charge currents and voltages */
+	for (i = 0; i < ARRAY_SIZE(init_data); i++) {
+		ret = bq24257_field_write(bq, init_data[i].field,
+					  init_data[i].value);
+		if (ret < 0)
+			return ret;
+	}
+
+	ret = bq24257_get_chip_state(bq, &state);
+	if (ret < 0)
+		return ret;
+
+	mutex_lock(&bq->lock);
+	bq->state = state;
+	mutex_unlock(&bq->lock);
+
+	if (!state.power_good)
+		/* activate D+/D- detection algorithm */
+		ret = bq24257_field_write(bq, F_DPDM_EN, 1);
+	else if (state.fault != FAULT_NO_BAT)
+		ret = bq24257_iilimit_autoset(bq);
+
+	return ret;
+}
+
+static enum power_supply_property bq24257_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 *bq24257_charger_supplied_to[] = {
+	"main-battery",
+};
+
+static int bq24257_power_supply_init(struct bq24257_device *bq)
+{
+	struct power_supply_config psy_cfg = { .drv_data = bq, };
+	struct power_supply_desc *psy_desc = &bq->charger_desc;
+
+	psy_desc->name = "bq24257-charger";
+	psy_desc->type = POWER_SUPPLY_TYPE_USB;
+	psy_desc->properties = bq24257_power_supply_props;
+	psy_desc->num_properties = ARRAY_SIZE(bq24257_power_supply_props);
+	psy_desc->get_property = bq24257_power_supply_get_property;
+
+	psy_cfg.supplied_to = bq24257_charger_supplied_to;
+	psy_cfg.num_supplicants = ARRAY_SIZE(bq24257_charger_supplied_to);
+
+	bq->charger = power_supply_register(bq->dev, psy_desc, &psy_cfg);
+	if (IS_ERR(bq->charger))
+		return PTR_ERR(bq->charger);
+
+	return 0;
+}
+
+static int bq24257_irq_probe(struct bq24257_device *bq)
+{
+	int ret;
+	struct gpio_desc *stat_irq;
+
+	stat_irq = devm_gpiod_get_index(bq->dev, BQ24257_STAT_IRQ, 0);
+	if (IS_ERR(stat_irq)) {
+		dev_err(bq->dev, "could not probe stat_irq pin\n");
+		return PTR_ERR(stat_irq);
+	}
+
+	ret = gpiod_direction_input(stat_irq);
+	if (ret < 0)
+		return ret;
+
+	return gpiod_to_irq(stat_irq);
+}
+
+static int bq24257_pg_gpio_probe(struct bq24257_device *bq)
+{
+	bq->pg = devm_gpiod_get_index(bq->dev, BQ24257_PG_GPIO, 0);
+	if (IS_ERR(bq->pg)) {
+		dev_err(bq->dev, "could not probe PG pin\n");
+		return PTR_ERR(bq->pg);
+	}
+
+	return gpiod_direction_input(bq->pg);
+}
+
+static int bq24257_fw_probe(struct bq24257_device *bq)
+{
+	int ret;
+	u32 property;
+
+	ret = device_property_read_u32(bq->dev, "ti,charge-current", &property);
+	if (ret < 0)
+		return ret;
+
+	bq->init_data.ichg = bq24257_find_idx(property, bq24257_ichg_map,
+					      BQ24257_ICHG_MAP_SIZE);
+
+	ret = device_property_read_u32(bq->dev, "ti,battery-regulation-voltage",
+				       &property);
+	if (ret < 0)
+		return ret;
+
+	bq->init_data.vbat = bq24257_find_idx(property, bq24257_vbat_map,
+					      BQ24257_VBAT_MAP_SIZE);
+
+	ret = device_property_read_u32(bq->dev, "ti,termination-current",
+				       &property);
+	if (ret < 0)
+		return ret;
+
+	bq->init_data.iterm = bq24257_find_idx(property, bq24257_iterm_map,
+					       BQ24257_ITERM_MAP_SIZE);
+
+	return 0;
+}
+
+static int bq24257_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 bq24257_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, &bq24257_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(bq24257_reg_fields); i++) {
+		const struct reg_field *reg_fields = bq24257_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);
+
+	INIT_DELAYED_WORK(&bq->iilimit_setup_work, bq24257_iilimit_setup_work);
+
+	if (!dev->platform_data) {
+		ret = bq24257_fw_probe(bq);
+		if (ret < 0) {
+			dev_err(dev, "Cannot read device properties.\n");
+			return ret;
+		}
+	} else {
+		return -ENODEV;
+	}
+
+	/* we can only check Power Good status by probing the PG pin */
+	ret = bq24257_pg_gpio_probe(bq);
+	if (ret < 0)
+		return ret;
+
+	/* reset all registers to defaults */
+	ret = bq24257_field_write(bq, F_RESET, 1);
+	if (ret < 0)
+		return ret;
+
+	/*
+	 * Put the RESET bit back to 0, in cache. For some reason the HW always
+	 * returns 1 on this bit, so this is the only way to avoid resetting the
+	 * chip every time we update another field in this register.
+	 */
+	ret = bq24257_field_write(bq, F_RESET, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = bq24257_hw_init(bq);
+	if (ret < 0) {
+		dev_err(dev, "Cannot initialize the chip.\n");
+		return ret;
+	}
+
+	if (client->irq <= 0)
+		client->irq = bq24257_irq_probe(bq);
+
+	if (client->irq < 0) {
+		dev_err(dev, "no irq resource found\n");
+		return client->irq;
+	}
+
+	ret = devm_request_threaded_irq(dev, client->irq, NULL,
+					bq24257_irq_handler_thread,
+					IRQF_TRIGGER_FALLING |
+					IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+					BQ24257_STAT_IRQ, bq);
+	if (ret)
+		return ret;
+
+	ret = bq24257_power_supply_init(bq);
+	if (ret < 0)
+		dev_err(dev, "Failed to register power supply\n");
+
+	return ret;
+}
+
+static int bq24257_remove(struct i2c_client *client)
+{
+	struct bq24257_device *bq = i2c_get_clientdata(client);
+
+	cancel_delayed_work_sync(&bq->iilimit_setup_work);
+
+	power_supply_unregister(bq->charger);
+
+	bq24257_field_write(bq, F_RESET, 1); /* reset to defaults */
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int bq24257_suspend(struct device *dev)
+{
+	struct bq24257_device *bq = dev_get_drvdata(dev);
+	int ret = 0;
+
+	cancel_delayed_work_sync(&bq->iilimit_setup_work);
+
+	/* reset all registers to default (and activate standalone mode) */
+	ret = bq24257_field_write(bq, F_RESET, 1);
+	if (ret < 0)
+		dev_err(bq->dev, "Cannot reset chip to standalone mode.\n");
+
+	return ret;
+}
+
+static int bq24257_resume(struct device *dev)
+{
+	int ret;
+	struct bq24257_device *bq = dev_get_drvdata(dev);
+
+	ret = regcache_drop_region(bq->rmap, BQ24257_REG_1, BQ24257_REG_7);
+	if (ret < 0)
+		return ret;
+
+	ret = bq24257_field_write(bq, F_RESET, 0);
+	if (ret < 0)
+		return ret;
+
+	ret = bq24257_hw_init(bq);
+	if (ret < 0) {
+		dev_err(bq->dev, "Cannot init chip after resume.\n");
+		return ret;
+	}
+
+	/* signal userspace, maybe state changed while suspended */
+	power_supply_changed(bq->charger);
+
+	return 0;
+}
+#endif
+
+static const struct dev_pm_ops bq24257_pm = {
+	SET_SYSTEM_SLEEP_PM_OPS(bq24257_suspend, bq24257_resume)
+};
+
+static const struct i2c_device_id bq24257_i2c_ids[] = {
+	{ "bq24257", 0 },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, bq24257_i2c_ids);
+
+static const struct of_device_id bq24257_of_match[] = {
+	{ .compatible = "ti,bq24257", },
+	{ },
+};
+MODULE_DEVICE_TABLE(of, bq24257_of_match);
+
+static const struct acpi_device_id bq24257_acpi_match[] = {
+	{"BQ242570", 0},
+	{},
+};
+MODULE_DEVICE_TABLE(acpi, bq24257_acpi_match);
+
+static struct i2c_driver bq24257_driver = {
+	.driver = {
+		.name = "bq24257-charger",
+		.of_match_table = of_match_ptr(bq24257_of_match),
+		.acpi_match_table = ACPI_PTR(bq24257_acpi_match),
+		.pm = &bq24257_pm,
+	},
+	.probe = bq24257_probe,
+	.remove = bq24257_remove,
+	.id_table = bq24257_i2c_ids,
+};
+module_i2c_driver(bq24257_driver);
+
+MODULE_AUTHOR("Laurentiu Palcu <laurentiu.palcu@...el.com>");
+MODULE_DESCRIPTION("bq24257 charger driver");
+MODULE_LICENSE("GPL");
-- 
1.9.1

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