power_supply: Add new lp8788 charger driver

TI LP8788 PMU supports regulators, battery charger, RTC, ADC, backlight
driver and current sinks.

This patch supports the charger operations including the charger
interrupt handling.

The LP8788 charger driver provides configurable platform data.  The
charger platform data includes ADC input ID, maximum battery voltage,
charging parameters and etc.

The ADC input is used for getting the battery voltage and temperature.
Charging parameters are used for updating the charger operations such
like setting charging current and setting End-of-charge conditions.

When the charging interrupt occurs, power supply uevents are generated
in order to update the user-space information.  For platform specific
charger action, the charger_event() function can be used in the
platform side.

Signed-off-by: Milo(Woogyom) Kim <milo.kim@ti.com>
Signed-off-by: Anton Vorontsov <anton.vorontsov@linaro.org>

drivers/power/Kconfig

@@ -254,6 +254,13 @@ config CHARGER_LP8727
 	help
 	  Say Y here to enable support for LP8727 Charger Driver.
 
+config CHARGER_LP8788
+	tristate "TI LP8788 charger driver"
+	depends on MFD_LP8788
+	depends on LP8788_ADC
+	help
+	  Say Y to enable support for the LP8788 linear charger.
+
 config CHARGER_GPIO
 	tristate "GPIO charger"
 	depends on GPIOLIB

drivers/power/Makefile

@@ -39,6 +39,7 @@ obj-$(CONFIG_CHARGER_ISP1704)	+= isp1704_charger.o
 obj-$(CONFIG_CHARGER_MAX8903)	+= max8903_charger.o
 obj-$(CONFIG_CHARGER_TWL4030)	+= twl4030_charger.o
 obj-$(CONFIG_CHARGER_LP8727)	+= lp8727_charger.o
+obj-$(CONFIG_CHARGER_LP8788)	+= lp8788-charger.o
 obj-$(CONFIG_CHARGER_GPIO)	+= gpio-charger.o
 obj-$(CONFIG_CHARGER_MANAGER)	+= charger-manager.o
 obj-$(CONFIG_CHARGER_MAX8997)	+= max8997_charger.o

drivers/power/lp8788-charger.c

@@ -0,0 +1,795 @@
+/*
+ * TI LP8788 MFD - battery charger driver
+ *
+ * Copyright 2012 Texas Instruments
+ *
+ * Author: Milo(Woogyom) Kim <milo.kim@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include <linux/err.h>
+#include <linux/iio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/irqdomain.h>
+#include <linux/mfd/lp8788.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/slab.h>
+#include <linux/workqueue.h>
+
+/* register address */
+#define LP8788_CHG_STATUS		0x07
+#define LP8788_CHG_IDCIN		0x13
+#define LP8788_CHG_IBATT		0x14
+#define LP8788_CHG_VTERM		0x15
+#define LP8788_CHG_EOC			0x16
+
+/* mask/shift bits */
+#define LP8788_CHG_INPUT_STATE_M	0x03	/* Addr 07h */
+#define LP8788_CHG_STATE_M		0x3C
+#define LP8788_CHG_STATE_S		2
+#define LP8788_NO_BATT_M		BIT(6)
+#define LP8788_BAD_BATT_M		BIT(7)
+#define LP8788_CHG_IBATT_M		0x1F	/* Addr 14h */
+#define LP8788_CHG_VTERM_M		0x0F	/* Addr 15h */
+#define LP8788_CHG_EOC_LEVEL_M		0x30	/* Addr 16h */
+#define LP8788_CHG_EOC_LEVEL_S		4
+#define LP8788_CHG_EOC_TIME_M		0x0E
+#define LP8788_CHG_EOC_TIME_S		1
+#define LP8788_CHG_EOC_MODE_M		BIT(0)
+
+#define LP8788_CHARGER_NAME		"charger"
+#define LP8788_BATTERY_NAME		"main_batt"
+
+#define LP8788_CHG_START		0x11
+#define LP8788_CHG_END			0x1C
+
+#define LP8788_BUF_SIZE			40
+#define LP8788_ISEL_MAX			23
+#define LP8788_ISEL_STEP		50
+#define LP8788_VTERM_MIN		4100
+#define LP8788_VTERM_STEP		25
+#define LP8788_MAX_BATT_CAPACITY	100
+#define LP8788_MAX_CHG_IRQS		11
+
+enum lp8788_charging_state {
+	LP8788_OFF,
+	LP8788_WARM_UP,
+	LP8788_LOW_INPUT = 0x3,
+	LP8788_PRECHARGE,
+	LP8788_CC,
+	LP8788_CV,
+	LP8788_MAINTENANCE,
+	LP8788_BATTERY_FAULT,
+	LP8788_SYSTEM_SUPPORT = 0xC,
+	LP8788_HIGH_CURRENT = 0xF,
+	LP8788_MAX_CHG_STATE,
+};
+
+enum lp8788_charger_adc_sel {
+	LP8788_VBATT,
+	LP8788_BATT_TEMP,
+	LP8788_NUM_CHG_ADC,
+};
+
+enum lp8788_charger_input_state {
+	LP8788_SYSTEM_SUPPLY = 1,
+	LP8788_FULL_FUNCTION,
+};
+
+/*
+ * struct lp8788_chg_irq
+ * @which        : lp8788 interrupt id
+ * @virq         : Linux IRQ number from irq_domain
+ */
+struct lp8788_chg_irq {
+	enum lp8788_int_id which;
+	int virq;
+};
+
+/*
+ * struct lp8788_charger
+ * @lp           : used for accessing the registers of mfd lp8788 device
+ * @charger      : power supply driver for the battery charger
+ * @battery      : power supply driver for the battery
+ * @charger_work : work queue for charger input interrupts
+ * @chan         : iio channels for getting adc values
+ *                 eg) battery voltage, capacity and temperature
+ * @irqs         : charger dedicated interrupts
+ * @num_irqs     : total numbers of charger interrupts
+ * @pdata        : charger platform specific data
+ */
+struct lp8788_charger {
+	struct lp8788 *lp;
+	struct power_supply charger;
+	struct power_supply battery;
+	struct work_struct charger_work;
+	struct iio_channel *chan[LP8788_NUM_CHG_ADC];
+	struct lp8788_chg_irq irqs[LP8788_MAX_CHG_IRQS];
+	int num_irqs;
+	struct lp8788_charger_platform_data *pdata;
+};
+
+static char *battery_supplied_to[] = {
+	LP8788_BATTERY_NAME,
+};
+
+static enum power_supply_property lp8788_charger_prop[] = {
+	POWER_SUPPLY_PROP_ONLINE,
+	POWER_SUPPLY_PROP_CURRENT_MAX,
+};
+
+static enum power_supply_property lp8788_battery_prop[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_HEALTH,
+	POWER_SUPPLY_PROP_PRESENT,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CAPACITY,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT,
+	POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX,
+	POWER_SUPPLY_PROP_TEMP,
+};
+
+static bool lp8788_is_charger_detected(struct lp8788_charger *pchg)
+{
+	u8 data;
+
+	lp8788_read_byte(pchg->lp, LP8788_CHG_STATUS, &data);
+	data &= LP8788_CHG_INPUT_STATE_M;
+
+	return data == LP8788_SYSTEM_SUPPLY || data == LP8788_FULL_FUNCTION;
+}
+
+static int lp8788_charger_get_property(struct power_supply *psy,
+					enum power_supply_property psp,
+					union power_supply_propval *val)
+{
+	struct lp8788_charger *pchg = dev_get_drvdata(psy->dev->parent);
+	u8 read;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = lp8788_is_charger_detected(pchg);
+		break;
+	case POWER_SUPPLY_PROP_CURRENT_MAX:
+		lp8788_read_byte(pchg->lp, LP8788_CHG_IDCIN, &read);
+		val->intval = LP8788_ISEL_STEP *
+				(min_t(int, read, LP8788_ISEL_MAX) + 1);
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int lp8788_get_battery_status(struct lp8788_charger *pchg,
+				union power_supply_propval *val)
+{
+	enum lp8788_charging_state state;
+	u8 data;
+	int ret;
+
+	ret = lp8788_read_byte(pchg->lp, LP8788_CHG_STATUS, &data);
+	if (ret)
+		return ret;
+
+	state = (data & LP8788_CHG_STATE_M) >> LP8788_CHG_STATE_S;
+	switch (state) {
+	case LP8788_OFF:
+		val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+		break;
+	case LP8788_PRECHARGE:
+	case LP8788_CC:
+	case LP8788_CV:
+	case LP8788_HIGH_CURRENT:
+		val->intval = POWER_SUPPLY_STATUS_CHARGING;
+		break;
+	case LP8788_MAINTENANCE:
+		val->intval = POWER_SUPPLY_STATUS_FULL;
+		break;
+	default:
+		val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+		break;
+	}
+
+	return 0;
+}
+
+static int lp8788_get_battery_health(struct lp8788_charger *pchg,
+				union power_supply_propval *val)
+{
+	u8 data;
+	int ret;
+
+	ret = lp8788_read_byte(pchg->lp, LP8788_CHG_STATUS, &data);
+	if (ret)
+		return ret;
+
+	if (data & LP8788_NO_BATT_M)
+		val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+	else if (data & LP8788_BAD_BATT_M)
+		val->intval = POWER_SUPPLY_HEALTH_DEAD;
+	else
+		val->intval = POWER_SUPPLY_HEALTH_GOOD;
+
+	return 0;
+}
+
+static int lp8788_get_battery_present(struct lp8788_charger *pchg,
+				union power_supply_propval *val)
+{
+	u8 data;
+	int ret;
+
+	ret = lp8788_read_byte(pchg->lp, LP8788_CHG_STATUS, &data);
+	if (ret)
+		return ret;
+
+	val->intval = !(data & LP8788_NO_BATT_M);
+	return 0;
+}
+
+static int lp8788_get_vbatt_adc(struct lp8788_charger *pchg,
+				unsigned int *result)
+{
+	struct iio_channel *channel = pchg->chan[LP8788_VBATT];
+	int scaleint;
+	int scalepart;
+	int ret;
+
+	if (!channel)
+		return -EINVAL;
+
+	ret = iio_read_channel_scale(channel, &scaleint, &scalepart);
+	if (ret != IIO_VAL_INT_PLUS_MICRO)
+		return -EINVAL;
+
+	/* unit: mV */
+	*result = (scaleint + scalepart * 1000000) / 1000;
+
+	return 0;
+}
+
+static int lp8788_get_battery_voltage(struct lp8788_charger *pchg,
+				union power_supply_propval *val)
+{
+	return lp8788_get_vbatt_adc(pchg, &val->intval);
+}
+
+static int lp8788_get_battery_capacity(struct lp8788_charger *pchg,
+				union power_supply_propval *val)
+{
+	struct lp8788 *lp = pchg->lp;
+	struct lp8788_charger_platform_data *pdata = pchg->pdata;
+	unsigned int max_vbatt;
+	unsigned int vbatt;
+	enum lp8788_charging_state state;
+	u8 data;
+	int ret;
+
+	if (!pdata)
+		return -EINVAL;
+
+	max_vbatt = pdata->max_vbatt_mv;
+	if (max_vbatt == 0)
+		return -EINVAL;
+
+	ret = lp8788_read_byte(lp, LP8788_CHG_STATUS, &data);
+	if (ret)
+		return ret;
+
+	state = (data & LP8788_CHG_STATE_M) >> LP8788_CHG_STATE_S;
+
+	if (state == LP8788_MAINTENANCE) {
+		val->intval = LP8788_MAX_BATT_CAPACITY;
+	} else {
+		ret = lp8788_get_vbatt_adc(pchg, &vbatt);
+		if (ret)
+			return ret;
+
+		val->intval = (vbatt * LP8788_MAX_BATT_CAPACITY) / max_vbatt;
+		val->intval = min(val->intval, LP8788_MAX_BATT_CAPACITY);
+	}
+
+	return 0;
+}
+
+static int lp8788_get_battery_temperature(struct lp8788_charger *pchg,
+				union power_supply_propval *val)
+{
+	struct iio_channel *channel = pchg->chan[LP8788_BATT_TEMP];
+	int scaleint;
+	int scalepart;
+	int ret;
+
+	if (!channel)
+		return -EINVAL;
+
+	ret = iio_read_channel_scale(channel, &scaleint, &scalepart);
+	if (ret != IIO_VAL_INT_PLUS_MICRO)
+		return -EINVAL;
+
+	/* unit: 0.1 'C */
+	val->intval = (scaleint + scalepart * 1000000) / 100;
+
+	return 0;
+}
+
+static int lp8788_get_battery_charging_current(struct lp8788_charger *pchg,
+				union power_supply_propval *val)
+{
+	u8 read;
+
+	lp8788_read_byte(pchg->lp, LP8788_CHG_IBATT, &read);
+	read &= LP8788_CHG_IBATT_M;
+	val->intval = LP8788_ISEL_STEP *
+			(min_t(int, read, LP8788_ISEL_MAX) + 1);
+
+	return 0;
+}
+
+static int lp8788_get_charging_termination_voltage(struct lp8788_charger *pchg,
+				union power_supply_propval *val)
+{
+	u8 read;
+
+	lp8788_read_byte(pchg->lp, LP8788_CHG_VTERM, &read);
+	read &= LP8788_CHG_VTERM_M;
+	val->intval = LP8788_VTERM_MIN + LP8788_VTERM_STEP * read;
+
+	return 0;
+}
+
+static int lp8788_battery_get_property(struct power_supply *psy,
+					enum power_supply_property psp,
+					union power_supply_propval *val)
+{
+	struct lp8788_charger *pchg = dev_get_drvdata(psy->dev->parent);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		return lp8788_get_battery_status(pchg, val);
+	case POWER_SUPPLY_PROP_HEALTH:
+		return lp8788_get_battery_health(pchg, val);
+	case POWER_SUPPLY_PROP_PRESENT:
+		return lp8788_get_battery_present(pchg, val);
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		return lp8788_get_battery_voltage(pchg, val);
+	case POWER_SUPPLY_PROP_CAPACITY:
+		return lp8788_get_battery_capacity(pchg, val);
+	case POWER_SUPPLY_PROP_TEMP:
+		return lp8788_get_battery_temperature(pchg, val);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT:
+		return lp8788_get_battery_charging_current(pchg, val);
+	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE_MAX:
+		return lp8788_get_charging_termination_voltage(pchg, val);
+	default:
+		return -EINVAL;
+	}
+}
+
+static inline bool lp8788_is_valid_charger_register(u8 addr)
+{
+	return addr >= LP8788_CHG_START && addr <= LP8788_CHG_END;
+}
+
+static int lp8788_update_charger_params(struct lp8788_charger *pchg)
+{
+	struct lp8788 *lp = pchg->lp;
+	struct lp8788_charger_platform_data *pdata = pchg->pdata;
+	struct lp8788_chg_param *param;
+	int i;
+	int ret;
+
+	if (!pdata || !pdata->chg_params) {
+		dev_info(lp->dev, "skip updating charger parameters\n");
+		return 0;
+	}
+
+	/* settting charging parameters */
+	for (i = 0; i < pdata->num_chg_params; i++) {
+		param = pdata->chg_params + i;
+
+		if (!param)
+			continue;
+
+		if (lp8788_is_valid_charger_register(param->addr)) {
+			ret = lp8788_write_byte(lp, param->addr, param->val);
+			if (ret)
+				return ret;
+		}
+	}
+
+	return 0;
+}
+
+static int lp8788_psy_register(struct platform_device *pdev,
+				struct lp8788_charger *pchg)
+{
+	pchg->charger.name = LP8788_CHARGER_NAME;
+	pchg->charger.type = POWER_SUPPLY_TYPE_MAINS;
+	pchg->charger.properties = lp8788_charger_prop;
+	pchg->charger.num_properties = ARRAY_SIZE(lp8788_charger_prop);
+	pchg->charger.get_property = lp8788_charger_get_property;
+	pchg->charger.supplied_to = battery_supplied_to;
+	pchg->charger.num_supplicants = ARRAY_SIZE(battery_supplied_to);
+
+	if (power_supply_register(&pdev->dev, &pchg->charger))
+		return -EPERM;
+
+	pchg->battery.name = LP8788_BATTERY_NAME;
+	pchg->battery.type = POWER_SUPPLY_TYPE_BATTERY;
+	pchg->battery.properties = lp8788_battery_prop;
+	pchg->battery.num_properties = ARRAY_SIZE(lp8788_battery_prop);
+	pchg->battery.get_property = lp8788_battery_get_property;
+
+	if (power_supply_register(&pdev->dev, &pchg->battery))
+		return -EPERM;
+
+	return 0;
+}
+
+static void lp8788_psy_unregister(struct lp8788_charger *pchg)
+{
+	power_supply_unregister(&pchg->battery);
+	power_supply_unregister(&pchg->charger);
+}
+
+static void lp8788_charger_event(struct work_struct *work)
+{
+	struct lp8788_charger *pchg =
+		container_of(work, struct lp8788_charger, charger_work);
+	struct lp8788_charger_platform_data *pdata = pchg->pdata;
+	enum lp8788_charger_event event = lp8788_is_charger_detected(pchg);
+
+	pdata->charger_event(pchg->lp, event);
+}
+
+static bool lp8788_find_irq_id(struct lp8788_charger *pchg, int virq, int *id)
+{
+	bool found;
+	int i;
+
+	for (i = 0; i < pchg->num_irqs; i++) {
+		if (pchg->irqs[i].virq == virq) {
+			*id = pchg->irqs[i].which;
+			found = true;
+			break;
+		}
+	}
+
+	return found;
+}
+
+static irqreturn_t lp8788_charger_irq_thread(int virq, void *ptr)
+{
+	struct lp8788_charger *pchg = ptr;
+	struct lp8788_charger_platform_data *pdata = pchg->pdata;
+	int id = -1;
+
+	if (!lp8788_find_irq_id(pchg, virq, &id))
+		return IRQ_NONE;
+
+	switch (id) {
+	case LP8788_INT_CHG_INPUT_STATE:
+	case LP8788_INT_CHG_STATE:
+	case LP8788_INT_EOC:
+	case LP8788_INT_BATT_LOW:
+	case LP8788_INT_NO_BATT:
+		power_supply_changed(&pchg->charger);
+		power_supply_changed(&pchg->battery);
+		break;
+	default:
+		break;
+	}
+
+	/* report charger dectection event if used */
+	if (!pdata)
+		goto irq_handled;
+
+	if (pdata->charger_event && id == LP8788_INT_CHG_INPUT_STATE)
+		schedule_work(&pchg->charger_work);
+
+irq_handled:
+	return IRQ_HANDLED;
+}
+
+static int lp8788_set_irqs(struct platform_device *pdev,
+			struct lp8788_charger *pchg, const char *name)
+{
+	struct resource *r;
+	struct irq_domain *irqdm = pchg->lp->irqdm;
+	int irq_start;
+	int irq_end;
+	int virq;
+	int nr_irq;
+	int i;
+	int ret;
+
+	/* no error even if no irq resource */
+	r = platform_get_resource_byname(pdev, IORESOURCE_IRQ, name);
+	if (!r)
+		return 0;
+
+	irq_start = r->start;
+	irq_end = r->end;
+
+	for (i = irq_start; i <= irq_end; i++) {
+		nr_irq = pchg->num_irqs;
+
+		virq = irq_create_mapping(irqdm, i);
+		pchg->irqs[nr_irq].virq = virq;
+		pchg->irqs[nr_irq].which = i;
+		pchg->num_irqs++;
+
+		ret = request_threaded_irq(virq, NULL,
+					lp8788_charger_irq_thread,
+					0, name, pchg);
+		if (ret)
+			break;
+	}
+
+	if (i <= irq_end)
+		goto err_free_irq;
+
+	return 0;
+
+err_free_irq:
+	for (i = 0; i < pchg->num_irqs; i++)
+		free_irq(pchg->irqs[i].virq, pchg);
+	return ret;
+}
+
+static int lp8788_irq_register(struct platform_device *pdev,
+				struct lp8788_charger *pchg)
+{
+	struct lp8788 *lp = pchg->lp;
+	const char *name[] = {
+		LP8788_CHG_IRQ, LP8788_PRSW_IRQ, LP8788_BATT_IRQ
+	};
+	int i;
+	int ret;
+
+	INIT_WORK(&pchg->charger_work, lp8788_charger_event);
+	pchg->num_irqs = 0;
+
+	for (i = 0; i < ARRAY_SIZE(name); i++) {
+		ret = lp8788_set_irqs(pdev, pchg, name[i]);
+		if (ret) {
+			dev_warn(lp->dev, "irq setup failed: %s\n", name[i]);
+			return ret;
+		}
+	}
+
+	if (pchg->num_irqs > LP8788_MAX_CHG_IRQS) {
+		dev_err(lp->dev, "invalid total number of irqs: %d\n",
+			pchg->num_irqs);
+		return -EINVAL;
+	}
+
+
+	return 0;
+}
+
+static void lp8788_irq_unregister(struct platform_device *pdev,
+				  struct lp8788_charger *pchg)
+{
+	int i;
+	int irq;
+
+	for (i = 0; i < pchg->num_irqs; i++) {
+		irq = pchg->irqs[i].virq;
+		if (!irq)
+			continue;
+
+		free_irq(irq, pchg);
+	}
+}
+
+static void lp8788_setup_adc_channel(struct lp8788_charger *pchg)
+{
+	struct lp8788_charger_platform_data *pdata = pchg->pdata;
+	struct device *dev = pchg->lp->dev;
+	struct iio_channel *chan;
+	enum lp8788_adc_id id;
+	const char *chan_name[LPADC_MAX] = {
+		[LPADC_VBATT_5P5] = "vbatt-5p5",
+		[LPADC_VBATT_6P0] = "vbatt-6p0",
+		[LPADC_VBATT_5P0] = "vbatt-5p0",
+		[LPADC_ADC1]      = "adc1",
+		[LPADC_ADC2]      = "adc2",
+		[LPADC_ADC3]      = "adc3",
+		[LPADC_ADC4]      = "adc4",
+	};
+
+	if (!pdata)
+		return;
+
+	id = pdata->vbatt_adc;
+	switch (id) {
+	case LPADC_VBATT_5P5:
+	case LPADC_VBATT_6P0:
+	case LPADC_VBATT_5P0:
+		chan = iio_channel_get(NULL, chan_name[id]);
+		pchg->chan[LP8788_VBATT] = IS_ERR(chan) ? NULL : chan;
+		break;
+	default:
+		dev_err(dev, "invalid ADC id for VBATT: %d\n", id);
+		pchg->chan[LP8788_VBATT] = NULL;
+		break;
+	}
+
+	id = pdata->batt_temp_adc;
+	switch (id) {
+	case LPADC_ADC1:
+	case LPADC_ADC2:
+	case LPADC_ADC3:
+	case LPADC_ADC4:
+		chan = iio_channel_get(NULL, chan_name[id]);
+		pchg->chan[LP8788_BATT_TEMP] = IS_ERR(chan) ? NULL : chan;
+		break;
+	default:
+		dev_err(dev, "invalid ADC id for BATT_TEMP : %d\n", id);
+		pchg->chan[LP8788_BATT_TEMP] = NULL;
+		break;
+	}
+}
+
+static void lp8788_release_adc_channel(struct lp8788_charger *pchg)
+{
+	int i;
+
+	for (i = 0; i < LP8788_NUM_CHG_ADC; i++) {
+		if (!pchg->chan[i])
+			continue;
+
+		iio_channel_release(pchg->chan[i]);
+		pchg->chan[i] = NULL;
+	}
+}
+
+static ssize_t lp8788_show_charger_status(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct lp8788_charger *pchg = dev_get_drvdata(dev);
+	enum lp8788_charging_state state;
+	char *desc[LP8788_MAX_CHG_STATE] = {
+		[LP8788_OFF] = "CHARGER OFF",
+		[LP8788_WARM_UP] = "WARM UP",
+		[LP8788_LOW_INPUT] = "LOW INPUT STATE",
+		[LP8788_PRECHARGE] = "CHARGING - PRECHARGE",
+		[LP8788_CC] = "CHARGING - CC",
+		[LP8788_CV] = "CHARGING - CV",
+		[LP8788_MAINTENANCE] = "NO CHARGING - MAINTENANCE",
+		[LP8788_BATTERY_FAULT] = "BATTERY FAULT",
+		[LP8788_SYSTEM_SUPPORT] = "SYSTEM SUPPORT",
+		[LP8788_HIGH_CURRENT] = "HIGH CURRENT",
+	};
+	u8 data;
+
+	lp8788_read_byte(pchg->lp, LP8788_CHG_STATUS, &data);
+	state = (data & LP8788_CHG_STATE_M) >> LP8788_CHG_STATE_S;
+
+	return scnprintf(buf, LP8788_BUF_SIZE, "%s\n", desc[state]);
+}
+
+static ssize_t lp8788_show_eoc_time(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct lp8788_charger *pchg = dev_get_drvdata(dev);
+	char *stime[] = { "400ms", "5min", "10min", "15min",
+			"20min", "25min", "30min" "No timeout" };
+	u8 val;
+
+	lp8788_read_byte(pchg->lp, LP8788_CHG_EOC, &val);
+	val = (val & LP8788_CHG_EOC_TIME_M) >> LP8788_CHG_EOC_TIME_S;
+
+	return scnprintf(buf, LP8788_BUF_SIZE, "End Of Charge Time: %s\n",
+			stime[val]);
+}
+
+static ssize_t lp8788_show_eoc_level(struct device *dev,
+				struct device_attribute *attr, char *buf)
+{
+	struct lp8788_charger *pchg = dev_get_drvdata(dev);
+	char *abs_level[] = { "25mA", "49mA", "75mA", "98mA" };
+	char *relative_level[] = { "5%", "10%", "15%", "20%" };
+	char *level;
+	u8 val;
+	u8 mode;
+
+	lp8788_read_byte(pchg->lp, LP8788_CHG_EOC, &val);
+
+	mode = val & LP8788_CHG_EOC_MODE_M;
+	val = (val & LP8788_CHG_EOC_LEVEL_M) >> LP8788_CHG_EOC_LEVEL_S;
+	level = mode ? abs_level[val] : relative_level[val];
+
+	return scnprintf(buf, LP8788_BUF_SIZE, "End Of Charge Level: %s\n",
+			level);
+}
+
+static DEVICE_ATTR(charger_status, S_IRUSR, lp8788_show_charger_status, NULL);
+static DEVICE_ATTR(eoc_time, S_IRUSR, lp8788_show_eoc_time, NULL);
+static DEVICE_ATTR(eoc_level, S_IRUSR, lp8788_show_eoc_level, NULL);
+
+static struct attribute *lp8788_charger_attr[] = {
+	&dev_attr_charger_status.attr,
+	&dev_attr_eoc_time.attr,
+	&dev_attr_eoc_level.attr,
+	NULL,
+};
+
+static const struct attribute_group lp8788_attr_group = {
+	.attrs = lp8788_charger_attr,
+};
+
+static __devinit int lp8788_charger_probe(struct platform_device *pdev)
+{
+	struct lp8788 *lp = dev_get_drvdata(pdev->dev.parent);
+	struct lp8788_charger *pchg;
+	int ret;
+
+	pchg = devm_kzalloc(lp->dev, sizeof(struct lp8788_charger), GFP_KERNEL);
+	if (!pchg)
+		return -ENOMEM;
+
+	pchg->lp = lp;
+	pchg->pdata = lp->pdata ? lp->pdata->chg_pdata : NULL;
+	platform_set_drvdata(pdev, pchg);
+
+	ret = lp8788_update_charger_params(pchg);
+	if (ret)
+		return ret;
+
+	lp8788_setup_adc_channel(pchg);
+
+	ret = lp8788_psy_register(pdev, pchg);
+	if (ret)
+		return ret;
+
+	ret = sysfs_create_group(&pdev->dev.kobj, &lp8788_attr_group);
+	if (ret) {
+		lp8788_psy_unregister(pchg);
+		return ret;
+	}
+
+	ret = lp8788_irq_register(pdev, pchg);
+	if (ret)
+		dev_warn(lp->dev, "failed to register charger irq: %d\n", ret);
+
+	return 0;
+}
+
+static int __devexit lp8788_charger_remove(struct platform_device *pdev)
+{
+	struct lp8788_charger *pchg = platform_get_drvdata(pdev);
+
+	flush_work(&pchg->charger_work);
+	lp8788_irq_unregister(pdev, pchg);
+	sysfs_remove_group(&pdev->dev.kobj, &lp8788_attr_group);
+	lp8788_psy_unregister(pchg);
+	lp8788_release_adc_channel(pchg);
+
+	return 0;
+}
+
+static struct platform_driver lp8788_charger_driver = {
+	.probe = lp8788_charger_probe,
+	.remove = __devexit_p(lp8788_charger_remove),
+	.driver = {
+		.name = LP8788_DEV_CHARGER,
+		.owner = THIS_MODULE,
+	},
+};
+module_platform_driver(lp8788_charger_driver);
+
+MODULE_DESCRIPTION("TI LP8788 Charger Driver");
+MODULE_AUTHOR("Milo Kim");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:lp8788-charger");