power_supply: Add driver for MAX8903 charger

MAX8903 is an integrated battery charger and selector with two
power inputs (USB and AC adapter). This driver enables the charger,
handles interrupts, and provides power-supply-class information to
userland.

Tested on Exynos4 NURI / S5PC210 SLP7 boards.

Signed-off-by: MyungJoo Ham <myungjoo.ham@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
---
 drivers/power/Kconfig                 |    8 +
 drivers/power/Makefile                |    1 +
 drivers/power/max8903_charger.c       |  391 +++++++++++++++++++++++++++++++++
 include/linux/power/max8903_charger.h |   57 +++++
 4 files changed, 457 insertions(+), 0 deletions(-)
 create mode 100644 drivers/power/max8903_charger.c
 create mode 100644 include/linux/power/max8903_charger.h

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index 61bf5d7..d234e40 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -189,6 +189,14 @@ config CHARGER_ISP1704
 	  Say Y to enable support for USB Charger Detection with
 	  ISP1707/ISP1704 USB transceivers.
 
+config CHARGER_MAX8903
+	tristate "MAX8903 Battery DC-DC Charger for USB and Adapter Power"
+	help
+	  Say Y to enable support for the MAX8903 DC-DC charger and sysfs.
+	  The driver supports controlling charger-enable and current-limit
+	  pins based on the status of charger connections with interrupt
+	  handlers.
+
 config CHARGER_TWL4030
 	tristate "OMAP TWL4030 BCI charger driver"
 	depends on TWL4030_CORE
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index 8385bfa..8fcd93f 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -32,5 +32,6 @@ obj-$(CONFIG_CHARGER_PCF50633)	+= pcf50633-charger.o
 obj-$(CONFIG_BATTERY_JZ4740)	+= jz4740-battery.o
 obj-$(CONFIG_BATTERY_INTEL_MID)	+= intel_mid_battery.o
 obj-$(CONFIG_CHARGER_ISP1704)	+= isp1704_charger.o
+obj-$(CONFIG_CHARGER_MAX8903)	+= max8903_charger.o
 obj-$(CONFIG_CHARGER_TWL4030)	+= twl4030_charger.o
 obj-$(CONFIG_CHARGER_GPIO)	+= gpio-charger.o
diff --git a/drivers/power/max8903_charger.c b/drivers/power/max8903_charger.c
new file mode 100644
index 0000000..33ff0e3
--- /dev/null
+++ b/drivers/power/max8903_charger.c
@@ -0,0 +1,391 @@
+/*
+ * max8903_charger.c - Maxim 8903 USB/Adapter Charger Driver
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ * MyungJoo Ham <myungjoo.ham@samsung.com>
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/slab.h>
+#include <linux/power_supply.h>
+#include <linux/platform_device.h>
+#include <linux/power/max8903_charger.h>
+
+struct max8903_data {
+	struct max8903_pdata *pdata;
+	struct device *dev;
+	struct power_supply psy;
+	bool fault;
+	bool usb_in;
+	bool ta_in;
+};
+
+static enum power_supply_property max8903_charger_props[] = {
+	POWER_SUPPLY_PROP_STATUS, /* Charger status output */
+	POWER_SUPPLY_PROP_ONLINE, /* External power source */
+	POWER_SUPPLY_PROP_HEALTH, /* Fault or OK */
+};
+
+static int max8903_get_property(struct power_supply *psy,
+		enum power_supply_property psp,
+		union power_supply_propval *val)
+{
+	struct max8903_data *data = container_of(psy,
+			struct max8903_data, psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		val->intval = POWER_SUPPLY_STATUS_UNKNOWN;
+		if (data->pdata->chg) {
+			if (gpio_get_value(data->pdata->chg) == 0)
+				val->intval = POWER_SUPPLY_STATUS_CHARGING;
+			else if (data->usb_in || data->ta_in)
+				val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
+			else
+				val->intval = POWER_SUPPLY_STATUS_DISCHARGING;
+		}
+		break;
+	case POWER_SUPPLY_PROP_ONLINE:
+		val->intval = 0;
+		if (data->usb_in || data->ta_in)
+			val->intval = 1;
+		break;
+	case POWER_SUPPLY_PROP_HEALTH:
+		val->intval = POWER_SUPPLY_HEALTH_GOOD;
+		if (data->fault)
+			val->intval = POWER_SUPPLY_HEALTH_UNSPEC_FAILURE;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+
+static irqreturn_t max8903_dcin(int irq, void *_data)
+{
+	struct max8903_data *data = _data;
+	struct max8903_pdata *pdata = data->pdata;
+	bool ta_in;
+	enum power_supply_type old_type;
+
+	ta_in = gpio_get_value(pdata->dok) ? false : true;
+
+	if (ta_in == data->ta_in)
+		return IRQ_HANDLED;
+
+	data->ta_in = ta_in;
+
+	/* Set Current-Limit-Mode 1:DC 0:USB */
+	if (pdata->dcm)
+		gpio_set_value(pdata->dcm, ta_in ? 1 : 0);
+
+	/* Charger Enable / Disable (cen is negated) */
+	if (pdata->cen)
+		gpio_set_value(pdata->cen, ta_in ? 0 :
+				(data->usb_in ? 0 : 1));
+
+	dev_dbg(data->dev, "TA(DC-IN) Charger %s.\n", ta_in ?
+			"Connected" : "Disconnected");
+
+	old_type = data->psy.type;
+
+	if (data->ta_in)
+		data->psy.type = POWER_SUPPLY_TYPE_MAINS;
+	else if (data->usb_in)
+		data->psy.type = POWER_SUPPLY_TYPE_USB;
+	else
+		data->psy.type = POWER_SUPPLY_TYPE_BATTERY;
+
+	if (old_type != data->psy.type)
+		power_supply_changed(&data->psy);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t max8903_usbin(int irq, void *_data)
+{
+	struct max8903_data *data = _data;
+	struct max8903_pdata *pdata = data->pdata;
+	bool usb_in;
+	enum power_supply_type old_type;
+
+	usb_in = gpio_get_value(pdata->uok) ? false : true;
+
+	if (usb_in == data->usb_in)
+		return IRQ_HANDLED;
+
+	data->usb_in = usb_in;
+
+	/* Do not touch Current-Limit-Mode */
+
+	/* Charger Enable / Disable (cen is negated) */
+	if (pdata->cen)
+		gpio_set_value(pdata->cen, usb_in ? 0 :
+				(data->ta_in ? 0 : 1));
+
+	dev_dbg(data->dev, "USB Charger %s.\n", usb_in ?
+			"Connected" : "Disconnected");
+
+	old_type = data->psy.type;
+
+	if (data->ta_in)
+		data->psy.type = POWER_SUPPLY_TYPE_MAINS;
+	else if (data->usb_in)
+		data->psy.type = POWER_SUPPLY_TYPE_USB;
+	else
+		data->psy.type = POWER_SUPPLY_TYPE_BATTERY;
+
+	if (old_type != data->psy.type)
+		power_supply_changed(&data->psy);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t max8903_fault(int irq, void *_data)
+{
+	struct max8903_data *data = _data;
+	struct max8903_pdata *pdata = data->pdata;
+	bool fault;
+
+	fault = gpio_get_value(pdata->flt) ? false : true;
+
+	if (fault == data->fault)
+		return IRQ_HANDLED;
+
+	data->fault = fault;
+
+	if (fault)
+		dev_err(data->dev, "Charger suffers a fault and stops.\n");
+	else
+		dev_err(data->dev, "Charger recovered from a fault.\n");
+
+	return IRQ_HANDLED;
+}
+
+static __devinit int max8903_probe(struct platform_device *pdev)
+{
+	struct max8903_data *data;
+	struct device *dev = &pdev->dev;
+	struct max8903_pdata *pdata = pdev->dev.platform_data;
+	int ret = 0;
+	int gpio;
+	int ta_in = 0;
+	int usb_in = 0;
+
+	data = kzalloc(sizeof(struct max8903_data), GFP_KERNEL);
+	if (data == NULL) {
+		dev_err(dev, "Cannot allocate memory.\n");
+		return -ENOMEM;
+	}
+	data->pdata = pdata;
+	data->dev = dev;
+	platform_set_drvdata(pdev, data);
+
+	if (pdata->dc_valid == false && pdata->usb_valid == false) {
+		dev_err(dev, "No valid power sources.\n");
+		ret = -EINVAL;
+		goto err;
+	}
+
+	if (pdata->dc_valid) {
+		if (pdata->dok && gpio_is_valid(pdata->dok) &&
+				pdata->dcm && gpio_is_valid(pdata->dcm)) {
+			gpio = pdata->dok; /* PULL_UPed Interrupt */
+			ta_in = gpio_get_value(gpio) ? 0 : 1;
+
+			gpio = pdata->dcm; /* Output */
+			gpio_set_value(gpio, ta_in);
+		} else {
+			dev_err(dev, "When DC is wired, DOK and DCM should"
+					" be wired as well.\n");
+			ret = -EINVAL;
+			goto err;
+		}
+	} else {
+		if (pdata->dcm) {
+			if (gpio_is_valid(pdata->dcm))
+				gpio_set_value(pdata->dcm, 0);
+			else {
+				dev_err(dev, "Invalid pin: dcm.\n");
+				ret = -EINVAL;
+				goto err;
+			}
+		}
+	}
+
+	if (pdata->usb_valid) {
+		if (pdata->uok && gpio_is_valid(pdata->uok)) {
+			gpio = pdata->uok;
+			usb_in = gpio_get_value(gpio) ? 0 : 1;
+		} else {
+			dev_err(dev, "When USB is wired, UOK should be wired."
+					"as well.\n");
+			ret = -EINVAL;
+			goto err;
+		}
+	}
+
+	if (pdata->cen) {
+		if (gpio_is_valid(pdata->cen)) {
+			gpio_set_value(pdata->cen, (ta_in || usb_in) ? 0 : 1);
+		} else {
+			dev_err(dev, "Invalid pin: cen.\n");
+			ret = -EINVAL;
+			goto err;
+		}
+	}
+
+	if (pdata->chg) {
+		if (!gpio_is_valid(pdata->chg)) {
+			dev_err(dev, "Invalid pin: chg.\n");
+			ret = -EINVAL;
+			goto err;
+		}
+	}
+
+	if (pdata->flt) {
+		if (!gpio_is_valid(pdata->flt)) {
+			dev_err(dev, "Invalid pin: flt.\n");
+			ret = -EINVAL;
+			goto err;
+		}
+	}
+
+	if (pdata->usus) {
+		if (!gpio_is_valid(pdata->usus)) {
+			dev_err(dev, "Invalid pin: usus.\n");
+			ret = -EINVAL;
+			goto err;
+		}
+	}
+
+	data->fault = false;
+	data->ta_in = ta_in;
+	data->usb_in = usb_in;
+
+	data->psy.name = "max8903_charger";
+	data->psy.type = (ta_in) ? POWER_SUPPLY_TYPE_MAINS :
+			((usb_in) ? POWER_SUPPLY_TYPE_USB :
+			 POWER_SUPPLY_TYPE_BATTERY);
+	data->psy.get_property = max8903_get_property;
+	data->psy.properties = max8903_charger_props;
+	data->psy.num_properties = ARRAY_SIZE(max8903_charger_props);
+
+	ret = power_supply_register(dev, &data->psy);
+	if (ret) {
+		dev_err(dev, "failed: power supply register.\n");
+		goto err;
+	}
+
+	if (pdata->dc_valid) {
+		ret = request_threaded_irq(gpio_to_irq(pdata->dok),
+				NULL, max8903_dcin,
+				IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
+				"MAX8903 DC IN", data);
+		if (ret) {
+			dev_err(dev, "Cannot request irq %d for DC (%d)\n",
+					gpio_to_irq(pdata->dok), ret);
+			goto err_psy;
+		}
+	}
+
+	if (pdata->usb_valid) {
+		ret = request_threaded_irq(gpio_to_irq(pdata->uok),
+				NULL, max8903_usbin,
+				IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
+				"MAX8903 USB IN", data);
+		if (ret) {
+			dev_err(dev, "Cannot request irq %d for USB (%d)\n",
+					gpio_to_irq(pdata->uok), ret);
+			goto err_dc_irq;
+		}
+	}
+
+	if (pdata->flt) {
+		ret = request_threaded_irq(gpio_to_irq(pdata->flt),
+				NULL, max8903_fault,
+				IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING,
+				"MAX8903 Fault", data);
+		if (ret) {
+			dev_err(dev, "Cannot request irq %d for Fault (%d)\n",
+					gpio_to_irq(pdata->flt), ret);
+			goto err_usb_irq;
+		}
+	}
+
+	return 0;
+
+err_usb_irq:
+	if (pdata->usb_valid)
+		free_irq(gpio_to_irq(pdata->uok), data);
+err_dc_irq:
+	if (pdata->dc_valid)
+		free_irq(gpio_to_irq(pdata->dok), data);
+err_psy:
+	power_supply_unregister(&data->psy);
+err:
+	kfree(data);
+	return ret;
+}
+
+static __devexit int max8903_remove(struct platform_device *pdev)
+{
+	struct max8903_data *data = platform_get_drvdata(pdev);
+
+	if (data) {
+		struct max8903_pdata *pdata = data->pdata;
+
+		if (pdata->flt)
+			free_irq(gpio_to_irq(pdata->flt), data);
+		if (pdata->usb_valid)
+			free_irq(gpio_to_irq(pdata->uok), data);
+		if (pdata->dc_valid)
+			free_irq(gpio_to_irq(pdata->dok), data);
+		power_supply_unregister(&data->psy);
+		kfree(data);
+	}
+
+	return 0;
+}
+
+static struct platform_driver max8903_driver = {
+	.probe	= max8903_probe,
+	.remove	= __devexit_p(max8903_remove),
+	.driver = {
+		.name	= "max8903-charger",
+		.owner	= THIS_MODULE,
+	},
+};
+
+static int __init max8903_init(void)
+{
+	return platform_driver_register(&max8903_driver);
+}
+module_init(max8903_init);
+
+static void __exit max8903_exit(void)
+{
+	platform_driver_unregister(&max8903_driver);
+}
+module_exit(max8903_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("MAX8903 Charger Driver");
+MODULE_AUTHOR("MyungJoo Ham <myungjoo.ham@samsung.com>");
+MODULE_ALIAS("max8903-charger");
diff --git a/include/linux/power/max8903_charger.h b/include/linux/power/max8903_charger.h
new file mode 100644
index 0000000..24f51db
--- /dev/null
+++ b/include/linux/power/max8903_charger.h
@@ -0,0 +1,57 @@
+/*
+ * max8903_charger.h - Maxim 8903 USB/Adapter Charger Driver
+ *
+ * Copyright (C) 2011 Samsung Electronics
+ * MyungJoo Ham <myungjoo.ham@samsung.com>
+ *
+ * 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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ */
+
+#ifndef __MAX8903_CHARGER_H__
+#define __MAX8903_CHARGER_H__
+
+struct max8903_pdata {
+	/*
+	 * GPIOs
+	 * cen, chg, flt, and usus are optional.
+	 * dok, dcm, and uok are not optional depending on the status of
+	 * dc_valid and usb_valid.
+	 */
+	int cen;	/* Charger Enable input */
+	int dok;	/* DC(Adapter) Power OK output */
+	int uok;	/* USB Power OK output */
+	int chg;	/* Charger status output */
+	int flt;	/* Fault output */
+	int dcm;	/* Current-Limit Mode input (1: DC, 2: USB) */
+	int usus;	/* USB Suspend Input (1: suspended) */
+
+	/*
+	 * DC(Adapter/TA) is wired
+	 * When dc_valid is true,
+	 *	dok and dcm should be valid.
+	 *
+	 * At least one of dc_valid or usb_valid should be true.
+	 */
+	bool dc_valid;
+	/*
+	 * USB is wired
+	 * When usb_valid is true,
+	 *	uok should be valid.
+	 */
+	bool usb_valid;
+};
+
+#endif /* __MAX8903_CHARGER_H__ */
-- 
1.7.1