Date:	Fri, 21 Sep 2012 21:40:14 +0530
From:	anish kumar <anish198519851985@...il.com>
To:	cbou@...l.ru, dwmw2@...radead.org, lars@...afoo.de, jic23@....ac.uk
Cc:	linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org,
	anish kumar <anish198519851985@...il.com>
Subject: [PATCH] [V3]power: battery: Generic battery driver using IIO

From: anish kumar <anish198519851985@...il.com>

In last version:
Addressed concerns raised by lars:
a. made the adc_bat per device.
b. get the IIO channel using hardcoded channel names.
c. Minor issues related to gpio_is_valid and some code
   refactoring.

In V1:
Addressed concerns raised by Anton:
a. changed the struct name to gab(generic adc battery).
b. Added some functions to neaten the code.
c. Some minor coding guidelines changes.
d. Used the latest function introduce by lars:
   iio_read_channel_processed to streamline the code.

In V2:
Addressed concerns by lars:
a. No need of allocating memory for channels.Make it array.
b. Code restructring, coding style and following kernel guidelines changes
   suggested by him.

In V3:
Addressed conerns by Anton:
a. Added the copyright.
b. Coding guidelines changes suggested by him.
c. Added Makefile and Kconfig

Signed-off-by: anish kumar <anish198519851985@...il.com>
---
 drivers/power/Kconfig                     |    7 +
 drivers/power/Makefile                    |    1 +
 drivers/power/generic-adc-battery.c       |  422 +++++++++++++++++++++++++++++
 include/linux/power/generic-adc-battery.h |   29 ++
 4 files changed, 459 insertions(+), 0 deletions(-)
 create mode 100644 drivers/power/generic-adc-battery.c
 create mode 100644 include/linux/power/generic-adc-battery.h

diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
index fcc1bb0..30a173a 100644
--- a/drivers/power/Kconfig
+++ b/drivers/power/Kconfig
@@ -29,6 +29,13 @@ config APM_POWER
 	  Say Y here to enable support APM status emulation using
 	  battery class devices.
 
+config GENERIC_ADC_BATTERY
+	tristate "Generic battery support using IIO"
+	depends on IIO
+	help
+	  Say Y here to enable support for the generic battery driver
+	  which uses IIO framework to read adc.
+
 config MAX8925_POWER
 	tristate "MAX8925 battery charger support"
 	depends on MFD_MAX8925
diff --git a/drivers/power/Makefile b/drivers/power/Makefile
index ee58afb..e0b4d42 100644
--- a/drivers/power/Makefile
+++ b/drivers/power/Makefile
@@ -5,6 +5,7 @@ power_supply-$(CONFIG_SYSFS)		+= power_supply_sysfs.o
 power_supply-$(CONFIG_LEDS_TRIGGERS)	+= power_supply_leds.o
 
 obj-$(CONFIG_POWER_SUPPLY)	+= power_supply.o
+obj-$(CONFIG_GENERIC_ADC_BATTERY)	+= generic-adc-battery.o
 
 obj-$(CONFIG_PDA_POWER)		+= pda_power.o
 obj-$(CONFIG_APM_POWER)		+= apm_power.o
diff --git a/drivers/power/generic-adc-battery.c b/drivers/power/generic-adc-battery.c
new file mode 100644
index 0000000..a34d52a
--- /dev/null
+++ b/drivers/power/generic-adc-battery.c
@@ -0,0 +1,422 @@
+/*
+ * Generic battery driver code using IIO
+ * Copyright (C) 2012, Anish Kumar <anish198519851985@...il.com>
+ * based on jz4740-battery.c
+ * based on s3c_adc_battery.c
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive for
+ * more details.
+ *
+ */
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/power_supply.h>
+#include <linux/gpio.h>
+#include <linux/err.h>
+#include <linux/timer.h>
+#include <linux/jiffies.h>
+#include <linux/errno.h>
+#include <linux/init.h>
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/iio/consumer.h>
+#include <linux/iio/types.h>
+#include <linux/power/generic-adc-battery.h>
+
+#define JITTER_DEFAULT 10 /* hope 10ms is enough */
+
+enum gab_chan_type {
+	GAB_VOLTAGE = 0,
+	GAB_CURRENT,
+	GAB_POWER,
+	GAB_MAX_CHAN_TYPE
+};
+
+/*
+ * gab_chan_name suggests the standard channel names for commonly used
+ * channel types.
+ */
+static const char *const gab_chan_name[] = {
+	[GAB_VOLTAGE]	= "voltage",
+	[GAB_CURRENT]	= "current",
+	[GAB_POWER]		= "power",
+};
+
+struct gab {
+	struct power_supply	psy;
+	struct iio_channel	*channel[GAB_MAX_CHAN_TYPE];
+	struct gab_platform_data	*pdata;
+	struct delayed_work bat_work;
+	int	level;
+	int	status;
+	bool cable_plugged;
+};
+
+struct gab *to_generic_bat(struct power_supply *psy)
+{
+	return container_of(psy, struct gab, psy);
+}
+
+static void gab_ext_power_changed(struct power_supply *psy)
+{
+	struct gab *adc_bat = to_generic_bat(psy);
+
+	schedule_delayed_work(&adc_bat->bat_work, msecs_to_jiffies(0));
+}
+
+static const enum power_supply_property gab_props[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN,
+	POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN,
+	POWER_SUPPLY_PROP_CHARGE_NOW,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_TECHNOLOGY,
+	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
+	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
+	POWER_SUPPLY_PROP_MODEL_NAME,
+};
+
+/*
+ * This properties are set based on the received platform data and this
+ * should correspond one-to-one with enum chan_type.
+ */
+static const enum power_supply_property gab_dyn_props[] = {
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_POWER_NOW,
+};
+
+static bool gab_charge_finished(struct gab *adc_bat)
+{
+	struct gab_platform_data *pdata = adc_bat->pdata;
+	bool ret = gpio_get_value(pdata->gpio_charge_finished);
+	bool inv = pdata->gpio_inverted;
+
+	if (!gpio_is_valid(pdata->gpio_charge_finished))
+		return false;
+	return ret ^ inv;
+}
+
+static int gab_get_status(struct gab *adc_bat)
+{
+	struct gab_platform_data *pdata = adc_bat->pdata;
+	struct power_supply_info *bat_info;
+
+	bat_info = &pdata->battery_info;
+	if (adc_bat->level == bat_info->charge_full_design)
+		return POWER_SUPPLY_STATUS_FULL;
+	return adc_bat->status;
+}
+
+enum gab_chan_type gab_prop_to_chan(enum power_supply_property psp)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_POWER_NOW:
+		return GAB_POWER;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		return GAB_VOLTAGE;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		return GAB_CURRENT;
+	default:
+		WARN_ON(1);
+		break;
+	}
+	return GAB_POWER;
+}
+
+static int read_channel(struct gab *adc_bat, enum power_supply_property psp,
+		int *result)
+{
+	int ret;
+	int chan_index;
+
+	chan_index = gab_prop_to_chan(psp);
+	ret = iio_read_channel_processed(adc_bat->channel[chan_index],
+			result);
+	if (ret < 0)
+		pr_err("read channel error\n");
+	return ret;
+}
+
+static int gab_get_property(struct power_supply *psy,
+		enum power_supply_property psp, union power_supply_propval *val)
+{
+	struct gab *adc_bat;
+	struct gab_platform_data *pdata;
+	struct power_supply_info *bat_info;
+	int result = 0;
+	int ret = 0;
+
+	adc_bat = to_generic_bat(psy);
+	if (!adc_bat) {
+		dev_err(psy->dev, "no battery infos ?!\n");
+		return -EINVAL;
+	}
+	pdata = adc_bat->pdata;
+	bat_info = &pdata->battery_info;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		gab_get_status(adc_bat);
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_EMPTY_DESIGN:
+		val->intval = 0;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_NOW:
+		val->intval = pdata->cal_charge(result);
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+	case POWER_SUPPLY_PROP_POWER_NOW:
+		ret = read_channel(adc_bat, psp, &result);
+		if (ret < 0)
+			goto err;
+		val->intval = result;
+		break;
+	case POWER_SUPPLY_PROP_TECHNOLOGY:
+		val->intval = bat_info->technology;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
+		val->intval = bat_info->voltage_min_design;
+		break;
+	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
+		val->intval = bat_info->voltage_max_design;
+		break;
+	case POWER_SUPPLY_PROP_CHARGE_FULL_DESIGN:
+		val->intval = bat_info->charge_full_design;
+		break;
+	case POWER_SUPPLY_PROP_MODEL_NAME:
+		val->strval = bat_info->name;
+		break;
+	default:
+		return -EINVAL;
+	}
+err:
+	return ret;
+}
+
+static void gab_work(struct work_struct *work)
+{
+	struct gab *adc_bat;
+	struct gab_platform_data *pdata;
+	struct delayed_work *delayed_work;
+	bool is_plugged;
+	int status;
+
+	delayed_work = container_of(work, struct delayed_work, work);
+	adc_bat = container_of(delayed_work, struct gab, bat_work);
+	pdata = adc_bat->pdata;
+	status = adc_bat->status;
+
+	is_plugged = power_supply_am_i_supplied(&adc_bat->psy);
+	adc_bat->cable_plugged = is_plugged;
+
+	if (!is_plugged)
+		adc_bat->status =  POWER_SUPPLY_STATUS_DISCHARGING;
+	else if (gab_charge_finished(adc_bat))
+		adc_bat->status = POWER_SUPPLY_STATUS_NOT_CHARGING;
+	else
+		adc_bat->status = POWER_SUPPLY_STATUS_CHARGING;
+
+	if (status != adc_bat->status)
+		power_supply_changed(&adc_bat->psy);
+}
+
+static irqreturn_t gab_charged(int irq, void *dev_id)
+{
+	struct gab *adc_bat = dev_id;
+	struct gab_platform_data *pdata = adc_bat->pdata;
+	int delay;
+
+	delay = pdata->jitter_delay ? pdata->jitter_delay : JITTER_DEFAULT;
+	schedule_delayed_work(&adc_bat->bat_work,
+			msecs_to_jiffies(delay));
+	return IRQ_HANDLED;
+}
+
+static int __devinit gab_probe(struct platform_device *pdev)
+{
+	struct gab *adc_bat;
+	struct power_supply *psy;
+	struct gab_platform_data *pdata = pdev->dev.platform_data;
+	enum power_supply_property *properties;
+	int ret = 0;
+	int chan;
+	int index = 0;
+
+	adc_bat = devm_kzalloc(&pdev->dev, sizeof(*adc_bat), GFP_KERNEL);
+	if (!adc_bat) {
+		dev_err(&pdev->dev, "failed to allocate memory\n");
+		return -ENOMEM;
+	}
+
+	psy = &adc_bat->psy;
+	psy->name = pdata->battery_info.name;
+
+	/* bootup default values for the battery */
+	adc_bat->cable_plugged = false;
+	adc_bat->status = POWER_SUPPLY_STATUS_DISCHARGING;
+	psy->type = POWER_SUPPLY_TYPE_BATTERY;
+	psy->get_property = gab_get_property;
+	psy->external_power_changed = gab_ext_power_changed;
+	adc_bat->pdata = pdata;
+
+	/* calculate the total number of channels */
+	chan = ARRAY_SIZE(gab_chan_name);
+
+	/*
+	 * copying the static properties and allocating extra memory for holding
+	 * the extra configurable properties received from platform data.
+	 */
+	psy->properties = kcalloc(ARRAY_SIZE(gab_props) +
+					ARRAY_SIZE(gab_chan_name),
+					sizeof(*psy->properties), GFP_KERNEL);
+	if (!psy->properties) {
+		ret = -ENOMEM;
+		goto first_mem_fail;
+	}
+
+	memcpy(psy->properties, gab_props, sizeof(gab_props));
+	properties = psy->properties + sizeof(gab_props);
+
+	/*
+	 * getting channel from iio and copying the battery properties
+	 * based on the channel supported by consumer device.
+	 */
+	for (chan = 0; chan < ARRAY_SIZE(gab_chan_name); chan++) {
+		adc_bat->channel[chan] = iio_channel_get(dev_name(&pdev->dev),
+						gab_chan_name[chan]);
+		if (IS_ERR(adc_bat->channel[chan])) {
+			ret = PTR_ERR(adc_bat->channel[chan]);
+		} else {
+			/* copying properties for supported channels only */
+			memcpy(properties + sizeof(*(psy->properties)) * index,
+					&gab_dyn_props[chan],
+					sizeof(gab_dyn_props[chan]));
+			index++;
+		}
+	}
+
+	/* none of the channels are supported so let's bail out */
+	if (index == ARRAY_SIZE(gab_chan_name))
+		goto second_mem_fail;
+
+	/*
+	 * Total number of properties is equal to static properties
+	 * plus the dynamic properties.Some properties may not be set
+	 * as come channels may be not be supported by the device.So
+	 * we need to take care of that.
+	 */
+	psy->num_properties = ARRAY_SIZE(gab_props) + index;
+
+	ret = power_supply_register(&pdev->dev, psy);
+	if (ret)
+		goto err_reg_fail;
+
+	INIT_DELAYED_WORK(&adc_bat->bat_work, gab_work);
+
+	if (gpio_is_valid(pdata->gpio_charge_finished)) {
+		int irq;
+		ret = gpio_request(pdata->gpio_charge_finished, "charged");
+		if (ret)
+			goto gpio_req_fail;
+
+		irq = gpio_to_irq(pdata->gpio_charge_finished);
+		ret = request_any_context_irq(irq, gab_charged,
+				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
+				"battery charged", adc_bat);
+		if (ret)
+			goto err_gpio;
+	}
+
+	platform_set_drvdata(pdev, adc_bat);
+
+	/* Schedule timer to check current status */
+	schedule_delayed_work(&adc_bat->bat_work,
+			msecs_to_jiffies(0));
+	return 0;
+
+err_gpio:
+	gpio_free(pdata->gpio_charge_finished);
+gpio_req_fail:
+	power_supply_unregister(psy);
+err_reg_fail:
+	for (chan = 0; ARRAY_SIZE(gab_chan_name); chan++)
+		iio_channel_release(adc_bat->channel[chan]);
+second_mem_fail:
+	kfree(psy->properties);
+first_mem_fail:
+	return ret;
+}
+
+static int __devexit gab_remove(struct platform_device *pdev)
+{
+	int chan;
+	struct gab *adc_bat = platform_get_drvdata(pdev);
+	struct gab_platform_data *pdata = adc_bat->pdata;
+
+	power_supply_unregister(&adc_bat->psy);
+
+	if (gpio_is_valid(pdata->gpio_charge_finished)) {
+		free_irq(gpio_to_irq(pdata->gpio_charge_finished), adc_bat);
+		gpio_free(pdata->gpio_charge_finished);
+	}
+
+	for (chan = 0; ARRAY_SIZE(gab_chan_name); chan++)
+		iio_channel_release(adc_bat->channel[chan]);
+
+	kfree(adc_bat->psy.properties);
+	cancel_delayed_work(&adc_bat->bat_work);
+	return 0;
+}
+
+#ifdef CONFIG_PM
+static int gab_suspend(struct device *dev)
+{
+	struct gab *adc_bat = dev_get_drvdata(dev);
+
+	cancel_delayed_work_sync(&adc_bat->bat_work);
+	adc_bat->status = POWER_SUPPLY_STATUS_UNKNOWN;
+	return 0;
+}
+
+static int gab_resume(struct device *dev)
+{
+	struct gab *adc_bat = dev_get_drvdata(dev);
+	struct gab_platform_data *pdata = adc_bat->pdata;
+	int delay;
+
+	delay = pdata->jitter_delay ? pdata->jitter_delay : JITTER_DEFAULT;
+
+	/* Schedule timer to check current status */
+	schedule_delayed_work(&adc_bat->bat_work,
+			msecs_to_jiffies(delay));
+	return 0;
+}
+
+static const struct dev_pm_ops gab_pm_ops = {
+	.suspend        = gab_suspend,
+	.resume         = gab_resume,
+};
+
+#define GAB_PM_OPS       (&gab_pm_ops)
+#else
+#define GAB_PM_OPS       (NULL)
+#endif
+
+static struct platform_driver gab_driver = {
+	.driver		= {
+		.name	= "generic-adc-battery",
+		.owner	= THIS_MODULE,
+		.pm	= GAB_PM_OPS
+	},
+	.probe		= gab_probe,
+	.remove		= __devexit_p(gab_remove),
+};
+module_platform_driver(gab_driver);
+
+MODULE_AUTHOR("anish kumar <anish198519851985@...il.com>");
+MODULE_DESCRIPTION("generic battery driver using IIO");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/power/generic-adc-battery.h b/include/linux/power/generic-adc-battery.h
new file mode 100644
index 0000000..b1ebe08
--- /dev/null
+++ b/include/linux/power/generic-adc-battery.h
@@ -0,0 +1,29 @@
+/*
+ * Copyright (C) 2012, Anish Kumar <anish198519851985@...il.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.
+ */
+
+#ifndef GENERIC_ADC_BATTERY_H
+#define GENERIC_ADC_BATTERY_H
+
+/**
+ * struct gab_platform_data - platform_data for generic adc iio battery driver.
+ * @battery_info:         recommended structure to specify static power supply
+ *			   parameters
+ * @cal_charge:           calculate charge level.
+ * @gpio_charge_finished: gpio for the charger.
+ * @gpio_inverted:        Should be 1 if the GPIO is active low otherwise 0
+ * @jitter_delay:         delay required after the interrupt to check battery
+ *			  status.Default set is 10ms.
+ */
+struct gab_platform_data {
+	struct power_supply_info battery_info;
+	int	(*cal_charge)(long value);
+	int	gpio_charge_finished;
+	bool	gpio_inverted;
+	int     jitter_delay;
+};
+
+#endif /* GENERIC_ADC_BATTERY_H */
-- 
1.7.1

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