Message-ID: <20120921225221.GA26715@lizard>
Date:	Fri, 21 Sep 2012 15:52:21 -0700
From:	Anton Vorontsov <cbouatmailru@...il.com>
To:	anish kumar <anish198519851985@...il.com>
Cc:	dwmw2@...radead.org, lars@...afoo.de, jic23@....ac.uk,
	linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org
Subject: Re: [PATCH] [V3]power: battery: Generic battery driver using IIO

On Fri, Sep 21, 2012 at 09:40:14PM +0530, anish kumar wrote:
> 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 the commit message itself it usually good idea to write a short
description for the patch: the rationale behind the driver. Just a few
sentences will work.

And changelog usually goes below the "---" separator, as we don't want it
in the commit log ("git am" command ignores anything below "---").

> 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>
> ---

OK, I belive it is good enough, and as it depends on IIO changes,
I believe now it's IIO maintainer's worry to pick it up. :-)

Acked-by: Anton Vorontsov <cbouatmailru@...il.com>

Thanks a lot for your work!

>  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;

bat_info can also go into the initializer.

> +	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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