Date:	Thu, 21 Oct 2010 18:14:07 +0400
From:	Anton Vorontsov <cbouatmailru@...il.com>
To:	Lars-Peter Clausen <lars@...afoo.de>
Cc:	rklein@...dia.com, broonie@...nsource.wolfsonmicro.com,
	achew@...dia.com, olof@...om.net, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] POWER: Add gpio chager driver

On Thu, Oct 21, 2010 at 02:25:57PM +0200, Lars-Peter Clausen wrote:
> This patch adds a simple driver for chargers indicating their online status
> through a GPIO pin.
> 
> Signed-off-by: Lars-Peter Clausen <lars@...afoo.de>

I agree, the GPIO name fits better. Rhyland, are you OK with that
driver, does it fit your needs?

Some comments down below.

[...]
> +struct gpio_charger {
> +	const struct gpio_charger_platform_data *pdata;
> +	int irq;

This can be unsigned.

> +
> +	struct power_supply charger;
> +};
> +
> +static irqreturn_t gpio_charger_irq(int irq, void *devid)
> +{
> +	struct power_supply *charger = devid;

Please add an empty line here.

> +	power_supply_changed(charger);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static inline struct gpio_charger *psy_to_gpio_charger(struct power_supply *psy)
> +{
> +	return container_of(psy, struct gpio_charger, charger);
> +}
> +
> +static int gpio_charger_get_property(struct power_supply *psy,
> +	enum power_supply_property psp, union power_supply_propval *val)

One more tab for here?

> +{
> +	struct gpio_charger *gpio_charger = psy_to_gpio_charger(psy);
> +	const struct gpio_charger_platform_data *pdata = gpio_charger->pdata;
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_ONLINE:
> +		val->intval = gpio_get_value(pdata->gpio);
> +		val->intval ^= pdata->gpio_active_low;
> +		break;
> +	default:
> +		return -EINVAL;
> +	}
> +
> +	return 0;
> +}
> +
> +static enum power_supply_property gpio_charger_properties[] = {
> +	POWER_SUPPLY_PROP_ONLINE,
> +};
> +
> +static int __devinit gpio_charger_probe(struct platform_device *pdev)
> +{
> +	const struct gpio_charger_platform_data *pdata = pdev->dev.platform_data;
> +	struct gpio_charger *gpio_charger;
> +	struct power_supply *charger;
> +	int ret;
> +
> +	if (!pdata) {
> +		dev_err(&pdev->dev, "No platform data");
> +		return -EINVAL;
> +	}
> +
> +	if (!gpio_is_valid(pdata->gpio)) {
> +		dev_err(&pdev->dev, "Invalid gpio pin\n");
> +		return -EINVAL;
> +	}
> +
> +	gpio_charger = kzalloc(sizeof(*gpio_charger), GFP_KERNEL);
> +
> +	charger = &gpio_charger->charger;
> +
> +	charger->name = pdata->name;
> +	charger->type = pdata->type;
> +	charger->properties = gpio_charger_properties;
> +	charger->num_properties = ARRAY_SIZE(gpio_charger_properties);
> +	charger->get_property  = gpio_charger_get_property;
> +	charger->supplied_to = pdata->supplied_to;
> +	charger->num_supplicants = pdata->num_supplicants;
> +
> +	ret = gpio_request(pdata->gpio, dev_name(&pdev->dev));
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to request gpio pin: %d\n", ret);
> +		goto err_free;
> +	}
> +	ret = gpio_direction_input(pdata->gpio);
> +	if (ret) {
> +		dev_err(&pdev->dev, "Failed to set gpio to input: %d\n", ret);
> +		goto err_gpio_free;
> +	}
> +
> +	gpio_charger->irq = gpio_to_irq(pdata->gpio);
> +	if (gpio_charger->irq >= 0) {

0 isn't valid IRQ number. The check should be just 'if (gpio_charger->irq)'.

> +		ret = request_irq(gpio_charger->irq, gpio_charger_irq,
> +				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
> +				dev_name(&pdev->dev), charger);
> +		if (ret) {
> +			dev_warn(&pdev->dev, "Failed to request gpio irq: %d\n", ret);
> +			gpio_charger->irq = -1;
> +		}
> +	}
> +
> +	gpio_charger->pdata = pdata;
> +
> +	ret = power_supply_register(&pdev->dev, charger);
> +	if (ret < 0) {
> +		dev_err(&pdev->dev, "Failed to register power supply: %d\n", ret);
> +		goto err_irq_free;
> +	}
> +
> +	platform_set_drvdata(pdev, gpio_charger);
> +
> +	return 0;
> +
> +err_irq_free:
> +	if (gpio_charger->irq >= 0)
> +		free_irq(gpio_charger->irq, charger);
> +err_gpio_free:
> +	gpio_free(pdata->gpio);
> +err_free:
> +	kfree(gpio_charger);
> +	return ret;
> +}
> +
> +static int __devexit gpio_charger_remove(struct platform_device *pdev)
> +{
> +	struct gpio_charger *gpio_charger = platform_get_drvdata(pdev);
> +	const struct gpio_charger_platform_data *pdata = gpio_charger->pdata;
> +
> +	power_supply_unregister(&gpio_charger->charger);
> +
> +	if (gpio_charger->irq >= 0)
> +		free_irq(gpio_charger->irq, &gpio_charger->charger);
> +	gpio_free(pdata->gpio);
> +
> +	platform_set_drvdata(pdev, NULL);
> +	kfree(gpio_charger);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver  gpio_charger_driver = {
> +	.probe = gpio_charger_probe,
> +	.remove = __devexit_p(gpio_charger_remove),
> +	.driver = {
> +		.name = "gpio-charger",
> +		.owner = THIS_MODULE,
> +	},
> +};
> +
> +static int __init gpio_charger_init(void)
> +{
> +	return platform_driver_register(&gpio_charger_driver);
> +}
> +module_init(gpio_charger_init);
> +
> +static void __exit gpio_charger_exit(void)
> +{
> +	platform_driver_unregister(&gpio_charger_driver);
> +}
> +module_exit(gpio_charger_exit);
> +
> +MODULE_AUTHOR("Lars-Peter Clausen <lars@...afoo.de>");
> +MODULE_DESCRIPTION("Driver for chargers which report their online status through a GPIO");
> +MODULE_LICENSE("GPL");
> +MODULE_ALIAS("platform:gpio-charger");
> diff --git a/include/linux/power/gpio-charger.h b/include/linux/power/gpio-charger.h
> new file mode 100644
> index 0000000..404d5e6
> --- /dev/null
> +++ b/include/linux/power/gpio-charger.h
> @@ -0,0 +1,39 @@
> +/*
> + *  Copyright (C) 2010, Lars-Peter Clausen <lars@...afoo.de>
> + *
> + *  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.
> + *
> + *  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.,
> + *  675 Mass Ave, Cambridge, MA 02139, USA.
> + *
> + */
> +
> +#ifndef __LINUX_POWER_GPIO_CHARGER_H__
> +#define __LINUX_POWER_GPIO_CHARGER_H__
> +
> +/*

Should be /**

> + * struct gpio_charger_platform_data - platform_data for gpio_charger devices
> + * @name:		Name for the chargers power_supply device
> + * @type:		Type of the charger
> + * @gpio:		GPIO which is used to indicate the chargers status
> + * @gpio_active_low:	Should be set to 1 if the GPIO is active low otherwise 0
> + * @supplied_to:	Array of battery names to which this chargers supplies power
> + * @num_supplicants:	Number of entries in the supplied_to array
> + */
> +

No need for this empty line.

> +struct gpio_charger_platform_data {
> +	const char *name;
> +	enum power_supply_type type;

#include <linux/power_supply.h> is needed for this.

> +
> +	int gpio;
> +	int gpio_active_low;
> +
> +	char **supplied_to;
> +	size_t num_supplicants;

And #include <linux/types.h> for this.

> +};
> +
> +#endif

Thanks!

-- 
Anton Vorontsov
email: cbouatmailru@...il.com
irc://irc.freenode.net/bd2
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