Re: [PATCH] Add support for power_supply on tosa

[Anton Vorontsov <cbouatmailru@gmail.com>]

On Fri, Jun 20, 2008 at 12:49:17PM +0400, Dmitry Baryshkov wrote:
> Support the battery management on Sharp Zaurus SL-6000.
> 
> This patch depends on the tc6393xb support as found in the arm:devel
> or linux-next trees.
> 
> Signed-off-by: Dmitry Baryshkov <dbaryshkov@gmail.com>
> ---

On Sun, Jun 22, 2008 at 07:21:09PM +0400, Dmitry Baryshkov wrote:
> Any comments on this? As this driver is protected by necessary
> dependencies in Kconfig, it can be merged even now.

Thanks for the patch and sorry for the delayed review. Few comments
below.

>  drivers/power/Kconfig        |    7 +
>  drivers/power/Makefile       |    1 +
>  drivers/power/tosa_battery.c |  485 ++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 493 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/power/tosa_battery.c
> 
> diff --git a/drivers/power/Kconfig b/drivers/power/Kconfig
> index 58c806e..e3a9c37 100644
> --- a/drivers/power/Kconfig
> +++ b/drivers/power/Kconfig
> @@ -49,4 +49,11 @@ config BATTERY_OLPC
>  	help
>  	  Say Y to enable support for the battery on the OLPC laptop.
>  
> +config BATTERY_TOSA
> +	tristate "Sharp SL-6000 (tosa) battery"
> +	depends on MACH_TOSA && MFD_TC6393XB
> +	help
> +	  Say Y to enable support for the battery on the Sharp Zaurus
> +	  SL-6000 (tosa) models.
> +
>  endif # POWER_SUPPLY
> diff --git a/drivers/power/Makefile b/drivers/power/Makefile
> index 6413ded..1e408fa 100644
> --- a/drivers/power/Makefile
> +++ b/drivers/power/Makefile
> @@ -20,3 +20,4 @@ obj-$(CONFIG_APM_POWER)		+= apm_power.o
>  obj-$(CONFIG_BATTERY_DS2760)	+= ds2760_battery.o
>  obj-$(CONFIG_BATTERY_PMU)	+= pmu_battery.o
>  obj-$(CONFIG_BATTERY_OLPC)	+= olpc_battery.o
> +obj-$(CONFIG_BATTERY_TOSA)	+= tosa_battery.o
> diff --git a/drivers/power/tosa_battery.c b/drivers/power/tosa_battery.c
> new file mode 100644
> index 0000000..7a99203
> --- /dev/null
> +++ b/drivers/power/tosa_battery.c
> @@ -0,0 +1,485 @@
> +/*
> + * Battery and Power Management code for the Sharp SL-6000x
> + *
> + * Copyright (c) 2005 Dirk Opfer
> + * Copyright (c) 2008 Dmitry Baryshkov
> + *
> + * 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/kernel.h>
> +#include <linux/module.h>
> +#include <linux/power_supply.h>
> +#include <linux/wm97xx.h>
> +#include <linux/delay.h>
> +#include <linux/spinlock.h>
> +#include <linux/interrupt.h>
> +#include <linux/gpio.h>
> +
> +#include <asm/mach-types.h>
> +#include <asm/arch/tosa.h>
> +
> +static DEFINE_MUTEX(bat_lock); /* protects gpio pins */
> +static struct work_struct bat_work;
> +
> +struct tosa_bat {
> +	int status;
> +	struct power_supply psy;
> +	int full_chrg;
> +
> +	struct mutex work_lock; /* protects data */
> +
> +	bool (*is_present)(struct tosa_bat *bat);
> +	int gpio_full;
> +	int gpio_charge_off;
> +
> +	int technology;
> +
> +	int gpio_bat;
> +	int adc_bat;
> +	int adc_bat_divider;
> +	int bat_max;
> +	int bat_min;
> +
> +	int gpio_temp;
> +	int adc_temp;
> +	int adc_temp_divider;
> +};
> +
> +static struct tosa_bat tosa_bat_main;
> +static struct tosa_bat tosa_bat_jacket;
> +
> +static unsigned long tosa_read_bat(struct tosa_bat *bat)
> +{
> +	unsigned long value = 0;
> +
> +	if (bat->gpio_bat < 0 || bat->adc_bat < 0)
> +		return 0;
> +
> +	mutex_lock(&bat_lock);
> +	gpio_set_value(bat->gpio_bat, 1);
> +	mdelay(5);

msleep() can be used here.

> +	value = wm97xx_read_aux_adc(bat->psy.dev->parent->driver_data,
> +			bat->adc_bat);
> +	gpio_set_value(bat->gpio_bat, 0);
> +	mutex_unlock(&bat_lock);
> +
> +	value = value * 1000000 / bat->adc_bat_divider;
> +
> +	return value;
> +}
> +
> +static unsigned long tosa_read_temp(struct tosa_bat *bat)
> +{
> +	unsigned long value = 0;
> +
> +	if (bat->gpio_temp < 0 || bat->adc_temp < 0)
> +		return 0;
> +
> +	mutex_lock(&bat_lock);
> +	gpio_set_value(bat->gpio_temp, 1);
> +	mdelay(5);

Ditto.

> +	value = wm97xx_read_aux_adc(bat->psy.dev->parent->driver_data,
> +			bat->adc_temp);
> +	gpio_set_value(bat->gpio_temp, 0);
> +	mutex_unlock(&bat_lock);
> +
> +	value = value * 10000 / bat->adc_temp_divider;
> +
> +	return value;
> +}
> +
> +static int tosa_bat_get_property(struct power_supply *psy,
> +			    enum power_supply_property psp,
> +			    union power_supply_propval *val)
> +{
> +	int ret = 0;
> +	struct tosa_bat *bat = container_of(psy, struct tosa_bat, psy);
> +
> +	if (bat->is_present && !bat->is_present(bat)
> +			&& psp != POWER_SUPPLY_PROP_PRESENT) {
> +		return -ENODEV;
> +	}
> +
> +	switch (psp) {
> +	case POWER_SUPPLY_PROP_STATUS:
> +		val->intval = bat->status;
> +		break;
> +	case POWER_SUPPLY_PROP_TECHNOLOGY:
> +		val->intval = bat->technology;
> +		break;
> +	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
> +		val->intval = tosa_read_bat(bat);
> +		break;
> +	case POWER_SUPPLY_PROP_VOLTAGE_MAX:
> +		if (bat->full_chrg == -1)
> +			val->intval = bat->bat_max;
> +		else
> +			val->intval = bat->full_chrg;
> +		break;
> +	case POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN:
> +		val->intval = bat->bat_max;
> +		break;
> +	case POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN:
> +		val->intval = bat->bat_min;
> +		break;
> +	case POWER_SUPPLY_PROP_TEMP:
> +		val->intval = tosa_read_temp(bat);
> +		break;
> +	case POWER_SUPPLY_PROP_PRESENT:
> +		val->intval = bat->is_present ? bat->is_present(bat) : 1;
> +		break;
> +	default:
> +		ret = -EINVAL;
> +		break;
> +	}
> +	return ret;
> +}
> +
> +static bool tosa_jacket_bat_is_present(struct tosa_bat *bat)
> +{
> +	return gpio_get_value(TOSA_GPIO_JACKET_DETECT) == 0;
> +}
> +
> +static void tosa_bat_external_power_changed(struct power_supply *psy)
> +{
> +	schedule_work(&bat_work);
> +}
> +
> +static irqreturn_t tosa_bat_gpio_isr(int irq, void *data)
> +{
> +	printk(KERN_ERR "bat_gpio irq: %d\n", gpio_get_value(irq_to_gpio(irq)));

Are you sure that this needs KERN_ERR?

> +	schedule_work(&bat_work);
> +	return IRQ_HANDLED;
> +}
> +
> +static char *status_text[] = {
> +	[POWER_SUPPLY_STATUS_UNKNOWN] =		"Unknown",
> +	[POWER_SUPPLY_STATUS_CHARGING] =	"Charging",
> +	[POWER_SUPPLY_STATUS_DISCHARGING] =	"Discharging",
> +	[POWER_SUPPLY_STATUS_NOT_CHARGING] =	"Not charging",
> +	[POWER_SUPPLY_STATUS_FULL] =		"Full",
> +};
> +
> +static void tosa_bat_update(struct tosa_bat *bat)
> +{
> +	int old;
> +	struct power_supply *psy = &bat->psy;
> +
> +	mutex_lock(&bat->work_lock);
> +
> +	old = bat->status;
> +
> +	if (bat->is_present && !bat->is_present(bat)) {
> +		printk(KERN_NOTICE "%s not present\n", psy->name);
> +		bat->status = POWER_SUPPLY_STATUS_NOT_CHARGING;

NOT_CHARGING is an error (usually), e.g. not charging because battery is
broken. In case of absent battery, status should be STATUS_UNKNOWN.

(..I should document that.)

> +		bat->full_chrg = -1;
> +	} else if (power_supply_am_i_supplied(psy)) {
> +		if (bat->status == POWER_SUPPLY_STATUS_DISCHARGING) {
> +			gpio_set_value(bat->gpio_charge_off, 0);
> +			mdelay(15);
> +		}
> +
> +		if (gpio_get_value(bat->gpio_full)) {
> +			if (old == POWER_SUPPLY_STATUS_CHARGING ||
> +					bat->full_chrg == -1)
> +				bat->full_chrg = tosa_read_bat(bat);
> +
> +			gpio_set_value(bat->gpio_charge_off, 1);
> +			bat->status = POWER_SUPPLY_STATUS_FULL;
> +		} else {
> +			gpio_set_value(bat->gpio_charge_off, 0);
> +			bat->status = POWER_SUPPLY_STATUS_CHARGING;
> +		}
> +	} else {
> +		gpio_set_value(bat->gpio_charge_off, 1);
> +		bat->status = POWER_SUPPLY_STATUS_DISCHARGING;
> +	}
> +
> +	if (old != bat->status) {
> +		printk(KERN_NOTICE "%s %s -> %s\n", psy->name,
> +				status_text[old],
> +				status_text[bat->status]);

Not sure if printing the notice for every status change is a good
idea...

If removed, we could also remove static char *status_text[]. :-)

> +		power_supply_changed(psy);
> +	}
> +
> +	mutex_unlock(&bat->work_lock);
> +}
> +
> +static void tosa_bat_work(struct work_struct *work)
> +{
> +	tosa_bat_update(&tosa_bat_main);
> +	tosa_bat_update(&tosa_bat_jacket);
> +}
> +
> +
> +static enum power_supply_property tosa_bat_main_props[] = {
> +	POWER_SUPPLY_PROP_STATUS,
> +	POWER_SUPPLY_PROP_TECHNOLOGY,
> +	POWER_SUPPLY_PROP_VOLTAGE_NOW,
> +	POWER_SUPPLY_PROP_VOLTAGE_MAX,
> +	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
> +	POWER_SUPPLY_PROP_TEMP,
> +	POWER_SUPPLY_PROP_PRESENT,
> +};
> +
> +static enum power_supply_property tosa_bat_bu_props[] = {
> +	POWER_SUPPLY_PROP_STATUS,
> +	POWER_SUPPLY_PROP_TECHNOLOGY,
> +	POWER_SUPPLY_PROP_VOLTAGE_MIN_DESIGN,
> +	POWER_SUPPLY_PROP_VOLTAGE_NOW,
> +	POWER_SUPPLY_PROP_VOLTAGE_MAX_DESIGN,
> +	POWER_SUPPLY_PROP_PRESENT,
> +};
> +
> +static struct tosa_bat tosa_bat_main = {
> +	.status = POWER_SUPPLY_STATUS_DISCHARGING,
> +	.full_chrg = -1,
> +	.psy = {
> +		.name		= "main-battery",
> +		.type		= POWER_SUPPLY_TYPE_BATTERY,
> +		.properties	= tosa_bat_main_props,
> +		.num_properties	= ARRAY_SIZE(tosa_bat_main_props),
> +		.get_property	= tosa_bat_get_property,
> +		.external_power_changed = tosa_bat_external_power_changed,
> +		.use_for_apm	= 1,
> +	},
> +
> +	.gpio_full = TOSA_GPIO_BAT0_CRG,
> +	.gpio_charge_off = TOSA_GPIO_CHARGE_OFF,
> +
> +	.technology = POWER_SUPPLY_TECHNOLOGY_LIPO,
> +
> +	.gpio_bat = TOSA_GPIO_BAT0_V_ON,
> +	.adc_bat = WM97XX_AUX_ID3,
> +	.adc_bat_divider = 414,
> +	.bat_max = 4310000,
> +	.bat_min = 1551 * 1000000 / 414,
> +
> +	.gpio_temp = TOSA_GPIO_BAT1_TH_ON,
> +	.adc_temp = WM97XX_AUX_ID2,
> +	.adc_temp_divider = 10000,
> +};
> +
> +static struct tosa_bat tosa_bat_jacket = {
> +	.status = POWER_SUPPLY_STATUS_DISCHARGING,
> +	.full_chrg = -1,
> +	.psy = {
> +		.name		= "jacket-battery",
> +		.type		= POWER_SUPPLY_TYPE_BATTERY,
> +		.properties	= tosa_bat_main_props,
> +		.num_properties	= ARRAY_SIZE(tosa_bat_main_props),
> +		.get_property	= tosa_bat_get_property,
> +		.external_power_changed = tosa_bat_external_power_changed,
> +	},
> +
> +	.is_present = tosa_jacket_bat_is_present,
> +	.gpio_full = TOSA_GPIO_BAT1_CRG,
> +	.gpio_charge_off = TOSA_GPIO_CHARGE_OFF_JC,
> +
> +	.technology = POWER_SUPPLY_TECHNOLOGY_LIPO,
> +
> +	.gpio_bat = TOSA_GPIO_BAT1_V_ON,
> +	.adc_bat = WM97XX_AUX_ID3,
> +	.adc_bat_divider = 414,
> +	.bat_max = 4310000,
> +	.bat_min = 1551 * 1000000 / 414,
> +
> +	.gpio_temp = TOSA_GPIO_BAT0_TH_ON,
> +	.adc_temp = WM97XX_AUX_ID2,
> +	.adc_temp_divider = 10000,
> +};
> +
> +static struct tosa_bat tosa_bat_bu = {
> +	.status = POWER_SUPPLY_STATUS_UNKNOWN,
> +	.full_chrg = -1,
> +
> +	.psy = {
> +		.name		= "backup-battery",
> +		.type		= POWER_SUPPLY_TYPE_BATTERY,
> +		.properties	= tosa_bat_bu_props,
> +		.num_properties	= ARRAY_SIZE(tosa_bat_bu_props),
> +		.get_property	= tosa_bat_get_property,
> +		.external_power_changed = tosa_bat_external_power_changed,
> +	},
> +
> +	.gpio_full = -1,
> +	.gpio_charge_off = -1,
> +
> +	.technology = POWER_SUPPLY_TECHNOLOGY_LiMn,
> +
> +	.gpio_bat = TOSA_GPIO_BU_CHRG_ON,
> +	.adc_bat = WM97XX_AUX_ID4,
> +	.adc_bat_divider = 1266,
> +
> +	.gpio_temp = -1,
> +	.adc_temp = -1,
> +	.adc_temp_divider = -1,
> +};
> +
> +static struct {
> +	int gpio;
> +	char *name;
> +	bool output;
> +	int value;
> +} gpios[] = {
> +	{ TOSA_GPIO_CHARGE_OFF,		"main charge off",	1, 1 },
> +	{ TOSA_GPIO_CHARGE_OFF_JC,	"jacket charge off",	1, 1 },
> +	{ TOSA_GPIO_BAT_SW_ON,		"battery switch",	1, 0 },
> +	{ TOSA_GPIO_BAT0_V_ON,		"main battery",		1, 0 },
> +	{ TOSA_GPIO_BAT1_V_ON,		"jacket battery",	1, 0 },
> +	{ TOSA_GPIO_BAT1_TH_ON,		"main battery temp",	1, 0 },
> +	{ TOSA_GPIO_BAT0_TH_ON,		"jacket battery temp",	1, 0 },
> +	{ TOSA_GPIO_BU_CHRG_ON,		"backup battery",	1, 0 },
> +	{ TOSA_GPIO_BAT0_CRG,		"main battery full",	0, 0 },
> +	{ TOSA_GPIO_BAT1_CRG,		"jacket battery full",	0, 0 },
> +	{ TOSA_GPIO_BAT0_LOW,		"main battery low",	0, 0 },
> +	{ TOSA_GPIO_BAT1_LOW,		"jacket battery low",	0, 0 },
> +	{ TOSA_GPIO_JACKET_DETECT,	"jacket detect",	0, 0 },
> +};
> +
> +#ifdef CONFIG_PM
> +static int tosa_bat_suspend(struct platform_device *dev, pm_message_t state)
> +{
> +	/* do nothing */
> +	flush_scheduled_work();

The comment is contradictory. It would be better if it explained why we
want to flush scheduled work on suspend.

> +	return 0;
> +}
> +
> +static int tosa_bat_resume(struct platform_device *dev)
> +{
> +	schedule_work(&bat_work);
> +	return 0;
> +}
> +#else
> +#define tosa_bat_suspend NULL
> +#define tosa_bat_resume NULL
> +#endif
> +
> +static int __devinit tosa_bat_probe(struct platform_device *dev)
> +{
> +	int ret;
> +	int i;
> +
> +	if (!machine_is_tosa())
> +		return -ENODEV;
> +
> +	for (i = 0; i < ARRAY_SIZE(gpios); i++) {
> +		ret = gpio_request(gpios[i].gpio, gpios[i].name);
> +		if (ret) {
> +			i--;
> +			goto err_gpio;
> +		}
> +
> +		if (gpios[i].output)
> +			ret = gpio_direction_output(gpios[i].gpio,
> +					gpios[i].value);
> +		else
> +			ret = gpio_direction_input(gpios[i].gpio);
> +
> +		if (ret)
> +			goto err_gpio;
> +	}
> +
> +	mutex_init(&tosa_bat_main.work_lock);
> +	mutex_init(&tosa_bat_jacket.work_lock);
> +
> +	INIT_WORK(&bat_work, tosa_bat_work);
> +
> +	ret = power_supply_register(&dev->dev, &tosa_bat_main.psy);
> +	if (ret)
> +		goto err_psy_reg_main;
> +	ret = power_supply_register(&dev->dev, &tosa_bat_jacket.psy);
> +	if (ret)
> +		goto err_psy_reg_jacket;
> +	ret = power_supply_register(&dev->dev, &tosa_bat_bu.psy);
> +	if (ret)
> +		goto err_psy_reg_bu;
> +
> +	ret = request_irq(gpio_to_irq(TOSA_GPIO_BAT0_CRG),
> +				tosa_bat_gpio_isr,
> +				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
> +				"main full", &tosa_bat_main);
> +	if (ret)
> +		goto err_req_main;
> +
> +	ret = request_irq(gpio_to_irq(TOSA_GPIO_BAT1_CRG),
> +				tosa_bat_gpio_isr,
> +				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
> +				"jacket full", &tosa_bat_jacket);
> +	if (ret)
> +		goto err_req_jacket;
> +
> +	ret = request_irq(gpio_to_irq(TOSA_GPIO_JACKET_DETECT),
> +				tosa_bat_gpio_isr,
> +				IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
> +				"jacket detect", &tosa_bat_jacket);
> +	if (!ret) {
> +		schedule_work(&bat_work);
> +		return 0;
> +	}
> +
> +	free_irq(gpio_to_irq(TOSA_GPIO_BAT1_CRG), &tosa_bat_jacket);
> +err_req_jacket:
> +	free_irq(gpio_to_irq(TOSA_GPIO_BAT0_CRG), &tosa_bat_main);
> +err_req_main:
> +	power_supply_unregister(&tosa_bat_bu.psy);
> +err_psy_reg_bu:
> +	power_supply_unregister(&tosa_bat_jacket.psy);
> +err_psy_reg_jacket:
> +	power_supply_unregister(&tosa_bat_main.psy);
> +err_psy_reg_main:
> +
> +	i--;
> +err_gpio:
> +	for (; i >= 0; i--)
> +		gpio_free(gpios[i].gpio);
> +
> +	return ret;
> +}
> +
> +static int __devexit tosa_bat_remove(struct platform_device *dev)
> +{
> +	int i;
> +
> +	free_irq(gpio_to_irq(TOSA_GPIO_JACKET_DETECT), &tosa_bat_jacket);
> +	free_irq(gpio_to_irq(TOSA_GPIO_BAT1_CRG), &tosa_bat_jacket);
> +	free_irq(gpio_to_irq(TOSA_GPIO_BAT0_CRG), &tosa_bat_main);
> +
> +	power_supply_unregister(&tosa_bat_bu.psy);
> +	power_supply_unregister(&tosa_bat_jacket.psy);
> +	power_supply_unregister(&tosa_bat_main.psy);

Because scheduled work doing tosa_bat_update() for both
tosa_bat_main and tosa_bat_jacket, such unregistering is racy. :-/

flush_scheduled_work() will not work because external_power_changed
callback might reschedule the work again.

This isn't trivial to fix, so if you don't want to fix this for now,
I think just TODO: or FIXME: ... comment will work.

> +	for (i = ARRAY_SIZE(gpios) - 1; i >= 0; i--)
> +		gpio_free(gpios[i].gpio);
> +
> +	return 0;
> +}
> +
> +static struct platform_driver tosa_bat_driver = {
> +	.driver.name	= "wm97xx-battery",
> +	.driver.owner	= THIS_MODULE,
> +	.probe		= tosa_bat_probe,
> +	.remove		= __devexit_p(tosa_bat_remove),
> +	.suspend	= tosa_bat_suspend,
> +	.resume		= tosa_bat_resume,
> +};
> +
> +static int __init tosa_bat_init(void)
> +{
> +	return platform_driver_register(&tosa_bat_driver);
> +}
> +
> +static void __exit tosa_bat_exit(void)
> +{
> +	platform_driver_unregister(&tosa_bat_driver);
> +}
> +
> +module_init(tosa_bat_init);
> +module_exit(tosa_bat_exit);
> +
> +MODULE_LICENSE("GPL");
> +MODULE_AUTHOR("Dmitry Baryshkov");
> +MODULE_DESCRIPTION("Tosa battery driver");
> -- 
> 1.5.5.3

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