linux-kernel - Re: [PATCH] power_supply: add CHARGE_COUNTER property and olpc

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Date:	Tue, 13 May 2008 12:42:14 +0400
From:	Anton Vorontsov <cbouatmailru@...il.com>
To:	Andres Salomon <dilinger@...ued.net>
Cc:	richard@...top.org, avorontsov@...mvista.com,
	Andrew Morton <akpm@...ux-foundation.org>,
	linux-kernel@...r.kernel.org, dwmw2@...radead.org
Subject: Re: [PATCH] power_supply: add CHARGE_COUNTER property and
	olpc_battery support for it

On Mon, May 12, 2008 at 09:46:29PM -0400, Andres Salomon wrote:
[...]
> From: Andres Salomon <dilinger@...ian.org>
> 
> This adds PROP_CHARGE_COUNTER to the power supply class (documenting it
> as well).  The OLPC battery driver uses this for spitting out its ACR
> values (in uAh).  We have some rounding errors (the data sheet claims
> 416.7, the math actually works out to 416.666667, so we're forced to
> choose between overflows or precision loss.  I chose precision loss,
> and stuck w/ data sheet values), but I don't think anyone will care
> that much.

Applied to battery-2.6.git, thanks.

And another thanks for keeping documentation in sync. :-)

> Signed-off-by: Andres Salomon <dilinger@...ian.org>
> ---
>  Documentation/power/power_supply_class.txt |    4 ++++
>  drivers/power/olpc_battery.c               |   11 ++++++++++-
>  drivers/power/power_supply_sysfs.c         |    1 +
>  include/linux/power_supply.h               |    1 +
>  4 files changed, 16 insertions(+), 1 deletions(-)
> 
> diff --git a/Documentation/power/power_supply_class.txt b/Documentation/power/power_supply_class.txt
> index a8686e5..c6cd495 100644
> --- a/Documentation/power/power_supply_class.txt
> +++ b/Documentation/power/power_supply_class.txt
> @@ -101,6 +101,10 @@ of charge when battery became full/empty". It also could mean "value of
>  charge when battery considered full/empty at given conditions (temperature,
>  age)". I.e. these attributes represents real thresholds, not design values.
>  
> +CHARGE_COUNTER - the current charge counter (in µAh).  This could easily
> +be negative; there is no empty or full value.  It is only useful for
> +relative, time-based measurements.
> +
>  ENERGY_FULL, ENERGY_EMPTY - same as above but for energy.
>  
>  CAPACITY - capacity in percents.
> diff --git a/drivers/power/olpc_battery.c b/drivers/power/olpc_battery.c
> index e3f6ec8..a928165 100644
> --- a/drivers/power/olpc_battery.c
> +++ b/drivers/power/olpc_battery.c
> @@ -19,7 +19,7 @@
>  
>  #define EC_BAT_VOLTAGE	0x10	/* uint16_t,	*9.76/32,    mV   */
>  #define EC_BAT_CURRENT	0x11	/* int16_t,	*15.625/120, mA   */
> -#define EC_BAT_ACR	0x12
> +#define EC_BAT_ACR	0x12	/* int16_t,	*416.7,      µAh  */
>  #define EC_BAT_TEMP	0x13	/* uint16_t,	*100/256,   °C  */
>  #define EC_AMB_TEMP	0x14	/* uint16_t,	*100/256,   °C  */
>  #define EC_BAT_STATUS	0x15	/* uint8_t,	bitmask */
> @@ -289,6 +289,14 @@ static int olpc_bat_get_property(struct power_supply *psy,
>  		ec_word = be16_to_cpu(ec_word);
>  		val->intval = ec_word * 100 / 256;
>  		break;
> +	case POWER_SUPPLY_PROP_CHARGE_COUNTER:
> +		ret = olpc_ec_cmd(EC_BAT_ACR, NULL, 0, (void *)&ec_word, 2);
> +		if (ret)
> +			return ret;
> +
> +		ec_word = be16_to_cpu(ec_word);
> +		val->intval = ec_word * 4167 / 10;
> +		break;
>  	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
>  		ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);
>  		if (ret)
> @@ -317,6 +325,7 @@ static enum power_supply_property olpc_bat_props[] = {
>  	POWER_SUPPLY_PROP_TEMP_AMBIENT,
>  	POWER_SUPPLY_PROP_MANUFACTURER,
>  	POWER_SUPPLY_PROP_SERIAL_NUMBER,
> +	POWER_SUPPLY_PROP_CHARGE_COUNTER,
>  };
>  
>  /* EEPROM reading goes completely around the power_supply API, sadly */
> diff --git a/drivers/power/power_supply_sysfs.c b/drivers/power/power_supply_sysfs.c
> index c444d6b..82e1246 100644
> --- a/drivers/power/power_supply_sysfs.c
> +++ b/drivers/power/power_supply_sysfs.c
> @@ -99,6 +99,7 @@ static struct device_attribute power_supply_attrs[] = {
>  	POWER_SUPPLY_ATTR(charge_empty),
>  	POWER_SUPPLY_ATTR(charge_now),
>  	POWER_SUPPLY_ATTR(charge_avg),
> +	POWER_SUPPLY_ATTR(charge_counter),
>  	POWER_SUPPLY_ATTR(energy_full_design),
>  	POWER_SUPPLY_ATTR(energy_empty_design),
>  	POWER_SUPPLY_ATTR(energy_full),
> diff --git a/include/linux/power_supply.h b/include/linux/power_supply.h
> index 68ed19c..ea96ead 100644
> --- a/include/linux/power_supply.h
> +++ b/include/linux/power_supply.h
> @@ -78,6 +78,7 @@ enum power_supply_property {
>  	POWER_SUPPLY_PROP_CHARGE_EMPTY,
>  	POWER_SUPPLY_PROP_CHARGE_NOW,
>  	POWER_SUPPLY_PROP_CHARGE_AVG,
> +	POWER_SUPPLY_PROP_CHARGE_COUNTER,
>  	POWER_SUPPLY_PROP_ENERGY_FULL_DESIGN,
>  	POWER_SUPPLY_PROP_ENERGY_EMPTY_DESIGN,
>  	POWER_SUPPLY_PROP_ENERGY_FULL,
> -- 
> 1.5.5.1
> 

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