linux-kernel - Re: [PATCH 1/2] power:bq27xxx: fix reading for bq27000 and bq27010

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Date:	Fri, 25 Dec 2015 14:20:04 +0100
From:	Pali Rohár <pali.rohar@...il.com>
To:	"H. Nikolaus Schaller" <hns@...delico.com>
Cc:	Sebastian Reichel <sre@...nel.org>,
	"Dmitry Eremin-Solenikov" <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	gta04-owner@...delico.com, marek@...delico.com
Subject: Re: [PATCH 1/2] power:bq27xxx: fix reading for bq27000 and bq27010

On Thursday 17 December 2015 11:12:53 H. Nikolaus Schaller wrote:
> bug: the driver reports funny capacity values:
> 
> root@...ux:/sys/class/power_supply/bq27000-battery# cat uevent
> POWER_SUPPLY_NAME=bq27000-battery
> POWER_SUPPLY_STATUS=Charging
> POWER_SUPPLY_PRESENT=1
> POWER_SUPPLY_VOLTAGE_NOW=3702000
> POWER_SUPPLY_CURRENT_NOW=-464635
> POWER_SUPPLY_CAPACITY=1536			<- over 100% is magic
> POWER_SUPPLY_CAPACITY_LEVEL=Normal
> POWER_SUPPLY_TEMP=311
> POWER_SUPPLY_TIME_TO_FULL_NOW=10440
> POWER_SUPPLY_TECHNOLOGY=Li-ion
> POWER_SUPPLY_CHARGE_FULL=805450
> POWER_SUPPLY_CHARGE_NOW=1068
> POWER_SUPPLY_CHARGE_FULL_DESIGN=8844998	<- battery has just 1200 mAh
> POWER_SUPPLY_CYCLE_COUNT=21
> POWER_SUPPLY_ENERGY_NOW=0
> POWER_SUPPLY_POWER_AVG=0
> POWER_SUPPLY_HEALTH=Good
> POWER_SUPPLY_MANUFACTURER=Texas Instruments
> 
> reason: the state of charge and the design capacity register are
> single byte only. The design capacity returns the higer order byte.
> 
> tested: GTA04 with Openmoko/FIC HF08x battery (using hdq)
> 
> Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
> ---
>  drivers/power/bq27xxx_battery.c | 12 +++++++++---
>  1 file changed, 9 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/power/bq27xxx_battery.c
> b/drivers/power/bq27xxx_battery.c index 880233c..e54a125 100644
> --- a/drivers/power/bq27xxx_battery.c
> +++ b/drivers/power/bq27xxx_battery.c
> @@ -471,7 +471,10 @@ static int bq27xxx_battery_read_soc(struct
> bq27xxx_device_info *di) {
>  	int soc;
> 
> -	soc = bq27xxx_read(di, BQ27XXX_REG_SOC, false);
> +	if (di->chip == BQ27000 || di->chip == BQ27010)
> +		soc = bq27xxx_read(di, BQ27XXX_REG_SOC, true);
> +	else
> +		soc = bq27xxx_read(di, BQ27XXX_REG_SOC, false);
> 
>  	if (soc < 0)
>  		dev_dbg(di->dev, "error reading State-of-Charge\n");
> @@ -536,7 +539,10 @@ static int bq27xxx_battery_read_dcap(struct
> bq27xxx_device_info *di) {
>  	int dcap;
> 
> -	dcap = bq27xxx_read(di, BQ27XXX_REG_DCAP, false);
> +	if (di->chip == BQ27000 || di->chip == BQ27010)
> +		dcap = bq27xxx_read(di, BQ27XXX_REG_DCAP, true);
> +	else
> +		dcap = bq27xxx_read(di, BQ27XXX_REG_DCAP, false);
> 
>  	if (dcap < 0) {
>  		dev_dbg(di->dev, "error reading initial last measured
> discharge\n"); @@ -544,7 +550,7 @@ static int
> bq27xxx_battery_read_dcap(struct bq27xxx_device_info *di) }
> 
>  	if (di->chip == BQ27000 || di->chip == BQ27010)
> -		dcap *= BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS;
> +		dcap = (dcap << 8) * BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS;
>  	else
>  		dcap *= 1000;

Hi!

This patch fixes commit d74534c27775857cb09abd0f92ed9539dc8d0a93 (power: 
bq27xxx_battery: Add support for additional bq27xxx family devices) in 
which this bug (all 3 patch chunks) were introduced.

Before that commit code was very similar after applying this patch. So:

Reviewed-by: Pali Rohár <pali.rohar@...il.com>

-- 
Pali Rohár
pali.rohar@...il.com

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