linux-kernel - Re: [PATCH 8/8] power: bq27xxx_battery: Cleanup health checking

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Message-ID: <20150723162212.GI29125@pali>
Date:	Thu, 23 Jul 2015 18:22:12 +0200
From:	Pali Rohár <pali.rohar@...il.com>
To:	"Andrew F. Davis" <afd@...com>
Cc:	Sebastian Reichel <sre@...nel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>,
	Dan Murphy <dmurphy@...com>, linux-pm@...r.kernel.org,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 8/8] power: bq27xxx_battery: Cleanup health checking

On Wednesday 22 July 2015 16:52:00 Andrew F. Davis wrote:
> Reorganize the logic checking battery health and under temperature
> condition checking.
> 
> Signed-off-by: Andrew F. Davis <afd@...com>
> ---
>  drivers/power/bq27xxx_battery.c | 62 +++++++++++++++++++++++++++--------------
>  1 file changed, 41 insertions(+), 21 deletions(-)
> 
> diff --git a/drivers/power/bq27xxx_battery.c b/drivers/power/bq27xxx_battery.c
> index f148222..6775f65 100644
> --- a/drivers/power/bq27xxx_battery.c
> +++ b/drivers/power/bq27xxx_battery.c
> @@ -54,6 +54,8 @@
>  #define BQ27XXX_FLAG_FC		BIT(9)
>  #define BQ27XXX_FLAG_OTD	BIT(14)
>  #define BQ27XXX_FLAG_OTC	BIT(15)
> +#define BQ27XXX_FLAG_UT		BIT(14)
> +#define BQ27XXX_FLAG_OT		BIT(15)
>  
>  /* BQ27000 has different layout for Flags register */
>  #define BQ27000_FLAG_EDVF	BIT(0) /* Final End-of-Discharge-Voltage flag */
> @@ -624,10 +626,34 @@ static int bq27xxx_battery_read_pwr_avg(struct bq27xxx_device_info *di)
>   */
>  static int bq27xxx_battery_overtemp(struct bq27xxx_device_info *di, u16 flags)
>  {
> -	if (di->chip == BQ27500 || di->chip == BQ27541)
> +	if (di->chip == BQ27500 || di->chip == BQ27541 || di->chip == BQ27545)
>  		return flags & (BQ27XXX_FLAG_OTC | BQ27XXX_FLAG_OTD);
> +	if (di->chip == BQ27530 || di->chip == BQ27421)
> +		return flags & BQ27XXX_FLAG_OT;
> +
> +	return false;
> +}
> +
> +/*
> + * Returns true if a battery under temperature condition is detected
> + */
> +static int bq27xxx_battery_undertemp(struct bq27xxx_device_info *di, u16 flags)
> +{
> +	if (di->chip == BQ27530 || di->chip == BQ27421)
> +			return flags & BQ27XXX_FLAG_UT;
> +
> +	return false;
> +}
> +
> +/*
> + * Returns true if a low state of charge condition is detected
> + */
> +static int bq27xxx_battery_dead(struct bq27xxx_device_info *di, u16 flags)
> +{
> +	if (di->chip == BQ27000 || di->chip == BQ27010)
> +		return flags & (BQ27000_FLAG_EDV1 | BQ27000_FLAG_EDVF);
>  	else
> -		return flags & BQ27XXX_FLAG_OTC;
> +		return flags & (BQ27XXX_FLAG_SOC1 | BQ27XXX_FLAG_SOCF);
>  }
>  
>  /*
> @@ -636,29 +662,23 @@ static int bq27xxx_battery_overtemp(struct bq27xxx_device_info *di, u16 flags)
>   */
>  static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di)
>  {
> -	u16 tval;
> +	u16 flags;
>  
> -	tval = bq27xxx_read(di, BQ27XXX_REG_FLAGS, false);
> -	if (tval < 0) {
> -		dev_err(di->dev, "error reading flag register:%d\n", tval);
> -		return tval;
> +	flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, false);
> +	if (flags < 0) {
> +		dev_err(di->dev, "error reading flag register:%d\n", flags);
> +		return flags;
>  	}
>  
> -	if (di->chip == BQ27000 || di->chip == BQ27010) {
> -		if (tval & BQ27000_FLAG_EDV1)
> -			tval = POWER_SUPPLY_HEALTH_DEAD;
> -		else
> -			tval = POWER_SUPPLY_HEALTH_GOOD;
> -	} else {
> -		if (tval & BQ27XXX_FLAG_SOCF)
> -			tval = POWER_SUPPLY_HEALTH_DEAD;
> -		else if (bq27xxx_battery_overtemp(di, tval))
> -			tval = POWER_SUPPLY_HEALTH_OVERHEAT;
> -		else
> -			tval = POWER_SUPPLY_HEALTH_GOOD;
> -	}
> +	/* Unlikely but important to return first */
> +	if (bq27xxx_battery_overtemp(di, flags))
> +		return POWER_SUPPLY_HEALTH_OVERHEAT;
> +	if (bq27xxx_battery_undertemp(di, flags))
> +		return POWER_SUPPLY_HEALTH_COLD;
> +	if (bq27xxx_battery_dead(di, flags))
> +		return POWER_SUPPLY_HEALTH_DEAD;

Good candidates for "if (unlikely(...))" ?

>  
> -	return tval;
> +	return POWER_SUPPLY_HEALTH_GOOD;
>  }
>  
>  static void bq27xxx_battery_update(struct bq27xxx_device_info *di)

-- 
Pali Rohár
pali.rohar@...il.com
--
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