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

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Message-ID: <55B29FBB.8080500@ti.com>
Date:	Fri, 24 Jul 2015 15:27:39 -0500
From:	"Andrew F. Davis" <afd@...com>
To:	Pali Rohár <pali.rohar@...il.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 07/23/2015 11:22 AM, Pali Rohár wrote:
> 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(...))" ?
> 

I wasn't sure, but I don't see why not. Added.

Thanks,
Andrew

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

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