linux-kernel - Re: [PATCH 1/1] power: supply: bq27xxx: expose battery data when CI=1

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Message-ID: <20220419215935.jtbcutnpi6345gqj@pali>
Date:   Tue, 19 Apr 2022 23:59:35 +0200
From:   Pali Rohár <pali@...nel.org>
To:     "Sicelo A. Mhlongo" <absicsz@...il.com>
Cc:     sre@...nel.org, linux-pm@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/1] power: supply: bq27xxx: expose battery data when CI=1

On Tuesday 19 April 2022 23:36:47 Sicelo A. Mhlongo wrote:
> When the Capacity Inaccurate flag is set, the chip still provides data
> about the battery, albeit inaccurate. Instead of discarding capacity
> values for CI=1, expose the stale data and use the
> POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED property to indicate that the
> values should be used with care.

Looks good! I did not know that there is CALIBRATION_REQUIRED property.

Reviewed-by: Pali Rohár <pali@...nel.org>

> Signed-off-by: Sicelo A. Mhlongo <absicsz@...il.com>
> ---
>  drivers/power/supply/bq27xxx_battery.c | 58 +++++++++++++-------------
>  1 file changed, 28 insertions(+), 30 deletions(-)
> 
> diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
> index 72e727cd31e8..a524237b758e 100644
> --- a/drivers/power/supply/bq27xxx_battery.c
> +++ b/drivers/power/supply/bq27xxx_battery.c
> @@ -1572,14 +1572,6 @@ static int bq27xxx_battery_read_charge(struct bq27xxx_device_info *di, u8 reg)
>   */
>  static inline int bq27xxx_battery_read_nac(struct bq27xxx_device_info *di)
>  {
> -	int flags;
> -
> -	if (di->opts & BQ27XXX_O_ZERO) {
> -		flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, true);
> -		if (flags >= 0 && (flags & BQ27000_FLAG_CI))
> -			return -ENODATA;
> -	}
> -
>  	return bq27xxx_battery_read_charge(di, BQ27XXX_REG_NAC);
>  }
>  
> @@ -1742,6 +1734,18 @@ static bool bq27xxx_battery_dead(struct bq27xxx_device_info *di, u16 flags)
>  		return flags & (BQ27XXX_FLAG_SOC1 | BQ27XXX_FLAG_SOCF);
>  }
>  
> +/*
> + * Returns true if reported battery capacity is inaccurate
> + */
> +static bool bq27xxx_battery_capacity_inaccurate(struct bq27xxx_device_info *di,
> +						 u16 flags)
> +{
> +	if (di->opts & BQ27XXX_O_HAS_CI)
> +		return (flags & BQ27000_FLAG_CI);
> +	else
> +		return false;
> +}
> +
>  static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di)
>  {
>  	/* Unlikely but important to return first */
> @@ -1751,6 +1755,8 @@ static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di)
>  		return POWER_SUPPLY_HEALTH_COLD;
>  	if (unlikely(bq27xxx_battery_dead(di, di->cache.flags)))
>  		return POWER_SUPPLY_HEALTH_DEAD;
> +	if (unlikely(bq27xxx_battery_capacity_inaccurate(di, di->cache.flags)))
> +		return POWER_SUPPLY_HEALTH_CALIBRATION_REQUIRED;
>  
>  	return POWER_SUPPLY_HEALTH_GOOD;
>  }
> @@ -1767,29 +1773,21 @@ void bq27xxx_battery_update(struct bq27xxx_device_info *di)
>  	if (cache.flags >= 0) {
>  		cache.temperature = bq27xxx_battery_read_temperature(di);
>  		if (has_ci_flag && (cache.flags & BQ27000_FLAG_CI)) {
> -			dev_info_once(di->dev, "battery is not calibrated! ignoring capacity values\n");
> -			cache.capacity = -ENODATA;
> -			cache.energy = -ENODATA;
> -			cache.time_to_empty = -ENODATA;
> -			cache.time_to_empty_avg = -ENODATA;
> -			cache.time_to_full = -ENODATA;
> -			cache.charge_full = -ENODATA;
> -			cache.health = -ENODATA;
> -		} else {
> -			if (di->regs[BQ27XXX_REG_TTE] != INVALID_REG_ADDR)
> -				cache.time_to_empty = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTE);
> -			if (di->regs[BQ27XXX_REG_TTECP] != INVALID_REG_ADDR)
> -				cache.time_to_empty_avg = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTECP);
> -			if (di->regs[BQ27XXX_REG_TTF] != INVALID_REG_ADDR)
> -				cache.time_to_full = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTF);
> -
> -			cache.charge_full = bq27xxx_battery_read_fcc(di);
> -			cache.capacity = bq27xxx_battery_read_soc(di);
> -			if (di->regs[BQ27XXX_REG_AE] != INVALID_REG_ADDR)
> -				cache.energy = bq27xxx_battery_read_energy(di);
> -			di->cache.flags = cache.flags;
> -			cache.health = bq27xxx_battery_read_health(di);
> +			dev_info_once(di->dev, "battery is not calibrated! capacity values are inaccurate\n");

Just one note: Do we still need this info message in dmesg? Now when
this information is going to be reported via sysfs API, I'm not sure if
it still has some value...

>  		}
> +		if (di->regs[BQ27XXX_REG_TTE] != INVALID_REG_ADDR)
> +			cache.time_to_empty = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTE);
> +		if (di->regs[BQ27XXX_REG_TTECP] != INVALID_REG_ADDR)
> +			cache.time_to_empty_avg = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTECP);
> +		if (di->regs[BQ27XXX_REG_TTF] != INVALID_REG_ADDR)
> +			cache.time_to_full = bq27xxx_battery_read_time(di, BQ27XXX_REG_TTF);
> +
> +		cache.charge_full = bq27xxx_battery_read_fcc(di);
> +		cache.capacity = bq27xxx_battery_read_soc(di);
> +		if (di->regs[BQ27XXX_REG_AE] != INVALID_REG_ADDR)
> +			cache.energy = bq27xxx_battery_read_energy(di);
> +		di->cache.flags = cache.flags;
> +		cache.health = bq27xxx_battery_read_health(di);
>  		if (di->regs[BQ27XXX_REG_CYCT] != INVALID_REG_ADDR)
>  			cache.cycle_count = bq27xxx_battery_read_cyct(di);
>  
> -- 
> 2.35.2
>