Re: [PATCH v2 3/3] power: supply: bq27xxx: make status more robust

[Sebastian Reichel <sre@kernel.org>]

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Hi,

On Wed, Mar 03, 2021 at 10:54:20AM +0100, Matthias Schiffer wrote:
> There are multiple issues in bq27xxx_battery_status():
> 
> - On BQ28Q610 is was observed that the "full" flag may be set even while
>   the battery is charging or discharging. With the current logic to make
>   "full" override everything else, it look a very long time (>20min) for
>   the status to change from "full" to "discharging" after unplugging the
>   supply on a device with low power consumption
> - The POWER_SUPPLY_STATUS_NOT_CHARGING check depends on
>   power_supply_am_i_supplied(), which will not work when the supply
>   doesn't exist as a separate device known to Linux
> 
> We can solve both issues by deriving the status from the current instead
> of the flags field. The flags are now only used to distinguish "full"
> from "not charging", and to determine the sign of the current on
> BQ27XXX_O_ZERO devices.
> 
> Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
> ---

Thanks, queued.

-- Sebastian

> 
> v2: no changes
> 
>  drivers/power/supply/bq27xxx_battery.c | 88 +++++++++++++-------------
>  1 file changed, 43 insertions(+), 45 deletions(-)
> 
> diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
> index 20e1dc8a87cf..b62a8cfd9d09 100644
> --- a/drivers/power/supply/bq27xxx_battery.c
> +++ b/drivers/power/supply/bq27xxx_battery.c
> @@ -1777,14 +1777,27 @@ static void bq27xxx_battery_poll(struct work_struct *work)
>  		schedule_delayed_work(&di->work, poll_interval * HZ);
>  }
>  
> +static bool bq27xxx_battery_is_full(struct bq27xxx_device_info *di, int flags)
> +{
> +	if (di->opts & BQ27XXX_O_ZERO)
> +		return (flags & BQ27000_FLAG_FC);
> +	else if (di->opts & BQ27Z561_O_BITS)
> +		return (flags & BQ27Z561_FLAG_FC);
> +	else
> +		return (flags & BQ27XXX_FLAG_FC);
> +}
> +
>  /*
> - * Return the battery average current in µA
> + * Return the battery average current in µA and the status
>   * Note that current can be negative signed as well
>   * Or 0 if something fails.
>   */
> -static int bq27xxx_battery_current(struct bq27xxx_device_info *di,
> -				   union power_supply_propval *val)
> +static int bq27xxx_battery_current_and_status(
> +	struct bq27xxx_device_info *di,
> +	union power_supply_propval *val_curr,
> +	union power_supply_propval *val_status)
>  {
> +	bool single_flags = (di->opts & BQ27XXX_O_ZERO);
>  	int curr;
>  	int flags;
>  
> @@ -1794,17 +1807,39 @@ static int bq27xxx_battery_current(struct bq27xxx_device_info *di,
>  		return curr;
>  	}
>  
> +	flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, single_flags);
> +	if (flags < 0) {
> +		dev_err(di->dev, "error reading flags\n");
> +		return flags;
> +	}
> +
>  	if (di->opts & BQ27XXX_O_ZERO) {
> -		flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, true);
>  		if (!(flags & BQ27000_FLAG_CHGS)) {
>  			dev_dbg(di->dev, "negative current!\n");
>  			curr = -curr;
>  		}
>  
> -		val->intval = curr * BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS;
> +		curr = curr * BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS;
>  	} else {
>  		/* Other gauges return signed value */
> -		val->intval = (int)((s16)curr) * 1000;
> +		curr = (int)((s16)curr) * 1000;
> +	}
> +
> +	if (val_curr)
> +		val_curr->intval = curr;
> +
> +	if (val_status) {
> +		if (curr > 0) {
> +			val_status->intval = POWER_SUPPLY_STATUS_CHARGING;
> +		} else if (curr < 0) {
> +			val_status->intval = POWER_SUPPLY_STATUS_DISCHARGING;
> +		} else {
> +			if (bq27xxx_battery_is_full(di, flags))
> +				val_status->intval = POWER_SUPPLY_STATUS_FULL;
> +			else
> +				val_status->intval =
> +					POWER_SUPPLY_STATUS_NOT_CHARGING;
> +		}
>  	}
>  
>  	return 0;
> @@ -1836,43 +1871,6 @@ static int bq27xxx_battery_pwr_avg(struct bq27xxx_device_info *di,
>  	return 0;
>  }
>  
> -static int bq27xxx_battery_status(struct bq27xxx_device_info *di,
> -				  union power_supply_propval *val)
> -{
> -	int status;
> -
> -	if (di->opts & BQ27XXX_O_ZERO) {
> -		if (di->cache.flags & BQ27000_FLAG_FC)
> -			status = POWER_SUPPLY_STATUS_FULL;
> -		else if (di->cache.flags & BQ27000_FLAG_CHGS)
> -			status = POWER_SUPPLY_STATUS_CHARGING;
> -		else
> -			status = POWER_SUPPLY_STATUS_DISCHARGING;
> -	} else if (di->opts & BQ27Z561_O_BITS) {
> -		if (di->cache.flags & BQ27Z561_FLAG_FC)
> -			status = POWER_SUPPLY_STATUS_FULL;
> -		else if (di->cache.flags & BQ27Z561_FLAG_DIS_CH)
> -			status = POWER_SUPPLY_STATUS_DISCHARGING;
> -		else
> -			status = POWER_SUPPLY_STATUS_CHARGING;
> -	} else {
> -		if (di->cache.flags & BQ27XXX_FLAG_FC)
> -			status = POWER_SUPPLY_STATUS_FULL;
> -		else if (di->cache.flags & BQ27XXX_FLAG_DSC)
> -			status = POWER_SUPPLY_STATUS_DISCHARGING;
> -		else
> -			status = POWER_SUPPLY_STATUS_CHARGING;
> -	}
> -
> -	if ((status == POWER_SUPPLY_STATUS_DISCHARGING) &&
> -	    (power_supply_am_i_supplied(di->bat) > 0))
> -		status = POWER_SUPPLY_STATUS_NOT_CHARGING;
> -
> -	val->intval = status;
> -
> -	return 0;
> -}
> -
>  static int bq27xxx_battery_capacity_level(struct bq27xxx_device_info *di,
>  					  union power_supply_propval *val)
>  {
> @@ -1960,7 +1958,7 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
>  
>  	switch (psp) {
>  	case POWER_SUPPLY_PROP_STATUS:
> -		ret = bq27xxx_battery_status(di, val);
> +		ret = bq27xxx_battery_current_and_status(di, NULL, val);
>  		break;
>  	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
>  		ret = bq27xxx_battery_voltage(di, val);
> @@ -1969,7 +1967,7 @@ static int bq27xxx_battery_get_property(struct power_supply *psy,
>  		val->intval = di->cache.flags < 0 ? 0 : 1;
>  		break;
>  	case POWER_SUPPLY_PROP_CURRENT_NOW:
> -		ret = bq27xxx_battery_current(di, val);
> +		ret = bq27xxx_battery_current_and_status(di, val, NULL);
>  		break;
>  	case POWER_SUPPLY_PROP_CAPACITY:
>  		ret = bq27xxx_simple_value(di->cache.capacity, val);
> -- 
> 2.17.1
> 

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