Hi,

On Wed, Mar 03, 2021 at 10:54:19AM +0100, Matthias Schiffer wrote:
> On all newer bq27xxx ICs, the AveragePower register contains a signed
> value; in addition to handling the raw value as unsigned, the driver
> code also didn't convert it to µW as expected.
> 
> At least for the BQ28Z610, the reference manual incorrectly states that
> the value is in units of 1mW and not 10mW. I have no way of knowing
> whether the manuals of other supported ICs contain the same error, or if
> there are models that actually use 1mW. At least, the new code shouldn't
> be *less* correct than the old version for any device.
> 
> power_avg is removed from the cache structure, se we don't have to
> extend it to store both a signed value and an error code. Always getting
> an up-to-date value may be desirable anyways, as it avoids inconsistent
> current and power readings when switching between charging and
> discharging.
> 
> Signed-off-by: Matthias Schiffer <matthias.schif...@ew.tq-group.com>
> ---

Thanks, queued.

-- Sebastian

> 
> v2: fixed units in commit message
> 
>  drivers/power/supply/bq27xxx_battery.c | 51 ++++++++++++++------------
>  include/linux/power/bq27xxx_battery.h  |  1 -
>  2 files changed, 27 insertions(+), 25 deletions(-)
> 
> diff --git a/drivers/power/supply/bq27xxx_battery.c 
> b/drivers/power/supply/bq27xxx_battery.c
> index cb6ebd2f905e..20e1dc8a87cf 100644
> --- a/drivers/power/supply/bq27xxx_battery.c
> +++ b/drivers/power/supply/bq27xxx_battery.c
> @@ -1661,27 +1661,6 @@ static int bq27xxx_battery_read_time(struct 
> bq27xxx_device_info *di, u8 reg)
>       return tval * 60;
>  }
>  
> -/*
> - * Read an average power register.
> - * Return < 0 if something fails.
> - */
> -static int bq27xxx_battery_read_pwr_avg(struct bq27xxx_device_info *di)
> -{
> -     int tval;
> -
> -     tval = bq27xxx_read(di, BQ27XXX_REG_AP, false);
> -     if (tval < 0) {
> -             dev_err(di->dev, "error reading average power register  %02x: 
> %d\n",
> -                     BQ27XXX_REG_AP, tval);
> -             return tval;
> -     }
> -
> -     if (di->opts & BQ27XXX_O_ZERO)
> -             return (tval * BQ27XXX_POWER_CONSTANT) / BQ27XXX_RS;
> -     else
> -             return tval;
> -}
> -
>  /*
>   * Returns true if a battery over temperature condition is detected
>   */
> @@ -1769,8 +1748,6 @@ void bq27xxx_battery_update(struct bq27xxx_device_info 
> *di)
>               }
>               if (di->regs[BQ27XXX_REG_CYCT] != INVALID_REG_ADDR)
>                       cache.cycle_count = bq27xxx_battery_read_cyct(di);
> -             if (di->regs[BQ27XXX_REG_AP] != INVALID_REG_ADDR)
> -                     cache.power_avg = bq27xxx_battery_read_pwr_avg(di);
>  
>               /* We only have to read charge design full once */
>               if (di->charge_design_full <= 0)
> @@ -1833,6 +1810,32 @@ static int bq27xxx_battery_current(struct 
> bq27xxx_device_info *di,
>       return 0;
>  }
>  
> +/*
> + * Get the average power in µW
> + * Return < 0 if something fails.
> + */
> +static int bq27xxx_battery_pwr_avg(struct bq27xxx_device_info *di,
> +                                union power_supply_propval *val)
> +{
> +     int power;
> +
> +     power = bq27xxx_read(di, BQ27XXX_REG_AP, false);
> +     if (power < 0) {
> +             dev_err(di->dev,
> +                     "error reading average power register %02x: %d\n",
> +                     BQ27XXX_REG_AP, power);
> +             return power;
> +     }
> +
> +     if (di->opts & BQ27XXX_O_ZERO)
> +             val->intval = (power * BQ27XXX_POWER_CONSTANT) / BQ27XXX_RS;
> +     else
> +             /* Other gauges return a signed value in units of 10mW */
> +             val->intval = (int)((s16)power) * 10000;
> +
> +     return 0;
> +}
> +
>  static int bq27xxx_battery_status(struct bq27xxx_device_info *di,
>                                 union power_supply_propval *val)
>  {
> @@ -2020,7 +2023,7 @@ static int bq27xxx_battery_get_property(struct 
> power_supply *psy,
>               ret = bq27xxx_simple_value(di->cache.energy, val);
>               break;
>       case POWER_SUPPLY_PROP_POWER_AVG:
> -             ret = bq27xxx_simple_value(di->cache.power_avg, val);
> +             ret = bq27xxx_battery_pwr_avg(di, val);
>               break;
>       case POWER_SUPPLY_PROP_HEALTH:
>               ret = bq27xxx_simple_value(di->cache.health, val);
> diff --git a/include/linux/power/bq27xxx_battery.h 
> b/include/linux/power/bq27xxx_battery.h
> index 111a40d0d3d5..8d5f4f40fb41 100644
> --- a/include/linux/power/bq27xxx_battery.h
> +++ b/include/linux/power/bq27xxx_battery.h
> @@ -53,7 +53,6 @@ struct bq27xxx_reg_cache {
>       int capacity;
>       int energy;
>       int flags;
> -     int power_avg;
>       int health;
>  };
>  
> -- 
> 2.17.1
> 

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