linux-kernel - Re: [PATCH v2 16/17] power: axp20x_battery: Support battery status without fuel gauge

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Date:   Thu, 9 Jun 2022 23:11:56 +0200
From:   Sebastian Reichel <sebastian.reichel@...labora.com>
To:     Aidan MacDonald <aidanmacdonald.0x0@...il.com>
Cc:     linus.walleij@...aro.org, brgl@...ev.pl, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, wens@...e.org, jic23@...nel.org,
        lee.jones@...aro.org, broonie@...nel.org,
        gregkh@...uxfoundation.org, lgirdwood@...il.com, lars@...afoo.de,
        rafael@...nel.org, quic_gurus@...cinc.com,
        linux-gpio@...r.kernel.org, devicetree@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH v2 16/17] power: axp20x_battery: Support battery status
 without fuel gauge

Hi,

On Tue, Jun 07, 2022 at 04:53:23PM +0100, Aidan MacDonald wrote:
> Add a "has_fg" flag to indicate that the chip has a fuel gauge.
> Report battery full status on chips with no fuel gauge using the
> battery voltage.
> 
> Signed-off-by: Aidan MacDonald <aidanmacdonald.0x0@...il.com>
> ---

Acked-by: Sebastian Reichel <sebastian.reichel@...labora.com>

-- Sebastian

>  drivers/power/supply/axp20x_battery.c | 34 ++++++++++++++++++++++++++-
>  1 file changed, 33 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/power/supply/axp20x_battery.c b/drivers/power/supply/axp20x_battery.c
> index 87fb958f2224..e9547e2d7c48 100644
> --- a/drivers/power/supply/axp20x_battery.c
> +++ b/drivers/power/supply/axp20x_battery.c
> @@ -62,6 +62,7 @@ struct axp_data {
>  	int	ccc_scale;
>  	int	ccc_offset;
>  	const int *ccc_table;
> +	bool	has_fg;
>  	bool	has_fg_valid;
>  	int	(*get_max_voltage)(struct axp20x_batt_ps *batt, int *val);
>  	int	(*set_max_voltage)(struct axp20x_batt_ps *batt, int val);
> @@ -190,7 +191,7 @@ static int axp20x_battery_get_prop(struct power_supply *psy,
>  				   union power_supply_propval *val)
>  {
>  	struct axp20x_batt_ps *axp20x_batt = power_supply_get_drvdata(psy);
> -	int ret = 0, reg, val1;
> +	int ret = 0, reg, val1, val2;
>  
>  	switch (psp) {
>  	case POWER_SUPPLY_PROP_PRESENT:
> @@ -224,6 +225,34 @@ static int axp20x_battery_get_prop(struct power_supply *psy,
>  			return 0;
>  		}
>  
> +		/*
> +		 * If the chip does not have a fuel gauge, we check battery full status
> +		 * using voltage instead.
> +		 */
> +		if (!axp20x_batt->data->has_fg) {
> +			ret = axp20x_batt->data->get_max_voltage(axp20x_batt, &val1);
> +			if (ret)
> +				return ret;
> +
> +			ret = iio_read_channel_processed(axp20x_batt->batt_v, &val2);
> +			if (ret)
> +				return ret;
> +
> +			/* IIO subsystem reports voltage in mV but we need uV */
> +			val2 *= 1000;
> +
> +			/*
> +			 * According to the AXP192 datasheet, charging will restart if
> +			 * the battery voltage drops below V_rch = V_tgt - 0.1 V, so we
> +			 * report the battery is full if its voltage is at least V_rch.
> +			 */
> +			if (val2 >= val1 - 100000)
> +				val->intval = POWER_SUPPLY_STATUS_FULL;
> +			else
> +				val->intval = POWER_SUPPLY_STATUS_NOT_CHARGING;
> +			break;
> +		}
> +
>  		ret = regmap_read(axp20x_batt->regmap, AXP20X_FG_RES, &val1);
>  		if (ret)
>  			return ret;
> @@ -546,6 +575,7 @@ static const struct power_supply_desc axp20x_batt_ps_desc = {
>  static const struct axp_data axp209_data = {
>  	.ccc_scale = 100000,
>  	.ccc_offset = 300000,
> +	.has_fg = true,
>  	.get_max_voltage = axp20x_battery_get_max_voltage,
>  	.set_max_voltage = axp20x_battery_set_max_voltage,
>  };
> @@ -553,6 +583,7 @@ static const struct axp_data axp209_data = {
>  static const struct axp_data axp221_data = {
>  	.ccc_scale = 150000,
>  	.ccc_offset = 300000,
> +	.has_fg = true,
>  	.has_fg_valid = true,
>  	.get_max_voltage = axp22x_battery_get_max_voltage,
>  	.set_max_voltage = axp22x_battery_set_max_voltage,
> @@ -561,6 +592,7 @@ static const struct axp_data axp221_data = {
>  static const struct axp_data axp813_data = {
>  	.ccc_scale = 200000,
>  	.ccc_offset = 200000,
> +	.has_fg = true,
>  	.has_fg_valid = true,
>  	.get_max_voltage = axp813_battery_get_max_voltage,
>  	.set_max_voltage = axp20x_battery_set_max_voltage,
> -- 
> 2.35.1
> 

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