linux-kernel - Re: [PATCH 3/4] power supply bq25890-charger: Handle temperature faults

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Date:   Sun, 7 Nov 2021 21:46:30 +0100
From:   Hans de Goede <hdegoede@...hat.com>
To:     Yauhen Kharuzhy <jekhor@...il.com>,
        Sebastian Reichel <sre@...nel.org>
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 3/4] power supply bq25890-charger: Handle temperature
 faults

Hi,

On 11/7/21 21:20, Yauhen Kharuzhy wrote:
> Add debug info about thermal failure to message in
> bq25890_get_chip_state().
> 
> Take into account possible thermal failure when calculating a
> POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX value as it described in
> datasheet (in cold conditions a current limit is decreased to 20% or 50% of
> ICHG field value depended on JEITA_ISET field).
> 
> Signed-off-by: Yauhen Kharuzhy <jekhor@...il.com>

Thank you for your patch,

Patch subject prefix should be: "power: supply: bq25890: "


> ---
>  drivers/power/supply/bq25890_charger.c | 33 +++++++++++++++++++++++---
>  1 file changed, 30 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/power/supply/bq25890_charger.c b/drivers/power/supply/bq25890_charger.c
> index 1c43555d5bd8..fb2f1578503c 100644
> --- a/drivers/power/supply/bq25890_charger.c
> +++ b/drivers/power/supply/bq25890_charger.c
> @@ -95,6 +95,7 @@ struct bq25890_state {
>  	u8 vsys_status;
>  	u8 boost_fault;
>  	u8 bat_fault;
> +	u8 ntc_fault;
>  };
>  
>  struct bq25890_device {
> @@ -384,6 +385,14 @@ enum bq25890_chrg_fault {
>  	CHRG_FAULT_TIMER_EXPIRED,
>  };
>  
> +enum bq25890_ntc_fault {
> +	NTC_FAULT_NORMAL = 0,
> +	NTC_FAULT_WARM = 2,
> +	NTC_FAULT_COOL = 3,
> +	NTC_FAULT_COLD = 5,
> +	NTC_FAULT_HOT = 6,
> +};
> +
>  static bool bq25890_is_adc_property(enum power_supply_property psp)
>  {
>  	switch (psp) {
> @@ -474,7 +483,19 @@ static int bq25890_power_supply_get_property(struct power_supply *psy,
>  		break;
>  
>  	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX:
> +		ret = bq25890_field_read(bq, F_JEITA_ISET);
> +		if (ret < 0)
> +			return ret;
> +

You only use the read value if bq->state.ntc_fault == NTC_FAULT_COOL
and i2c reads are somewhat expensive (or at least slow), can you
please move this to inside the
"if (bq->state.ntc_fault == NTC_FAULT_COOL) {" block ?

This is esp. relevant since this condition will normally be false,
so normally this will save us an i2c_read for every read of the
POWER_SUPPLY_PROP_CONSTANT_CHARGE_CURRENT_MAX property.

>  		val->intval = bq25890_find_val(bq->init_data.ichg, TBL_ICHG);
> +
> +		/* When temperature is too low, charge current is decreased */
> +		if (bq->state.ntc_fault == NTC_FAULT_COOL) {
> +			if (ret)
> +				val->intval /= 5;
> +			else
> +				val->intval /= 2;
> +		}
>  		break;
>  
>  	case POWER_SUPPLY_PROP_CONSTANT_CHARGE_VOLTAGE:
> @@ -487,6 +508,10 @@ static int bq25890_power_supply_get_property(struct power_supply *psy,
>  		if (ret < 0)
>  			return ret;
>  
> +		ret = bq25890_field_read(bq, F_JEITA_VSET);
> +		if (ret < 0)
> +			return ret;
> +
>  		/* converted_val = 2.304V + ADC_val * 20mV (table 10.3.15) */
>  		val->intval = 2304000 + ret * 20000;
>  		break;
> @@ -550,7 +575,8 @@ static int bq25890_get_chip_state(struct bq25890_device *bq,
>  		{F_VSYS_STAT,	&state->vsys_status},
>  		{F_BOOST_FAULT, &state->boost_fault},
>  		{F_BAT_FAULT,	&state->bat_fault},
> -		{F_CHG_FAULT,	&state->chrg_fault}
> +		{F_CHG_FAULT,	&state->chrg_fault},
> +		{F_CHG_FAULT,	&state->ntc_fault}

Copy paste error? Surely the field in the second line must be F_NTG_FAULT ?

>  	};
>  
>  	for (i = 0; i < ARRAY_SIZE(state_fields); i++) {
> @@ -561,9 +587,10 @@ static int bq25890_get_chip_state(struct bq25890_device *bq,
>  		*state_fields[i].data = ret;
>  	}
>  
> -	dev_dbg(bq->dev, "S:CHG/PG/VSYS=%d/%d/%d, F:CHG/BOOST/BAT=%d/%d/%d\n",
> +	dev_dbg(bq->dev, "S:CHG/PG/VSYS=%d/%d/%d, F:CHG/BOOST/BAT/NTC=%d/%d/%d/%d\n",
>  		state->chrg_status, state->online, state->vsys_status,
> -		state->chrg_fault, state->boost_fault, state->bat_fault);
> +		state->chrg_fault, state->boost_fault, state->bat_fault,
> +		state->ntc_fault);
>  
>  	return 0;
>  }
> 

Regards,

Hans