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Date:   Sat, 16 Nov 2019 15:08:46 +0100
From:   Artur Rojek <contact@artur-rojek.eu>
To:     Paul Cercueil <paul@crapouillou.net>
Cc:     Sebastian Reichel <sre@kernel.org>, linux-pm@vger.kernel.org,
        linux-kernel@vger.kernel.org, od@zcrc.me, stable@vger.kernel.org
Subject: Re: [PATCH v3] power/supply: ingenic-battery: Don't change scale if
 there's only one
In-Reply-To: <20191116135619.9545-1-paul@crapouillou.net>
References: <20191116135619.9545-1-paul@crapouillou.net>
Message-ID: <d5d13a62c1652ce109136dcb3b2e1e51@artur-rojek.eu>
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On 2019-11-16 14:56, Paul Cercueil wrote:
> The ADC in the JZ4740 can work either in high-precision mode with a 
> 2.5V
> range, or in low-precision mode with a 7.5V range. The code in place in
> this driver will select the proper scale according to the maximum
> voltage of the battery.
> 
> The JZ4770 however only has one mode, with a 6.6V range. If only one
> scale is available, there's no need to change it (and nothing to change
> it to), and trying to do so will fail with -EINVAL.
> 
> Fixes: fb24ccfbe1e0 ("power: supply: add Ingenic JZ47xx battery 
> driver.")
> 
> Signed-off-by: Paul Cercueil <paul@crapouillou.net>
> Cc: stable@vger.kernel.org

Looks good to me!

Acked-by: Artur Rojek <contact@artur-rojek.eu>

> ---
> 
> Notes:
>     v2: Rebased on v5.4-rc7
>     v3: Move code after check for max scale voltage
> 
>  drivers/power/supply/ingenic-battery.c | 15 +++++++++++----
>  1 file changed, 11 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/power/supply/ingenic-battery.c
> b/drivers/power/supply/ingenic-battery.c
> index 35816d4b3012..2748715c4c75 100644
> --- a/drivers/power/supply/ingenic-battery.c
> +++ b/drivers/power/supply/ingenic-battery.c
> @@ -100,10 +100,17 @@ static int ingenic_battery_set_scale(struct
> ingenic_battery *bat)
>  		return -EINVAL;
>  	}
> 
> -	return iio_write_channel_attribute(bat->channel,
> -					   scale_raw[best_idx],
> -					   scale_raw[best_idx + 1],
> -					   IIO_CHAN_INFO_SCALE);
> +	/* Only set scale if there is more than one (fractional) entry */
> +	if (scale_len > 2) {
> +		ret = iio_write_channel_attribute(bat->channel,
> +						  scale_raw[best_idx],
> +						  scale_raw[best_idx + 1],
> +						  IIO_CHAN_INFO_SCALE);
> +		if (ret)
> +			return ret;
> +	}
> +
> +	return 0;
>  }
> 
>  static enum power_supply_property ingenic_battery_properties[] = {