Re: [PATCH] power: supply: ltc4162l: Use GENMASK macro in bitmask operation

From: Sebastian Reichel
Date: Wed Jan 15 2025 - 15:41:00 EST


Hi,

On Tue, Jan 14, 2025 at 09:13:18AM +0800, Kim Seer Paller wrote:
> Replace the bitmask operation BIT(6) - 1 with GENMASK(5, 0) to
> make the code clearer and readable.
>
> Signed-off-by: Kim Seer Paller <kimseer.paller@xxxxxxxxxx>
> ---

Please also get rid of the comments. I expect somebody reading the
code to understand what GENMASK does and the comment makes things
actually worse by sometimes speaking about lower 5 bits and
sometimes about "only 6 bits" :)

Greetings,

-- Sebastian

> drivers/power/supply/ltc4162-l-charger.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/power/supply/ltc4162-l-charger.c b/drivers/power/supply/ltc4162-l-charger.c
> index 24b62f000..db1a75c9b 100644
> --- a/drivers/power/supply/ltc4162-l-charger.c
> +++ b/drivers/power/supply/ltc4162-l-charger.c
> @@ -410,7 +410,7 @@ static int ltc4162l_get_icharge(struct ltc4162l_info *info,
> if (ret)
> return ret;
>
> - regval &= BIT(6) - 1; /* Only the lower 5 bits */
> + regval &= GENMASK(5, 0); /* Only the lower 5 bits */
>
> /* The charge current servo level: (icharge_dac + 1) × 1mV/RSNSB */
> ++regval;
> @@ -449,7 +449,7 @@ static int ltc4162l_get_vcharge(struct ltc4162l_info *info,
> if (ret)
> return ret;
>
> - regval &= BIT(6) - 1; /* Only the lower 5 bits */
> + regval &= GENMASK(5, 0); /* Only the lower 5 bits */
>
> /*
> * charge voltage setting can be computed from
> @@ -500,7 +500,7 @@ static int ltc4015_get_vcharge(struct ltc4162l_info *info,
> if (ret)
> return ret;
>
> - regval &= BIT(6) - 1; /* Only the lower 5 bits */
> + regval &= GENMASK(5, 0); /* Only the lower 5 bits */
>
> /*
> * charge voltage setting can be computed from:
> @@ -636,7 +636,7 @@ static int ltc4162l_get_iin_limit_dac(struct ltc4162l_info *info,
> if (ret)
> return ret;
>
> - regval &= BIT(6) - 1; /* Only 6 bits */
> + regval &= GENMASK(5, 0); /* Only 6 bits */
>
> /* (iin_limit_dac + 1) × 500μV / RSNSI */
> ++regval;
>
> base-commit: a3a8799165ff83bb764fd800c6559c3cba0ddac3
> --
> 2.34.1
>

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