On Thu, Sep 23, 2021 at 12:48:01PM +0300, Paul Fertser wrote:
> Current code produces -24999 for 0b1110011100000000 input in standard
> format due to always rounding up rather than "away from zero". Use the
> common macro for division, unify and simplify the conversion code along
> the way.
>
> Signed-off-by: Paul Fertser <fercerpav@xxxxxxxxx>
This patch should probably have a Fixes: tag.
Guenter
> ---
>
> Changes from v1:
> - Trivial rebase
>
> drivers/hwmon/tmp421.c | 24 ++++++++----------------
> 1 file changed, 8 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/hwmon/tmp421.c b/drivers/hwmon/tmp421.c
> index 9f0a4db695db..c77c9f3bbd21 100644
> --- a/drivers/hwmon/tmp421.c
> +++ b/drivers/hwmon/tmp421.c
> @@ -100,23 +100,17 @@ struct tmp421_data {
> s16 temp[4];
> };
>
> -static int temp_from_s16(s16 reg)
> +static int temp_from_raw(u16 reg, bool extended)
> {
> /* Mask out status bits */
> int temp = reg & ~0xf;
>
> - return (temp * 1000 + 128) / 256;
> -}
> -
> -static int temp_from_u16(u16 reg)
> -{
> - /* Mask out status bits */
> - int temp = reg & ~0xf;
> -
> - /* Add offset for extended temperature range. */
> - temp -= 64 * 256;
> + if (extended)
> + temp = temp - 64 * 256;
> + else
> + temp = (s16)temp;
>
> - return (temp * 1000 + 128) / 256;
> + return DIV_ROUND_CLOSEST(temp * 1000, 256);
> }
>
> static int tmp421_update_device(struct tmp421_data *data)
> @@ -175,10 +169,8 @@ static int tmp421_read(struct device *dev, enum hwmon_sensor_types type,
>
> switch (attr) {
> case hwmon_temp_input:
> - if (tmp421->config & TMP421_CONFIG_RANGE)
> - *val = temp_from_u16(tmp421->temp[channel]);
> - else
> - *val = temp_from_s16(tmp421->temp[channel]);
> + *val = temp_from_raw(tmp421->temp[channel],
> + tmp421->config & TMP421_CONFIG_RANGE);
> return 0;
> case hwmon_temp_fault:
> /*
