From: James Calligeros Date: Sat, 25 Apr 2026 00:44:05 +0000 (+1000) Subject: ASoC: tas2770: Fix order of operations for temperature calculation X-Git-Tag: v7.1-rc2~24^2~5^2~9 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c7ecb6a61908c2604dda6e42da66724d256de7b9;p=thirdparty%2Fkernel%2Flinux.git ASoC: tas2770: Fix order of operations for temperature calculation The order of operations to derive the temperature from the temp register values was wrong, since 1000 / 16 is not an integer. This resulted in the calculated temperature value deviating from the value represented by the registers slightly, which was most obvious when the registers were zeroed (-92.265 *C vs the expected -93.000 *C). Scale the reading before dividing the whole thing by 16 to correct this. Fixes: ff73e2780169 ("ASoC: tas2770: expose die temp to hwmon") Signed-off-by: James Calligeros Link: https://patch.msgid.link/20260425-tas27xx-hwmon-fixes-v1-3-83c13b8e8f54@gmail.com Signed-off-by: Mark Brown --- diff --git a/sound/soc/codecs/tas2770.c b/sound/soc/codecs/tas2770.c index d4d7d056141b..50501bcbe916 100644 --- a/sound/soc/codecs/tas2770.c +++ b/sound/soc/codecs/tas2770.c @@ -624,7 +624,7 @@ static int tas2770_read_die_temp(struct tas2770_priv *tas2770, long *result) /* * As per datasheet: divide register by 16 and subtract 93 to get * degrees Celsius. hwmon requires millidegrees. Let's avoid rounding - * errors by subtracting 93 * 16 then multiplying by 1000 / 16. + * errors by subtracting 93 * 16 and scaling before dividing. * * NOTE: The ADC registers are initialised to 0 on reset. This means * that the temperature will read -93 *C until the chip is brought out @@ -633,7 +633,7 @@ static int tas2770_read_die_temp(struct tas2770_priv *tas2770, long *result) * value read back from its registers will be the last value sampled * before entering software shutdown. */ - *result = (reading - (93 * 16)) * (1000 / 16); + *result = (reading - (93 * 16)) * 1000 / 16; return 0; }