From 5fdfc48bb0da2aa8a912024a6ecca06486eb9141 Mon Sep 17 00:00:00 2001 From: Leo Yan Date: Tue, 29 Mar 2016 19:23:32 +0800 Subject: [PATCH] thermal: hisilicon: increase temperature resolution When calculate temperature, old code firstly do division and then convert to "millicelsius" unit. This will lose resolution and only can read back temperature with "Celsius" unit. So firstly scale step value to "millicelsius" and then do division, so finally we can increase resolution for temperature value. Also refine the calculation from temperature value to step value. Signed-off-by: Leo Yan Signed-off-by: Eduardo Valentin --- drivers/thermal/hisi_thermal.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c index 36d0729..5e820b5 100644 --- a/drivers/thermal/hisi_thermal.c +++ b/drivers/thermal/hisi_thermal.c @@ -68,12 +68,12 @@ static inline int _step_to_temp(int step) * Every step equals (1 * 200) / 255 celsius, and finally * need convert to millicelsius. */ - return (HISI_TEMP_BASE + (step * 200 / 255)) * 1000; + return (HISI_TEMP_BASE * 1000 + (step * 200000 / 255)); } static inline long _temp_to_step(long temp) { - return ((temp / 1000 - HISI_TEMP_BASE) * 255 / 200); + return ((temp - HISI_TEMP_BASE * 1000) * 255) / 200000; } static long hisi_thermal_get_sensor_temp(struct hisi_thermal_data *data, -- 2.7.4