diff mbox

thermal: hisilicon: increase temperature resolution

Message ID 1451452382-4498-1-git-send-email-leo.yan@linaro.org
State Accepted
Commit 5fdfc48bb0da2aa8a912024a6ecca06486eb9141
Headers show

Commit Message

Leo Yan Dec. 30, 2015, 5:13 a.m. UTC 
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 <leo.yan@linaro.org>

---
 drivers/thermal/hisi_thermal.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

-- 
1.9.1

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diff mbox

Patch

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,