linux-kernel - [PATCH] thermal: hisilicon: increase temperature resolution

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1451452382-4498-1-git-send-email-leo.yan@linaro.org>
Date:	Wed, 30 Dec 2015 13:13:02 +0800
From:	Leo Yan <leo.yan@...aro.org>
To:	Zhang Rui <rui.zhang@...el.com>,
	Eduardo Valentin <edubezval@...il.com>,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	kongxinwei <kong.kongxinwei@...ilicon.com>
Cc:	Leo Yan <leo.yan@...aro.org>
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 <leo.yan@...aro.org>
---
 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,
-- 
1.9.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/