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authorEzequiel Garcia <ezequiel.garcia@free-electrons.com>2013-03-22 09:23:02 -0300
committerZhang Rui <rui.zhang@intel.com>2013-03-26 22:12:20 +0800
commit696b6075afa97b42b3f59f96809ed586eb691c96 (patch)
tree0106c28ed0a284e4d42ba548b1fe9a15b4186ee1
parent02519d3397b57bf723f6df69c92b0b66ecafb11a (diff)
thermal: kirkwood: Fix thermal sensor formula
The currently formula has been taken from the 88AP510 SoC datasheet, which is not exactly correct. The correct value for the temperature in Celcius of the sensor present in this SoC is: Celsius = (322-reg)/1.3625 Signed-off-by: Lior Amsalem <alior@marvell.com> Signed-off-by: Ezequiel Garcia <ezequiel.garcia@free-electrons.com> Acked-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: Zhang Rui <rui.zhang@intel.com>
-rw-r--r--drivers/thermal/kirkwood_thermal.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/drivers/thermal/kirkwood_thermal.c b/drivers/thermal/kirkwood_thermal.c
index d2e05eec722a..dfeceaffbc03 100644
--- a/drivers/thermal/kirkwood_thermal.c
+++ b/drivers/thermal/kirkwood_thermal.c
@@ -49,13 +49,13 @@ static int kirkwood_get_temp(struct thermal_zone_device *thermal,
}
/*
- * Calculate temperature. See Section 8.10.1 of the 88AP510,
- * datasheet, which has the same sensor.
- * Documentation/arm/Marvell/README
+ * Calculate temperature. According to Marvell internal
+ * documentation the formula for this is:
+ * Celsius = (322-reg)/1.3625
*/
reg = (reg >> KIRKWOOD_THERMAL_TEMP_OFFSET) &
KIRKWOOD_THERMAL_TEMP_MASK;
- *temp = ((2281638UL - (7298*reg)) / 10);
+ *temp = ((3220000000UL - (10000000UL * reg)) / 13625);
return 0;
}