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authorAndres Salomon <dilinger@queued.net>2008-05-14 16:20:38 -0700
committerAnton Vorontsov <cbouatmailru@gmail.com>2008-05-19 01:44:36 +0400
commit75d8807962fc7529b4946e9ec92cae197be5a967 (patch)
tree9e5370ea7e1c727a18c4cb47c8403779456cbebe /drivers/power
parent8e552c36d90c03d2cabf5373788998966751b609 (diff)
downloadlinux-75d8807962fc7529b4946e9ec92cae197be5a967.tar.gz
power_supply: fix up CHARGE_COUNTER output to be more precise
As Richard Smith pointed out, ACR * 6250 / 15 provides for less
precision loss than ACR * 4167 / 10, _and_ it doesn't overflow.  Switch
to using that equation for CHARGE_COUNTER.

Signed-off-by: Andres Salomon <dilinger@debian.org>
Cc: "Richard A. Smith" <richard@laptop.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
Diffstat (limited to 'drivers/power')
-rw-r--r--drivers/power/olpc_battery.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/drivers/power/olpc_battery.c b/drivers/power/olpc_battery.c
index 9dd1589733c2..32570af3c5c9 100644
--- a/drivers/power/olpc_battery.c
+++ b/drivers/power/olpc_battery.c
@@ -19,7 +19,7 @@
 
 #define EC_BAT_VOLTAGE	0x10	/* uint16_t,	*9.76/32,    mV   */
 #define EC_BAT_CURRENT	0x11	/* int16_t,	*15.625/120, mA   */
-#define EC_BAT_ACR	0x12	/* int16_t,	*416.7,      µAh  */
+#define EC_BAT_ACR	0x12	/* int16_t,	*6250/15,    µAh  */
 #define EC_BAT_TEMP	0x13	/* uint16_t,	*100/256,   °C  */
 #define EC_AMB_TEMP	0x14	/* uint16_t,	*100/256,   °C  */
 #define EC_BAT_STATUS	0x15	/* uint8_t,	bitmask */
@@ -295,7 +295,7 @@ static int olpc_bat_get_property(struct power_supply *psy,
 			return ret;
 
 		ec_word = be16_to_cpu(ec_word);
-		val->intval = ec_word * 4167 / 10;
+		val->intval = ec_word * 6250 / 15;
 		break;
 	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
 		ret = olpc_ec_cmd(EC_BAT_SERIAL, NULL, 0, (void *)&ser_buf, 8);