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>
diff --git a/drivers/power/olpc_battery.c b/drivers/power/olpc_battery.c
index 9dd1589..32570af 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 @@
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);