linux-kernel - [PATCH] power: max17042: do not lose accuracy calculating current

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Message-ID: <D8CE7665-74C6-4717-B377-EE17D3DA5F91@marvell.com>
Date:	Fri, 12 Aug 2011 21:19:57 -0700
From:	Philip Rakity <prakity@...vell.com>
To:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:	Anton Vorontsov <cbouatmailru@...il.com>,
	Kyungmin Park <kyungmin.park@...sung.com>,
	"myungjoo.ham@...sung.com" <myungjoo.ham@...sung.com>
Subject: [PATCH] power: max17042: do not lose accuracy calculating
 current_now 

PROP_CURRENT_NOW value is first divided then multiplied up
causing a lose of accuracy.  Use the same method as
PROP_CURRENT_AVG to do the calculation.

Signed-off-by: Philip Rakity <prakity@...vell.com>
---
 drivers/power/max17042_battery.c |    3 +--
 1 files changed, 1 insertions(+), 2 deletions(-)

diff --git a/drivers/power/max17042_battery.c b/drivers/power/max17042_battery.c
index 4245806..7b7762a 100644
--- a/drivers/power/max17042_battery.c
+++ b/drivers/power/max17042_battery.c
@@ -153,8 +153,7 @@ static int max17042_get_property(struct power_supply *psy,
 				val->intval++;
 				val->intval *= -1;
 			}
-			val->intval >>= 4;
-			val->intval *= 1000000 * 25 / chip->pdata->r_sns;
+			val->intval *= 1562500 / chip->pdata->r_sns;
 		} else {
 			return -EINVAL;
 		}
-- 
1.7.0.4


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