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authorPaer-Olof Haakansson <par-olof.hakansson@stericsson.com>2013-01-11 14:13:05 +0100
committerAnton Vorontsov <anton@enomsg.org>2013-01-16 02:44:44 +0100
commitf902dadc123376b973e5f9cb216a22675a2a9181 (patch)
tree57120e6d0891005a173dc1b37d53cd19e805ad77 /drivers/power
parentab8500_charger: Adds support for legacy USB chargers (diff)
downloadlinux-f902dadc123376b973e5f9cb216a22675a2a9181.tar.xz
linux-f902dadc123376b973e5f9cb216a22675a2a9181.zip
ab8500_fg: Overflow in current calculation
When calculating the average current the nominator will overflow when the charging current is high. Signed-off-by: Lee Jones <lee.jones@linaro.org> Signed-off-by: Henrik Sölver <henrik.solver@stericsson.com> Reviewed-by: Par-Olof HAKANSSON <par-olof.hakansson@stericsson.com> Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com> Tested-by: Par-Olof HAKANSSON <par-olof.hakansson@stericsson.com> Signed-off-by: Anton Vorontsov <anton@enomsg.org>
Diffstat (limited to 'drivers/power')
-rw-r--r--drivers/power/ab8500_fg.c9
1 files changed, 4 insertions, 5 deletions
diff --git a/drivers/power/ab8500_fg.c b/drivers/power/ab8500_fg.c
index 2917def7621c..570577c32ade 100644
--- a/drivers/power/ab8500_fg.c
+++ b/drivers/power/ab8500_fg.c
@@ -805,12 +805,9 @@ static void ab8500_fg_acc_cur_work(struct work_struct *work)
/*
* Convert to unit value in mA
- * Full scale input voltage is
- * 66.660mV => LSB = 66.660mV/(4096*res) = 1.627mA
- * Given a 250ms conversion cycle time the LSB corresponds
- * to 112.9 nAh. Convert to current by dividing by the conversion
+ * by dividing by the conversion
* time in hours (= samples / (3600 * 4)h)
- * 112.9nAh assumes 10mOhm, but fg_res is in 0.1mOhm
+ * and multiply with 1000
*/
di->avg_curr = (val * QLSB_NANO_AMP_HOURS_X10 * 36) /
(1000 * di->bm->fg_res * (di->fg_samples / 4));
@@ -821,6 +818,8 @@ static void ab8500_fg_acc_cur_work(struct work_struct *work)
queue_work(di->fg_wq, &di->fg_work);
+ dev_dbg(di->dev, "fg_res: %d, fg_samples: %d, gasg: %d, accu_charge: %d \n",
+ di->bm->fg_res, di->fg_samples, val, di->accu_charge);
return;
exit:
dev_err(di->dev,