linux-kernel - [PATCH 1/2] power:bq27xxx: fix reading for bq27000 and bq27010

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Date:	Thu, 17 Dec 2015 11:12:53 +0100
From:	"H. Nikolaus Schaller" <hns@...delico.com>
To:	Pali Rohár <pali.rohar@...il.com>,
	Sebastian Reichel <sre@...nel.org>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	David Woodhouse <dwmw2@...radead.org>
Cc:	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	gta04-owner@...delico.com, marek@...delico.com,
	"H. Nikolaus Schaller" <hns@...delico.com>
Subject: [PATCH 1/2] power:bq27xxx: fix reading for bq27000 and bq27010

bug: the driver reports funny capacity values:

root@...ux:/sys/class/power_supply/bq27000-battery# cat uevent
POWER_SUPPLY_NAME=bq27000-battery
POWER_SUPPLY_STATUS=Charging
POWER_SUPPLY_PRESENT=1
POWER_SUPPLY_VOLTAGE_NOW=3702000
POWER_SUPPLY_CURRENT_NOW=-464635
POWER_SUPPLY_CAPACITY=1536			<- over 100% is magic
POWER_SUPPLY_CAPACITY_LEVEL=Normal
POWER_SUPPLY_TEMP=311
POWER_SUPPLY_TIME_TO_FULL_NOW=10440
POWER_SUPPLY_TECHNOLOGY=Li-ion
POWER_SUPPLY_CHARGE_FULL=805450
POWER_SUPPLY_CHARGE_NOW=1068
POWER_SUPPLY_CHARGE_FULL_DESIGN=8844998	<- battery has just 1200 mAh
POWER_SUPPLY_CYCLE_COUNT=21
POWER_SUPPLY_ENERGY_NOW=0
POWER_SUPPLY_POWER_AVG=0
POWER_SUPPLY_HEALTH=Good
POWER_SUPPLY_MANUFACTURER=Texas Instruments

reason: the state of charge and the design capacity register are single
byte only. The design capacity returns the higer order byte.

tested: GTA04 with Openmoko/FIC HF08x battery (using hdq)

Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
---
 drivers/power/bq27xxx_battery.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/power/bq27xxx_battery.c b/drivers/power/bq27xxx_battery.c
index 880233c..e54a125 100644
--- a/drivers/power/bq27xxx_battery.c
+++ b/drivers/power/bq27xxx_battery.c
@@ -471,7 +471,10 @@ static int bq27xxx_battery_read_soc(struct bq27xxx_device_info *di)
 {
 	int soc;
 
-	soc = bq27xxx_read(di, BQ27XXX_REG_SOC, false);
+	if (di->chip == BQ27000 || di->chip == BQ27010)
+		soc = bq27xxx_read(di, BQ27XXX_REG_SOC, true);
+	else
+		soc = bq27xxx_read(di, BQ27XXX_REG_SOC, false);
 
 	if (soc < 0)
 		dev_dbg(di->dev, "error reading State-of-Charge\n");
@@ -536,7 +539,10 @@ static int bq27xxx_battery_read_dcap(struct bq27xxx_device_info *di)
 {
 	int dcap;
 
-	dcap = bq27xxx_read(di, BQ27XXX_REG_DCAP, false);
+	if (di->chip == BQ27000 || di->chip == BQ27010)
+		dcap = bq27xxx_read(di, BQ27XXX_REG_DCAP, true);
+	else
+		dcap = bq27xxx_read(di, BQ27XXX_REG_DCAP, false);
 
 	if (dcap < 0) {
 		dev_dbg(di->dev, "error reading initial last measured discharge\n");
@@ -544,7 +550,7 @@ static int bq27xxx_battery_read_dcap(struct bq27xxx_device_info *di)
 	}
 
 	if (di->chip == BQ27000 || di->chip == BQ27010)
-		dcap *= BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS;
+		dcap = (dcap << 8) * BQ27XXX_CURRENT_CONSTANT / BQ27XXX_RS;
 	else
 		dcap *= 1000;
 
-- 
2.5.1

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