linux-kernel - [PATCH] power:bq27xxx: 27000/10 read FLAGS register as single

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Message-Id: <6ff28e18f78d1b9581cba5fd214fcc00e4a6d23a.1468858328.git.hns@goldelico.com>
Date:	Mon, 18 Jul 2016 18:12:09 +0200
From:	"H. Nikolaus Schaller" <hns@...delico.com>
To:	"Andrew F . Davis" <afd@...com>,
	Ivaylo Dimitrov <ivo.g.dimitrov.75@...il.com>,
	Andrzej Hajda <a.hajda@...sung.com>,
	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,
	letux-kernel@...nphoenux.org,
	"H. Nikolaus Schaller" <hns@...delico.com>
Subject: [PATCH] power:bq27xxx: 27000/10 read FLAGS register as single

The bq27000 and bq27010 have a single byte FLAGS register.
Other gauges have 16 bit FLAGS registers.

For reading the FLAGS register it is sufficient to read the single
register instead of reading RSOC at the next higher address as
well and then ignore the high byte.

This does not change functionality but optimizes i2c and hdq
traffic.

Signed-off-by: H. Nikolaus Schaller <hns@...delico.com>
---
 drivers/power/bq27xxx_battery.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/power/bq27xxx_battery.c b/drivers/power/bq27xxx_battery.c
index 45f6ebf..56712b2 100644
--- a/drivers/power/bq27xxx_battery.c
+++ b/drivers/power/bq27xxx_battery.c
@@ -656,8 +656,9 @@ static bool bq27xxx_battery_dead(struct bq27xxx_device_info *di, u16 flags)
 static int bq27xxx_battery_read_health(struct bq27xxx_device_info *di)
 {
 	int flags;
+	bool has_singe_flag = di->chip == BQ27000 || di->chip == BQ27010;
 
-	flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, false);
+	flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, has_singe_flag);
 	if (flags < 0) {
 		dev_err(di->dev, "error reading flag register:%d\n", flags);
 		return flags;
@@ -760,7 +761,7 @@ static int bq27xxx_battery_current(struct bq27xxx_device_info *di,
 	}
 
 	if (di->chip == BQ27000 || di->chip == BQ27010) {
-		flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, false);
+		flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, true);
 		if (flags & BQ27000_FLAG_CHGS) {
 			dev_dbg(di->dev, "negative current!\n");
 			curr = -curr;
-- 
2.7.3