linux-kernel - [PATCH 5/5] power: supply: bq27xxx: Correct supply status with current draw

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Message-Id: <20170430182727.24412-5-contact@paulk.fr>
Date:   Sun, 30 Apr 2017 20:27:27 +0200
From:   Paul Kocialkowski <contact@...lk.fr>
To:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Pali Rohár <pali.rohar@...il.com>,
        "Andrew F . Davis" <afd@...com>,
        Sebastian Reichel <sre@...nel.org>,
        Chris Lapa <chris@...a.com.au>,
        Matt Ranostay <mranostay@...il.com>,
        Paul Kocialkowski <contact@...lk.fr>
Subject: [PATCH 5/5] power: supply: bq27xxx: Correct supply status with current draw

The status reported directly by the battery controller is not always
reliable and should be corrected based on the current draw information.

This implements such a correction with a dedicated function, called
when retrieving the supply status.

Signed-off-by: Paul Kocialkowski <contact@...lk.fr>
---
 drivers/power/supply/bq27xxx_battery.c | 28 ++++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)

diff --git a/drivers/power/supply/bq27xxx_battery.c b/drivers/power/supply/bq27xxx_battery.c
index cade00df6162..f7694e775e68 100644
--- a/drivers/power/supply/bq27xxx_battery.c
+++ b/drivers/power/supply/bq27xxx_battery.c
@@ -1171,8 +1171,22 @@ static int bq27xxx_battery_status(struct bq27xxx_device_info *di,
 				  union power_supply_propval *val)
 {
 	int status;
+	int curr;
+	int flags;
+
+	curr = bq27xxx_read(di, BQ27XXX_REG_AI, false);
+	if (curr < 0) {
+		dev_err(di->dev, "error reading current\n");
+		return curr;
+	}
 
 	if (di->chip == BQ27000 || di->chip == BQ27010) {
+		flags = bq27xxx_read(di, BQ27XXX_REG_FLAGS, true);
+		if (flags & BQ27000_FLAG_CHGS) {
+			dev_dbg(di->dev, "negative current!\n");
+			curr = -curr;
+		}
+
 		if (di->cache.flags & BQ27000_FLAG_FC)
 			status = POWER_SUPPLY_STATUS_FULL;
 		else if (di->cache.flags & BQ27000_FLAG_CHGS)
@@ -1182,6 +1196,8 @@ static int bq27xxx_battery_status(struct bq27xxx_device_info *di,
 		else
 			status = POWER_SUPPLY_STATUS_DISCHARGING;
 	} else {
+		curr = (int)((s16)curr) * 1000;
+
 		if (di->cache.flags & BQ27XXX_FLAG_FC)
 			status = POWER_SUPPLY_STATUS_FULL;
 		else if (di->cache.flags & BQ27XXX_FLAG_DSC)
@@ -1190,6 +1206,18 @@ static int bq27xxx_battery_status(struct bq27xxx_device_info *di,
 			status = POWER_SUPPLY_STATUS_CHARGING;
 	}
 
+
+	if (curr == 0 && status != POWER_SUPPLY_STATUS_NOT_CHARGING)
+		status = POWER_SUPPLY_STATUS_FULL;
+
+	if (status == POWER_SUPPLY_STATUS_FULL) {
+		/* Drawing or providing current when full */
+		if (curr > 0)
+			status = POWER_SUPPLY_STATUS_CHARGING;
+		else if (curr < 0)
+			status = POWER_SUPPLY_STATUS_DISCHARGING;
+	}
+
 	if (di->status_retry == 0 && di->status_change_reference != status) {
 		di->status_change_reference = status;
 		power_supply_changed(di->bat);
-- 
2.12.2