linux-kernel - [PATCH v4] power: supply: sbs-battery: don't assume i2c errors as battery disconnect

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Message-Id: <20200828043626.1247250-1-ikjn@chromium.org>
Date:   Fri, 28 Aug 2020 12:36:26 +0800
From:   Ikjoon Jang <ikjn@...omium.org>
To:     Sebastian Reichel <sre@...nel.org>, linux-pm@...r.kernel.org
Cc:     linux-kernel@...r.kernel.org, drinkcat@...omium.org,
        dianders@...omium.org, briannorris@...omium.org,
        Ikjoon Jang <ikjn@...omium.org>
Subject: [PATCH v4] power: supply: sbs-battery: don't assume i2c errors as battery disconnect

Current sbs-battery considers all smbus errors as disconnection events
when battery-detect pin isn't supplied, and restored to present state back
when any successful transaction is made.

This can lead to unwanted state changes between present and !present
when there's one i2c error and other following commands were successful.

This patch provides a unified way of checking presence by calling
sbs_get_battery_presence_and_health() when detect pin is not used.

Signed-off-by: Ikjoon Jang <ikjn@...omium.org>
---
v4: rebase from merge conflict, amend commit messages
v3: check return value of get_presence_and_health()
v2: combine get_presence_and_health functions to reuse
---

 drivers/power/supply/sbs-battery.c | 25 +++++++++++++++++--------
 1 file changed, 17 insertions(+), 8 deletions(-)

diff --git a/drivers/power/supply/sbs-battery.c b/drivers/power/supply/sbs-battery.c
index 6273211cd673..dacc4bc1c013 100644
--- a/drivers/power/supply/sbs-battery.c
+++ b/drivers/power/supply/sbs-battery.c
@@ -959,10 +959,17 @@ static int sbs_get_property(struct power_supply *psy,
 		return -EINVAL;
 	}
 
-	if (!chip->gpio_detect &&
-		chip->is_present != (ret >= 0)) {
-		sbs_update_presence(chip, (ret >= 0));
-		power_supply_changed(chip->power_supply);
+	if (!chip->gpio_detect && chip->is_present != (ret >= 0)) {
+		bool old_present = chip->is_present;
+		union power_supply_propval val;
+
+		ret = sbs_get_battery_presence_and_health(
+				client, POWER_SUPPLY_PROP_PRESENT, &val);
+
+		sbs_update_presence(chip, !ret && val.intval);
+
+		if (old_present != chip->is_present)
+			power_supply_changed(chip->power_supply);
 	}
 
 done:
@@ -1147,11 +1154,13 @@ static int sbs_probe(struct i2c_client *client)
 	 * to the battery.
 	 */
 	if (!(force_load || chip->gpio_detect)) {
-		rc = sbs_read_word_data(client, sbs_data[REG_STATUS].addr);
+		union power_supply_propval val;
 
-		if (rc < 0) {
-			dev_err(&client->dev, "%s: Failed to get device status\n",
-				__func__);
+		rc = sbs_get_battery_presence_and_health(
+				client, POWER_SUPPLY_PROP_PRESENT, &val);
+		if (rc < 0 || !val.intval) {
+			dev_err(&client->dev, "Failed to get present status\n");
+			rc = -ENODEV;
 			goto exit_psupply;
 		}
 	}
-- 
2.28.0.402.g5ffc5be6b7-goog