linux-kernel - [PATCH] power: supply: sbs-battery: Handle unsupported PROP_TIME_TO_EMPTY

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Date: Thu, 07 Mar 2024 17:05:10 -0500
From: Nícolas F. R. A. Prado <nfraprado@...labora.com>
To: Sebastian Reichel <sre@...nel.org>
Cc: kernel@...labora.com, linux-pm@...r.kernel.org, 
 linux-kernel@...r.kernel.org, 
 Nícolas F. R. A. Prado <nfraprado@...labora.com>
Subject: [PATCH] power: supply: sbs-battery: Handle unsupported
 PROP_TIME_TO_EMPTY_NOW

Despite the RunTimeToEmpty() (0x11) function being defined in the SBS
specification as required, it seems that not all batteries implement it.
On platforms with such batteries, reading the property will cause an
error to be printed:

power_supply sbs-8-000b: driver failed to report `time_to_empty_now' property: -5

This not only pollutes the log, distracting from real problems on the
device, but also prevents the uevent file from being read since it
contains all properties, including the faulty one.

The following table summarizes the findings for a handful of platforms:

Platform                                Status  Manufacturer    Model
------------------------------------------------------------------------
mt8186-corsola-steelix-sku131072        OK      BYD             L22B3PG0
mt8195-cherry-tomato-r2                 NOT OK  PANASON         AP16L5J
mt8192-asurada-spherion-r0              NOT OK  PANASON         AP15O5L
mt8183-kukui-jacuzzi-juniper-sku16      NOT OK  LGC KT0         AP16L8J
mt8173-elm-hana                         OK      Sunwoda         L18D3PG1
sc7180-trogdor-lazor-limozeen-nots-r5   NOT OK  Murata          AP18C4K
sc7180-trogdor-kingoftown               NOT OK  333-AC-0D-A     GG02047XL
rk3399-gru-kevin                        OK      SDI             4352D51

Identify during probe, based on the battery model, if this is one of the
quirky batteries, and if so, don't register the
POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW property.

Signed-off-by: Nícolas F. R. A. Prado <nfraprado@...labora.com>
---
 drivers/power/supply/sbs-battery.c | 45 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

diff --git a/drivers/power/supply/sbs-battery.c b/drivers/power/supply/sbs-battery.c
index a6c204c08232..85ff331cf87a 100644
--- a/drivers/power/supply/sbs-battery.c
+++ b/drivers/power/supply/sbs-battery.c
@@ -1112,6 +1112,49 @@ static const struct power_supply_desc sbs_default_desc = {
 	.external_power_changed = sbs_external_power_changed,
 };
 
+static const char * const unsupported_time_to_empty_now_models[] = {
+	"AP16L5J", "AP15O5L", "AP16L8J", "AP18C4K", "GG02047XL"
+};
+
+static void sbs_remove_unsupported_properties(struct power_supply_config *psy_cfg,
+					      struct power_supply_desc *sbs_desc)
+{
+	enum power_supply_property *new_properties;
+	struct sbs_info *chip = psy_cfg->drv_data;
+	bool missing_time_to_empty_now = false;
+	const char *model_name;
+	unsigned int new_num_properties;
+	unsigned int i = 0, j = 0;
+
+	model_name = sbs_get_constant_string(chip, POWER_SUPPLY_PROP_MODEL_NAME);
+	if (IS_ERR(model_name))
+		return;
+
+	for (i = 0; i < ARRAY_SIZE(unsupported_time_to_empty_now_models); i++) {
+		if (!strcmp(model_name, unsupported_time_to_empty_now_models[i])) {
+			missing_time_to_empty_now = true;
+			break;
+		}
+	}
+
+	if (!missing_time_to_empty_now)
+		return;
+
+	new_num_properties = ARRAY_SIZE(sbs_properties) - 1;
+	new_properties = devm_kzalloc(&chip->client->dev, new_num_properties * sizeof(sbs_properties[0]), GFP_KERNEL);
+
+	for (i = 0; i < sbs_desc->num_properties; i++) {
+		if (sbs_desc->properties[i] == POWER_SUPPLY_PROP_TIME_TO_EMPTY_NOW)
+			continue;
+
+		new_properties[j] = sbs_desc->properties[i];
+		j++;
+	}
+
+	sbs_desc->properties = new_properties;
+	sbs_desc->num_properties = new_num_properties;
+};
+
 static int sbs_probe(struct i2c_client *client)
 {
 	struct sbs_info *chip;
@@ -1210,6 +1253,8 @@ static int sbs_probe(struct i2c_client *client)
 	if (rc)
 		return rc;
 
+	sbs_remove_unsupported_properties(&psy_cfg, sbs_desc);
+
 	chip->power_supply = devm_power_supply_register(&client->dev, sbs_desc,
 						   &psy_cfg);
 	if (IS_ERR(chip->power_supply))

---
base-commit: 11afac187274a6177a7ac82997f8691c0f469e41
change-id: 20240307-sbs-time-empty-now-error-322bc074d3f2

Best regards,
-- 
Nícolas F. R. A. Prado <nfraprado@...labora.com>