linux-kernel - [PATCH 4/7] power: supply: core: hide unused HWMON labels

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Message-Id: <9dc504550be598dd333ebf41d28484b886ffd7c0.1585837575.git.mirq-linux@rere.qmqm.pl>
Date:   Thu, 02 Apr 2020 16:57:03 +0200
From:   Michał Mirosław <mirq-linux@...e.qmqm.pl>
To:     Andrey Smirnov <andrew.smirnov@...il.com>,
        Guenter Roeck <linux@...ck-us.net>,
        Sebastian Reichel <sebastian.reichel@...labora.com>
Cc:     linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: [PATCH 4/7] power: supply: core: hide unused HWMON labels

Currently HWMON emulation shows all labels (temp and ambient temp)
regardless if power supply supports reading the values. Check that at
least one property is enabled for each label.

Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
---
 drivers/power/supply/power_supply_hwmon.c | 43 +++++++++++++++++++++--
 1 file changed, 40 insertions(+), 3 deletions(-)

diff --git a/drivers/power/supply/power_supply_hwmon.c b/drivers/power/supply/power_supply_hwmon.c
index 83318a21fb52..118d73a2ab4a 100644
--- a/drivers/power/supply/power_supply_hwmon.c
+++ b/drivers/power/supply/power_supply_hwmon.c
@@ -103,6 +103,40 @@ static bool power_supply_hwmon_is_a_label(enum hwmon_sensor_types type,
 	return type == hwmon_temp && attr == hwmon_temp_label;
 }
 
+static bool power_supply_hwmon_has_property(
+	const struct power_supply_hwmon *psyhw,
+	enum hwmon_sensor_types type, u32 attr, int channel)
+{
+	int prop = power_supply_hwmon_to_property(type, attr, channel);
+
+	return prop >= 0 && test_bit(prop, psyhw->props);
+}
+
+static bool power_supply_hwmon_has_input(
+	const struct power_supply_hwmon *psyhw,
+	enum hwmon_sensor_types type, int channel)
+{
+	static const enum hwmon_temp_attributes temp_attrs[] = {
+		hwmon_temp_input,
+		hwmon_temp_min, hwmon_temp_max,
+		hwmon_temp_min_alarm, hwmon_temp_max_alarm,
+	};
+	size_t i;
+
+	switch (type) {
+	case hwmon_temp:
+		for (i = 0; i < ARRAY_SIZE(temp_attrs); ++i)
+			if (power_supply_hwmon_has_property(psyhw, type,
+					temp_attrs[i], channel))
+				return true;
+		break;
+	default:
+		break;
+	}
+
+	return false;
+}
+
 static bool power_supply_hwmon_is_writable(enum hwmon_sensor_types type,
 					   u32 attr)
 {
@@ -129,9 +163,12 @@ static umode_t power_supply_hwmon_is_visible(const void *data,
 	const struct power_supply_hwmon *psyhw = data;
 	int prop;
 
-
-	if (power_supply_hwmon_is_a_label(type, attr))
-		return 0444;
+	if (power_supply_hwmon_is_a_label(type, attr)) {
+		if (power_supply_hwmon_has_input(psyhw, type, channel))
+			return 0444;
+		else
+			return 0;
+	}
 
 	prop = power_supply_hwmon_to_property(type, attr, channel);
 	if (prop < 0 || !test_bit(prop, psyhw->props))
-- 
2.20.1