linux-kernel - [PATCH v4 1/4] power: supply: core: tabularize HWMON temperature labels

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Date:   Fri, 01 May 2020 17:11:18 +0200
From:   Michał Mirosław <mirq-linux@...e.qmqm.pl>
To:     Sebastian Reichel <sebastian.reichel@...labora.com>
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        clang-built-linux@...glegroups.com
Subject: [PATCH v4 1/4] power: supply: core: tabularize HWMON temperature
 labels

Rework power_supply_hwmon_read_string() to check it's parameters.
This allows to extend it later with labels for other types of
measurements.

Signed-off-by: Michał Mirosław <mirq-linux@...e.qmqm.pl>
---
v2: split from fix temperature labels
v3: remove power_supply_hwmon_read_string() parameter checks
    as it is internal API (suggested by Guenter Roeck)
v4: remove unreachable() as it triggers compiler bugs
---
 drivers/power/supply/power_supply_hwmon.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/power_supply_hwmon.c b/drivers/power/supply/power_supply_hwmon.c
index af72e5693f65..f5d538485aaa 100644
--- a/drivers/power/supply/power_supply_hwmon.c
+++ b/drivers/power/supply/power_supply_hwmon.c
@@ -13,6 +13,11 @@ struct power_supply_hwmon {
 	unsigned long *props;
 };
 
+static const char *const ps_temp_label[] = {
+	"temp",
+	"ambient temp",
+};
+
 static int power_supply_hwmon_in_to_property(u32 attr)
 {
 	switch (attr) {
@@ -180,7 +185,20 @@ static int power_supply_hwmon_read_string(struct device *dev,
 					  u32 attr, int channel,
 					  const char **str)
 {
-	*str = channel ? "temp ambient" : "temp";
+	switch (type) {
+	case hwmon_temp:
+		*str = ps_temp_label[channel];
+		break;
+	default:
+		/* unreachable, but see:
+		 * gcc bug #51513 [1] and clang bug #978 [2]
+		 *
+		 * [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=51513
+		 * [2] https://github.com/ClangBuiltLinux/linux/issues/978
+		 */
+		break;
+	}
+
 	return 0;
 }
 
-- 
2.20.1