[PATCH] power: supply: register HWMON devices with valid names

[Romain Izard]

With the introduction of the HWMON compatibility layer to the power
supply framework in Linux 5.3, all power supply devices' names can be
used directly to create HWMON devices with the same names.

But HWMON has rules on allowable names that are different from the power
supply framework. The dash character is forbidden, as it is used by the
libsensors library in userspace as a separator, whereas this character
is used in the device names in more than half of the existing power
supply drivers. This last case is consistent with the typical naming
usage with MFD and Device Tree.

This leads to warnings in the kernel log, with the format:

power_supply gpio-charger: hwmon: \
	'gpio-charger' is not a valid name attribute, please fix

Add a protection to power_supply_add_hwmon_sysfs() that replaces any
dash in the device name with an underscore when registering with the
HWMON framework. Other forbidden characters (star, slash, space, tab,
newline) are not replaced, as they are not in common use.

Fixes: e67d4dfc9ff1 ("power: supply: Add HWMON compatibility layer")
Signed-off-by: Romain Izard <romain.izard.pro@xxxxxxxxx>
---
 drivers/power/supply/power_supply_hwmon.c | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/drivers/power/supply/power_supply_hwmon.c b/drivers/power/supply/power_supply_hwmon.c
index 51fe60440d12..ebe964bd512c 100644
--- a/drivers/power/supply/power_supply_hwmon.c
+++ b/drivers/power/supply/power_supply_hwmon.c
@@ -284,6 +284,7 @@ int power_supply_add_hwmon_sysfs(struct power_supply *psy)
 	struct device *dev = &psy->dev;
 	struct device *hwmon;
 	int ret, i;
+	const char *name;
 
 	if (!devres_open_group(dev, power_supply_add_hwmon_sysfs,
 			       GFP_KERNEL))
@@ -334,7 +335,19 @@ int power_supply_add_hwmon_sysfs(struct power_supply *psy)
 		}
 	}
 
-	hwmon = devm_hwmon_device_register_with_info(dev, psy->desc->name,
+	name = psy->desc->name;
+	if (strchr(name, '-')) {
+		char *new_name;
+
+		new_name = devm_kstrdup(dev, name, GFP_KERNEL);
+		if (!new_name) {
+			ret = -ENOMEM;
+			goto error;
+		}
+		strreplace(new_name, '-', '_');
+		name = (const char *) new_name;
+	}
+	hwmon = devm_hwmon_device_register_with_info(dev, name,
 						psyhw,
 						&power_supply_hwmon_chip_info,
 						NULL);
-- 
2.17.1