[PATCH] platform/x86: asus-wmi: fix unclear usage of bd->props.power

[Denis Benato <denis.benato@linux.dev>]

The bd->props.power is checked in parts of the driver correctly comparing with
BACKLIGHT_POWER_ON, while in others with a raw usage of bd->props.power
and !bd->props.power, moreover in certain checks the logic has been
inverted due to BACKLIGHT_POWER_ON being defined as 0: fix both the wrong
usage and the inconsistencies by using proper comparisons.

Fixes: 130d29c5627c ("platform/x86: asus-wmi: adjust screenpad power/brightness handling")
Closes: https://lore.kernel.org/all/178362762638.911488.8564892548331679884@eldamar.lan/
Closes: https://lore.kernel.org/all/ea9c63d1-4776-49d5-9dc4-6c09498f99c9@linux.dev/
Signed-off-by: Denis Benato <denis.benato@linux.dev>
---
 drivers/platform/x86/asus-wmi.c | 12 +++++++++---
 1 file changed, 9 insertions(+), 3 deletions(-)

diff --git a/drivers/platform/x86/asus-wmi.c b/drivers/platform/x86/asus-wmi.c
index 8610663b8269..3600dddd8f36 100644
--- a/drivers/platform/x86/asus-wmi.c
+++ b/drivers/platform/x86/asus-wmi.c
@@ -4500,7 +4500,8 @@ static int update_screenpad_bl_status(struct backlight_device *bd)
 	u32 ctrl_param = bd->props.brightness;
 	int err = 0;
 
-	if (bd->props.power) {
+	switch (bd->props.power) {
+	case BACKLIGHT_POWER_ON:
 		err = asus_wmi_set_devstate(ASUS_WMI_DEVID_SCREENPAD_POWER, 1, NULL);
 		if (err < 0)
 			return err;
@@ -4508,12 +4509,17 @@ static int update_screenpad_bl_status(struct backlight_device *bd)
 		err = asus_wmi_set_devstate(ASUS_WMI_DEVID_SCREENPAD_LIGHT, ctrl_param, NULL);
 		if (err < 0)
 			return err;
-	}
+		break;
 
-	if (!bd->props.power) {
+	case BACKLIGHT_POWER_OFF:
 		err = asus_wmi_set_devstate(ASUS_WMI_DEVID_SCREENPAD_POWER, 0, NULL);
 		if (err < 0)
 			return err;
+		break;
+
+	default:
+		pr_warn("Invalid screenpad backlight power state: %d\n", bd->props.power);
+		return -EINVAL;
 	}
 
 	return err;
-- 
2.47.3