[PATCH] HID: apple: fix endianness of keyboard backlight reports

[PATCH] HID: apple: fix endianness of keyboard backlight reports

[Andre Eikmeyer]

The raw reports used by the T2 butterfly keyboard backlight contain
little-endian 16-bit fields. They are currently read and written as native
u16 values, leaving the wire format dependent on host endianness.

We should describe these fields as __le16 and convert them explicitly when
reading the backlight limits and writing the brightness and transition
rate.

Reported-by: Sashiko AI review <sashiko-bot@kernel.org>
Link: https://lore.kernel.org/r/20260718123641.DA2FF1F000E9@smtp.kernel.org
Signed-off-by: Andre Eikmeyer <dev@deq.rocks>
---
 drivers/hid/hid-apple.c | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/hid/hid-apple.c b/drivers/hid/hid-apple.c
index bf7dd0fbf249..473b6722938e 100644
--- a/drivers/hid/hid-apple.c
+++ b/drivers/hid/hid-apple.c
@@ -94,14 +94,16 @@ struct apple_sc_backlight {
 struct apple_backlight_config_report {
 	u8 report_id;
 	u8 version;
-	u16 backlight_off, backlight_on_min, backlight_on_max;
+	__le16 backlight_off;
+	__le16 backlight_on_min;
+	__le16 backlight_on_max;
 };
 
 struct apple_backlight_set_report {
 	u8 report_id;
 	u8 version;
-	u16 backlight;
-	u16 rate;
+	__le16 backlight;
+	__le16 rate;
 };
 
 struct apple_magic_backlight {
@@ -803,8 +805,8 @@ static int apple_backlight_set(struct hid_device *hdev, u16 value, u16 rate)
 
 	rep->report_id = 0xB0;
 	rep->version = 1;
-	rep->backlight = value;
-	rep->rate = rate;
+	rep->backlight = cpu_to_le16(value);
+	rep->rate = cpu_to_le16(rate);
 
 	ret = hid_hw_raw_request(hdev, 0xB0u, (u8 *) rep, sizeof(*rep),
 				 HID_OUTPUT_REPORT, HID_REQ_SET_REPORT);
@@ -848,7 +850,9 @@ static int apple_backlight_init(struct hid_device *hdev)
 	}
 
 	hid_dbg(hdev, "backlight config: off=%u, on_min=%u, on_max=%u\n",
-		rep->backlight_off, rep->backlight_on_min, rep->backlight_on_max);
+		le16_to_cpu(rep->backlight_off),
+		le16_to_cpu(rep->backlight_on_min),
+		le16_to_cpu(rep->backlight_on_max));
 
 	asc->backlight = devm_kzalloc(&hdev->dev, sizeof(*asc->backlight), GFP_KERNEL);
 	if (!asc->backlight) {
@@ -858,7 +862,7 @@ static int apple_backlight_init(struct hid_device *hdev)
 
 	asc->backlight->hdev = hdev;
 	asc->backlight->cdev.name = "apple::kbd_backlight";
-	asc->backlight->cdev.max_brightness = rep->backlight_on_max;
+	asc->backlight->cdev.max_brightness = le16_to_cpu(rep->backlight_on_max);
 	asc->backlight->cdev.brightness_set_blocking = apple_backlight_led_set;
 	asc->backlight->cdev.flags = LED_CORE_SUSPENDRESUME;
 
-- 
2.55.0