platform/x86: thinkpad_acpi: Change hotkey_reserved_mask initialization

Change the hotkey_reserved_mask initialization to hardcode the list
of reserved keys. There are only a few reserved keys and the code to
iterate over the keymap will be removed when moving to sparse-keymaps.

Note only the 32 original hotkeys are affected by the hotkey_*_mask values:

	if (i < sizeof(hotkey_reserved_mask)*8)
		hotkey_reserved_mask |= 1 << i;

The (i < sizeof(hotkey_reserved_mask)*8) condition translates to (i < 32)
so this code only ever set bits in hotkey_reserved_mask for the 32 original
hotkeys. Therefor this patch does not set any bits in hotkey_reserved_mask
for the KEY_RESERVED mappings for the adaptive keyboard scancodes.
Tested-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Reviewed-by: Mark Pearson <mpearson-lenovo@squebb.ca>
Reviewed-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Link: https://lore.kernel.org/r/20240424122834.19801-17-hdegoede@redhat.com

drivers/platform/x86/thinkpad_acpi.c

@@ -3545,6 +3545,19 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
 	dbg_printk(TPACPI_DBG_INIT | TPACPI_DBG_HKEY,
 		   "using keymap number %lu\n", keymap_id);
 
+	/* Keys which should be reserved on both IBM and Lenovo models */
+	hotkey_reserved_mask = TP_ACPI_HKEY_KBD_LIGHT_MASK |
+			       TP_ACPI_HKEY_VOLUP_MASK |
+			       TP_ACPI_HKEY_VOLDWN_MASK |
+			       TP_ACPI_HKEY_MUTE_MASK;
+	/*
+	 * Reserve brightness up/down unconditionally on IBM models, on Lenovo
+	 * models these are disabled based on acpi_video_get_backlight_type().
+	 */
+	if (keymap_id == TPACPI_KEYMAP_IBM_GENERIC)
+		hotkey_reserved_mask |= TP_ACPI_HKEY_BRGHTUP_MASK |
+					TP_ACPI_HKEY_BRGHTDWN_MASK;
+
 	hotkey_keycode_map = kmemdup(&tpacpi_keymaps[keymap_id],
 			TPACPI_HOTKEY_MAP_SIZE,	GFP_KERNEL);
 	if (!hotkey_keycode_map) {
@@ -3560,9 +3573,6 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
 		if (hotkey_keycode_map[i] != KEY_RESERVED) {
 			input_set_capability(tpacpi_inputdev, EV_KEY,
 						hotkey_keycode_map[i]);
-		} else {
-			if (i < sizeof(hotkey_reserved_mask)*8)
-				hotkey_reserved_mask |= 1 << i;
 		}
 	}
 
@@ -3587,9 +3597,8 @@ static int __init hotkey_init(struct ibm_init_struct *iibm)
 		/* Disable brightness up/down on Lenovo thinkpads when
 		 * ACPI is handling them, otherwise it is plain impossible
 		 * for userspace to do something even remotely sane */
-		hotkey_reserved_mask |=
-			(1 << TP_ACPI_HOTKEYSCAN_FNHOME)
-			| (1 << TP_ACPI_HOTKEYSCAN_FNEND);
+		hotkey_reserved_mask |= TP_ACPI_HKEY_BRGHTUP_MASK |
+					TP_ACPI_HKEY_BRGHTDWN_MASK;
 		hotkey_unmap(TP_ACPI_HOTKEYSCAN_FNHOME);
 		hotkey_unmap(TP_ACPI_HOTKEYSCAN_FNEND);
 	}