[PATCH v2] platform/x86: lenovo/ymc: Only match lower byte in WMI lid switch query response

[Julian Haarmann]

On newer Lenovo Yoga devices like the "Yoga 9 2-in-1 14IPH11 - Type 83SE",
the hinge switch WMI query returns extra data in the upper bits
(e.g. 0x50001 laptop mode, 0x50002 tablet mode, ect.).

The driver previously checked for exact matches (0x01 laptop, 0x02 tablet,
ect.) causing newer switches to not work.

Mask the WMI query result to only match the lower byte and ignore upper
bits.

Signed-off-by: Julian Haarmann <julian.haarmann@xxxxxxxxxxxxxxx>
---
Changes in v2:
- Replaced raw bit mask with GENMASK() and FIELD_GET().

 drivers/platform/x86/lenovo/ymc.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/platform/x86/lenovo/ymc.c b/drivers/platform/x86/lenovo/ymc.c
index 1b73a55f1b89..015e046b0fce 100644
--- a/drivers/platform/x86/lenovo/ymc.c
+++ b/drivers/platform/x86/lenovo/ymc.c
@@ -8,6 +8,8 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
 #include <linux/acpi.h>
+#include <linux/bitfield.h>
+#include <linux/bits.h>
 #include <linux/dmi.h>
 #include <linux/input.h>
 #include <linux/input/sparse-keymap.h>
@@ -20,6 +22,8 @@
 #define LENOVO_YMC_QUERY_INSTANCE 0
 #define LENOVO_YMC_QUERY_METHOD 0x01
 
+#define LENOVO_YMC_STATE_MASK GENMASK(7, 0)
+
 static bool force;
 module_param(force, bool, 0444);
 MODULE_PARM_DESC(force, "Force loading on boards without a convertible DMI chassis-type");
@@ -85,7 +89,9 @@ static void lenovo_ymc_notify(struct wmi_device *wdev, union acpi_object *data)
 			"WMI event data is not an integer\n");
 		goto free_obj;
 	}
-	code = obj->integer.value;
+
+	/* strip upper bits (e.g. 0x50000) on newer devices */
+	code = FIELD_GET(LENOVO_YMC_STATE_MASK, obj->integer.value);
 
 	if (!sparse_keymap_report_event(priv->input_dev, code, 1, true))
 		dev_warn(&wdev->dev, "Unknown key %d pressed\n", code);
-- 
2.54.0