Re: [PATCH v5] HID: logitech-hidpp: Add support for HID++ Multi-Platform feature (0x4531)

On Wed, 2026-07-01 at 10:37 +0300, DevExalt wrote:

From: "Baraa Atta (Dev Exalt)" <redacted>

<snip>

+
+#define HIDPP_MULTIPLATFORM_FEAT_ID			0x4531
+#define HIDPP_MULTIPLATFORM_GET_FEATURE_INFO		0x00
+#define HIDPP_MULTIPLATFORM_GET_PLATFORM_DESCRIPTOR	0x10
+#define HIDPP_MULTIPLATFORM_SET_CURRENT_PLATFORM	0x30
+
+#define
HIDPP_MULTIPLATFORM_PLATFORM_MASK_TIZEN		BIT(0)
+#define HIDPP_MULTIPLATFORM_PLATFORM_MASK_WINDOWS	BIT(8)
+#define HIDPP_MULTIPLATFORM_PLATFORM_MASK_WINEMB	BIT(9)
+#define
HIDPP_MULTIPLATFORM_PLATFORM_MASK_LINUX		BIT(10)
+#define HIDPP_MULTIPLATFORM_PLATFORM_MASK_CHROME	BIT(11)
+#define HIDPP_MULTIPLATFORM_PLATFORM_MASK_ANDROID	BIT(12)
+#define
HIDPP_MULTIPLATFORM_PLATFORM_MASK_MACOS		BIT(13)
+#define HIDPP_MULTIPLATFORM_PLATFORM_MASK_IOS		BIT(14)
+#define
HIDPP_MULTIPLATFORM_PLATFORM_MASK_WEBOS		BIT(15)
+
+struct hidpp_platform_desc {
+	u8 plat_idx;
+	u8 desc_idx;
+	u16 plat_mask;
+};
+
+/*
+ * Platform names exposed through the "platform" sysfs attribute.
The order of
+ * this array must stay in sync with multiplatform_masks[] below, as
the index
+ * returned by sysfs_match_string() is used to look up the matching
mask.
+ */
+static const char * const multiplatform_names[] = {
+	"windows", "winemb", "linux", "chrome",
+	"android", "macos", "ios", "webos", "tizen", NULL
+};
+
+static const u16 multiplatform_masks[] = {
+	HIDPP_MULTIPLATFORM_PLATFORM_MASK_WINDOWS,
+	HIDPP_MULTIPLATFORM_PLATFORM_MASK_WINEMB,
+	HIDPP_MULTIPLATFORM_PLATFORM_MASK_LINUX,
+	HIDPP_MULTIPLATFORM_PLATFORM_MASK_CHROME,
+	HIDPP_MULTIPLATFORM_PLATFORM_MASK_ANDROID,
+	HIDPP_MULTIPLATFORM_PLATFORM_MASK_MACOS,
+	HIDPP_MULTIPLATFORM_PLATFORM_MASK_IOS,
+	HIDPP_MULTIPLATFORM_PLATFORM_MASK_WEBOS,
+	HIDPP_MULTIPLATFORM_PLATFORM_MASK_TIZEN,

Wouldn't something like:
static enum multiplatform_masks = {
	HIDPP_MULTIPLATFORM_PLATFORM_MASK_WINDOWS = 8,
	HIDPP_MULTIPLATFORM_PLATFORM_MASK_WINEMB = 9,
...
};

followed by:
static const char * const multiplatform_names[] = {
  [HIDPP_MULTIPLATFORM_PLATFORM_MASK_WINDOWS] = "windows",
...
};

work? It makes the array a little bit bigger, but not hugely.

That way it completely negates the need to keep 2 arrays, and both of
them in sync.

That hunk shouldn't be necessary (since
e04a0442d33b8cf183bba38646447b891bb02123) unless the device was
absolutely unusable without the HID++ driver.

Rest looks fine, I'll try to test it on my Slim Solar+.

Cheers