[PATCH v4] HID: input: Add support for Programmable Buttons

[Thomas Weißschuh]

Map them to KEY_MACRO# event codes.

These buttons are defined by HID as follows:
"The user defines the function of these buttons to control software applications or GUI objects."

This matches the semantics of the KEY_MACRO# input event codes that Linux supports.

Also add support for HID "Named Array" collections.
Also add hid-debug support for KEY_MACRO#.

Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---

---

v1: https://lore.kernel.org/linux-input/20210519160349.609690-1-linux@xxxxxxxxxxxxxx/

v1 -> v2: Only handle the 30 keys known

v2: https://lore.kernel.org/linux-input/20210519174345.614467-1-linux@xxxxxxxxxxxxxx/

v2 -> v3:
 * Use hex constants for consistency
 * Validate that the button is part of a "Programmable Buttons" Named Array.
   Otherwise the condition would also apply to "Function Buttons".
 * Ignore non-"Programmable Buttons" buttons.

v3: https://lore.kernel.org/linux-input/20210520084805.685486-1-linux@xxxxxxxxxxxxxx/

v3 -> v4:
 * Mention new support for HID "Named Array" collections in commit message.
 * Mention new support KEY_MACRO# in hid-debug.


 drivers/hid/hid-debug.c | 11 +++++++++++
 drivers/hid/hid-input.c | 22 ++++++++++++++++++++++
 include/linux/hid.h     |  1 +
 3 files changed, 34 insertions(+)

diff --git a/drivers/hid/hid-debug.c b/drivers/hid/hid-debug.c
index a311fb87b02a..fa57d05badf7 100644
--- a/drivers/hid/hid-debug.c
+++ b/drivers/hid/hid-debug.c
@@ -122,6 +122,7 @@ static const struct hid_usage_entry hid_usage_table[] = {
   {  9, 0, "Button" },
   { 10, 0, "Ordinal" },
   { 12, 0, "Consumer" },
+      {0, 0x003, "ProgrammableButtons"},
       {0, 0x238, "HorizontalWheel"},
   { 13, 0, "Digitizers" },
     {0, 0x01, "Digitizer"},
@@ -942,6 +943,16 @@ static const char *keys[KEY_MAX + 1] = {
 	[KEY_KBDINPUTASSIST_NEXTGROUP] = "KbdInputAssistNextGroup",
 	[KEY_KBDINPUTASSIST_ACCEPT] = "KbdInputAssistAccept",
 	[KEY_KBDINPUTASSIST_CANCEL] = "KbdInputAssistCancel",
+	[KEY_MACRO1] = "Macro1", [KEY_MACRO2] = "Macro2", [KEY_MACRO3] = "Macro3",
+	[KEY_MACRO4] = "Macro4", [KEY_MACRO5] = "Macro5", [KEY_MACRO6] = "Macro6",
+	[KEY_MACRO7] = "Macro7", [KEY_MACRO8] = "Macro8", [KEY_MACRO9] = "Macro9",
+	[KEY_MACRO10] = "Macro10", [KEY_MACRO11] = "Macro11", [KEY_MACRO12] = "Macro12",
+	[KEY_MACRO13] = "Macro13", [KEY_MACRO14] = "Macro14", [KEY_MACRO15] = "Macro15",
+	[KEY_MACRO16] = "Macro16", [KEY_MACRO17] = "Macro17", [KEY_MACRO18] = "Macro18",
+	[KEY_MACRO19] = "Macro19", [KEY_MACRO20] = "Macro20", [KEY_MACRO21] = "Macro21",
+	[KEY_MACRO22] = "Macro22", [KEY_MACRO23] = "Macro23", [KEY_MACRO24] = "Macro24",
+	[KEY_MACRO25] = "Macro25", [KEY_MACRO26] = "Macro26", [KEY_MACRO27] = "Macro27",
+	[KEY_MACRO28] = "Macro28", [KEY_MACRO29] = "Macro29", [KEY_MACRO30] = "Macro30",
 };
 
 static const char *relatives[REL_MAX + 1] = {
diff --git a/drivers/hid/hid-input.c b/drivers/hid/hid-input.c
index abbfa91e73e4..99557641be80 100644
--- a/drivers/hid/hid-input.c
+++ b/drivers/hid/hid-input.c
@@ -567,6 +567,16 @@ static void hidinput_update_battery(struct hid_device *dev, int value)
 }
 #endif	/* CONFIG_HID_BATTERY_STRENGTH */
 
+static bool hidinput_field_in_collection(struct hid_device *device, struct hid_field *field,
+					 unsigned int type, unsigned int usage)
+{
+	struct hid_collection *collection;
+
+	collection = &device->collection[field->usage->collection_index];
+
+	return collection->type == type && collection->usage == usage;
+}
+
 static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_field *field,
 				     struct hid_usage *usage)
 {
@@ -632,6 +642,18 @@ static void hidinput_configure_usage(struct hid_input *hidinput, struct hid_fiel
 				else
 					code += BTN_TRIGGER_HAPPY - 0x10;
 				break;
+		case HID_CP_CONSUMER_CONTROL:
+				if (hidinput_field_in_collection(device, field,
+								 HID_COLLECTION_NAMED_ARRAY,
+								 HID_CP_PROGRAMMABLEBUTTONS)) {
+					if (code <= 0x1d)
+						code += KEY_MACRO1;
+					else
+						code += BTN_TRIGGER_HAPPY - 0x1e;
+				} else {
+					goto ignore;
+				}
+				break;
 		default:
 			switch (field->physical) {
 			case HID_GD_MOUSE:
diff --git a/include/linux/hid.h b/include/linux/hid.h
index 10e922cee4eb..f05bf96a0d21 100644
--- a/include/linux/hid.h
+++ b/include/linux/hid.h
@@ -102,6 +102,7 @@ struct hid_item {
 #define HID_COLLECTION_PHYSICAL		0
 #define HID_COLLECTION_APPLICATION	1
 #define HID_COLLECTION_LOGICAL		2
+#define HID_COLLECTION_NAMED_ARRAY	4
 
 /*
  * HID report descriptor global item tags

base-commit: 231bc539066760aaa44d46818c85b14ca2f56d9f
-- 
2.32.0