HID: add usage_index in struct hid_usage.

Currently, there is no way to know the index of the current field
in the .input_mapping and .event callbacks  when this field is inside
an array of HID fields.
This patch adds this index to the struct hid_usage so that this
information is available to input_mapping and event callbacks.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@gmail.com>
Acked-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/hid/hid-core.c b/drivers/hid/hid-core.c
index f5004e2ca0c5..b5974cd45968 100644
--- a/drivers/hid/hid-core.c
+++ b/drivers/hid/hid-core.c
@@ -92,6 +92,7 @@ EXPORT_SYMBOL_GPL(hid_register_report);
 static struct hid_field *hid_register_field(struct hid_report *report, unsigned usages, unsigned values)
 {
         struct hid_field *field;
+        int i;
 
         if (report->maxfield == HID_MAX_FIELDS) {
                 hid_err(report->device, "too many fields in report\n");
@@ -110,6 +111,9 @@ static struct hid_field *hid_register_field(struct hid_report *report, unsigned
         field->value = (s32 *)(field->usage + usages);
         field->report = report;
 
+        for (i = 0; i < usages; i++)
+                field->usage[i].usage_index = i;
+
         return field;
 }