HID: convert defines of HID class requests into a proper enum

This allows to export the type in BTF and so in the automatically
generated vmlinux.h. It will also add some static checks on the users
when we change the ll driver API (see not below).

Note that we need to also do change in the ll_driver API, but given
that this will have a wider impact outside of this tree, we leave this
as a TODO for the future.

Reviewed-by: Greg Kroah-Hartman <[e-mail]>
Signed-off-by: Benjamin Tissoires <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]

drivers/hid/hid-core.c

···
  * DO NOT USE in hid drivers directly, but through hid_hw_request instead.
  */
 int __hid_request(struct hid_device *hid, struct hid_report *report,
-		int reqtype)
+		enum hid_class_request reqtype)
 {
 	char *buf;
 	int ret;
···
  * @reqtype: hid request type
  */
 void hid_hw_request(struct hid_device *hdev,
-		    struct hid_report *report, int reqtype)
+		    struct hid_report *report, enum hid_class_request reqtype)
 {
 	if (hdev->ll_driver->request)
 		return hdev->ll_driver->request(hdev, report, reqtype);
···
  */
 int hid_hw_raw_request(struct hid_device *hdev,
 		       unsigned char reportnum, __u8 *buf,
-		       size_t len, enum hid_report_type rtype, int reqtype)
+		       size_t len, enum hid_report_type rtype, enum hid_class_request reqtype)
 {
 	if (len < 1 || len > HID_MAX_BUFFER_SIZE || !buf)
 		return -EINVAL;

include/linux/hid.h

···
 unsigned int hidinput_count_leds(struct hid_device *hid);
 __s32 hidinput_calc_abs_res(const struct hid_field *field, __u16 code);
 void hid_output_report(struct hid_report *report, __u8 *data);
-int __hid_request(struct hid_device *hid, struct hid_report *rep, int reqtype);
+int __hid_request(struct hid_device *hid, struct hid_report *rep, enum hid_class_request reqtype);
 u8 *hid_alloc_report_buf(struct hid_report *report, gfp_t flags);
 struct hid_device *hid_allocate_device(void);
 struct hid_report *hid_register_report(struct hid_device *device,
···
 int __must_check hid_hw_open(struct hid_device *hdev);
 void hid_hw_close(struct hid_device *hdev);
 void hid_hw_request(struct hid_device *hdev,
-		    struct hid_report *report, int reqtype);
+		    struct hid_report *report, enum hid_class_request reqtype);
 int hid_hw_raw_request(struct hid_device *hdev,
 		       unsigned char reportnum, __u8 *buf,
-		       size_t len, enum hid_report_type rtype, int reqtype);
+		       size_t len, enum hid_report_type rtype,
+		       enum hid_class_request reqtype);
 int hid_hw_output_report(struct hid_device *hdev, __u8 *buf, size_t len);
 
 /**
···
  * @reqtype: hid request type
  */
 static inline int hid_hw_idle(struct hid_device *hdev, int report, int idle,
-		int reqtype)
+		enum hid_class_request reqtype)
 {
 	if (hdev->ll_driver->idle)
 		return hdev->ll_driver->idle(hdev, report, idle, reqtype);

include/uapi/linux/hid.h

···
  * HID class requests
  */
 
-#define HID_REQ_GET_REPORT		0x01
-#define HID_REQ_GET_IDLE		0x02
-#define HID_REQ_GET_PROTOCOL		0x03
-#define HID_REQ_SET_REPORT		0x09
-#define HID_REQ_SET_IDLE		0x0A
-#define HID_REQ_SET_PROTOCOL		0x0B
+enum hid_class_request {
+	HID_REQ_GET_REPORT		= 0x01,
+	HID_REQ_GET_IDLE		= 0x02,
+	HID_REQ_GET_PROTOCOL		= 0x03,
+	HID_REQ_SET_REPORT		= 0x09,
+	HID_REQ_SET_IDLE		= 0x0A,
+	HID_REQ_SET_PROTOCOL		= 0x0B,
+};
 
 /*
  * HID class descriptor types