Commit 6edb8cd8 authored by Kerem Karabay's avatar Kerem Karabay Committed by Jiri Kosina
Browse files

HID: core: add helper for finding a field with a certain usage 



This helper will allow HID drivers to easily determine if they should
bind to a hid_device by checking for the prescence of a certain field
when its ID is not enough, which can be the case on USB devices with
multiple interfaces and/or configurations.

Convert google-hammer driver to use it, and remove now superfluous
hammer_has_usage().

[jkosina@suse.com: expand changelog with the information about
 google-hammer being added as user of this API ]
Signed-off-by: default avatarKerem Karabay <kekrby@gmail.com>
Signed-off-by: default avatarAditya Garg <gargaditya08@live.com>
Signed-off-by: default avatarJiri Kosina <jkosina@suse.com>
parent 6b5faec9

drivers/hid/hid-core.c

+25 −0
Original line number Diff line number Diff line
@@ -1912,6 +1912,31 @@ int hid_set_field(struct hid_field *field, unsigned offset, __s32 value) 
}

EXPORT_SYMBOL_GPL(hid_set_field);



struct hid_field *hid_find_field(struct hid_device *hdev, unsigned int report_type,

				 unsigned int application, unsigned int usage)

{

	struct list_head *report_list = &hdev->report_enum[report_type].report_list;

	struct hid_report *report;

	int i, j;



	list_for_each_entry(report, report_list, list) {

		if (report->application != application)

			continue;



		for (i = 0; i < report->maxfield; i++) {

			struct hid_field *field = report->field[i];



			for (j = 0; j < field->maxusage; j++) {

				if (field->usage[j].hid == usage)

					return field;

			}

		}

	}



	return NULL;

}

EXPORT_SYMBOL_GPL(hid_find_field);



static struct hid_report *hid_get_report(struct hid_report_enum *report_enum,

		const u8 *data)

{

drivers/hid/hid-google-hammer.c

+2 −25
Original line number Diff line number Diff line
@@ -418,38 +418,15 @@ static int hammer_event(struct hid_device *hid, struct hid_field *field, 
	return 0;

}



static bool hammer_has_usage(struct hid_device *hdev, unsigned int report_type,

			unsigned application, unsigned usage)

{

	struct hid_report_enum *re = &hdev->report_enum[report_type];

	struct hid_report *report;

	int i, j;



	list_for_each_entry(report, &re->report_list, list) {

		if (report->application != application)

			continue;



		for (i = 0; i < report->maxfield; i++) {

			struct hid_field *field = report->field[i];



			for (j = 0; j < field->maxusage; j++)

				if (field->usage[j].hid == usage)

					return true;

		}

	}



	return false;

}



static bool hammer_has_folded_event(struct hid_device *hdev)

{

	return hammer_has_usage(hdev, HID_INPUT_REPORT,

	return !!hid_find_field(hdev, HID_INPUT_REPORT,

				HID_GD_KEYBOARD, HID_USAGE_KBD_FOLDED);

}



static bool hammer_has_backlight_control(struct hid_device *hdev)

{

	return hammer_has_usage(hdev, HID_OUTPUT_REPORT,

	return !!hid_find_field(hdev, HID_OUTPUT_REPORT,

				HID_GD_KEYBOARD, HID_AD_BRIGHTNESS);

}

include/linux/hid.h

+2 −0
Original line number Diff line number Diff line
@@ -940,6 +940,8 @@ extern void hidinput_report_event(struct hid_device *hid, struct hid_report *rep 
extern int hidinput_connect(struct hid_device *hid, unsigned int force);

extern void hidinput_disconnect(struct hid_device *);



struct hid_field *hid_find_field(struct hid_device *hdev, unsigned int report_type,

				 unsigned int application, unsigned int usage);

int hid_set_field(struct hid_field *, unsigned, __s32);

int hid_input_report(struct hid_device *hid, enum hid_report_type type, u8 *data, u32 size,

		     int interrupt);