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

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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: Kerem Karabay <kekrby@gmail.com>
Signed-off-by: Aditya Garg <gargaditya08@live.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
This commit is contained in:
Kerem Karabay 2024-07-05 11:17:42 +00:00 committed by Jiri Kosina
parent 6b5faec9f5
commit 6edb8cd87c
3 changed files with 29 additions and 25 deletions
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25
drivers/hid/hid-core.c
View File

@ -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)
{

27
drivers/hid/hid-google-hammer.c
View File

@ -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);
}

2
include/linux/hid.h
View File

@ -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);