drivers/hid/hid-holtekff.c

Source file repositories/reference/linux-study-clean/drivers/hid/hid-holtekff.c

File Facts

System
Linux kernel
Corpus path
drivers/hid/hid-holtekff.c
Extension
.c
Size
5522 bytes
Lines
220
Domain
Driver Families
Bucket
drivers/hid
Inferred role
Driver Families: implementation source
Status
source implementation candidate

Why This File Exists

Repeatable hardware-adapter layer. Deep compatibility for every driver is out of scope; this atlas records patterns, probe lifecycles, bus glue, IRQ/DMA usage, and links back to core abstractions.

Dependency Surface

Detected Declarations

Annotated Snippet

struct holtekff_device {
	struct hid_field *field;
};

static void holtekff_send(struct holtekff_device *holtekff,
			  struct hid_device *hid,
			  const u8 data[HOLTEKFF_MSG_LENGTH])
{
	int i;

	for (i = 0; i < HOLTEKFF_MSG_LENGTH; i++) {
		holtekff->field->value[i] = data[i];
	}

	dbg_hid("sending %7ph\n", data);

	hid_hw_request(hid, holtekff->field->report, HID_REQ_SET_REPORT);
}

static int holtekff_play(struct input_dev *dev, void *data,
			 struct ff_effect *effect)
{
	struct hid_device *hid = input_get_drvdata(dev);
	struct holtekff_device *holtekff = data;
	int left, right;
	/* effect type 1, length 65535 msec */
	u8 buf[HOLTEKFF_MSG_LENGTH] =
		{ 0x01, 0x01, 0xff, 0xff, 0x10, 0xe0, 0x00 };

	left = effect->u.rumble.strong_magnitude;
	right = effect->u.rumble.weak_magnitude;
	dbg_hid("called with 0x%04x 0x%04x\n", left, right);

	if (!left && !right) {
		holtekff_send(holtekff, hid, stop_all6);
		return 0;
	}

	if (left)
		buf[1] |= 0x80;
	if (right)
		buf[1] |= 0x40;

	/* The device takes a single magnitude, so we just sum them up. */
	buf[6] = min(0xf, (left >> 12) + (right >> 12));

	holtekff_send(holtekff, hid, buf);
	holtekff_send(holtekff, hid, start_effect_1);

	return 0;
}

static int holtekff_init(struct hid_device *hid)
{
	struct holtekff_device *holtekff;
	struct hid_report *report;
	struct hid_input *hidinput;
	struct list_head *report_list =
			&hid->report_enum[HID_OUTPUT_REPORT].report_list;
	struct input_dev *dev;
	int error;

	if (list_empty(&hid->inputs)) {
		hid_err(hid, "no inputs found\n");
		return -ENODEV;
	}
	hidinput = list_entry(hid->inputs.next, struct hid_input, list);
	dev = hidinput->input;

	if (list_empty(report_list)) {
		hid_err(hid, "no output report found\n");
		return -ENODEV;
	}

	report = list_entry(report_list->next, struct hid_report, list);

	if (report->maxfield < 1 || report->field[0]->report_count != 7) {
		hid_err(hid, "unexpected output report layout\n");
		return -ENODEV;
	}

	holtekff = kzalloc_obj(*holtekff);
	if (!holtekff)
		return -ENOMEM;

	set_bit(FF_RUMBLE, dev->ffbit);

	holtekff->field = report->field[0];

	/* initialize the same way as win driver does */

Annotation

Implementation Notes