drivers/hid/hid-mf.c

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

File Facts

System
Linux kernel
Corpus path
drivers/hid/hid-mf.c
Extension
.c
Size
4455 bytes
Lines
171
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 mf_device {
	struct hid_report *report;
};

static int mf_play(struct input_dev *dev, void *data, struct ff_effect *effect)
{
	struct hid_device *hid = input_get_drvdata(dev);
	struct mf_device *mf = data;
	int strong, weak;

	strong = effect->u.rumble.strong_magnitude;
	weak = effect->u.rumble.weak_magnitude;

	dbg_hid("Called with 0x%04x 0x%04x.\n", strong, weak);

	strong = strong * 0xff / 0xffff;
	weak = weak * 0xff / 0xffff;

	dbg_hid("Running with 0x%02x 0x%02x.\n", strong, weak);

	mf->report->field[0]->value[0] = weak;
	mf->report->field[0]->value[1] = strong;
	hid_hw_request(hid, mf->report, HID_REQ_SET_REPORT);

	return 0;
}

static int mf_init(struct hid_device *hid)
{
	struct mf_device *mf;

	struct list_head *report_list =
			&hid->report_enum[HID_OUTPUT_REPORT].report_list;

	struct list_head *report_ptr;
	struct hid_report *report;

	struct list_head *input_ptr = &hid->inputs;
	struct hid_input *input;

	struct input_dev *dev;

	int error;

	/* Setup each of the four inputs */
	list_for_each(report_ptr, report_list) {
		report = list_entry(report_ptr, struct hid_report, list);

		if (report->maxfield < 1 || report->field[0]->report_count < 2) {
			hid_err(hid, "Invalid report, this should never happen!\n");
			return -ENODEV;
		}

		if (list_is_last(input_ptr, &hid->inputs)) {
			hid_err(hid, "Missing input, this should never happen!\n");
			return -ENODEV;
		}

		input_ptr = input_ptr->next;
		input = list_entry(input_ptr, struct hid_input, list);

		mf = kzalloc_obj(struct mf_device);
		if (!mf)
			return -ENOMEM;

		dev = input->input;
		set_bit(FF_RUMBLE, dev->ffbit);

		error = input_ff_create_memless(dev, mf, mf_play);
		if (error) {
			kfree(mf);
			return error;
		}

		mf->report = report;
		mf->report->field[0]->value[0] = 0x00;
		mf->report->field[0]->value[1] = 0x00;
		hid_hw_request(hid, mf->report, HID_REQ_SET_REPORT);
	}

	hid_info(hid, "Force feedback for HJZ Mayflash game controller "
		      "adapters by Marcel Hasler <mahasler@gmail.com>\n");

	return 0;
}

static int mf_probe(struct hid_device *hid, const struct hid_device_id *id)
{
	int error;

Annotation

Implementation Notes