drivers/hid/hid-zpff.c

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

File Facts

System
Linux kernel
Corpus path
drivers/hid/hid-zpff.c
Extension
.c
Size
3153 bytes
Lines
143
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 zpff_device {
	struct hid_report *report;
};

static int zpff_play(struct input_dev *dev, void *data,
			 struct ff_effect *effect)
{
	struct hid_device *hid = input_get_drvdata(dev);
	struct zpff_device *zpff = data;
	int left, right;

	/*
	 * The following is specified the other way around in the Zeroplus
	 * datasheet but the order below is correct for the XFX Executioner;
	 * however it is possible that the XFX Executioner is an exception
	 */

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

	left = left * 0x7f / 0xffff;
	right = right * 0x7f / 0xffff;

	zpff->report->field[2]->value[0] = left;
	zpff->report->field[3]->value[0] = right;
	dbg_hid("running with 0x%02x 0x%02x\n", left, right);
	hid_hw_request(hid, zpff->report, HID_REQ_SET_REPORT);

	return 0;
}

static int zpff_init(struct hid_device *hid)
{
	struct zpff_device *zpff;
	struct hid_report *report;
	struct hid_input *hidinput;
	struct input_dev *dev;
	int i, 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;

	for (i = 0; i < 4; i++) {
		report = hid_validate_values(hid, HID_OUTPUT_REPORT, 0, i, 1);
		if (!report)
			return -ENODEV;
	}

	zpff = kzalloc_obj(struct zpff_device);
	if (!zpff)
		return -ENOMEM;

	set_bit(FF_RUMBLE, dev->ffbit);

	error = input_ff_create_memless(dev, zpff, zpff_play);
	if (error) {
		kfree(zpff);
		return error;
	}

	zpff->report = report;
	zpff->report->field[0]->value[0] = 0x00;
	zpff->report->field[1]->value[0] = 0x02;
	zpff->report->field[2]->value[0] = 0x00;
	zpff->report->field[3]->value[0] = 0x00;
	hid_hw_request(hid, zpff->report, HID_REQ_SET_REPORT);

	hid_info(hid, "force feedback for Zeroplus based devices by Anssi Hannula <anssi.hannula@gmail.com>\n");

	return 0;
}
#else
static inline int zpff_init(struct hid_device *hid)
{
	return 0;
}
#endif

static int zp_probe(struct hid_device *hdev, const struct hid_device_id *id)
{
	int ret;

	ret = hid_parse(hdev);
	if (ret) {
		hid_err(hdev, "parse failed\n");

Annotation

Implementation Notes