drivers/hid/hid-sjoy.c

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

File Facts

System
Linux kernel
Corpus path
drivers/hid/hid-sjoy.c
Extension
.c
Size
4544 bytes
Lines
175
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 sjoyff_device {
	struct hid_report *report;
};

static int hid_sjoyff_play(struct input_dev *dev, void *data,
			 struct ff_effect *effect)
{
	struct hid_device *hid = input_get_drvdata(dev);
	struct sjoyff_device *sjoyff = data;
	u32 left, right;

	left = effect->u.rumble.strong_magnitude;
	right = effect->u.rumble.weak_magnitude;
	dev_dbg(&dev->dev, "called with 0x%08x 0x%08x\n", left, right);

	left = left * 0xff / 0xffff;
	right = (right != 0); /* on/off only */

	sjoyff->report->field[0]->value[1] = right;
	sjoyff->report->field[0]->value[2] = left;
	dev_dbg(&dev->dev, "running with 0x%02x 0x%02x\n", left, right);
	hid_hw_request(hid, sjoyff->report, HID_REQ_SET_REPORT);

	return 0;
}

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

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

	list_for_each_entry(hidinput, &hid->inputs, list) {
		report_ptr = report_ptr->next;

		if (report_ptr == report_list) {
			hid_err(hid, "required output report is missing\n");
			return -ENODEV;
		}

		report = list_entry(report_ptr, struct hid_report, list);
		if (report->maxfield < 1) {
			hid_err(hid, "no fields in the report\n");
			return -ENODEV;
		}

		if (report->field[0]->report_count < 3) {
			hid_err(hid, "not enough values in the field\n");
			return -ENODEV;
		}

		sjoyff = kzalloc_obj(struct sjoyff_device);
		if (!sjoyff)
			return -ENOMEM;

		dev = hidinput->input;

		set_bit(FF_RUMBLE, dev->ffbit);

		sjoyff->report = report;
		sjoyff->report->field[0]->value[0] = 0x01;
		sjoyff->report->field[0]->value[1] = 0x00;
		sjoyff->report->field[0]->value[2] = 0x00;
		hid_hw_request(hid, sjoyff->report, HID_REQ_SET_REPORT);

		error = input_ff_create_memless(dev, sjoyff, hid_sjoyff_play);
		if (error) {
			kfree(sjoyff);
			return error;
		}
	}

	hid_info(hid, "Force feedback for SmartJoy PLUS PS2/USB adapter\n");

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

Annotation

Implementation Notes