drivers/input/touchscreen/fujitsu_ts.c

Source file repositories/reference/linux-study-clean/drivers/input/touchscreen/fujitsu_ts.c

File Facts

System
Linux kernel
Corpus path
drivers/input/touchscreen/fujitsu_ts.c
Extension
.c
Size
3912 bytes
Lines
173
Domain
Driver Families
Bucket
drivers/input
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 fujitsu {
	struct input_dev *dev;
	struct serio *serio;
	int idx;
	unsigned char data[FUJITSU_LENGTH];
	char phys[32];
};

/*
 * Decode serial data (5 bytes per packet)
 * First byte
 * 1 C 0 0 R S S S
 * Where C is 1 while in calibration mode (which we don't use)
 * R is 1 when no coordinate corection was done.
 * S are button state
 */
static irqreturn_t fujitsu_interrupt(struct serio *serio,
				     unsigned char data, unsigned int flags)
{
	struct fujitsu *fujitsu = serio_get_drvdata(serio);
	struct input_dev *dev = fujitsu->dev;

	if (fujitsu->idx == 0) {
		/* resync skip until start of frame */
		if ((data & 0xf0) != 0x80)
			return IRQ_HANDLED;
	} else {
		/* resync skip garbage */
		if (data & 0x80) {
			fujitsu->idx = 0;
			return IRQ_HANDLED;
		}
	}

	fujitsu->data[fujitsu->idx++] = data;
	if (fujitsu->idx == FUJITSU_LENGTH) {
		input_report_abs(dev, ABS_X,
				 (fujitsu->data[2] << 7) | fujitsu->data[1]);
		input_report_abs(dev, ABS_Y,
				 (fujitsu->data[4] << 7) | fujitsu->data[3]);
		input_report_key(dev, BTN_TOUCH,
				 (fujitsu->data[0] & 0x03) != 2);
		input_sync(dev);
		fujitsu->idx = 0;
	}

	return IRQ_HANDLED;
}

/*
 * fujitsu_disconnect() is the opposite of fujitsu_connect()
 */
static void fujitsu_disconnect(struct serio *serio)
{
	struct fujitsu *fujitsu = serio_get_drvdata(serio);

	input_get_device(fujitsu->dev);
	input_unregister_device(fujitsu->dev);
	serio_close(serio);
	serio_set_drvdata(serio, NULL);
	input_put_device(fujitsu->dev);
	kfree(fujitsu);
}

/*
 * fujitsu_connect() is the routine that is called when someone adds a
 * new serio device that supports the Fujitsu protocol and registers it
 * as input device.
 */
static int fujitsu_connect(struct serio *serio, struct serio_driver *drv)
{
	struct fujitsu *fujitsu;
	struct input_dev *input_dev;
	int err;

	fujitsu = kzalloc_obj(*fujitsu);
	input_dev = input_allocate_device();
	if (!fujitsu || !input_dev) {
		err = -ENOMEM;
		goto fail1;
	}

	fujitsu->serio = serio;
	fujitsu->dev = input_dev;
	scnprintf(fujitsu->phys, sizeof(fujitsu->phys), "%s/input0", serio->phys);

	input_dev->name = "Fujitsu Serial Touchscreen";
	input_dev->phys = fujitsu->phys;
	input_dev->id.bustype = BUS_RS232;
	input_dev->id.vendor = SERIO_FUJITSU;

Annotation

Implementation Notes