drivers/input/touchscreen/tsc40.c

Source file repositories/reference/linux-study-clean/drivers/input/touchscreen/tsc40.c

File Facts

System
Linux kernel
Corpus path
drivers/input/touchscreen/tsc40.c
Extension
.c
Size
3652 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 tsc_ser {
	struct input_dev *dev;
	struct serio *serio;
	u32 idx;
	unsigned char data[PACKET_LENGTH];
	char phys[32];
};

static void tsc_process_data(struct tsc_ser *ptsc)
{
	struct input_dev *dev = ptsc->dev;
	u8 *data = ptsc->data;
	u32 x;
	u32 y;

	x = ((data[1] & 0x03) << 8) | data[2];
	y = ((data[3] & 0x03) << 8) | data[4];

	input_report_abs(dev, ABS_X, x);
	input_report_abs(dev, ABS_Y, y);
	input_report_key(dev, BTN_TOUCH, 1);

	input_sync(dev);
}

static irqreturn_t tsc_interrupt(struct serio *serio,
		unsigned char data, unsigned int flags)
{
	struct tsc_ser *ptsc = serio_get_drvdata(serio);
	struct input_dev *dev = ptsc->dev;

	ptsc->data[ptsc->idx] = data;
	switch (ptsc->idx++) {
	case 0:
		if (unlikely((data & 0x3e) != 0x10)) {
			dev_dbg(&serio->dev,
				"unsynchronized packet start (0x%02x)\n", data);
			ptsc->idx = 0;
		} else if (!(data & 0x01)) {
			input_report_key(dev, BTN_TOUCH, 0);
			input_sync(dev);
			ptsc->idx = 0;
		}
		break;

	case 1:
	case 3:
		if (unlikely(data & 0xfc)) {
			dev_dbg(&serio->dev,
				"unsynchronized data 0x%02x at offset %d\n",
				data, ptsc->idx - 1);
			ptsc->idx = 0;
		}
		break;

	case 4:
		tsc_process_data(ptsc);
		ptsc->idx = 0;
		break;
	}

	return IRQ_HANDLED;
}

static int tsc_connect(struct serio *serio, struct serio_driver *drv)
{
	struct tsc_ser *ptsc;
	struct input_dev *input_dev;
	int error;

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

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

	input_dev->name = "TSC-10/25/40 Serial TouchScreen";
	input_dev->phys = ptsc->phys;
	input_dev->id.bustype = BUS_RS232;
	input_dev->id.vendor = SERIO_TSC40;
	input_dev->id.product = 40;
	input_dev->id.version = 0x0001;
	input_dev->dev.parent = &serio->dev;

	input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);

Annotation

Implementation Notes