Commit 1ce316ef authored by Shaun Jackman's avatar Shaun Jackman Committed by Dmitry Torokhov
Browse files

Input: elo - fix checksum calculation 



Fix 10-byte protocol checksum calculation and do not discard packet early
unless it is missing lead in byte.

Signed-off-by: default avatarShaun Jackman <sjackman@gmail.com>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 6b50d8b8

drivers/input/touchscreen/elo.c

+29 −26
Original line number Diff line number Diff line
@@ -36,6 +36,10 @@ MODULE_LICENSE("GPL"); 


#define ELO_MAX_LENGTH		10



#define ELO10_LEAD_BYTE		'U'



#define ELO10_TOUCH_PACKET	'T'



/*

 * Per-touchscreen data.

 */
@@ -54,37 +58,36 @@ static void elo_process_data_10(struct elo* elo, unsigned char data, struct pt_r 
{

	struct input_dev *dev = elo->dev;



	elo->csum += elo->data[elo->idx] = data;



	elo->data[elo->idx] = data;

	switch (elo->idx++) {



		case 0:

			if (data != 'U') {

			elo->csum = 0xaa;

			if (data != ELO10_LEAD_BYTE) {

				pr_debug("elo: unsynchronized data: 0x%02x\n", data);

				elo->idx = 0;

				elo->csum = 0;

			}

			break;



		case 1:

			if (data != 'T') {

		case 9:

			elo->idx = 0;

				elo->csum = 0;

			if (data != elo->csum) {

				pr_debug("elo: bad checksum: 0x%02x, expected 0x%02x\n",

					 data, elo->csum);

				break;

			}

			if (elo->data[1] != ELO10_TOUCH_PACKET) {

				pr_debug(elo: "unexpected packet: 0x%02x\n", elo->data[1]);

				break;



		case 9:

			if (elo->csum) {

			}

			input_regs(dev, regs);

			input_report_abs(dev, ABS_X, (elo->data[4] << 8) | elo->data[3]);

			input_report_abs(dev, ABS_Y, (elo->data[6] << 8) | elo->data[5]);

			input_report_abs(dev, ABS_PRESSURE, (elo->data[8] << 8) | elo->data[7]);

			input_report_key(dev, BTN_TOUCH, elo->data[8] || elo->data[7]);

			input_sync(dev);

			}

			elo->idx = 0;

			elo->csum = 0;

			break;

	}

	elo->csum += data;

}



static void elo_process_data_6(struct elo *elo, unsigned char data, struct pt_regs *regs)