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Commit 7894f21b authored by JJ Ding's avatar JJ Ding Committed by Dmitry Torokhov
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Input: elantech - packet checking for v2 hardware 



For v2 hardware, there is no real parity check, but we can still check
some constant bits for data integrity.

Also rename elantech_check_parity_v1 to elantech_packet_check_v1 to make
these packet checking function names consistent.

Signed-off-by: default avatarJJ Ding <jj_ding@emc.com.tw>
Acked-by: default avatarDaniel Kurtz <djkurtz@chromium.org>
Acked-by: default avatarÉric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: default avatarDmitry Torokhov <dtor@mail.ru>
parent 8a360d09

drivers/input/mouse/elantech.c

+34 −5
Original line number Diff line number Diff line
@@ -350,7 +350,7 @@ static void elantech_report_absolute_v2(struct psmouse *psmouse) 
	input_sync(dev);

}



static int elantech_check_parity_v1(struct psmouse *psmouse)

static int elantech_packet_check_v1(struct psmouse *psmouse)

{

	struct elantech_data *etd = psmouse->private;

	unsigned char *packet = psmouse->packet;
@@ -374,6 +374,34 @@ static int elantech_check_parity_v1(struct psmouse *psmouse) 
	       etd->parity[packet[3]] == p3;

}



static int elantech_packet_check_v2(struct psmouse *psmouse)

{

	struct elantech_data *etd = psmouse->private;

	unsigned char *packet = psmouse->packet;



	/*

	 * V2 hardware has two flavors. Older ones that do not report pressure,

	 * and newer ones that reports pressure and width. With newer ones, all

	 * packets (1, 2, 3 finger touch) have the same constant bits. With

	 * older ones, 1/3 finger touch packets and 2 finger touch packets

	 * have different constant bits.

	 * With all three cases, if the constant bits are not exactly what I

	 * expected, I consider them invalid.

	 */

	if (etd->reports_pressure)

		return (packet[0] & 0x0c) == 0x04 &&

		       (packet[3] & 0x0f) == 0x02;



	if ((packet[0] & 0xc0) == 0x80)

		return (packet[0] & 0x0c) == 0x0c &&

		       (packet[3] & 0x0e) == 0x08;



	return (packet[0] & 0x3c) == 0x3c &&

	       (packet[1] & 0xf0) == 0x00 &&

	       (packet[3] & 0x3e) == 0x38 &&

	       (packet[4] & 0xf0) == 0x00;

}



/*

 * Process byte stream from mouse and handle complete packets

 */
@@ -389,14 +417,16 @@ static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse) 


	switch (etd->hw_version) {

	case 1:

		if (etd->paritycheck && !elantech_check_parity_v1(psmouse))

		if (etd->paritycheck && !elantech_packet_check_v1(psmouse))

			return PSMOUSE_BAD_DATA;



		elantech_report_absolute_v1(psmouse);

		break;



	case 2:

		/* We don't know how to check parity in protocol v2 */

		if (etd->paritycheck && !elantech_packet_check_v2(psmouse))

			return PSMOUSE_BAD_DATA;



		elantech_report_absolute_v2(psmouse);

		break;

	}
@@ -795,8 +825,7 @@ int elantech_init(struct psmouse *psmouse) 
		etd->hw_version = 2;

		/* For now show extra debug information */

		etd->debug = 1;

		/* Don't know how to do parity checking for version 2 */

		etd->paritycheck = 0;

		etd->paritycheck = 1;



		if (etd->fw_version >= 0x020800)

			etd->reports_pressure = true;