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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: JJ Ding <jj_ding@emc.com.tw>
Acked-by: Daniel Kurtz <djkurtz@chromium.org>
Acked-by: Éric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
JJ Ding 2011-09-09 10:28:04 -07:00 committed by Dmitry Torokhov
parent 8a360d09b1
commit 7894f21b10
1 changed files with 34 additions and 5 deletions
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39
drivers/input/mouse/elantech.c
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@ -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;