lkml.org 
[lkml]   [2011]   [Aug]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v4 5/8] Input: elantech - packet checking for v2 hardware
    Date
    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>
    ---
    drivers/input/mouse/elantech.c | 39 ++++++++++++++++++++++++++++++++++-----
    1 files changed, 34 insertions(+), 5 deletions(-)

    diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
    index 282b8b6..008e8c2 100644
    --- a/drivers/input/mouse/elantech.c
    +++ b/drivers/input/mouse/elantech.c
    @@ -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;
    --
    1.7.4.1


    \
     
     \ /
      Last update: 2011-08-29 10:29    [W:0.024 / U:1.556 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site