Re: [PATCH 3/6] Input: elantech - packet checking for v2 hardware

Éric Piel
2011-08-19T12:22:50Z

Op 18-08-11 03:57, JJ Ding schreef:
> For v2 hardware, there is no real parity check, but we can still check
> some constant bits for data integrity.
>
> Signed-off-by: JJ Ding<jj_ding@emc.com.tw>
If you add some comments, as suggest by Dmitry, it looks perfect :-)

Signed-off-by: Éric Piel <eric.piel@tremplin-utc.net>

Éric

> ---
> drivers/input/mouse/elantech.c | 26 +++++++++++++++++++++++---
> 1 files changed, 23 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/input/mouse/elantech.c b/drivers/input/mouse/elantech.c
> index cf41f23..032181c 100644
> --- a/drivers/input/mouse/elantech.c
> +++ b/drivers/input/mouse/elantech.c
> @@ -376,6 +376,25 @@ static int elantech_check_parity_v1(struct psmouse *psmouse)
> etd->parity[packet[3]] == p3;
> }
>
> +static int packet_simple_check_v2(struct psmouse *psmouse)
> +{
> + struct elantech_data *etd = psmouse->private;
> + unsigned char *packet = psmouse->packet;
> +
> + 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
> */
> @@ -398,7 +417,9 @@ static psmouse_ret_t elantech_process_byte(struct psmouse *psmouse)
> break;
>
> case 2:
> - /* We don't know how to check parity in protocol v2 */
> + if (etd->paritycheck&& !packet_simple_check_v2(psmouse))
> + return PSMOUSE_BAD_DATA;
> +
> elantech_report_absolute_v2(psmouse);
> break;
> }
> @@ -799,8 +820,7 @@ 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;