Re: [PATCH 28/40] Input: atmel_mxt_ts - Add CHG line handling in bootloader code

[Benson Leung <bleung@chromium.org>]

On Fri, Feb 22, 2013 at 9:58 AM, Nick Dyer <nick.dyer@itdev.co.uk> wrote:
> The bootloader state machine toggles the CHG/Interrupt line to indicate when
> it has transitioned between states. Waiting for this event improves bootloader
> reliability.
>
> Signed-off-by: Nick Dyer <nick.dyer@itdev.co.uk>
> ---
>  drivers/input/touchscreen/atmel_mxt_ts.c |   29 +++++++++++++++++++++++++++--
>  1 file changed, 27 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c
> index a1f196b..f182228 100644
> --- a/drivers/input/touchscreen/atmel_mxt_ts.c
> +++ b/drivers/input/touchscreen/atmel_mxt_ts.c
> @@ -430,6 +430,27 @@ static int mxt_probe_bootloader(struct mxt_data *data)
>         return 0;
>  }
>
> +static int mxt_wait_for_chg(struct mxt_data *data)
> +{
> +       int timeout_counter = 0;
> +       int count = 1E6;
> +
> +       if (data->pdata->read_chg == NULL) {

This also assumes the existence of data->pdata. If data->pdata ==
NULL, you're going to have a bad time.

> +               msleep(20);
> +               return 0;
> +       }
> +
> +       while ((timeout_counter++ <= count) && data->pdata->read_chg())
> +               udelay(20);
> +
> +       if (timeout_counter > count) {
> +               dev_err(&data->client->dev, "mxt_wait_for_chg() timeout!\n");
> +               return -EIO;
> +       }
> +
> +       return 0;
> +}
> +

> --
> 1.7.10.4
>



-- 
Benson Leung
Software Engineer, Chrom* OS
bleung@chromium.org