Re: [PATCH v4 2/3] Input: atmel_mxt_ts - support wakeup methods

Linus Walleij
2021-01-23T23:01:15Z

On Fri, Jan 22, 2021 at 9:07 PM Dmitry Osipenko <digetx@gmail.com> wrote:

> According to datasheets, chips like mXT1386 have a WAKE line, it is used
> to wake the chip up from deep sleep mode before communicating with it via
> the I2C-compatible interface.
>
> If the WAKE line is connected to a GPIO line, the line must be asserted
> 25 ms before the host attempts to communicate with the controller. If the
> WAKE line is connected to the SCL pin, the controller will send a NACK on
> the first attempt to address it, the host must then retry 25 ms later.
>
> Implement the wake-up methods in the driver. Touchscreen now works
> properly on devices like Acer A500 tablet, fixing problems like this:
>
> atmel_mxt_ts 0-004c: __mxt_read_reg: i2c transfer failed (-121)
> atmel_mxt_ts 0-004c: mxt_bootloader_read: i2c recv failed (-121)
> atmel_mxt_ts 0-004c: Trying alternate bootloader address
> atmel_mxt_ts 0-004c: mxt_bootloader_read: i2c recv failed (-121)
> atmel_mxt_ts: probe of 0-004c failed with error -121
>
> Signed-off-by: Jiada Wang <jiada_wang@mentor.com>
> Signed-off-by: Dmitry Osipenko <digetx@gmail.com>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij