linux-kernel - Re: [PATCH v4 2/3] Input: atmel_mxt_ts

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Message-ID: <CACRpkda+wjjr3+=taNmKgj4HH8A6pSAmMwtB3CZh4ixnhDt_Dw@mail.gmail.com>
Date:   Sat, 23 Jan 2021 23:59:33 +0100
From:   Linus Walleij <linus.walleij@...aro.org>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Nick Dyer <nick@...anahar.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Rob Herring <robh+dt@...nel.org>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Jiada Wang <jiada_wang@...tor.com>,
        Linux Input <linux-input@...r.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        linux-tegra <linux-tegra@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 2/3] Input: atmel_mxt_ts - support wakeup methods

On Fri, Jan 22, 2021 at 9:07 PM Dmitry Osipenko <digetx@...il.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@...tor.com>
> Signed-off-by: Dmitry Osipenko <digetx@...il.com>

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

Yours,
Linus Walleij