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From:   Harry Cutts <hcutts@chromium.org>
Date:   Mon, 12 Apr 2021 10:56:49 -0700
Message-ID: <CA+jURcu2a91quZc+gto=HixCH+O_V+fPVdKrO_9HvR2pcu9RmQ@mail.gmail.com>
Subject: Re: [PATCH v2] HID: i2c-hid: Skip ELAN power-on command after reset
To:     Johnny Chuang <johnny.chuang.emc@gmail.com>
Cc:     Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        Peter Hutterer <peter.hutterer@who-t.net>,
        lkml <linux-kernel@vger.kernel.org>,
        linux-input <linux-input@vger.kernel.org>,
        Johnny Chuang <johnny.chuang@emc.com.tw>,
        James Chen <james.chen@emc.com.tw>,
        Jennifer Tsai <jennifer.tsai@emc.com.tw>,
        Paul Liang <paul.liang@emc.com.tw>,
        Jeff Chuang <jeff.chuang@emc.com.tw>,
        Douglas Anderson <dianders@chromium.org>,
        Jingle <jingle.wu@emc.com.tw>
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On Sun, 11 Apr 2021 at 18:21, Johnny Chuang <johnny.chuang.emc@gmail.com> wrote:
>
> Previous commit 43b7029f475e ("HID: i2c-hid:
> Send power-on command after reset"), it fixed issue for SIS touchscreen.
>
> For ELAN touchscreen, we found our boot code of IC was not flexible enough
> to receive and handle this command.
> Once the FW main code of our controller is crashed for some reason,
> the controller could not be enumerated successfully to be recognized
> by the system host. therefore, it lost touch functionality.
>
> Add quirk for skip send power-on command after reset.
> It will impact to ELAN touchscreen and touchpad on HID over I2C projects.
>
> Signed-off-by: Johnny Chuang <johnny.chuang.emc@gmail.com>

It's probably a good idea to add a Fixes: tag, like so:

    Fixes: 43b7029f475e ("HID: i2c-hid: Send power-on command after reset")

Other than that,

Reviewed-by: Harry Cutts <hcutts@chromium.org>

Harry Cutts
Chrome OS Touch/Input team

> ---
> Changes in v2:
>     - move comment to quirk entry
> ---
>  drivers/hid/i2c-hid/i2c-hid-core.c | 10 +++++++++-
>  1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/hid/i2c-hid/i2c-hid-core.c b/drivers/hid/i2c-hid/i2c-hid-core.c
> index 9993133..957d865 100644
> --- a/drivers/hid/i2c-hid/i2c-hid-core.c
> +++ b/drivers/hid/i2c-hid/i2c-hid-core.c
> @@ -45,6 +45,7 @@
>  #define I2C_HID_QUIRK_BOGUS_IRQ                        BIT(4)
>  #define I2C_HID_QUIRK_RESET_ON_RESUME          BIT(5)
>  #define I2C_HID_QUIRK_BAD_INPUT_SIZE           BIT(6)
> +#define I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET    BIT(7)
>
>
>  /* flags */
> @@ -178,6 +179,12 @@ static const struct i2c_hid_quirks {
>                  I2C_HID_QUIRK_RESET_ON_RESUME },
>         { USB_VENDOR_ID_ITE, I2C_DEVICE_ID_ITE_LENOVO_LEGION_Y720,
>                 I2C_HID_QUIRK_BAD_INPUT_SIZE },
> +/*
> + * Sending the wakeup after reset actually break ELAN touchscreen controller
> + * Add I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET to skip wakeup after reset
> + */
> +       { USB_VENDOR_ID_ELAN, HID_ANY_ID,
> +                I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET },
>         { 0, 0 }
>  };
>
> @@ -461,7 +468,8 @@ static int i2c_hid_hwreset(struct i2c_client *client)
>         }
>
>         /* At least some SIS devices need this after reset */
> -       ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
> +       if (!(ihid->quirks & I2C_HID_QUIRK_NO_WAKEUP_AFTER_RESET))
> +               ret = i2c_hid_set_power(client, I2C_HID_PWR_ON);
>
>  out_unlock:
>         mutex_unlock(&ihid->reset_lock);
> --
> 2.7.4
>