linux-kernel - [PATCH v3 0/2] Fix Goodix touchscreen power leakage for MT8186 boards

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Date:   Wed, 26 Apr 2023 22:44:20 +0800
From:   Fei Shao <fshao@...omium.org>
To:     Jeff LaBundy <jeff@...undy.com>,
        Douglas Anderson <dianders@...omium.org>,
        Benjamin Tissoires <benjamin.tissoires@...hat.com>,
        Rob Herring <robh+dt@...nel.org>
Cc:     linux-mediatek <linux-mediatek@...ts.infradead.org>,
        Fei Shao <fshao@...omium.org>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Jiri Kosina <jikos@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Matthias Kaehlcke <mka@...omium.org>,
        Stephen Kitt <steve@....org>, devicetree@...r.kernel.org,
        linux-input@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH v3 0/2] Fix Goodix touchscreen power leakage for MT8186 boards

These changes are based on the series in [1], which modified the
i2c-hid-of-goodix driver and removed the workaround for a power leakage
issue, so the issue revisits on Mediatek MT8186 boards (Steelix).

The root cause is that the touchscreen can be powered in different ways
depending on the hardware designs, and it's not as easy to come up with
a solution that is both simple and elegant for all the known designs.

To address the issue, I ended up adding a new boolean property for the
driver so that we can control the power up/down sequence depending on
that.

Adding a new property might not be the cleanest approach for this, but
at least the intention would be easy enough to understand, and it
introduces relatively small change to the code and fully preserves the
original control flow.
I hope this is something acceptable, and I'm open to any better
approaches.

[1] https://lore.kernel.org/all/20230207024816.525938-1-dianders@chromium.org/

Changes in v3:
- In power-down, only skip the GPIO but not the regulator calls if the
  flag is set

Changes in v2:
- Use a more accurate property name and with "goodix," prefix.
- Do not change the regulator_enable logic during power-up.

Fei Shao (2):
  dt-bindings: input: goodix: Add "goodix,no-reset-during-suspend"
    property
  HID: i2c-hid: goodix: Add support for "goodix,no-reset-during-suspend"
    property

 .../bindings/input/goodix,gt7375p.yaml           |  9 +++++++++
 drivers/hid/i2c-hid/i2c-hid-of-goodix.c          | 16 +++++++++++++++-
 2 files changed, 24 insertions(+), 1 deletion(-)

-- 
2.40.1.495.gc816e09b53d-goog