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Message-ID: <0837856f-bdd5-e8b7-3a08-01244843dbd8@linaro.org>
Date:   Fri, 26 May 2023 21:29:44 +0200
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Subject: Re: [PATCH 0/9] drm/panel and i2c-hid: Allow panels and touchscreens
 to power sequence together
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To:     Douglas Anderson <dianders@chromium.org>,
        Jiri Kosina <jikos@kernel.org>,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>,
        Bjorn Andersson <andersson@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Neil Armstrong <neil.armstrong@linaro.org>,
        Sam Ravnborg <sam@ravnborg.org>,
        Maarten Lankhorst <maarten.lankhorst@linux.intel.com>,
        Maxime Ripard <mripard@kernel.org>,
        Thomas Zimmermann <tzimmermann@suse.de>
Cc:     dri-devel@lists.freedesktop.org, linux-input@vger.kernel.org,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>, hsinyi@google.com,
        devicetree@vger.kernel.org,
        yangcong5@huaqin.corp-partner.google.com,
        linux-kernel@vger.kernel.org, Daniel Vetter <daniel@ffwll.ch>,
        linux-arm-msm@vger.kernel.org, cros-qcom-dts-watchers@chromium.org
References: <20230523193017.4109557-1-dianders@chromium.org>
From:   Konrad Dybcio <konrad.dybcio@linaro.org>
In-Reply-To: <20230523193017.4109557-1-dianders@chromium.org>
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Precedence: bulk


On 23.05.2023 21:27, Douglas Anderson wrote:
> 
> The big motivation for this patch series is mostly described in the patch
> ("drm/panel: Add a way for other devices to follow panel state"), but to
> quickly summarize here: for touchscreens that are connected to a panel we
> need the ability to power sequence the two device together. This is not a
> new need, but so far we've managed to get by through a combination of
> inefficiency, added costs, or perhaps just a little bit of brokenness.
> It's time to do better. This patch series allows us to do better.
Panels with integrated touchscreens have been shipping in mainstream devices
since at least 2016. Thanks a lot for looking into this!

Konrad
> 
> Assuming that people think this patch series looks OK, we'll have to
> figure out the right way to land it. The panel patches and i2c-hid
> patches will go through very different trees and so either we'll need
> an Ack from one side or the other or someone to create a tag for the
> other tree to pull in. This will _probably_ require the true drm-misc
> maintainers to get involved, not a lowly committer. ;-)
> 
> 
> Douglas Anderson (9):
>   dt-bindings: HID: i2c-hid: Add "panel" property to i2c-hid backed
>     panels
>   drm/panel: Check for already prepared/enabled in drm_panel
>   drm/panel: Add a way for other devices to follow panel state
>   HID: i2c-hid: Switch to SYSTEM_SLEEP_PM_OPS()
>   HID: i2c-hid: Rearrange probe() to power things up later
>   HID: i2c-hid: Make suspend and resume into helper functions
>   HID: i2c-hid: Support being a panel follower
>   HID: i2c-hid: Do panel follower work on the system_wq
>   arm64: dts: qcom: sc7180: Link trogdor touchscreens to the panels
> 
>  .../bindings/input/elan,ekth6915.yaml         |   6 +
>  .../bindings/input/goodix,gt7375p.yaml        |   6 +
>  .../bindings/input/hid-over-i2c.yaml          |   6 +
>  .../boot/dts/qcom/sc7180-trogdor-coachz.dtsi  |   1 +
>  .../dts/qcom/sc7180-trogdor-homestar.dtsi     |   1 +
>  .../boot/dts/qcom/sc7180-trogdor-lazor.dtsi   |   1 +
>  .../boot/dts/qcom/sc7180-trogdor-pompom.dtsi  |   1 +
>  .../qcom/sc7180-trogdor-quackingstick.dtsi    |   1 +
>  .../dts/qcom/sc7180-trogdor-wormdingler.dtsi  |   1 +
>  drivers/gpu/drm/drm_panel.c                   | 194 +++++++++-
>  drivers/hid/i2c-hid/i2c-hid-core.c            | 330 +++++++++++++-----
>  include/drm/drm_panel.h                       |  89 +++++
>  12 files changed, 542 insertions(+), 95 deletions(-)
>