From: Matthias Kaehlcke <mka@chromium.org>
To: Douglas Anderson <dianders@chromium.org>
Cc: Bjorn Andersson <andersson@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
Jiri Kosina <jikos@kernel.org>,
Benjamin Tissoires <benjamin.tissoires@redhat.com>,
linux-input@vger.kernel.org, linux-arm-msm@vger.kernel.org,
Dmitry Torokhov <dmitry.torokhov@gmail.com>,
devicetree@vger.kernel.org, Stephen Kitt <steve@sk2.org>,
Konrad Dybcio <konrad.dybcio@linaro.org>,
Andy Gross <agross@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/7] arm64: dts: qcom: sc7280: Add 3ms ramp to herobrine's pp3300_left_in_mlb
Date: Tue, 7 Feb 2023 18:15:46 +0000 [thread overview]
Message-ID: <Y+KVUgRecTSPvdUs@google.com> (raw)
In-Reply-To: <20230206184744.2.I13814cefc5ab3e0a39ebd09f052e3fd25d4e8f1d@changeid>
On Mon, Feb 06, 2023 at 06:48:11PM -0800, Douglas Anderson wrote:
> The "pp3300_left_in_mlb" rail on herobrine eventually connects up to
> "vreg_edp_3p3" on the qcard. On several herobrine designs this rail
> has been measured to need more than 1ms to turn on.
>
> While technically a herobrine derivative (defined as anyone including
> the "herobrine.dtsi") could change the board to make the rail rise
> faster or slower, the fact that two boards (evoker and villager) both
> measured it as taking more than 1ms implies that it's probably going
> to be the norm. Thus, let's add a "regulator-enable-ramp-delay"
> straight into the herobrine.dtsi to handle this. If a particular
> derivative board needs a faster or slower one then they can override
> it, though that feels unlikely.
>
> While we measured something a bit over 1ms, we'll choose 3ms to give
> us a tiny bit of margin. This isn't a rail that turns off and on all
> the time anyway and 3ms is nothing compared to the total amount of
> time to power on a panel.
>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Matthias Kaehlcke <mka@chromium.org>
next prev parent reply other threads:[~2023-02-07 18:15 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-07 2:48 [PATCH 0/7] arm: qcom: Fix touchscreen voltage for sc7280-herobrine boards Douglas Anderson
2023-02-07 2:48 ` [PATCH 1/7] arm64: dts: qcom: sc7280: On QCard, regulator L3C should be 1.8V Douglas Anderson
2023-02-07 18:12 ` Matthias Kaehlcke
2023-02-07 2:48 ` [PATCH 2/7] arm64: dts: qcom: sc7280: Add 3ms ramp to herobrine's pp3300_left_in_mlb Douglas Anderson
2023-02-07 18:15 ` Matthias Kaehlcke [this message]
2023-02-07 2:48 ` [PATCH 3/7] arm64: dts: qcom: sc7280: Hook up the touchscreen IO rail on villager Douglas Anderson
2023-02-07 18:18 ` Matthias Kaehlcke
2023-02-07 2:48 ` [PATCH 4/7] HID: i2c-hid: goodix: Stop tying the reset line to the regulator Douglas Anderson
2023-02-07 3:58 ` Dmitry Torokhov
2023-02-07 18:31 ` Matthias Kaehlcke
2023-02-07 2:48 ` [PATCH 5/7] dt-bindings: HID: i2c-hid: goodix: Add mainboard-vddio-supply Douglas Anderson
2023-02-07 4:01 ` Dmitry Torokhov
2023-02-07 21:19 ` Rob Herring
2023-02-07 2:48 ` [PATCH 6/7] " Douglas Anderson
2023-02-07 4:02 ` Dmitry Torokhov
2023-02-07 18:46 ` Matthias Kaehlcke
2023-02-07 2:48 ` [PATCH 7/7] arm64: dts: qcom: sc7280: Hook up the touchscreen IO rail on evoker Douglas Anderson
2023-02-07 18:47 ` Matthias Kaehlcke
2023-02-09 4:22 ` (subset) [PATCH 0/7] arm: qcom: Fix touchscreen voltage for sc7280-herobrine boards Bjorn Andersson
2023-02-09 13:50 ` Benjamin Tissoires
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