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From: Johan Hovold <johan+linaro@kernel.org>
To: Jiri Kosina <jikos@kernel.org>,
	Benjamin Tissoires <benjamin.tissoires@redhat.com>
Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Bjorn Andersson <andersson@kernel.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Douglas Anderson <dianders@chromium.org>,
	linux-input@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Johan Hovold <johan+linaro@kernel.org>
Subject: [PATCH 3/6] dt-bindings: HID: i2c-hid: elan: add 'no-reset-on-power-off' property
Date: Tue, 23 Apr 2024 15:46:08 +0200	[thread overview]
Message-ID: <20240423134611.31979-4-johan+linaro@kernel.org> (raw)
In-Reply-To: <20240423134611.31979-1-johan+linaro@kernel.org>

When the power supply is shared with other peripherals the reset line
can be wired in such a way that it can remain deasserted regardless of
whether the supply is on or not.

This is important as it can be used to avoid holding the controller in
reset for extended periods of time when it remains powered, something
which can lead to increased power consumption. Leaving reset deasserted
also avoids leaking current through the reset circuitry pull-up
resistors.

Add a new 'no-reset-on-power-off' devicetree property which can be used
by the OS to determine when reset needs to be asserted on power down.

Note that this property can also be used when the supply cannot be
turned off by the OS at all.

Signed-off-by: Johan Hovold <johan+linaro@kernel.org>
---
 Documentation/devicetree/bindings/input/elan,ekth6915.yaml | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Documentation/devicetree/bindings/input/elan,ekth6915.yaml b/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
index c3a6f901ff45..3d20673f10b2 100644
--- a/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
+++ b/Documentation/devicetree/bindings/input/elan,ekth6915.yaml
@@ -37,6 +37,12 @@ properties:
   reset-gpios:
     description: Reset GPIO; not all touchscreens using eKTH6915 hook this up.
 
+  no-reset-on-power-off:
+    type: boolean
+    description:
+      Reset line is wired so that it can be left deasserted when the power
+      supply is off.
+
   vcc33-supply:
     description: The 3.3V supply to the touchscreen.
 
-- 
2.43.2


  parent reply	other threads:[~2024-04-23 13:46 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-23 13:46 [PATCH 0/6] HID/arm64: dts: qcom: sc8280xp-x13s: fix touchscreen power on Johan Hovold
2024-04-23 13:46 ` [PATCH 1/6] dt-bindings: HID: i2c-hid: add dedicated Ilitek ILI2901 schema Johan Hovold
2024-04-23 16:23   ` Krzysztof Kozlowski
2024-04-23 13:46 ` [PATCH 2/6] dt-bindings: HID: i2c-hid: elan: add Elan eKTH5015M Johan Hovold
2024-04-23 16:24   ` Krzysztof Kozlowski
2024-04-24  7:03     ` Johan Hovold
2024-04-24  8:32       ` Krzysztof Kozlowski
2024-04-23 13:46 ` Johan Hovold [this message]
2024-04-23 16:29   ` [PATCH 3/6] dt-bindings: HID: i2c-hid: elan: add 'no-reset-on-power-off' property Krzysztof Kozlowski
2024-04-24  7:34     ` Johan Hovold
2024-04-25  9:39       ` Krzysztof Kozlowski
2024-05-02  9:56         ` Johan Hovold
2024-05-03  9:11           ` Krzysztof Kozlowski
2024-05-03  9:25             ` Johan Hovold
2024-05-03  7:40   ` Linus Walleij
2024-05-03  8:47     ` Johan Hovold
2024-05-06  6:29       ` Linus Walleij
2024-05-07 14:30         ` Johan Hovold
2024-04-23 13:46 ` [PATCH 4/6] HID: i2c-hid: elan: fix reset suspend current leakage Johan Hovold
2024-04-23 20:37   ` Doug Anderson
2024-04-24 10:56     ` Johan Hovold
2024-04-24 16:24       ` Doug Anderson
2024-04-26  9:29         ` Johan Hovold
2024-04-23 13:46 ` [PATCH 5/6] arm64: dts: qcom: sc8280xp-x13s: fix touchscreen power on Johan Hovold
2024-04-23 13:46 ` [PATCH 6/6] arm64: dts: qcom: sc8280xp-crd: use external pull up for touch reset Johan Hovold
2024-04-23 19:34 ` [PATCH 0/6] HID/arm64: dts: qcom: sc8280xp-x13s: fix touchscreen power on Steev Klimaszewski
2024-04-24  7:38   ` Johan Hovold
2024-04-23 20:36 ` Doug Anderson
2024-04-24  8:50   ` Johan Hovold
2024-04-24 16:24     ` Doug Anderson

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