From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-244107.protonmail.ch (mail-244107.protonmail.ch [109.224.244.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 753742550AF for ; Tue, 29 Apr 2025 19:02:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=109.224.244.107 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745953342; cv=none; b=eXGNC+venuGLRNCsK++/x5uFu/uzOFnFayTPDVyIeZsxfDqQi2Zqm51r6XdpMjj2g58WmuMrvI/UglDBCr5lKL/w9dqDFzMGDvuO8zvEItxeqLXItsIQHdUimFffa007ytss7FJaaoKaZXlBER8h1B7LGAlc7yDO1kOUhvO/S48= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1745953342; c=relaxed/simple; bh=ZogMkcg1Vv62KgOALOq9xcS0XYjBf/i30u5wYAowTXs=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID: MIME-Version:Content-Type; b=G+xmHzJeEUDAjkyRajTpCPzqKs6BnCpJlUtH00gv/+szAckMIF25b2VMbd82PhMQtcU2j8X3rqs/DWHyY5aN2lVx2WJLBR1SSabi4pMJawg/B913Krx5vInsi4t6M/asRiZPtfiFDeEY71ucBYjs/3zvTHBgf9xcAnU9xn0JvwQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=geanix.com; spf=pass smtp.mailfrom=geanix.com; dkim=pass (2048-bit key) header.d=geanix.com header.i=@geanix.com header.b=BLiUhj87; arc=none smtp.client-ip=109.224.244.107 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=geanix.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=geanix.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=geanix.com header.i=@geanix.com header.b="BLiUhj87" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=geanix.com; s=protonmail; t=1745953336; x=1746212536; bh=1YjWb/Jn/3bYxh7+rmCEcUaERkMf0JFBVzH01YCTxkc=; h=From:To:Cc:Subject:In-Reply-To:References:Date:Message-ID:From:To: Cc:Date:Subject:Reply-To:Feedback-ID:Message-ID:BIMI-Selector: List-Unsubscribe:List-Unsubscribe-Post; b=BLiUhj87ccPj20knCWXb1RKgwwnGzYmFui9nq/odyJDIvWLFa7i2E3cvecS6quwTX /0t9MriOZ+Pw0KMfv1elpYqK0cV+gM2Rk9yxn1xP4U5c0+Fsw73cvqkPj2FcIQ2VOb pjEdLd3hkVT6Q7sCHsr43HWqx1TGSCauHP/jp8djuXn/vmtg3yrred3iRX37PNVxvZ t5fAjR6HN2I2ruIZ+IAhRAWTrsxKzS7DHTtTdySvQeDuq0H1yQ8dnSC9tdFdeE9NK4 T4AlB6QroC03tqoD4G9KV1oJXNRza+FvnHtk2jmO+KXB6wG3plaEvsBR+sUDIRizzv e0FjHv3ApfiCA== X-Pm-Submission-Id: 4Zn8nf5gPRzLT From: Esben Haabendal To: "Dmitry Torokhov" Cc: "Conor Dooley" , "Rob Herring" , "Krzysztof Kozlowski" , "Conor Dooley" , "Hans de Goede" , , , Subject: Re: [PATCH v2 1/2] dt-bindings: input: touchscreen: goodix: Add no-reset-pull-up property In-Reply-To: <2qwfe6yw3pil5tumibiagikqhgwct27vevi674fklfieabzozc@hzjwatn3vjss> (Dmitry Torokhov's message of "Tue, 29 Apr 2025 09:09:58 -0700") References: <20250429-goodix-no-reset-pull-up-v2-0-0687a4ad5a04@geanix.com> <20250429-goodix-no-reset-pull-up-v2-1-0687a4ad5a04@geanix.com> <20250429-effects-subscript-58eb41737816@spud> <87selrt1vl.fsf@geanix.com> <2qwfe6yw3pil5tumibiagikqhgwct27vevi674fklfieabzozc@hzjwatn3vjss> Date: Tue, 29 Apr 2025 21:02:14 +0200 Message-ID: <87o6weu6yx.fsf@geanix.com> User-Agent: Gnus/5.13 (Gnus v5.13) Precedence: bulk X-Mailing-List: linux-input@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain "Dmitry Torokhov" writes: > On Tue, Apr 29, 2025 at 05:37:34PM +0200, Esben Haabendal wrote: >> "Conor Dooley" writes: >> >> > On Tue, Apr 29, 2025 at 11:56:11AM +0200, Esben Haabendal wrote: >> >> This should be added for boards where there is no pull-up on the reset pin, >> >> as the driver will otherwise switch the reset signal to high-impedance to >> >> save power, which obviously not safe without pull-up. >> >> >> >> Signed-off-by: Esben Haabendal >> >> --- >> >> Documentation/devicetree/bindings/input/touchscreen/goodix.yaml | 4 ++++ >> >> 1 file changed, 4 insertions(+) >> >> >> >> diff --git a/Documentation/devicetree/bindings/input/touchscreen/goodix.yaml b/Documentation/devicetree/bindings/input/touchscreen/goodix.yaml >> >> index eb4992f708b70fef93bd4b59b9565123f7c6ad5d..21ac13046b6e021eeb403d854aabc945801dd29f 100644 >> >> --- a/Documentation/devicetree/bindings/input/touchscreen/goodix.yaml >> >> +++ b/Documentation/devicetree/bindings/input/touchscreen/goodix.yaml >> >> @@ -45,6 +45,10 @@ properties: >> >> reset-gpios: >> >> maxItems: 1 >> >> >> >> + goodix,no-reset-pull-up: >> >> + type: boolean >> >> + description: There is no pull-up on reset pin >> > >> > I have to wonder, why are these system using the reset property if the >> > reset is not usable? Shouldn't the property be omitted? >> >> The reset are fully functional. It just have to be controlled in >> push-pull mode. >> >> Because of the lack of external pull-up, configuring the reset gpio as >> input (to save power) puts the reset pin in an unknown state. > > How much power do we save by doing this? I don't recall other drivers > trying to switch reset GPIO into input mode after performing reset... I don't know. I also don't recall seeing this in other drivers. But as not knowing how much power it is, I did not feel comofortable proposing to remove it. /Esben