From patchwork Wed Nov 15 03:57:52 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Chris Packham X-Patchwork-Id: 744144 Received: from lindbergh.monkeyblade.net (lindbergh.monkeyblade.net [23.128.96.19]) (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 8F2A1A55 for ; Wed, 15 Nov 2023 03:58:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=alliedtelesis.co.nz header.i=@alliedtelesis.co.nz header.b="HTiTsnjB" Received: from gate2.alliedtelesis.co.nz (gate2.alliedtelesis.co.nz [202.36.163.20]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 79DEFE4 for ; Tue, 14 Nov 2023 19:58:02 -0800 (PST) Received: from svr-chch-seg1.atlnz.lc (mmarshal3.atlnz.lc [10.32.18.43]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (4096 bits) server-digest SHA256) (Client did not present a certificate) by gate2.alliedtelesis.co.nz (Postfix) with ESMTPS id AE1BA2C04EC; Wed, 15 Nov 2023 16:58:00 +1300 (NZDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alliedtelesis.co.nz; s=mail181024; t=1700020680; bh=nuXpiTc5KMpjZuPeua6pFPuqtUeESCBp8Bsq5TMv/zA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=HTiTsnjBRTpO1kHK8Er+ewHNb1qLDldNdo1MZw1o2NC2shsZST2/I9A8G4bWxupD6 g6zHS66yUo+NeDI/XK/IAYEdFA289XW5ZIGvy61tiJ8EtINa5s85k9T/26dLNM7SAp gdLs/UWHUEuMO7nxFFPlLh920rHCTb65HK7Qwul969gDuYJremElHOmwm4nM9YDQq1 RH8TfUmsAEGYymH3d5EMjyHp/OEKRK3qsqQvVoVXGj3H2yHwKSYmM4X2cFj3ae0C3z X2nJ/crrzmzZ5U+HIF2bGmXU0zFY8aCEfQsqu7Zhb3VrS6h5DuQbEc/3e07KMLWoyH 7+RntO4QVgKng== Received: from pat.atlnz.lc (Not Verified[10.32.16.33]) by svr-chch-seg1.atlnz.lc with Trustwave SEG (v8,2,6,11305) id ; Wed, 15 Nov 2023 16:58:00 +1300 Received: from chrisp-dl.ws.atlnz.lc (chrisp-dl.ws.atlnz.lc [10.33.22.30]) by pat.atlnz.lc (Postfix) with ESMTP id 6267F13EE3F; Wed, 15 Nov 2023 16:58:00 +1300 (NZDT) Received: by chrisp-dl.ws.atlnz.lc (Postfix, from userid 1030) id 5F8D3280590; Wed, 15 Nov 2023 16:58:00 +1300 (NZDT) From: Chris Packham To: wsa@kernel.org, andi.shyti@kernel.org, robh+dt@kernel.org, krzysztof.kozlowski+dt@linaro.org, conor+dt@kernel.org, gregory.clement@bootlin.com Cc: linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Chris Packham Subject: [PATCH v6 1/2] dt-bindings: i2c: add bus-reset-gpios property Date: Wed, 15 Nov 2023 16:57:52 +1300 Message-ID: <20231115035753.925534-2-chris.packham@alliedtelesis.co.nz> X-Mailer: git-send-email 2.42.0 In-Reply-To: <20231115035753.925534-1-chris.packham@alliedtelesis.co.nz> References: <20231115035753.925534-1-chris.packham@alliedtelesis.co.nz> Precedence: bulk X-Mailing-List: devicetree@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-SEG-SpamProfiler-Analysis: v=2.3 cv=L6ZjvNb8 c=1 sm=1 tr=0 a=KLBiSEs5mFS1a/PbTCJxuA==:117 a=BNY50KLci1gA:10 a=k44-534mOdnrxw8nBDMA:9 X-SEG-SpamProfiler-Score: 0 x-atlnz-ls: pat Add bus-reset-gpios and bus-reset-duration-us properties to the binding description for i2c busses. These can be used to describe hardware where a common reset GPIO is connected to all downstream devices on and I2C bus. This reset will be asserted then released before the downstream devices on the bus are probed. Signed-off-by: Chris Packham --- Notes: I expect the first reaction to this will be a request to convert the binding to dtschema. I can attempt such a conversion but given it's one of the more core bindings I expect others may have strong opinions. I didn't want to start a conversion without hearing those opinions (or if I could get away without doing the conversion). It's also likely to spin off a whole lot of work to bring existing device trees into line. Changes in v6: - Retarget changes at the i2c core instead of an individual driver Changes in v5: - Rename reset-gpios and reset-duration-us to bus-reset-gpios and bus-reset-duration-us as requested by Wolfram Changes in v4: - Add r-by from Krzysztof Changes in v3: - Rename reset-delay-us to reset-duration-us to better reflect its purpose - Add default: for reset-duration-us - Add description: for reset-gpios Changes in v2: - Update commit message - Add reset-delay-us property Documentation/devicetree/bindings/i2c/i2c.txt | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt index fc3dd7ec0445..3f95d71b9985 100644 --- a/Documentation/devicetree/bindings/i2c/i2c.txt +++ b/Documentation/devicetree/bindings/i2c/i2c.txt @@ -99,6 +99,14 @@ wants to support one of the below features, it should adapt these bindings. indicates that the system is accessible via this bus as an endpoint for MCTP over I2C transport. +- bus-reset-gpios: + GPIO pin providing a common reset for all downstream devices. This GPIO + will be asserted then released before the downstream devices are probed. + +- bus-reset-duration-us: + Reset duration in us. + default: 1 + Required properties (per child device) --------------------------------------