From patchwork Sat Jul 22 09:57:09 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Krzysztof Kozlowski X-Patchwork-Id: 705527 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BF4D4EB64DC for ; Sat, 22 Jul 2023 09:57:18 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230080AbjGVJ5R (ORCPT ); Sat, 22 Jul 2023 05:57:17 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34392 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230076AbjGVJ5Q (ORCPT ); Sat, 22 Jul 2023 05:57:16 -0400 Received: from mail-ej1-x635.google.com (mail-ej1-x635.google.com [IPv6:2a00:1450:4864:20::635]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 836A5E74 for ; Sat, 22 Jul 2023 02:57:15 -0700 (PDT) Received: by mail-ej1-x635.google.com with SMTP id a640c23a62f3a-992af8b3b1bso438924366b.1 for ; Sat, 22 Jul 2023 02:57:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1690019834; x=1690624634; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:from:to:cc:subject:date:message-id:reply-to; bh=nyKDRJkgNpqdQ6Lp+ez6Jz58IxlTBjt/lNLl3Cr0hHU=; b=C8xl8o0HfyCAiQQy6sXroqvzsUsViienqWCv2AcFrVv5AY1NcoPPAxw+7+N5C/pImo W90Ytyx+k/Vo+H0wt0kIRU3OQBFZejUG2uwTwSq6HjzPtP+sBdoLL0oR5DQYVtxLO9jB 2EPeFj+KL187+y4RECG2MTuezhuQoTWLmlhyPjocjGHV3L0S62TEBAaEbfJ9RDg95zbC dySg9y+MdoROytCaZe+KJYhMyUHVnhFewjMuATJWPC6WjpO0TS7tk6dEpLxW5sx95O7O So3ILWLnRxDtE3MlL81UT9ccb9feADdUOVp2+eENGiOOBjYLGPNToNNUcma9C/Y2zkF5 f7dw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690019834; x=1690624634; h=content-transfer-encoding:mime-version:message-id:date:subject:cc :to:from:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=nyKDRJkgNpqdQ6Lp+ez6Jz58IxlTBjt/lNLl3Cr0hHU=; b=Wtq0R65g5tFr6gwFsQBWMOeGTvotxiyMQkA73SWsO9a2wsQbYkAHyebtacqjPF21js t+edaXi7J8lY3oMb+GGzrrkDAAm5q2aDqS68IWQhzDk3i5vRYWxggzvRxatxeNiVz0Ce aUPtqTNrwvNnCtP8t9pmtmHz/NQ72wVG2Wa8bT3ofqJ9Nb4++TcXbNrLQsdmsAKholgK 5qdHvakxfPHjBm8rWEYMrDqUXiw3Cwojymbvh2MwmCRKmb6t8w2ppE495USp9DXit+E2 S0zTRE9/J65LmH2cU8AMc/tLKuTrA/RjXFQkhoajgR+n1pC3Lv3nVhdC4h758YLxeOGI wsng== X-Gm-Message-State: ABy/qLaxyyc8sfTKmOpmMNtl/HXx+9p3Dv7UTeT1ASgmcGP8ZYT3Fi3l XchjrikzfixDjJcfV60jxtqFwA== X-Google-Smtp-Source: APBJJlHoy+j8gBrdVp1q4DMm0RN6W5Prso7OXRda014campZdajHUv38DTwKwcyqTsoAVCfPySPxCw== X-Received: by 2002:a17:906:74d6:b0:993:e695:b589 with SMTP id z22-20020a17090674d600b00993e695b589mr3747344ejl.20.1690019833926; Sat, 22 Jul 2023 02:57:13 -0700 (PDT) Received: from krzk-bin.. ([178.197.223.104]) by smtp.gmail.com with ESMTPSA id d12-20020a17090648cc00b00992b7ff3993sm3281038ejt.126.2023.07.22.02.57.12 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 22 Jul 2023 02:57:13 -0700 (PDT) From: Krzysztof Kozlowski To: Peter Rosin , Andi Shyti , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Doug Anderson , linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Krzysztof Kozlowski Subject: [PATCH 1/2] dt-bindings: i2c: nxp,pca9541: convert to DT schema Date: Sat, 22 Jul 2023 11:57:09 +0200 Message-Id: <20230722095710.17496-1-krzysztof.kozlowski@linaro.org> X-Mailer: git-send-email 2.34.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Convert the bindings for NXP PCA9541 I2C bus master selector to DT schema. Signed-off-by: Krzysztof Kozlowski Acked-by: Peter Rosin Reviewed-by: Conor Dooley Acked-by: Andi Shyti --- Changes in v2: 1. New patch (Doug) --- .../devicetree/bindings/i2c/nxp,pca9541.txt | 29 ---------- .../devicetree/bindings/i2c/nxp,pca9541.yaml | 56 +++++++++++++++++++ 2 files changed, 56 insertions(+), 29 deletions(-) delete mode 100644 Documentation/devicetree/bindings/i2c/nxp,pca9541.txt create mode 100644 Documentation/devicetree/bindings/i2c/nxp,pca9541.yaml diff --git a/Documentation/devicetree/bindings/i2c/nxp,pca9541.txt b/Documentation/devicetree/bindings/i2c/nxp,pca9541.txt deleted file mode 100644 index 42bfc09c8918..000000000000 --- a/Documentation/devicetree/bindings/i2c/nxp,pca9541.txt +++ /dev/null @@ -1,29 +0,0 @@ -* NXP PCA9541 I2C bus master selector - -Required Properties: - - - compatible: Must be "nxp,pca9541" - - - reg: The I2C address of the device. - - The following required properties are defined externally: - - - I2C arbitration bus node. See i2c-arb.txt in this directory. - - -Example: - - i2c-arbitrator@74 { - compatible = "nxp,pca9541"; - reg = <0x74>; - - i2c-arb { - #address-cells = <1>; - #size-cells = <0>; - - eeprom@54 { - compatible = "atmel,24c08"; - reg = <0x54>; - }; - }; - }; diff --git a/Documentation/devicetree/bindings/i2c/nxp,pca9541.yaml b/Documentation/devicetree/bindings/i2c/nxp,pca9541.yaml new file mode 100644 index 000000000000..b65c25c1a435 --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/nxp,pca9541.yaml @@ -0,0 +1,56 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/i2c/nxp,pca9541.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: NXP PCA9541 I2C bus master selector + +maintainers: + - Peter Rosin + +properties: + compatible: + const: nxp,pca9541 + + reg: + maxItems: 1 + + i2c-arb: + type: object + $ref: /schemas/i2c/i2c-controller.yaml + unevaluatedProperties: false + description: + I2C arbitration bus node. + +required: + - compatible + - reg + - i2c-arb + +additionalProperties: false + +examples: + - | + #include + #include + + i2c { + #address-cells = <1>; + #size-cells = <0>; + + i2c-arbitrator@74 { + compatible = "nxp,pca9541"; + reg = <0x74>; + + i2c-arb { + #address-cells = <1>; + #size-cells = <0>; + + eeprom@54 { + compatible = "atmel,24c08"; + reg = <0x54>; + }; + }; + }; + }; From patchwork Sat Jul 22 09:57:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Krzysztof Kozlowski X-Patchwork-Id: 705947 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 57B11EB64DA for ; Sat, 22 Jul 2023 09:57:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229552AbjGVJ5T (ORCPT ); Sat, 22 Jul 2023 05:57:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34410 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230094AbjGVJ5S (ORCPT ); Sat, 22 Jul 2023 05:57:18 -0400 Received: from mail-ej1-x62e.google.com (mail-ej1-x62e.google.com [IPv6:2a00:1450:4864:20::62e]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CA53C10F4 for ; Sat, 22 Jul 2023 02:57:16 -0700 (PDT) Received: by mail-ej1-x62e.google.com with SMTP id a640c23a62f3a-992ace062f3so440854266b.2 for ; Sat, 22 Jul 2023 02:57:16 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; t=1690019835; x=1690624635; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=woFGdxs67jlM9TolmaMHkh2hVrHZae/JREG4F0Tldjs=; b=rHT92357naLfyIvlUABWxIna5SLJFAluExAXbwKDVyDgIdrbVckRvqwTKDOni4CPT+ YWzleJ20spX7sevP+hGBlldGXWdh+zyNYcSAwhDaCssHi2cUcGu48N/VvW+h8L5A7mFX xafH6BOnDA7cFuC6NVPtV21KcwlF3NFpjnWflcml/02+p3BGihvqRwTniLFtXtshHWBC Q4W3K2AiWT8rKEK8Zcw1/UfPX9Btln7wZcEn2AoMdm9n8xzMpHFjgTxl2SHjVhCN/x2F mngFw8Ylm6OdUk0CFnb3/mBVtMZiLSLWR3TrpNM/VjLigngH0Ev6qT3nm3E9M8/aXCBR liyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690019835; x=1690624635; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=woFGdxs67jlM9TolmaMHkh2hVrHZae/JREG4F0Tldjs=; b=B6aAMXvHmeXJglPPw8fPVc/2aX3sQcwqeho/M/FppolsFktnesMN7xLMqyZvj6TL0G SEsGfD0iUgd5EhZG+PMyxJdIDbxvqriOdpLJ4pecYKkklxHqlyxLtl+M/QlJjjiks04j r79cyKhca1kD3vACGBH4gRMx0zn/WHKMYj9I9HnwQ9T7KumI4GEZyYBVfePmt8+8Dfe7 O8EdrSHjc/WRnde/UElEQOkrDSTccFGyLoSOn56hIhXpqlVHVVapk5rR0xe+gAgxmhFM ZS78OoWmYPDZF2nYn7KHGulqPIdwcUY/sxwO/7qQ/jZMJf+ucVSqGyVFUdQiOUF/syCf 0jMA== X-Gm-Message-State: ABy/qLZgZj7ZSOfR/5g7Q/D//89wxRrW2Hjc01mnoF+RO1iv9mUS6ro+ f/Ei2II8KbStj3iiex37PBlhvQ== X-Google-Smtp-Source: APBJJlEO4imdHPS8TaUhZOyM72jJlHITdv2EKtv7i+fQLJ0hJmS4SBw1Sdj7LLrxG4P+HaQG0xeDtA== X-Received: by 2002:a17:906:3f1e:b0:99b:504d:d9c7 with SMTP id c30-20020a1709063f1e00b0099b504dd9c7mr4313666ejj.67.1690019835200; Sat, 22 Jul 2023 02:57:15 -0700 (PDT) Received: from krzk-bin.. ([178.197.223.104]) by smtp.gmail.com with ESMTPSA id d12-20020a17090648cc00b00992b7ff3993sm3281038ejt.126.2023.07.22.02.57.14 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 22 Jul 2023 02:57:14 -0700 (PDT) From: Krzysztof Kozlowski To: Peter Rosin , Andi Shyti , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Doug Anderson , linux-i2c@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Krzysztof Kozlowski Subject: [PATCH 2/2] dt-bindings: i2c: arb-gpio-challange: convert to DT schema Date: Sat, 22 Jul 2023 11:57:10 +0200 Message-Id: <20230722095710.17496-2-krzysztof.kozlowski@linaro.org> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230722095710.17496-1-krzysztof.kozlowski@linaro.org> References: <20230722095710.17496-1-krzysztof.kozlowski@linaro.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-i2c@vger.kernel.org Convert the bindings for GPIO-based I2C Arbitration Using a Challenge & Response Mechanism to DT schema. Signed-off-by: Krzysztof Kozlowski Acked-by: Douglas Anderson --- The text of original bindings was written by Doug, so please kindly ack if you agree to relicense it from GPL-2 to (GPL-2.0-only OR BSD-2-Clause). Changes in v2: 1. Drop i2c-controller $ref in top-level part, because only children are I2C controllers. 2. Add Ack. --- .../bindings/i2c/i2c-arb-gpio-challenge.txt | 82 ----------- .../bindings/i2c/i2c-arb-gpio-challenge.yaml | 135 ++++++++++++++++++ .../devicetree/bindings/i2c/i2c-arb.txt | 35 ----- 3 files changed, 135 insertions(+), 117 deletions(-) delete mode 100644 Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt create mode 100644 Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.yaml delete mode 100644 Documentation/devicetree/bindings/i2c/i2c-arb.txt diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt deleted file mode 100644 index 548a73cde796..000000000000 --- a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.txt +++ /dev/null @@ -1,82 +0,0 @@ -GPIO-based I2C Arbitration Using a Challenge & Response Mechanism -================================================================= -This uses GPIO lines and a challenge & response mechanism to arbitrate who is -the master of an I2C bus in a multimaster situation. - -In many cases using GPIOs to arbitrate is not needed and a design can use -the standard I2C multi-master rules. Using GPIOs is generally useful in -the case where there is a device on the bus that has errata and/or bugs -that makes standard multimaster mode not feasible. - -Note that this scheme works well enough but has some downsides: -* It is nonstandard (not using standard I2C multimaster) -* Having two masters on a bus in general makes it relatively hard to debug - problems (hard to tell if i2c issues were caused by one master, another, or - some device on the bus). - - -Algorithm: - -All masters on the bus have a 'bus claim' line which is an output that the -others can see. These are all active low with pull-ups enabled. We'll -describe these lines as: - -- OUR_CLAIM: output from us signaling to other hosts that we want the bus -- THEIR_CLAIMS: output from others signaling that they want the bus - -The basic algorithm is to assert your line when you want the bus, then make -sure that the other side doesn't want it also. A detailed explanation is best -done with an example. - -Let's say we want to claim the bus. We: -1. Assert OUR_CLAIM. -2. Waits a little bit for the other sides to notice (slew time, say 10 - microseconds). -3. Check THEIR_CLAIMS. If none are asserted then the we have the bus and we are - done. -4. Otherwise, wait for a few milliseconds and see if THEIR_CLAIMS are released. -5. If not, back off, release the claim and wait for a few more milliseconds. -6. Go back to 1 (until retry time has expired). - - -Required properties: -- compatible: i2c-arb-gpio-challenge -- our-claim-gpio: The GPIO that we use to claim the bus. -- their-claim-gpios: The GPIOs that the other sides use to claim the bus. - Note that some implementations may only support a single other master. -- I2C arbitration bus node. See i2c-arb.txt in this directory. - -Optional properties: -- slew-delay-us: microseconds to wait for a GPIO to go high. Default is 10 us. -- wait-retry-us: we'll attempt another claim after this many microseconds. - Default is 3000 us. -- wait-free-us: we'll give up after this many microseconds. Default is 50000 us. - - -Example: - i2c@12ca0000 { - compatible = "acme,some-i2c-device"; - #address-cells = <1>; - #size-cells = <0>; - }; - - i2c-arbitrator { - compatible = "i2c-arb-gpio-challenge"; - - i2c-parent = <&{/i2c@12CA0000}>; - - our-claim-gpio = <&gpf0 3 1>; - their-claim-gpios = <&gpe0 4 1>; - slew-delay-us = <10>; - wait-retry-us = <3000>; - wait-free-us = <50000>; - - i2c-arb { - #address-cells = <1>; - #size-cells = <0>; - - i2c@52 { - // Normal I2C device - }; - }; - }; diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.yaml b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.yaml new file mode 100644 index 000000000000..5bf6ce14c2dc --- /dev/null +++ b/Documentation/devicetree/bindings/i2c/i2c-arb-gpio-challenge.yaml @@ -0,0 +1,135 @@ +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause +%YAML 1.2 +--- +$id: http://devicetree.org/schemas/i2c/i2c-arb-gpio-challenge.yaml# +$schema: http://devicetree.org/meta-schemas/core.yaml# + +title: GPIO-based I2C Arbitration Using a Challenge & Response Mechanism + +maintainers: + - Doug Anderson + - Peter Rosin + +description: | + This uses GPIO lines and a challenge & response mechanism to arbitrate who is + the master of an I2C bus in a multimaster situation. + + In many cases using GPIOs to arbitrate is not needed and a design can use the + standard I2C multi-master rules. Using GPIOs is generally useful in the case + where there is a device on the bus that has errata and/or bugs that makes + standard multimaster mode not feasible. + + Note that this scheme works well enough but has some downsides: + * It is nonstandard (not using standard I2C multimaster) + * Having two masters on a bus in general makes it relatively hard to debug + problems (hard to tell if i2c issues were caused by one master, another, + or some device on the bus). + + Algorithm: + All masters on the bus have a 'bus claim' line which is an output that the + others can see. These are all active low with pull-ups enabled. We'll + describe these lines as: + * OUR_CLAIM: output from us signaling to other hosts that we want the bus + * THEIR_CLAIMS: output from others signaling that they want the bus + + The basic algorithm is to assert your line when you want the bus, then make + sure that the other side doesn't want it also. A detailed explanation is + best done with an example. + + Let's say we want to claim the bus. We: + 1. Assert OUR_CLAIM. + 2. Waits a little bit for the other sides to notice (slew time, say 10 + microseconds). + 3. Check THEIR_CLAIMS. If none are asserted then the we have the bus and we + are done. + 4. Otherwise, wait for a few milliseconds and see if THEIR_CLAIMS are released. + 5. If not, back off, release the claim and wait for a few more milliseconds. + 6. Go back to 1 (until retry time has expired). + +properties: + compatible: + const: i2c-arb-gpio-challenge + + i2c-parent: + $ref: /schemas/types.yaml#/definitions/phandle + description: + The I2C bus that this multiplexer's master-side port is connected to. + + our-claim-gpios: + maxItems: 1 + description: + The GPIO that we use to claim the bus. + + slew-delay-us: + default: 10 + description: + Time to wait for a GPIO to go high. + + their-claim-gpios: + minItems: 1 + maxItems: 2 + description: + The GPIOs that the other sides use to claim the bus. Note that some + implementations may only support a single other master. + + wait-free-us: + default: 50000 + description: + We'll give up after this many microseconds. + + wait-retry-us: + default: 3000 + description: + We'll attempt another claim after this many microseconds. + + i2c-arb: + type: object + $ref: /schemas/i2c/i2c-controller.yaml + unevaluatedProperties: false + description: + I2C arbitration bus node. + +required: + - compatible + - i2c-arb + - our-claim-gpios + - their-claim-gpios + +additionalProperties: false + +examples: + - | + #include + #include + + i2c-arbitrator { + compatible = "i2c-arb-gpio-challenge"; + i2c-parent = <&i2c_4>; + + our-claim-gpios = <&gpf0 3 GPIO_ACTIVE_LOW>; + their-claim-gpios = <&gpe0 4 GPIO_ACTIVE_LOW>; + slew-delay-us = <10>; + wait-retry-us = <3000>; + wait-free-us = <50000>; + + i2c-arb { + #address-cells = <1>; + #size-cells = <0>; + + sbs-battery@b { + compatible = "sbs,sbs-battery"; + reg = <0xb>; + sbs,poll-retry-count = <1>; + }; + + embedded-controller@1e { + compatible = "google,cros-ec-i2c"; + reg = <0x1e>; + interrupts = <6 IRQ_TYPE_LEVEL_HIGH>; + interrupt-parent = <&gpx1>; + pinctrl-names = "default"; + pinctrl-0 = <&ec_irq>; + wakeup-source; + }; + }; + }; diff --git a/Documentation/devicetree/bindings/i2c/i2c-arb.txt b/Documentation/devicetree/bindings/i2c/i2c-arb.txt deleted file mode 100644 index 59abf9277bdc..000000000000 --- a/Documentation/devicetree/bindings/i2c/i2c-arb.txt +++ /dev/null @@ -1,35 +0,0 @@ -Common i2c arbitration bus properties. - -- i2c-arb child node - -Required properties for the i2c-arb child node: -- #address-cells = <1>; -- #size-cells = <0>; - -Optional properties for i2c-arb child node: -- Child nodes conforming to i2c bus binding - - -Example : - - /* - An NXP pca9541 I2C bus master selector at address 0x74 - with a NXP pca8574 GPIO expander attached. - */ - - arb@74 { - compatible = "nxp,pca9541"; - reg = <0x74>; - - i2c-arb { - #address-cells = <1>; - #size-cells = <0>; - - gpio@38 { - compatible = "nxp,pca8574"; - reg = <0x38>; - #gpio-cells = <2>; - gpio-controller; - }; - }; - };