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 A4C56C433EF for ; Mon, 29 Nov 2021 04:39:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238601AbhK2EmS (ORCPT ); Sun, 28 Nov 2021 23:42:18 -0500 Received: from fllv0016.ext.ti.com ([198.47.19.142]:46600 "EHLO fllv0016.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233993AbhK2EkP (ORCPT ); Sun, 28 Nov 2021 23:40:15 -0500 Received: from lelv0266.itg.ti.com ([10.180.67.225]) by fllv0016.ext.ti.com (8.15.2/8.15.2) with ESMTP id 1AT4aZVA103393; Sun, 28 Nov 2021 22:36:35 -0600 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ti.com; s=ti-com-17Q1; t=1638160595; bh=T5ua16ilPFMaScWb+OoNmTXhxlYu6YduhMgRmagewJU=; h=From:Subject:To:CC:References:Date:In-Reply-To; b=Dql1PpzBGgHWPkere5NpJg6Vl1zEgoP5jH+keEuopHBBoh/cnvRsTQHBkDJKOBnW3 SIaBmnUNxTX/R3ssF28leIIXM0XiUDGY6tYBokPdQTNi4TuBU5ZnFCBIpznPwWLGVS rPQgBgzSp21BcQZT3BxxIEjDapCY4eGQDiraEJ94= Received: from DFLE105.ent.ti.com (dfle105.ent.ti.com [10.64.6.26]) by lelv0266.itg.ti.com (8.15.2/8.15.2) with ESMTPS id 1AT4aZw6033420 (version=TLSv1.2 cipher=AES256-GCM-SHA384 bits=256 verify=FAIL); Sun, 28 Nov 2021 22:36:35 -0600 Received: from DFLE104.ent.ti.com (10.64.6.25) by DFLE105.ent.ti.com (10.64.6.26) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14; Sun, 28 Nov 2021 22:36:35 -0600 Received: from lelv0326.itg.ti.com (10.180.67.84) by DFLE104.ent.ti.com (10.64.6.25) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2308.14 via Frontend Transport; Sun, 28 Nov 2021 22:36:34 -0600 Received: from [10.250.232.185] (ileax41-snat.itg.ti.com [10.172.224.153]) by lelv0326.itg.ti.com (8.15.2/8.15.2) with ESMTP id 1AT4aVaE061174; Sun, 28 Nov 2021 22:36:31 -0600 From: Aswath Govindraju Subject: Re: [PATCH RFC v3 1/4] dt-bindings: mux: Increase the number of arguments in mux-controls To: Peter Rosin CC: Vignesh Raghavendra , Nishanth Menon , Rob Herring , Wolfgang Grandegger , Marc Kleine-Budde , Kishon Vijay Abraham I , Vinod Koul , , , , References: <20211123081222.27979-1-a-govindraju@ti.com> <20211123081222.27979-2-a-govindraju@ti.com> <24781209-928b-dea4-de0b-b103dac8de82@axentia.se> Message-ID: <5f455c4d-5edb-4382-1193-a519a7a227a5@ti.com> Date: Mon, 29 Nov 2021 10:06:30 +0530 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.14.0 MIME-Version: 1.0 In-Reply-To: <24781209-928b-dea4-de0b-b103dac8de82@axentia.se> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-EXCLAIMER-MD-CONFIG: e1e8a2fd-e40a-4ac6-ac9b-f7e9cc9ee180 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Peter, On 25/11/21 7:05 pm, Peter Rosin wrote: > Hi! > > You need to have some description on how #mux-control-cells now work. > The previous description is in mux-consumer.yaml and an update there > is needed. > > However, I have realized that the adg792a binding uses #mux-control-cells > to indicate if it should expose its three muxes with one mux-control > and operate the muxes in parallel, or if it should be expose three > independent mux-controls. So, the approach in this series to always > have the #mux-control-cells property fixed at <2> when indicating a > state will not work for that binding. And I see no fix for that binding > without adding a new property. > > So, I would like a different approach. Since I dislike how mux-controls > -after this series- is not (always) specifying a mux-control like the name > says, but instead optionally a specific state, the new property I would > like to add is #mux-state-cells such that it would always be one more > than #mux-control-cells. > > mux: mux-controller { > compatible = "gpio-mux"; > #mux-control-cells = <0>; > #mux-state-cells = <1>; > > mux-gpios = <...>; > }; > > can-phy { > compatible = "ti,tcan1043"; > ... > mux-states = <&mux 1>; > }; > > That solves the naming issue, the unused argument for mux-conrtrollers > that previously had #mux-control-cells = <0>, and the binding for adg792a > need no longer be inconsistent. > > Or, how should this be solved? I'm sure there are other options... > I feel that the new approach using mux-state-cells seems to be overpopulating the device tree nodes, when the state can be represented using the control cells. I understand that the definition for mux-controls is to only specify the control line to be used in a given mux. Can't it now be upgraded to also represent the state at which the control line has to be set to? With respect to adg792a, it is inline with the current implementation and the only change I think would be required in the driver is, diff --git a/drivers/mux/adg792a.c b/drivers/mux/adg792a.c index e8fc2fc1ab09..2cd3bb8a40d4 100644 --- a/drivers/mux/adg792a.c +++ b/drivers/mux/adg792a.c @@ -73,8 +73,6 @@ static int adg792a_probe(struct i2c_client *i2c) ret = device_property_read_u32(dev, "#mux-control-cells", &cells); if (ret < 0) return ret; - if (cells >= 2) - return -EINVAL; mux_chip = devm_mux_chip_alloc(dev, cells ? 3 : 1, 0); if (IS_ERR(mux_chip)) And the following series should be compatible with it. If adg792a driver is the only issue then would there be any issue with only changing it and using this implementation? Thanks, Aswath > Cheers, > Peter > > On 2021-11-23 09:12, Aswath Govindraju wrote: >> Increase the allowed number of arguments in mux-controls to add support for >> passing information regarding the state of the mux to be set, for a given >> device. >> >> Signed-off-by: Aswath Govindraju >> --- >> Documentation/devicetree/bindings/mux/gpio-mux.yaml | 2 +- >> Documentation/devicetree/bindings/mux/mux-controller.yaml | 2 +- >> 2 files changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/Documentation/devicetree/bindings/mux/gpio-mux.yaml b/Documentation/devicetree/bindings/mux/gpio-mux.yaml >> index 0a7c8d64981a..c810b7df39de 100644 >> --- a/Documentation/devicetree/bindings/mux/gpio-mux.yaml >> +++ b/Documentation/devicetree/bindings/mux/gpio-mux.yaml >> @@ -26,7 +26,7 @@ properties: >> List of gpios used to control the multiplexer, least significant bit first. >> >> '#mux-control-cells': >> - const: 0 >> + enum: [ 0, 1, 2 ] >> >> idle-state: >> default: -1 >> diff --git a/Documentation/devicetree/bindings/mux/mux-controller.yaml b/Documentation/devicetree/bindings/mux/mux-controller.yaml >> index 736a84c3b6a5..0b4b067a97bf 100644 >> --- a/Documentation/devicetree/bindings/mux/mux-controller.yaml >> +++ b/Documentation/devicetree/bindings/mux/mux-controller.yaml >> @@ -73,7 +73,7 @@ properties: >> pattern: '^mux-controller(@.*|-[0-9a-f]+)?$' >> >> '#mux-control-cells': >> - enum: [ 0, 1 ] >> + enum: [ 0, 1, 2 ] >> >> idle-state: >> $ref: /schemas/types.yaml#/definitions/int32 >>