From mboxrd@z Thu Jan 1 00:00:00 1970 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 66FACC433EF for ; Thu, 21 Apr 2022 09:44:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1387794AbiDUJrV (ORCPT ); Thu, 21 Apr 2022 05:47:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:50464 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1380705AbiDUJrU (ORCPT ); Thu, 21 Apr 2022 05:47:20 -0400 Received: from ssl.serverraum.org (ssl.serverraum.org [IPv6:2a01:4f8:151:8464::1:2]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B0E2F25593; Thu, 21 Apr 2022 02:44:30 -0700 (PDT) Received: from apollo.. (unknown [IPv6:2a02:810b:4340:43bf:4685:ff:fe12:5967]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-384) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ssl.serverraum.org (Postfix) with ESMTPSA id 5588F2222E; Thu, 21 Apr 2022 11:44:28 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=walle.cc; s=mail2016061301; t=1650534268; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=K01P/G+CWauK4toU/LzXTmQWdHHNJGWFolPPvXFB4f8=; b=YJYZ8QLxWmTaBccIVDc7P7vwdCKrddAJuGkjwLtP8zppuvfIzApujj8b9VklHCIz31mP/C uy2D00edLX1hDmIAs6v2xHCTb0E5LGq9xcrbhX3Y5MY+mHCQq9mSrv2zv0xQm9Txxos+3o Ys3W1c38UAzP9S+ryQ1usgPt8IsBWPs= From: Michael Walle To: krzysztof.kozlowski@linaro.org Cc: broonie@kernel.org, devicetree@vger.kernel.org, jerry.huang@nxp.com, krzysztof.kozlowski+dt@linaro.org, leoyang.li@nxp.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, linux-spi@vger.kernel.org, robh+dt@kernel.org, shawnguo@kernel.org, Vladimir Oltean , Michael Walle Subject: Re: [EXT] Re: [PATCH 1/2 v4] dt-bindings: dspi: added for semtech sx1301 Date: Thu, 21 Apr 2022 11:44:21 +0200 Message-Id: <20220421094421.288672-1-michael@walle.cc> X-Mailer: git-send-email 2.30.2 In-Reply-To: References: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org On 21/04/2022 11:11, Jerry Huang wrote: >> Please also answer Michael's comments. >> >> [Jerry Huang] I double checked the MikroBus devices, we used two MikcroBus devices: >> BLE P click: https://www.mikroe.com/ble-p-click >> BEE click: https://www.mikroe.com/bee-click >> Both of them are SPI interface connect to ls1028ardb through MiKcroBus interface. >> So the name "semtech sx1301" is not correct for this node. > > I asked to remove the words "Devicetree bindings" and this was not finished. > > Now you mention that entire name of device is wrong... It's confusing. I > don't know what device you are describing here. I expect you know. :) > > What is this binding about exactly? I *think* it's just exposing the mikrobus connector as an spidev device. There was a former attempt by Vladimir here [1]. Now as it the nature of such a connector that you can connect a myriad of devices there, it doesn't really make sense to have a just particular one described. What happens if that one will switch from spidev to a real driver in the kernel? So using "spidev" for the compatible would be the first reflex. But as described in the spidev driver this is plain wrong (and also causes a warning/info message it) because it should describe the actual hardware. Thus I proposed to use DT overlays which are loaded according to what is actually attached to the header, so a real driver could be loaded. But there *could* be a sane default which then could be replaced in an DT overlay. Like "mirkobus-socket" or similar, which might expose spidev. Actually it is more than just SPI, there is GPIO and resets and I2C. Maybe it should be an MFD? I don't know. But that is something for the DT maintainers to decide if they'll allow such "generic" devices. -michael [1] https://lore.kernel.org/linux-devicetree/20200318001603.9650-13-olteanv@gmail.com/