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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 53D3DC43334 for ; Fri, 15 Jul 2022 16:04:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=XHECU5lWM1fVRCxrd5eZ9EmXznTMQog0HzMiyrptaMk=; b=QCcr2buaTfbJoN3kH5rlkzrxbv nHgh5WCdQGEYY3hWZh4zoU0tTsLd4kuqg/FhNfJzfbC35ccZ9qzP6+12YE+R+lFCcVHrZ52/53qDt 58DrH2t7jRPWS3E2G70kURIaZ0B5XyXlctNYWyYJXx2wGDsBAmen1n4Vi9C/oYATKmxp+wg2MOmoa 9cZrXu1WRa0zGxqOBRqN0vDfVcvO4v8Eh+au/SF/Xb5YKzgMdzQ+CpmBlUxpDznU+scrXmWP1cNPa 4xHOAQrAQDLI4TJbhur9jOHZvdgnfD5WNjEC3DO8qNUFEOEmbl7UxLCUrREtVr4r/dhYZhxYqrRYB nc5FkD2A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oCNnf-008cuv-Lv; Fri, 15 Jul 2022 16:04:19 +0000 Received: from ams.source.kernel.org ([145.40.68.75]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oCNn2-008cTi-Be; Fri, 15 Jul 2022 16:03:41 +0000 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id A5B6FB82D32; Fri, 15 Jul 2022 16:03:38 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 66131C34115; Fri, 15 Jul 2022 16:03:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1657901017; bh=jrlFeUIlmq6USCDUyOFysJvOq822JHFZZ7Z40MxY9qw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=dadoHH8CNpbJL21+f44Epd5J674JaHKpzitYi5Yt6EmFV684hfkDRo+FU0AUmtQqS z1+Hz1CQ6Pw7Y+OIeVoXKvDwcNmTI/60tTPCQ8DFUG/j8lkQnjDvcE94j18yHU/By2 Phhwo4EiJ/3/rQz9AuknKwC9JQR0+oZh5Yls6JEYUch/QOKB1zjBpeTlsPpc3MAnEK WQ1wuH8tWlBKZemmAsiWSaQW3jCKJAkMbHD6WfEpsc7lryOKiga4QG0/3uAqnFeGgF pKQuDymcNVqLw8AZQNAgogELOmcLaCvQoV/n3JomfnruEUbYSGz9jwTWulu9U4d4yp ETqG4+zPC0Crw== Date: Fri, 15 Jul 2022 17:03:31 +0100 From: Mark Brown To: "Mahapatra, Amit Kumar" Cc: Michal Simek , Amit Kumar Mahapatra , Krzysztof Kozlowski , "p.yadav@ti.com" , "miquel.raynal@bootlin.com" , "richard@nod.at" , "vigneshr@ti.com" , "git@xilinx.com" , "linux-spi@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "michael@walle.cc" , "linux-mtd@lists.infradead.org" , "git (AMD-Xilinx)" Subject: Re: [RFC PATCH 1/2] spi: Add multiple CS support for a single SPI device Message-ID: References: <20220606112607.20800-1-amit.kumar-mahapatra@xilinx.com> <20220606112607.20800-2-amit.kumar-mahapatra@xilinx.com> <40110ff8-5c19-bc54-759b-a51a919788eb@xilinx.com> MIME-Version: 1.0 In-Reply-To: X-Cookie: You dialed 5483. X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220715_090340_736007_E47EA359 X-CRM114-Status: GOOD ( 18.30 ) X-BeenThere: linux-mtd@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Linux MTD discussion mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============3106050919524161457==" Sender: "linux-mtd" Errors-To: linux-mtd-bounces+linux-mtd=archiver.kernel.org@lists.infradead.org --===============3106050919524161457== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="DxORmGk94Y1lYeUm" Content-Disposition: inline --DxORmGk94Y1lYeUm Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Jul 15, 2022 at 03:36:23PM +0000, Mahapatra, Amit Kumar wrote: > Thank you for the clarification. > As per my understanding we would not be needing a new DT=20 > property for expressing multi chip select support in the driver. > We can use "num-cs" property of the spi controller for=20 > broadcasting multi chip select support of the driver. > If "num-cs" value is greater than 1 then the driver can support=20 > multiple chip selects. That's true in some sense but not in the sense of being actually able to use more than one chip select for a single device. If the controller hardware manages the chip selects it may not be physically possible for it to control more than one chip select. While it's not an issue for the bindings even hardware that can physically do it is going to need a driver update (in the core for GPIO stuff) to do so. --DxORmGk94Y1lYeUm Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmLRj9IACgkQJNaLcl1U h9ASdQf/ca/l2sFbQii/WohGkZhhQqY8tP78zj73reO3O08IgMatkP91Qg1cm/g4 C9lTmIC/jAtn3id4aXNkli7H7ZJhq8dOfzd+O5T32FIULoAvLJUnyw6roTsncRul RUooo3/llgKSEX9sZ3w/nfOoyBg49Sj/n6hkxuvIIj33Cys2E8y5JzXiVbEyFCkh Q9amQxSAa4p+jyDj4zQ1MtY4J58LsepXJkU+E1F/8HuJHieKxChblZKC4LCGwZ2k UWVdCUxSTg25IpkLJLrjbJBRuwuwJl9ZGTeDj78Sf9OM/x1vbkgKPwk5RVGioKMV vWkEa2d0/0ioERCpoUjzCYH27X8bxg== =AYb4 -----END PGP SIGNATURE----- --DxORmGk94Y1lYeUm-- --===============3106050919524161457== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline ______________________________________________________ Linux MTD discussion mailing list http://lists.infradead.org/mailman/listinfo/linux-mtd/ --===============3106050919524161457==--