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 X-Spam-Level: X-Spam-Status: No, score=-9.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BCDF3C64E7A for ; Tue, 1 Dec 2020 17:13:04 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 47AB1206D8 for ; Tue, 1 Dec 2020 17:13:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="BgB3WbMz" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729092AbgLARND (ORCPT ); Tue, 1 Dec 2020 12:13:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:45926 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727368AbgLARNC (ORCPT ); Tue, 1 Dec 2020 12:13:02 -0500 Received: from localhost (cpc102334-sgyl38-2-0-cust884.18-2.cable.virginm.net [92.233.91.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id D5522206D8; Tue, 1 Dec 2020 17:12:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1606842742; bh=LA/wyI+AskkviTCy4hXkk/OQ8SI/xkbgqynthnKkfrE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=BgB3WbMzAIPQBd6ApotKIIDrl50qszhyaW2UkK+t8EHwqSRABA9g/yztKH3hOALVF U5WetMNXk9HG97zmBOeXIuSt+551K9WAAP13xTs33vDe9rIBB/ITd1iGCpkPZKY1li 9sWqzWIAxvsucj1nr+CQ8R7F+nXhjB+moOApdDw4= Date: Tue, 1 Dec 2020 17:11:53 +0000 From: Mark Brown To: "H. Nikolaus Schaller" Cc: Linus Walleij , Sven Van Asbroeck , kernel list , Laurent Pinchart , Discussions about the Letux Kernel Subject: Re: [BUG] SPI broken for SPI based panel drivers Message-ID: <20201201171153.GM5239@sirena.org.uk> Mail-Followup-To: "H. Nikolaus Schaller" , Linus Walleij , Sven Van Asbroeck , kernel list , Laurent Pinchart , Discussions about the Letux Kernel References: <2D7916FA-678F-4236-B478-C953CADF2FFA@goldelico.com> <4AC29229-9542-4E77-B993-217E29C7E209@goldelico.com> <20201201121620.GB5239@sirena.org.uk> <20201201162035.GK5239@sirena.org.uk> <8D0E8CDA-96EA-4900-B5B2-0AD371EAD046@goldelico.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="WuedheRyq6FDfQ9j" Content-Disposition: inline In-Reply-To: <8D0E8CDA-96EA-4900-B5B2-0AD371EAD046@goldelico.com> X-Cookie: Who was that masked man? User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --WuedheRyq6FDfQ9j Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Dec 01, 2020 at 05:41:54PM +0100, H. Nikolaus Schaller wrote: > > Am 01.12.2020 um 17:20 schrieb Mark Brown : > > I think the problem here is more to do with where we started than where > > we're going or how we got there - things have been glued together or > > happened to work in ways that mean I'm not sure we reasonably understand > > the situation we started from or all the requirements it has. As you > > say I'm not sure anything beyond throwing the API away and starting > > afresh would really help here, but that's not really how we tend to do > > things for a bunch of very good reasons. > I think the key problem is GPIO_ACTIVE_HIGH 0 and GPIO_ACTIVE_LOW 1 > in device tree blobs. But that is so fundamental that we have to live with it. > So I guess that even a new API from scratch wouldn't improve that. Yeah, that's definitely part of it - more generally there's multiple places trying to determine if the signal is inverted with different interactions/expectations. Having it in an ABI definitely contributes a lot to causing trouble though. --WuedheRyq6FDfQ9j Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl/GeVgACgkQJNaLcl1U h9CPMQf/SsrwU3DUXaX7CJ7+bYc0OzNzeBvjKkMchBWxHcnEyR7EKhZwHXxNhxbq cH5SzVmeuM5I/HsQ0FGpI07ZRWo3nAUlA2QVEOjXYJ7fPFw/bMn10xi7KJzo2aNg gWjAJtp8PfaW2J+bjoVCcRxyS5ppsBNj5AmSHr1ZDxHee4TZUZ8MvlbMvBXGkt6L 4PO0uMJ79QY3KuNzKr+GnceyW+mhcGIuW9OSJepMx+yK2m4ZmsRKy9kduN7Rg0WJ ugMF9UY0qZHpsyXEjlgbaUJTOUBMZYhX36f6iUh3hHuTMZXrfEaoK3CEAj9jToYl d3aLIj3j80SU6HUmqHYfdkfAqmMcsA== =45IK -----END PGP SIGNATURE----- --WuedheRyq6FDfQ9j--