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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 73802C64E7B for ; Tue, 1 Dec 2020 16:11:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0398E2225D for ; Tue, 1 Dec 2020 16:11:57 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="HbdJcTrT" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2403950AbgLAQLm (ORCPT ); Tue, 1 Dec 2020 11:11:42 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33946 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388364AbgLAQLl (ORCPT ); Tue, 1 Dec 2020 11:11:41 -0500 Received: from mail-ua1-x92c.google.com (mail-ua1-x92c.google.com [IPv6:2607:f8b0:4864:20::92c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 567CAC0613CF for ; Tue, 1 Dec 2020 08:11:01 -0800 (PST) Received: by mail-ua1-x92c.google.com with SMTP id h26so734993uan.10 for ; Tue, 01 Dec 2020 08:11:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=lZdKwyZiumYGvQbLwgvXVvBks2dSrXavoorQLj9ViOo=; b=HbdJcTrT+Bm5snlT4I8yNuYKtWRopqXB48P4o3VVBeVAKEZL2VohViYi5I7dTIuu6p 5zwVGXKQl/m16KeuJUWiQw6oE7pRxrRVuNZmMiUOWVQKYSDRVWBgOugNyNB0k+1cAd/j lGNwiuuUgxQMVVqUebDRL1GyK2PGnDmOeWg6OInjZ27Kg39hr0Kpt1HL5wTZESE3UD3R DnHIlKTYC86/oUVGyrZGOTd4DuGfvxHr4lRRuk9rIWdYRuvGDnML7bVuMl3jAauWNYwx jk1OPrdKd7DZ3mSdzI1B6o1RjaruFzkJy3Z2HGj9lcMjSyz1zRsAe0gpbeb/QokLF16Z aByw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=lZdKwyZiumYGvQbLwgvXVvBks2dSrXavoorQLj9ViOo=; b=hY/l4KfN3jCy2TY9w74R/m0FZgTWD/kLoCkAVB4mzPzJ8yq6wJVQCSqvSV0r1ulfgd U4tOXw5ygomwsn+Cr5Cg86ke5OYdioin2Wu4KLfVwiCKfy+gegLvZ6dL/9L4wX+ltSnm Q3gn1yNCAQuuSpB7wGSYJbbRc8ONoq3vVlQw4Q4el+Q3/m/SFQLFCc2VjjH8gZJr9ay/ 9sG445PdSrg4vgiVh8DrY9hSl0UXjAUMeFjbP0Ooabn12cXNecmCYbo4j+csL1LemWu4 xitLf/z4N8XQAC0GegTCX+qhIfVurHwzxHmeDmIFZ0m+G2yVvifItlSWB4HrWeNtq4nW Y9EQ== X-Gm-Message-State: AOAM531vAlayh2F+SO4hR80o3FJNn14VHdJU2YMrHvnQaA+isdYuzDjb j0xlxpioPPQiY8u57hHBwW2RRZAnpH7vJ0mIE4/Fr1L6jZE= X-Google-Smtp-Source: ABdhPJzC5bdBhz03oVkaK+E87pEZIqovGzW//4BAUBwEFgEahQ/wGQXo8XGxcbvjVJw0FYa/0y0Wve3lHwiwhYTo0A0= X-Received: by 2002:ab0:45c6:: with SMTP id u64mr748318uau.58.1606839060547; Tue, 01 Dec 2020 08:11:00 -0800 (PST) MIME-Version: 1.0 References: <2D7916FA-678F-4236-B478-C953CADF2FFA@goldelico.com> <4AC29229-9542-4E77-B993-217E29C7E209@goldelico.com> <20201201121620.GB5239@sirena.org.uk> <6283C16F-549C-4463-BC08-E2C1A1D78B2F@goldelico.com> In-Reply-To: <6283C16F-549C-4463-BC08-E2C1A1D78B2F@goldelico.com> From: Sven Van Asbroeck Date: Tue, 1 Dec 2020 11:10:49 -0500 Message-ID: Subject: Re: [BUG] SPI broken for SPI based panel drivers To: "H. Nikolaus Schaller" Cc: Linus Walleij , Mark Brown , kernel list , Laurent Pinchart , Discussions about the Letux Kernel Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Nikolaus, On Tue, Dec 1, 2020 at 9:38 AM H. Nikolaus Schaller wrote: > > Let's work on a fix for the fix now. > Are you quite sure the chip-select of the tpo,td028ttec1 panel is active-high? A quick google produced a datasheet which seems to indicate that XCS is active-low? See page 17 here: http://www.lcd-source.com/datasheet/TPO/TD028TTEC1.pdf It is of course possible that you are driving that line behind some inverting circuitry. Hardware designers seem to do that all the time, if they need to go from one voltage domain to the other, etc.