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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 EFB67C4743D for ; Tue, 8 Jun 2021 04:55:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id CBCD261263 for ; Tue, 8 Jun 2021 04:55:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230254AbhFHE4w (ORCPT ); Tue, 8 Jun 2021 00:56:52 -0400 Received: from ni.piap.pl ([195.187.100.5]:60968 "EHLO ni.piap.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229457AbhFHE4v (ORCPT ); Tue, 8 Jun 2021 00:56:51 -0400 Received: from t19.piap.pl (OSB1819.piap.pl [10.0.9.19]) (using TLSv1.2 with cipher AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ni.piap.pl (Postfix) with ESMTPSA id 6393344423B; Tue, 8 Jun 2021 06:54:57 +0200 (CEST) DKIM-Filter: OpenDKIM Filter v2.11.0 ni.piap.pl 6393344423B DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=piap.pl; s=mail; t=1623128097; bh=/stu7ctuibAfiv1X5o6r5DPEF2P5U2Vh+/K/Hb/4FvM=; h=From:To:Cc:Subject:References:Date:In-Reply-To:From; b=FIKygQWJu7fMFBf6d2M45Okhkz3JID53xc9dg9C8iWmgROrfAFR2kUhJaKq9IQWCj bLM/O/lt/QQe6YI/9Nbu3L0VsdnrVReJwytj4FGxiAMUJhgoZx3z7ZeR9RvZngIleK wLZJLQ1l890AEDuztyTcvurxCubX2c443vHM0dWo= From: =?utf-8?Q?Krzysztof_Ha=C5=82asa?= To: Tim Harvey Cc: Hans Verkuil , Mauro Carvalho Chehab , linux-media , lkml Subject: Re: [PATCH] TDA1997x: enable EDID support References: Sender: khalasa@piap.pl Date: Tue, 08 Jun 2021 06:54:57 +0200 In-Reply-To: (Tim Harvey's message of "Mon, 7 Jun 2021 08:48:19 -0700") Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-KLMS-Rule-ID: 4 X-KLMS-Message-Action: skipped X-KLMS-AntiSpam-Status: not scanned, whitelist X-KLMS-AntiPhishing: not scanned, whitelist X-KLMS-AntiVirus: Kaspersky Security for Linux Mail Server, version 8.0.3.30, not scanned, whitelist Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Tim, Tim Harvey writes: >> I'm looking at the previous version of this driver from Gateworks and it >> contains: >> >> /* Configure EDID >> * >> * EDID_ENABLE bits: >> * 7 - nack_off >> * 6 - edid_only >> * 1 - edid_b_en >> * 0 - edid_a_en >> */ >> reg =3D io_read(REG_EDID_ENABLE); >> if (!tda1997x->internal_edid) >> reg &=3D ~0x83; /* EDID Nack ON */ >> else >> reg |=3D 0x83; /* EDID Nack OFF */ >> io_write(REG_EDID_ENABLE, reg); > Not sure where the source above is from (this was all so long ago) but That's your gateworks_fslc_3.14_1.0.x_ga branch (3.14 is the kernel and 1.0.x_ga is IIRC some Freescale versioning) :-) > my guess is that 'internal_edid' meant an EDID had been provided via > software and the else case meant there was no EDID available. > There is no support on that chip for an external EEPROM. Right. I guess the else meant it was available and &=3D ~83 meant no EDID... Anyway one could simply drop a 24c02 or a similar chip directly to SDA/SCL HDMI lines, that's what the monitor makers had been doing for a long time. Then, I guess, you would need the internal_edid =3D 0 (otherwise the TDA chip would be fighting the EEPROM on the SDA line). Not that I know of any such design using this driver, I guess we can safely skip this part. --=20 Krzysztof Ha=C5=82asa Sie=C4=87 Badawcza =C5=81ukasiewicz Przemys=C5=82owy Instytut Automatyki i Pomiar=C3=B3w PIAP Al. Jerozolimskie 202, 02-486 Warszawa