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 A101BCD342C for ; Wed, 6 May 2026 08:07:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:MIME-Version:In-Reply-To: Content-Type: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=/Oq1nvSBQ5WV5VwbQiKRBhF+o6GZZv+XrOzWTSzAD9c=; b=Urc+NL0jrVD9XMDWP5mSmnrGeJ lbiYVH3vchgW+mU3wriGwzshEPkgc5tAKVM87FMBKtdVdpC73nW4RxJmT55JUd8/EyMBOPIL4WsAQ GzdiDV28/hmdFsBY6P6S/IudRKuArOsSqEhRP9dkMAqMpa05DouB7Dvw6+WhOg5iOyZ5fbXNzmtuy TMbUf3A4MGk+Pm6IQYZ3iQpvxmp37FUYg5dlVvZueT+Ov09BEm1VhqrAITr2Iq04YhkTRvaxQ2V6X vA9qc3SOYEgGBdUdw/JVn/Uv55nMaYL4nfge8TOCtVGBU09ycFtvrjmWy3+GPPJVoBAybJmfxtMkj TZ4d9bPA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wKXIL-000000006wk-1e7M; Wed, 06 May 2026 08:07:49 +0000 Received: from mail-westeuropeazlp170100001.outbound.protection.outlook.com ([2a01:111:f403:c201::1] helo=AM0PR83CU005.outbound.protection.outlook.com) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wKXIK-000000006wM-12j4 for linux-arm-kernel@lists.infradead.org; Wed, 06 May 2026 08:07:48 +0000 ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=O9MYbzCtQ6eJnS7XMebnncPg31RNfoxJ464CXWLob5Irk2vOzThRrRsbDFzHA6k72WG3/pJ6KDRJbk/Ppq+8pOh53w5dhAo4Ru13c6IyMBzt93kqs5Nqb/Fj+pah1aaOBSjCwdFBFN5GE3jf6fxPIknH91ZEDdHCbJCAO+pszfB0jHxG1zG62M+tjRIZ1PeIndbRPjGZJF2Js96zuesOzURY5rFAW496dWxZ7AgB+SmvR71F8Ah0xpQwCt4xJc8xdShMbQl5ccIBkTops04w3AQMXzI3lNKpYiOHWtCDvwsXLEHduHFyDkuWLJYgArYsX61u6e1SZlR03OhvyPT9Kg== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector10001; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-AntiSpam-MessageData-ChunkCount:X-MS-Exchange-AntiSpam-MessageData-0:X-MS-Exchange-AntiSpam-MessageData-1; bh=/Oq1nvSBQ5WV5VwbQiKRBhF+o6GZZv+XrOzWTSzAD9c=; b=GuWRwlSP50Y9xt0SbGhB5r9QcuZVBE+3MZ1eMPJx3y7j/3WymbvxQ36WGNhWlqN2R1VqV1xez7/kb+hOEQrp/i+4aRevn2sWy5NvnwbvFnwGfQs6iafBjP/wwdzLTpmVrS7wJ3XQFmXXOLtrUieiELnwxNqSp/65Fn7BAhaGJW1ULggVOWxw2TQqfKX9exHy+KUQGTg8hzPztgzcMYvXfdekxzMbetq6pENOQcs+LsbfdgEHq2Jy345iA3KV9r1rAKHeCtt8z93RaWDdeFgQq2GeJlibbY3IlckrCH+qtFlemj2oFATyfEg6tLRajVrUm8EWwDcpl9r3Q3YfORjRBQ== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nxp.com; dmarc=pass action=none header.from=nxp.com; dkim=pass header.d=nxp.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=nxp.com; s=selector1; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=/Oq1nvSBQ5WV5VwbQiKRBhF+o6GZZv+XrOzWTSzAD9c=; b=oDNUNejfBsCMQQli0kB6gLe7kGofs6jaenquieygTa2lYvlEkNLq0Rz9vFcCZmdXMRS+HsRxD4nNq+eFXs7tBDQwIUUxadukk+fvzvHjUlJuTHdp6cuJ65hGbBCmD5vTOR14bBbFmrqEt2EB/UENWF4Jk3OZomQmEsZpoTShffzyL3UC4JzLETEhaZ/DPkU3J1F10UPaRk6g3nB1wzRz9W+uHNdMhLnxsccTFICbqPjEMGMgQuPI0q7+Vkb2bUtLAyKImduZ+7pOysRpVnR0sdKT58xA4JchckSNQhnfUv6Q4Q6EoBIHj4OWK2H9NLFuJWbrSxvB38He5VWyAmJ/CQ== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nxp.com; Received: from AS1PR04MB9287.eurprd04.prod.outlook.com (2603:10a6:20b:4dd::8) by AS8PR04MB8868.eurprd04.prod.outlook.com (2603:10a6:20b:42f::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9870.25; Wed, 6 May 2026 08:07:43 +0000 Received: from AS1PR04MB9287.eurprd04.prod.outlook.com ([fe80::6f30:763d:17d2:b79c]) by AS1PR04MB9287.eurprd04.prod.outlook.com ([fe80::6f30:763d:17d2:b79c%3]) with mapi id 15.20.9891.008; Wed, 6 May 2026 08:07:43 +0000 Date: Wed, 6 May 2026 16:09:01 +0800 From: Liu Ying To: Marco Felsch Cc: Rob Herring , Andrzej Hajda , Neil Armstrong , Robert Foss , Laurent Pinchart , Jonas Karlman , Jernej Skrabec , Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Simona Vetter , Krzysztof Kozlowski , Conor Dooley , Marek Vasut , Frank Li , Sascha Hauer , Pengutronix Kernel Team , Fabio Estevam , laurentiu.palcu@oss.nxp.com, dri-devel@lists.freedesktop.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, imx@lists.linux.dev, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 2/4] Revert "dt-bindings: display: bridge: ldb: Fill in reg property" Message-ID: References: <20260504-v7-1-topic-ldb-fixes-v1-0-0125d937ff7f@pengutronix.de> <20260504-v7-1-topic-ldb-fixes-v1-2-0125d937ff7f@pengutronix.de> <20260505141538.GA2547282-robh@kernel.org> <2bl2mwpk57xgkuye2gydliymjkzikiovnb7ovnb73olwtfkjwn@byn3732grvnh> Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2bl2mwpk57xgkuye2gydliymjkzikiovnb7ovnb73olwtfkjwn@byn3732grvnh> X-ClientProxiedBy: SI1PR02CA0027.apcprd02.prod.outlook.com (2603:1096:4:1f4::18) To AS1PR04MB9287.eurprd04.prod.outlook.com (2603:10a6:20b:4dd::8) MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: AS1PR04MB9287:EE_|AS8PR04MB8868:EE_ X-MS-Office365-Filtering-Correlation-Id: 70e378ba-408d-40de-81e4-08deab468c91 X-LD-Processed: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635,ExtAddr X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|19092799006|1800799024|7416014|376014|18002099003|56012099003|22082099003; X-Microsoft-Antispam-Message-Info: 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 X-Forefront-Antispam-Report: CIP:255.255.255.255;CTRY:;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:AS1PR04MB9287.eurprd04.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(366016)(19092799006)(1800799024)(7416014)(376014)(18002099003)(56012099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?JvYBodxEvnUsYixqrDsORvAIbYaR8JzKaIyRxqd8801p/s+Onl1uPk2bTFpI?= =?us-ascii?Q?oEMQ988bOuD5nvjt+qtOMniOrL8xAfrcLzy2gMZ3g7Uol/M1pzr/igUy+QXj?= =?us-ascii?Q?au+68QU5+C7bs9LySV0Wxb9YPNlehhwpe46IHBQlIxC4mMQH8BnKBWynRZAr?= =?us-ascii?Q?gtPnKKSV9qtPR36D9yPESnmIKnfjvl7UsxpoKEdHnHlYv1Eeb68hKAUD7fWk?= =?us-ascii?Q?8GHium/DAaL2SkVmR0RC7GcoOWKhyEjQFo1u5NWrj4EH51eSwBOnpfi7kXBK?= =?us-ascii?Q?74poNmBgcv6RHlNMIYntEvXpAGv3xXuKwFRiBmdtXqW7YYTu7puYDcA1mL0f?= =?us-ascii?Q?A/umeOfSZMgx2kHRbZybplbpZFkn/hGzB84lKf8lFZKVOf4GeUQGp1+l3UDs?= =?us-ascii?Q?l7ZypYsRZKsQPwUW5gBZlya23NrnfbCz5QtaEnlE0UbUcBrwQwh60rcNGn9i?= =?us-ascii?Q?81xgqI3OxQUVQc79r/yttiOJJLPUJ4yclLuPrF/yMrBXyeaQmcWkxXZNsBs5?= =?us-ascii?Q?SeAtA/O5H1mtLilNIHOJbETAXGAtLeXycZAV504j4ejCVJOysnvQO0OdJvt1?= =?us-ascii?Q?C13uOFgj+3qBk0pb7+dI7KxX87n++QaQTwn/FqZOZ9tZe35nwbIWlwe/YTZR?= =?us-ascii?Q?5wPs79kjiP6YvJDFdx3VFyyQS5qcCUyIb4EKG2DAlHAChaiGjirt6yyBpkK3?= =?us-ascii?Q?Yy0U+PuORSPKXJ0QsEnCZTOWgqZKV3awdztlARI9/0JXvOSktYISoQZHmB/W?= =?us-ascii?Q?to+dee3hVk8gRFOiAIhpLZjx5Sx85LwjK00v3VDWbaQt0uafK/PK9co4X2AG?= =?us-ascii?Q?TkRrIkPyED7q0iH9GYdCfdOsiGRfKedbCqBGZTAuDfhlR5XdTvpMq2w213+t?= =?us-ascii?Q?ypBkaoNspNp/BffTAX10qizEixc4A2BvJgvomfUzzHqUkedwagvMdWJ2qvw5?= =?us-ascii?Q?S56MbpA+54i34Ez1ZZIuPiGxmZ/9E/5P6If4lFbXFKO9pe9TM8b+yqaFPcqf?= =?us-ascii?Q?jNQtdPGD96i0y+L40knHeS9X9MlOwEdDEE00fsY5RKNcBx5iW147pzjWipKi?= =?us-ascii?Q?/tTyDbcefVDL2+zBFNrXSd0rE7cXZKXobkZ206H4Yz+dj0xALeINo/5A4TVO?= =?us-ascii?Q?h/Q9caf76Euerwy0A4ZVtnKUD8Wlh3KGNu0Mq+yVdXfftUlPzuijnAonwieA?= =?us-ascii?Q?qerFK6Zqd/QqttbsOsNhIP4PJyp59cLR8/bC0fWsls0VwIANPHdlX509hEjF?= =?us-ascii?Q?kp7ccjDMDEAn+XuKYOcRqsC51xilXZo9r15+FJctbEn6mhgXhOLoW+viaan1?= =?us-ascii?Q?HLy+SN/qn8JZqZbIn/Xa+waGM1Ih8Ow3ygiXttMDRRGgMMeVzHwXtL8TAYU/?= =?us-ascii?Q?mAcGo4sHJvmpIAEGmluk+vgzBDxfFKnDXsCanSQMtxuV/yvLgjxSYxFqkwJf?= =?us-ascii?Q?0ovmH/eNeDBvQcExYaLDXh7yUTatErCXfkLUzpGDQJfB2NkH5D02fYH2agls?= =?us-ascii?Q?yM6n8MDiWQdeBd+ttmeQiBmP2nktPDhUcHNxVGlQUdjAm8hKou7L+yl6Yzfe?= =?us-ascii?Q?OyarUjzXQrnIu7xKBgXgEVJv9ehsj0PTDb7rTvopr+5JBXMZfGxgPk259QMV?= =?us-ascii?Q?PwdNgSbpuiYEZICpltPbpIbh8H6GzjocW2h7Jjw2v3MYhUI0NLqDX6G228uP?= =?us-ascii?Q?e+Xh+5c67zQtI6F2eFfSUoiItJb/MXF77EG+Wsi7phwK5SrItU/G730LTHxb?= =?us-ascii?Q?paHtVJhL2g=3D=3D?= X-OriginatorOrg: nxp.com X-MS-Exchange-CrossTenant-Network-Message-Id: 70e378ba-408d-40de-81e4-08deab468c91 X-MS-Exchange-CrossTenant-AuthSource: AS1PR04MB9287.eurprd04.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 06 May 2026 08:07:42.9447 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 686ea1d3-bc2b-4c6f-a92c-d99c5c301635 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: F9mZ9x+zfUfgBSDh7K4TkMglP6VGKcGSIHhFjXsdRxlrVGj80ryXU0NaNYbM1UkzEyLOdd3FB9zGdt+eBK6gNA== X-MS-Exchange-Transport-CrossTenantHeadersStamped: AS8PR04MB8868 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20260506_010748_290978_0C55E201 X-CRM114-Status: GOOD ( 27.60 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue, May 05, 2026 at 05:45:56PM +0200, Marco Felsch wrote: > On 26-05-05, Rob Herring wrote: > > On Mon, May 04, 2026 at 10:21:42PM +0200, Marco Felsch wrote: > > > This reverts commit 16c8d76abe83d75b578d72ee22d25a52c764e14a. > > > > > > Remove the 'reg' and 'reg-names' property from the LDB. > > > > > > The LDB is either part of the IOMUX_GPR (i.MX6SX) or the BLKCTRL > > > (i.MX8MP, i.MX93) register space. Both IOMUX_GPR and BLKCTRL are > > > register ranges with loose register definitions. E.g. > > > > > > - On the i.MX8MP there is one register which controls the AXI > > > threshold for two different IPs (BIT(31:16) - IP1, BIT(15:0) - IP2). > > > - On the i.MX6SX IOMUXC_GPR5 controlls: CSI2 mux, WDOG3 settings, PXP > > > handshake, ... > > > > > > In conclusion: it can't be ensured that one register belongs to one > > > dedicated IP and the LDB is rather an exception than the rule. > > > > It is fine if there's a child node for LDB if the LDB registers are > > consistent, but the other misc things are represented by the parent > > node. It is certainly not a requirement that either everything be in > > child nodes or nothing be in child nodes. > > > > What I don't see in this series is what problem does this fix? If you > > are going to break compatibility, then there had better be a good > > reason. > > Hi Rob, > > with the upcoming i.MX9x SoCs the parent syscon (BLKCTRL) controlls > multiple other IPs, e.g. a DPI mux added by commit 3feaa4342637 > ("dt-bindings: soc: imx93-media-blk-ctrl: Add PDFC subnode to schema and > example"). > > During the discussion of the above commit we agreed that the sub-devices > of the syscon shall not use the reg property due to the fact that one > register serves multiple purposes. In the above case the same register > controlling the dpi-mux also controlls MIPI-DSI bits. The MIPI-DSI bits > can be abstracted as drm-bridge as well. Two sub-devs using the same > 'reg' property below the same parent seems odd and I don't know if this > allowed either. The MIPI-DSI bits are not modelled as sub-devs, but instead, according to fsl,imx93-mipi-dsi.yaml[1], an i.MX93 MIPI DSI driver would access the bits directly through the syscon. Here, dpi-mux is a sub-dev while the MIPI-DSI bits are "misc things represented by the parent node"(Rob's words). I don't see any problem here at least for Linux since regmap provides register access synchronization if everyone accesses registers through parent node's regmap. [1] https://elixir.bootlin.com/linux/v7.0/source/Documentation/devicetree/bindings/display/bridge/fsl,imx93-mipi-dsi.yaml#L43-L47 -- Regards, Liu Ying