From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from PH7PR06CU001.outbound.protection.outlook.com (mail-westus3azon11010029.outbound.protection.outlook.com [52.101.201.29]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 691FC34A784; Thu, 12 Mar 2026 08:41:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=52.101.201.29 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773304878; cv=fail; b=DwFqIF1tQ20tYs0huHah5DIXA6dPx+Me3rH+TudTdRVkfSntXYt9cPsXifYC4i25zvjxQlzDyZp2kAwxZEAOpimZHIxo1EcatnBOfF/nqP+poON8O2EVZ/F2FyFvLhhhBUSlxNTqqF9w/5aDER2Xi1ay+pWJJUAuugnyVRP71mU= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773304878; c=relaxed/simple; bh=cdp5RjNZB7F7OB/rNquu+kwHnUshdEz57ynR+Tk9VrE=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=XDvafhBjW411/GkKu7vgJq2BRj3ncYQFYYc2GKWpGuNxhEm0HLRwWOe9xcj6jPlbTZaMQ5IEHHGWKxsSL1N042PgCz5NIFwJrG7KXOxFtxOjYozAZ69yCLayl7+qeaZ9FShnhsQjxi1FI/GDvPRY9NgEu68hlefdAbhrYBaBoMw= ARC-Authentication-Results:i=2; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com; spf=fail smtp.mailfrom=nvidia.com; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b=JlFy3IrQ; arc=fail smtp.client-ip=52.101.201.29 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=nvidia.com Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=nvidia.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=Nvidia.com header.i=@Nvidia.com header.b="JlFy3IrQ" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=F7mxFi3Yl4Gx7zyFCStxpjei1LHOQ+QfyNlHnRpCzkACJaE4eF1UEaYX9AhDLNY0h6LDPlTvSzsfvA1k3VLLNrR7n4sbpFQKiC1eO6E/g4ANxqmunn0tjQ7b0ci2y5pOjdhdNLEyhwoRdza2w5vbC2WBcWeP1ZtHQkM4UbGP37KAALazKMgeVjVcCpK0Y9xNnEkmFA3KEjNCds2yUGuJllq3shTmrZgrhn74j8cu7FuKUrlPWDj8KBu34Z/ToavjCOtLCCbtmaIzXDf6fp9GQ/CZQTtpVPNlhE3ry99X+3X7N7D13dslxH77uIvUMV9Eb69qrnyG1Pz0volyfjoRjQ== 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=nlNzPcZqWTUEZHCFLlLKvRemunPyu8m4TRxYqKDk3lY=; b=GMXYlI3NuAOyGGbkfABkVFuOp75J5oyYM2+Fk6n8FC52ekIYQqGpMKIn22cfJXEUwpBjv4mOKQWxlGqrkmJMxcb/gOhZOibe+VEa/3bTKYA9t+1W/3YVg2YoIjyjQebJXI3Lw2Vs6B0EoVQDN9y05xwOUfXv5MbYT/p4SRSOIMVIlATl4lIW7hPn1nqUZHD7Bb5SwFDyy1DpkXtVe/FIK+hx24aeAOsQWEDujCNr9YjmGpnu5R5LqMcQ5EhTvF+UhK8NI0K1EiUp2FwV80DAtjjJRUTzbYBSxOucsbrMreIf5DbFgaueYTq0IrX8GgXCGrDEMCZdR+Msok7B5DRT6Q== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=nlNzPcZqWTUEZHCFLlLKvRemunPyu8m4TRxYqKDk3lY=; b=JlFy3IrQjdbAkEllyHlA4Ido10xW+glVcEz8Wun7wtkdMzrtoSna7kZYZ66NU/J1AFjyu+0nnBB7grwx4havtLGQtJWuLNKfePB1CTNcdNqWfKL70OwSouVyVw7YaG5W3lVm1rHIihsCOhea6UZgmXejnaWxZ+Na2jnF2dhGybDHdeUV0z4yxTo6QwkHIPbB5fEHLkpwXMuix7r9QNJ1fb2QEUjKwKly/TYv7gT7I6Q691aloxRhf+TjRn+sgRkH3Z3kN1CQ1LG6lEc7GinbeSWfzeRaTOBBIjyvda7CqaNiS3o5rc135vOAlOBnCwCH3OVBcKGWADqSvVbhJkHtoA== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DS2PR12MB9750.namprd12.prod.outlook.com (2603:10b6:8:2b0::12) by LV2PR12MB5773.namprd12.prod.outlook.com (2603:10b6:408:17b::14) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9723.4; Thu, 12 Mar 2026 08:41:10 +0000 Received: from DS2PR12MB9750.namprd12.prod.outlook.com ([fe80::56a8:d6bf:e24c:b391]) by DS2PR12MB9750.namprd12.prod.outlook.com ([fe80::56a8:d6bf:e24c:b391%5]) with mapi id 15.20.9723.000; Thu, 12 Mar 2026 08:41:09 +0000 Message-ID: <2d4e69cb-a43c-4d13-9f7b-20b95cee43a7@nvidia.com> Date: Thu, 12 Mar 2026 08:41:03 +0000 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 03/10] gpiolib: implement low-level, shared GPIO support To: wens@kernel.org, Andy Shevchenko , Bartosz Golaszewski Cc: Kees Cook , Mika Westerberg , Dmitry Torokhov , Andrew Morton , Linus Walleij , Manivannan Sadhasivam , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Saravana Kannan , Greg Kroah-Hartman , Andy Shevchenko , Catalin Marinas , Will Deacon , Srinivas Kandagatla , Liam Girdwood , Mark Brown , Jaroslav Kysela , Takashi Iwai , Alexey Klimov , Bjorn Andersson , Konrad Dybcio , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org, linux-gpio@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sound@vger.kernel.org, linux-arm-msm@vger.kernel.org, Bartosz Golaszewski , "linux-tegra@vger.kernel.org" References: <20251112-gpio-shared-v4-0-b51f97b1abd8@linaro.org> <20251112-gpio-shared-v4-3-b51f97b1abd8@linaro.org> <921ba8ce-b18e-4a99-966d-c763d22081e2@nvidia.com> <64f6e02d-c7cb-40cb-b1fb-2d3523433c66@nvidia.com> From: Jon Hunter Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: LO2P265CA0359.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:d::35) To DS2PR12MB9750.namprd12.prod.outlook.com (2603:10b6:8:2b0::12) Precedence: bulk X-Mailing-List: linux-hardening@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DS2PR12MB9750:EE_|LV2PR12MB5773:EE_ X-MS-Office365-Filtering-Correlation-Id: 6cc4a31d-d609-48c0-a9f1-08de80131c07 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|7416014|376014|366016|1800799024|22082099003|56012099003|18002099003; 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:DS2PR12MB9750.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(7416014)(376014)(366016)(1800799024)(22082099003)(56012099003)(18002099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?b2JpeDFYNEkxcFVhOTdGSDJ3cjBCcFUyMkZHY1Z5THpVWnpHdVVycS8wK1Js?= =?utf-8?B?d0VvMnlmVWtLNnhZakczWkRBWnVpY3pMV0UweGVaMGV3VGp5dEo2WG1pVzRy?= =?utf-8?B?bklwaDQzaUNTcjd1R2RHMmdhclJNK3NJOXFzdHhOWXlET3BJQTRJcnNFd0dw?= =?utf-8?B?ZSsvSHhDSFZDVjVncTRaYUZUNDNKTm56R2d5ZlBmUC9TdzgzamlESVVZNTds?= =?utf-8?B?cE1yV0hQcGxkUTVNcGxocEwvQWo0TU5jMjlDTDhBdXMyWFdEdFgvcjdZVnNr?= =?utf-8?B?R0E4U0RFbitZRVlaTGJYTjBCT2hYWFlPSFJtajdFSzZTUDhzZ2VzQWxlUDVC?= =?utf-8?B?dmRVbDc2Vy9jV2p0RFV2NkNadHZZZDhKNUtNVlQ1eVNyazhsZ1MyaC9VRDJx?= =?utf-8?B?U29CcHZFd1BSRXdDcnV0Vk0yTWxWZ0NCUmxjdXRaM3Y3ZkNoNFJZa0hiOTBz?= =?utf-8?B?aTFMQXZBdDRzZW45aVBPMXNCay9UTCtXRkRydG11SW52MVcvbENyWFh1RnE3?= =?utf-8?B?Nm9RaUdPYjZHbmI5OEJTYXc2eHc1N3ZsMGM3bi9RSjFSZDBwUnQ5dC8vTnpE?= =?utf-8?B?eEFIMHNhUVpwOWlNMzBrMmNNWmMrc2NjemFndkROcWoweERCUzlrNm8yVzVh?= =?utf-8?B?ZytidlN6Ykp2NnlrNHMwbkpBazZjUVVkczJPM2xUcWtEa2pzbzlCYlQ0VkVD?= =?utf-8?B?Mis2NDViMWZFNEhZRExMNDhZcTl5Z0RyUU5rWmxybE5WelpsK3cwaDBnMHIv?= =?utf-8?B?LzNyZGY3UTE1RHBreTdna014VTlQUHFIZmcvaXk3ZkxoYzV3bVpFYnVOclZG?= =?utf-8?B?L2FmN2kzYklrYXVJYS9pcDdHQndydmoyUlpVeDBDZ1VrY2NlcDNjVnQzdFlL?= =?utf-8?B?OFFkYmVEcWIwWmdzQkZRZ2gzdFN4dGQxT1FQVVprbU9BbVhYdnZyTXdxZHZU?= =?utf-8?B?WTBGMFhRNHlyMDQxRjVFeDJVSm5CNjl2eVBZc21EUWlwQTlkV29BU3RjTGVP?= =?utf-8?B?OGxEektWYU1tU2ZCZ091SFVGY3J6dER0aFZZVnlOUXI1N2RZZGlxUStqY0hi?= =?utf-8?B?TmdKaFlkamV0WnB1dGNpcFAySWk2M2c1dXVYWVprb1FOV1piWTZvUjVnOTZG?= =?utf-8?B?TDJoc2Y2TFhWRndGN3dkZDNtbHV1QksyTVJ6bXpKMmtKZzhGYjliMFhHb2Y2?= =?utf-8?B?YlNwY3dvdXF4dnhIbkkxM2V0elNwY2lrY0V5aXBaN1o4SXFGbm5XZkd0V3Uw?= =?utf-8?B?VC9BRU5QczRldG0zZmhPN0xVZDhDdzE3REU5OGtqWStQSlNKNVJ4OEU0WUVt?= =?utf-8?B?em83ZkJiVUt3cFFQREFadVo1S1RwR0tiOTY4V2s1VktmeTBicitMZDZuZExS?= =?utf-8?B?c2lNUnFVQ2xIcFRmaHFIZUR3dlR0dnI0NDlrSDdhbTh0eG4xMTZ1WTVsWktu?= =?utf-8?B?N3NRNHJ6Y1VBcE51NWhzNXYzSnFCYTF1RnJzczZyVS9XVVhwaXYvaVJTa2ZM?= =?utf-8?B?VVVLMUd2WUNWbnNEbG9Pem15MCtsZ09uY2xtVEYxOC9xRVhzMDg4RlNidENl?= =?utf-8?B?Z2Npc1Q4SEE1aVhiUXVyKzNFeG5EVXhVYlFwTWdhWURrU3FjcFJFVXpZU0to?= =?utf-8?B?a0czUVJRTDNGUFord1RRc1l6Y3VMMGpubld0K01vU3NFRE9jTGEwZTE0VXo0?= =?utf-8?B?TUlhdFlndFY4ZS9jeVhpQzU2V3pnZ0ZZbzhybHdkVWdNbzJSTktXWS9kVjNZ?= =?utf-8?B?eU5YNmVkYUE1YTlGRnRhd1ZVcEtqVitvbDFtSFFPTXU0K0FBL3N5R0ppMHdW?= =?utf-8?B?ZE54Nm95MUNpWmJrSEpNVGNESC9CeDFudllPc25NMDNxNjlkL0Z6OUJuTXNS?= =?utf-8?B?UFhQNHpTaE51bUVJWXEzL1p4QVJPS0MrczRhVDIvdFVpV2ZEcms3VkFkMEdw?= =?utf-8?B?bUtiMVc2NG5mUVZLaFFRc2t4UWFwVjRpcVcwRzQwVFJ2V1U2Wk9TVExyODFu?= =?utf-8?B?ampMTmVyd1oxdFB2MXM0eDk3YU9CaVV2U3RDS2xpWUYxYXF5Ri96dG1rTVBI?= =?utf-8?B?VEpwa1R0TmZvVUcwQVZGWmdJTlpVYmFjdXEwelhyTUcxWXVldEJDTTVpOHFU?= =?utf-8?B?dzRCenMzWUNxSVQvMUtWSFBla1EyeXJzOEM5NFNxdEZkZ1ExcS9TbFl1NitP?= =?utf-8?B?eFo4cWk1T0tGNlZ5cktUR2xoVUpSNWEyTENtY1Y3UnJpcXErV24xKzM5Q3c4?= =?utf-8?B?SkxXSW1kcG5QZytRcDIxYy9Pc0YxdEphWTJyV0RwVTNSRi9KZ3ZLaElTWnJs?= =?utf-8?B?SUl1SVd1dlR0UnQ2S2RiU3VRaGYydmgrRW16aFNpZEw3eWc2N2d1dz09?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 6cc4a31d-d609-48c0-a9f1-08de80131c07 X-MS-Exchange-CrossTenant-AuthSource: DS2PR12MB9750.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 12 Mar 2026 08:41:09.7136 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: XD2urBqzAWTlsriMyU+Vy8gYS2kXo/hQDy0prrDrE2lS1s9SEeztB4S++uKHtRI9Q88eKbO1wz0shZ4fX15amg== X-MS-Exchange-Transport-CrossTenantHeadersStamped: LV2PR12MB5773 On 12/03/2026 07:49, Chen-Yu Tsai wrote: ... >>> To me it sounds like a bad design of the driver for this SoC/platform. >> >> I am not sure why you think that. Assuming a 1:1 mapping of the kernel's >> GPIO index to the GPIO controller + h/w port + 1 GPIO number seems fragile. > > If the hardware has uneven number of actual pins for each bank, either > you end up using the deprecated static GPIO number allocation and > have holes in the GPIO range (sunxi currently does this), or you use > dynamic allocation, which gives you no holes in the GPIO range, but > not directly calculable mapping between DT and GPIO numbers. > > The driver handles the mapping by providing an .xlate callback. A > consumer shouldn't assume anything. The shared GPIO library probably > shouldn't be try parsing the property itself and use the result to > grab the GPIO descriptor, but just rely on the gpiochip's .xlate > callback in some way. Right. I was thinking that isn't this why we have the xlate callbacks in the first place to handle such things and not make these assumptions? I am curious if other platforms could have the same issue? I did not see this immediately with v6.19 because it is only one specific platform we have that showed this. So very much a corner case that will only be seen if a platform uses shared GPIOs and the shared GPIO happens to be high enough to overflow the descriptor array. Even if we don't crash, at least for Tegra, we could be using the wrong descriptor too for shared GPIOs. Jon -- nvpublic