From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from CH5PR02CU005.outbound.protection.outlook.com (mail-northcentralusazon11012028.outbound.protection.outlook.com [40.107.200.28]) (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 A0B143446C5; Tue, 28 Jul 2026 09:35:02 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=fail smtp.client-ip=40.107.200.28 ARC-Seal:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785231303; cv=fail; b=lvw0Qz1uYxB5yu3Hsy1QdNiWIB62M5I+jEZq0DaUOToFqcuqL34myiNh95kQgBvSnUxjtG8xciBTlu9NLWp6w9W/krysmOzVnwdiz0z5k+OZbBdBDb+9Xb7pTzzky6FUIfe2KgcBx4J9WgMflZ/qDxKFiNhfHI+C+sarZttA2gE= ARC-Message-Signature:i=2; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785231303; c=relaxed/simple; bh=LxOk9nSoqpLgML4rOu5Zbcx91E7tVhvPsUXXxvvAfNM=; h=Message-ID:Date:Subject:To:Cc:References:From:In-Reply-To: Content-Type:MIME-Version; b=Scb+Zb9go2OUwsT3fkV1C49NDue3ey1N3qlUEX7Fw+4ygglnKrgiTDayuCHrvc+YM2/2OGKzBOwVl+U0hUN5oG09C0wVxkZwXLyMkbmdHnp7PzOwROoZoTE8d2JRz6lZp1XPlQ5RvSm6s+hOJgIM5g0+fv5/jqr/h3D4mihJNys= 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=D1LmCTeG; arc=fail smtp.client-ip=40.107.200.28 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="D1LmCTeG" ARC-Seal: i=1; a=rsa-sha256; s=arcselector10001; d=microsoft.com; cv=none; b=wNjqUZB0AGt7zXwcVHkHy/sxT0bwDPkoNQ65IloOlZrCWvHUf9eZFGwCIbvqBxcaqWWaObP3/N5cTwVHisiD6IT2LGvwHzyJVrXmsdGl8T4NRtDCYkWm6uYudt+s26QNIczVhcZAuIfj3eJqGwTpmgnQANOTqoKM0M069Ip67JVtHratxTn2Q3Wl6WV0t3jLUeZ3fG5BrM2lyOogMlFYCXeqJZJoNLmiUccV6XNor6RS+Abu4mjzc+1C62ADzU3Bv8+xPyylrYY2nxZCWLln/ZttPI+KtWEa0yTsMKhz4wFW+BIZTZp44ZzJBeeKuPKAN1bfpq7dZeFPyd2A2CoyWQ== 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=eYziq67DyXN8DWR3gUgDiyjYIlRvm0uhIOFzxJfPtFc=; b=ETATWqtoZC+eDHw9XruW+CJBiko9sK9Xcu7534UOsui1evQsy9qCqjMZnqLl24OLpzxEjZvpMGbJM2R81Bp49OKW+gh9QsFw6v2f/rQ30guYecmPiHg2MX0j9Bi44GxTVE+23P1SWZOB0mbQ6jYeeO1ar+rW+I8CNWbJ4IhOfZUEBEQ+oIUArHFZW2X6bcMfx/iyKAhSAMXWqXKaBYXE3nf4M1PQVsHm2zxc7mOs48AJ3hwvf1VqyoUGIPweEm/QUPWbulcS5aPmfstsfT41zHrOfj0PJNxigRJ0ZQv3ReADQKIJDrQX+DKAwWN38Hks/fq20584RuUJBPNyWZJxeg== 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=eYziq67DyXN8DWR3gUgDiyjYIlRvm0uhIOFzxJfPtFc=; b=D1LmCTeGtDb1CW/77pv6BRwBG90QqUHO341Bw8JNX4owYJQKEENcVMt9TY8scoUtCkyp22FDePlcCyCwhHPVrX5FGFyoTLqWcGboMlz4AjJcab7+jGi5WcPbTJH3ED36SauoVIFNkatOO3YKLi7Hl1efxuOcKozE3fT9LNRT3KV8NZAunCvDzLEPjlQHImHxKbYgb3O85mAJn26748CwKg/FtQ7YDSglJHIGFAOVMZPiRowBq2pmz8HpnotokqT8s32eCojEKgC9VZhfgtl8nU2uzWSNoRa8gP7LbBqvmB+M4HVkcMbqr38w31nw/1vVIoT+F3h4cnL22elnKRS4Rw== Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=nvidia.com; Received: from DM4PR12MB6063.namprd12.prod.outlook.com (2603:10b6:8:b1::19) by DS0PR12MB7728.namprd12.prod.outlook.com (2603:10b6:8:13a::10) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.21.245.13; Tue, 28 Jul 2026 09:34:58 +0000 Received: from DM4PR12MB6063.namprd12.prod.outlook.com ([fe80::c06b:5df:6a68:1b06]) by DM4PR12MB6063.namprd12.prod.outlook.com ([fe80::c06b:5df:6a68:1b06%3]) with mapi id 15.21.0270.009; Tue, 28 Jul 2026 09:34:57 +0000 Message-ID: <9c196ab1-1945-49fc-a89a-5588d1e50046@nvidia.com> Date: Tue, 28 Jul 2026 10:34:52 +0100 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] spi: tegra114: initialize native chip selects inactive To: Abraham Zukor , Mark Brown , Laxman Dewangan Cc: Thierry Reding , linux-spi@vger.kernel.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org References: <20260725042944.1204409-1-abe@maticrobots.com> <20260728025503.162543-1-abe@maticrobots.com> From: Jon Hunter Content-Language: en-US In-Reply-To: <20260728025503.162543-1-abe@maticrobots.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-ClientProxiedBy: LO3P265CA0014.GBRP265.PROD.OUTLOOK.COM (2603:10a6:600:bb::19) To DM4PR12MB6063.namprd12.prod.outlook.com (2603:10b6:8:b1::19) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: DM4PR12MB6063:EE_|DS0PR12MB7728:EE_ X-MS-Office365-Filtering-Correlation-Id: 11d910d5-8b38-4a78-4d82-08deec8b7c9f X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|1800799024|366016|23010399003|376014|4143699003|11063799006|5023799004|56012099006|10067099003|18002099003|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:DM4PR12MB6063.namprd12.prod.outlook.com;PTR:;CAT:NONE;SFS:(13230040)(1800799024)(366016)(23010399003)(376014)(4143699003)(11063799006)(5023799004)(56012099006)(10067099003)(18002099003)(22082099003);DIR:OUT;SFP:1101; X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?utf-8?B?ejd5VlJTaG1QeWNka2hyT21GeUJMaWZ1SjBCQm1iVGlWakpKQVRldFl5QTd5?= =?utf-8?B?eU5MQll4UlhWUFdsbE1YanI1aDQvdncySStwZkZXd1FtR042KzBzV0pUZVNo?= =?utf-8?B?cEZBUnk2cWpPQ01KNnBQMkRWSDVmYjBZYjhwYktXbnBTdnRWeElDckNGMDFz?= =?utf-8?B?eXlCQlNvOGlkOHhDVnp1aUhvcHgxTitROXMzeEdKclgxMW92NFU4cklZc0ps?= =?utf-8?B?YUJLeTlaYk5wNjZJQm5zN3RyWVFmMDc2L2hJckZ1eHh1MVFQREFiaG5Ld0k1?= =?utf-8?B?K1RFNVFlQk1PVmthS29GQ282VmhWUEFlcWdsbnRrY0lQaUpVc0x1R2JXR0tP?= =?utf-8?B?QUxLZkRvZlV2Y1laY3FnSCt5Ymlrcy94YnJlRnNUejI3N3gxa2poMTNHUjFM?= =?utf-8?B?MDJuU0tqR2gzK2JPVkZDSGZ2WUVKVmdFYVdnZU5LUWtXNmwrQzZRL2w0ZDBE?= =?utf-8?B?cWdEVlBIeTQvVG55K1FMa3BzR1V2WGcxbzYvRzVLWVhtcGc2MVlhbGxkdC9s?= =?utf-8?B?Tk91b3ZRYkNOblBvRDZLUjVTR3JYODRDOGNWNUhDVUY3R1M5aDZnVmcyT0g0?= =?utf-8?B?aWhWcExDUmNGWkZjUExFVlprY00yUFoxMW9mTGxDNkZvRVA3VmNhbDdySysy?= =?utf-8?B?OU85amNtdkovMnV1dWN2Q2hZU1lxVWRMY1BPWXZDcDZXR2JFWUFRQjV5K2Uw?= =?utf-8?B?eVY5VU15QTY4UmI5enNKZzN4L0VKSGlXeVJnSHV1R1NjTnk1TG85VTkySnM1?= =?utf-8?B?Z1VTclZMbnNhSGxiZlVBM1NndXQxcitQOWdmN3pXaGM4cCtBNG5uMnBoL01i?= =?utf-8?B?MUJIQUplSUxwMlhpd1NOREFBa3N4ZlYzZU1wUWhrRzhYSEU4ZUVVVXNMYlIz?= =?utf-8?B?VVV0ejdYYW1nNmMyNFQwL0l4aVNFRHVJWFZqNFNHcUdSUzV1YjNkWUE2QS9p?= =?utf-8?B?c0UwRHpDcm9nYlBGcDBpRXRDOEl1ZUZFR2E0VXFUTis4bXlWTVlhV3NZaU53?= =?utf-8?B?REVhQ3FPVlYyL3FJckhPTjMvbTVBL3pna0RQYkQxemJ1NHcvMVc0WCtSZlNw?= =?utf-8?B?VTF3aHBadXhwMkhPczdzUnl6N0c4MENwWHVONmQ3VkVXZ3VaMDM3TUpKVGN4?= =?utf-8?B?eVVkQWlCWk9Mbll5MTcvUDZoMFVRWCs2OFkzSmpUTGJTa2V0S3dXQnN4QWx5?= =?utf-8?B?YXFBeUxRMnA1MUxkQzdBYm43bEY0Q0xmeVRyUjhJL3N0bGtXUXEyak9STFo0?= =?utf-8?B?elBuK25xYzFHaVY0N0YzVFBURG03emRwdlVyUzhNSXluWGF3cmt0RDk0Mndj?= =?utf-8?B?SlczcFFuemg0ajhZcFhuYUkxUm56QjhpWTdXa2d0eDh0S1U4RVFsNHUrTDBC?= =?utf-8?B?VTM5Z2s5cGUxMlgrOWpZVDZ5dVg2Z3JJanU0SmJtOXppYmZ2MGZBZVpick1C?= =?utf-8?B?YndmWXhKN1lMb2s0VTRqdDlTSUdMMUN3TjhiUDN5UVZOaVdveHV5NzdJYUhN?= =?utf-8?B?cXE5am8zTUVtK2lpRUpTSkowOHBNM2NWaWJXNVFiVVRUUFBiZUJDZGV5bHhT?= =?utf-8?B?WHk4SDI2bU9PNjN5eWRKTmo5MkRoek5DZEhKanhuZWR1M21VM05hbHluRzhq?= =?utf-8?B?ZnROWEFRMmhHL1htWHRwTStrMDJJNDZPS2gzMU9mTFU2WmlFRitLNy9oMnRv?= =?utf-8?B?Y1AzRzdpWVRLdmpkdTNlUEkxdXhGdlNndjhESWZHZXlGSmUxN1I5ZEhmSS80?= =?utf-8?B?cFJuTURTSHV2YTg1Y29qY29CQ09hUmVva1JwTXhBWlh4ZEVoN0UzSlJUV3dt?= =?utf-8?B?TUtBY3cxb1ZrZyttRU1PUlNoNk9yL01rdnlEbi9TcUh0STBqanoxS01hMTVo?= =?utf-8?B?YTRTcVN6RWMwQW9PVFg5N0ExNW5iaEpXa0hzRW1Hb2plZVlyb3RqWkptd0xD?= =?utf-8?B?ekFDb2QrMXNTNnJaRFErM3AyRUNJb3hSMlVELzBWQVdiVmhSZy9Td3p3QnJk?= =?utf-8?B?WEttMUZ3eWdqK24yS3ZLbER4VmlmbEVEc1RTVVgzWkxMZUhtejNLVHBURity?= =?utf-8?B?RDlveHY5eUxDY29QbU1PZ3VYYkJPWDhtZFdZYmdNTU4vNEVsOHlwTzdyancw?= =?utf-8?B?bWxRWDZYdVpzeXA2cDZacGlyMTMwOEoydU9YZk1maXR5QjNsS0o2Smp4Vi8w?= =?utf-8?B?S1I1dHBNK0FVMitpQlJaZC90WWpSRUpUT0psOG5aZUt0Z3hJbnNmaDhZTkhI?= =?utf-8?B?VGdYTVZmRjRHemtDNC9RVzV0d0tlSkVFQ3Nkc2UrdlBPSXRiVkdWVjVGNHVl?= =?utf-8?B?M1U5VEl3cnNoaXBJd1VJamdHd2dPVEcxRFJYbFNkWit2TEhSbWxRdz09?= X-OriginatorOrg: Nvidia.com X-MS-Exchange-CrossTenant-Network-Message-Id: 11d910d5-8b38-4a78-4d82-08deec8b7c9f X-MS-Exchange-CrossTenant-AuthSource: DM4PR12MB6063.namprd12.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 28 Jul 2026 09:34:57.1119 (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: 5ZxHUWMTzK/W7DLecQgMtjZrz1igN0UUhyntKh3+ZoMWEa430W3J5UFWLc6Cv+EtUny6JeTl2+2a766pb3OUVw== X-MS-Exchange-Transport-CrossTenantHeadersStamped: DS0PR12MB7728 On 28/07/2026 03:53, Abraham Zukor wrote: > On 27/07/2026 13:07, Jon Hunter wrote: >> What about the case where the SPI devices CS is active high or a >> mixture of the two? > > An all-active-high bus is the case the window gets right today: probe > writes zero to the field, so an active-high CS idles deasserted and an > active-low one sits asserted. This patch inverts that. No single > constant covers a mixed board - one polarity or the other is asserted > until tegra_spi_setup() runs for that device - so the question is > which default is the right one, and active low is what the SPI core > assumes when a device says nothing. Exactly. That's my point. Which is the right one? The answer is probably neither, but whatever is present on the bus. -- nvpublic