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b=fHT6j0P/2KVO5IGrqd5bP8pCAQ30nSlrvNrjoeUw+VfVl/3DsNAwGKlJDVJWx2GsP1o16qjYSmxwlEX0kWixFMgzkbU2jT1YWC8tqowrovok1w5BPKHr+vyfzlzNPts7xaVORUeFSOUkZofxxigTKGK0fNRx8tecSF4vaYSoB34= Authentication-Results: dkim=none (message not signed) header.d=none;dmarc=none action=none header.from=prevas.dk; Received: from DB7PR10MB2475.EURPRD10.PROD.OUTLOOK.COM (2603:10a6:10:41::17) by GVXPR10MB8379.EURPRD10.PROD.OUTLOOK.COM (2603:10a6:150:1e2::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.8534.33; Thu, 20 Mar 2025 11:17:39 +0000 Received: from DB7PR10MB2475.EURPRD10.PROD.OUTLOOK.COM ([fe80::7e2c:5309:f792:ded4]) by DB7PR10MB2475.EURPRD10.PROD.OUTLOOK.COM ([fe80::7e2c:5309:f792:ded4%5]) with mapi id 15.20.8534.031; Thu, 20 Mar 2025 11:17:39 +0000 From: Rasmus Villemoes To: Colin Foster Cc: Lee Jones , linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, Felix Blix Everberg Subject: Re: [PATCH 3/8] mfd: ocelot: rework SPI (re-)initialization after chip reset In-Reply-To: (Colin Foster's message of "Wed, 19 Mar 2025 17:08:08 -0500") References: <20250319123058.452202-1-ravi@prevas.dk> <20250319123058.452202-4-ravi@prevas.dk> Date: Thu, 20 Mar 2025 12:17:37 +0100 Message-ID: <87v7s4rlwu.fsf@prevas.dk> User-Agent: Gnus/5.13 (Gnus v5.13) Content-Type: text/plain X-ClientProxiedBy: MM0P280CA0101.SWEP280.PROD.OUTLOOK.COM (2603:10a6:190:9::27) To DB7PR10MB2475.EURPRD10.PROD.OUTLOOK.COM (2603:10a6:10:41::17) 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: DB7PR10MB2475:EE_|GVXPR10MB8379:EE_ X-MS-Office365-Filtering-Correlation-Id: 13d528de-0028-4cd2-491c-08dd67a0d361 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|52116014|366016|376014|1800799024|7053199007|38350700014; 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X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1 X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?zu0BZaC643oGSbzHFPafBCMy3naFbzhWIpCobpFhvpMQvJLKh06LwOHAx8nj?= =?us-ascii?Q?M3JGNJPaPVlXfB90VAaCJQtloYXyJnBK7GIn/Wqp6G8fuBqe8f1P+8vgWWF+?= =?us-ascii?Q?XhSsG5cbbzVsg2nXMgXdNqiHuYotFc1elncoAkH3jI5FF5vD+wzPK68UArTK?= =?us-ascii?Q?7/8R/uFKAYIejisjVrNcfTRA8OiUXdv8YrpBXuaQ3TuoL+GN+v1hbs0fuCPJ?= =?us-ascii?Q?UeiH+79TrhiKrWg32DZVySROMFDoQ/Vyl21DuJM0mwMsZTJkvpEst9fucZeV?= =?us-ascii?Q?aux+s/qjf4AmCrF+Exzst6H2xXavBb7WZh7kdjjfYWhR/PKhGvL49KTMZeDc?= =?us-ascii?Q?zTELmMjs+WYvYs8+k2W7fVildZmJmR67rto37J8bwrpzc19JvS3ZdkH/07Cx?= =?us-ascii?Q?ONrGciZY5tFLB0unAk42I0c8G1Xtnx7ZdprsISIESySlgP4bh3O8/AplnJ01?= =?us-ascii?Q?YneLm7L2gACeKCRXdFJ3DyqcGmvgPZnvtjbJj+DcNhSxaSUXrg6AmFphidL2?= =?us-ascii?Q?tq5H5NOD/yy6JWI8ha7E+tcz5nZgndq9kY3SmMWgb2i4qW33zmHxT6QBO81L?= =?us-ascii?Q?Y7v+Sb8IO+nFW7eWLiExyLCydriD0GtMXzucJzbAmfcpUkLiJ8g1Y4Ijt14A?= =?us-ascii?Q?slxxcLm/S5Qrbl7hVJMoPRSgjxk94qBY5A7/XW5TUD05WcBmDNtZA6YliTGK?= =?us-ascii?Q?FOKgK/dWoS1INXB/EsONOLaCsZ/6z9QSH6iec6PL706uDlX5GImKAgWBEBZn?= =?us-ascii?Q?I/4lqq/9UaWlnAE31T4QCejP5CH1AIJaYPS1nSVIZLfD/YZEomNY8JFSime2?= =?us-ascii?Q?tsRe35yCUFNg0C7qV/e23G3BYF6hYEVQ05NnyCLn1P9jw5irATBJl7N2IKLt?= =?us-ascii?Q?4oWzisudg6aV5VZXZDPk4PqKlOU1kVDkzaSEK7v3wAR4P8HCsMfsDxYNuWz8?= =?us-ascii?Q?/+OvdJdPmc7gWjY063VMERsq+c0rrBfk2xwHoRpAJW23W6lmx2+rA4DgLjVX?= =?us-ascii?Q?vRsn3hn+DIfg04Rm2z+tWmRRNqymQLbmudWzJzXBGkbprEuV0g1+PJnTt+RN?= =?us-ascii?Q?34O8p2rhvGjNB0df/u/hEzW0I3IBgztx+0UIhSLwXuu/02vuPxd6wSJTb5XZ?= =?us-ascii?Q?U4/WsvOjsrGGWTi6rtJGWq966GcF8Sx7itSrVJ8KhvUEiyOYCcVdui0WUvAj?= =?us-ascii?Q?rS8H/hFlF8T9Ss1gFasqSGo0+HG2JMQbSm1HgBp2iNovUm85+zqtjauZVUBF?= =?us-ascii?Q?1OmdkDXuk2wm8/gKavpt0BwZVvYePau/VsutO/aLmDJK06fkQEGGksJRck7l?= =?us-ascii?Q?ndaET7hKmmssEZIz9DaXVlklzsn35NS1vlllAbHfo8jDzi2g4LZGqaqtshrf?= =?us-ascii?Q?2IdJGncY8c2tfCBA053bF26OFgMDBvhaIld/WZvSkTfTX6MBo8n/8m/b4NBq?= =?us-ascii?Q?MPJCIRO4XL3248LUgwFSHXy7muQoO3Y4iNWctB4lDfCBLLPdPPnnRM6tBCBp?= =?us-ascii?Q?tjVZcpLfatVkn4b7ScfWvMXK1O9D1EZEiJp5vTwaFptDRwF0NGzAvJ+gwKSg?= =?us-ascii?Q?1T/HzA9IDMMjZboX0eQaGlJ02RR22oZeO9m1nVNp0MlNGjKFzil3dgFvGx0J?= =?us-ascii?Q?Cw=3D=3D?= X-OriginatorOrg: prevas.dk X-MS-Exchange-CrossTenant-Network-Message-Id: 13d528de-0028-4cd2-491c-08dd67a0d361 X-MS-Exchange-CrossTenant-AuthSource: DB7PR10MB2475.EURPRD10.PROD.OUTLOOK.COM X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-OriginalArrivalTime: 20 Mar 2025 11:17:39.7399 (UTC) X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted X-MS-Exchange-CrossTenant-Id: d350cf71-778d-4780-88f5-071a4cb1ed61 X-MS-Exchange-CrossTenant-MailboxType: HOSTED X-MS-Exchange-CrossTenant-UserPrincipalName: yO5lOlLM1Eez+Nl503Z1RNo5aZI/8rAqvWvikJnhUHGzBvoxzcyq86degBaSociO3QTrYffaZ5p4RvezVfjl2ktushaZT6cXt9UD/tQHnXg= X-MS-Exchange-Transport-CrossTenantHeadersStamped: GVXPR10MB8379 Hi Colin On Wed, Mar 19 2025, Colin Foster wrote: > On Wed, Mar 19, 2025 at 01:30:53PM +0100, Rasmus Villemoes wrote: >> As the comments in ocelot-spi.c explain, after a chip reset, the >> CFGSTAT register must be written again setting the appropriate number >> of padding bytes; otherwise reads are not reliable. >> >> However, the way the code is currently structured violates that: After >> the BIT_SOFT_CHIP_RST is written, ocelot_chip_reset() immediately >> enters a readx_poll_timeout(). > > I ran this new version and everything worked - and I've not seen an > issue in previous versions. I'm looking for guidance as to whether this > should include a Fixes tag and be backported. Thanks a lot for testing and reviewing! As for backporting, IDK, I think we'd at least first have to know that it really fixes a bug for somebody. > Great find, by the way! Is there any information you would like from my > setup? Certainly I'd like to know if you do in fact use a SPI clock > 500 kHz? And if so, could you try inserting a read and printk of e.g. CHIP_REGS.CHIP_ID immediately after the fsleep(), but before the re-initialization, just so we can see if my theory that the values are off-by-8-bits plus 8 bits of MISO "garbage" is correct? Because that register should have a fairly easily recognizable value. Thanks, Rasmus