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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 6E6C7C43331 for ; Fri, 6 Sep 2019 09:05:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 483EA2082C for ; Fri, 6 Sep 2019 09:05:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388932AbfIFJFl convert rfc822-to-8bit (ORCPT ); Fri, 6 Sep 2019 05:05:41 -0400 Received: from eu-smtp-delivery-151.mimecast.com ([146.101.78.151]:37363 "EHLO eu-smtp-delivery-151.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388545AbfIFJFl (ORCPT ); Fri, 6 Sep 2019 05:05:41 -0400 Received: from AcuMS.aculab.com (156.67.243.126 [156.67.243.126]) (Using TLS) by relay.mimecast.com with ESMTP id uk-mta-39-q--cHczUMTKFUx84CmEraQ-1; Fri, 06 Sep 2019 10:05:37 +0100 Received: from AcuMS.Aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) by AcuMS.aculab.com (fd9f:af1c:a25b:0:43c:695e:880f:8750) with Microsoft SMTP Server (TLS) id 15.0.1347.2; Fri, 6 Sep 2019 10:05:36 +0100 Received: from AcuMS.Aculab.com ([fe80::43c:695e:880f:8750]) by AcuMS.aculab.com ([fe80::43c:695e:880f:8750%12]) with mapi id 15.00.1347.000; Fri, 6 Sep 2019 10:05:36 +0100 From: David Laight To: 'Alexandre Belloni' , Linus Walleij CC: Ludovic Desroches , Nicolas Ferre , "Claudiu.Beznea@microchip.com" , "linux-gpio@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH v2] pinctrl: at91-pio4: implement .get_multiple and .set_multiple Thread-Topic: [PATCH v2] pinctrl: at91-pio4: implement .get_multiple and .set_multiple Thread-Index: AQHVY/kRQYKuMyjlyU+DkxaSF5MIvaceWwkA Date: Fri, 6 Sep 2019 09:05:36 +0000 Message-ID: <2261eadf98584d13a490f2abd8777d4a@AcuMS.aculab.com> References: <20190905144849.24882-1-alexandre.belloni@bootlin.com> In-Reply-To: <20190905144849.24882-1-alexandre.belloni@bootlin.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-ms-exchange-transport-fromentityheader: Hosted x-originating-ip: [10.202.205.107] MIME-Version: 1.0 X-MC-Unique: q--cHczUMTKFUx84CmEraQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT Sender: linux-gpio-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-gpio@vger.kernel.org From: Alexandre Belloni > Implement .get_multiple and .set_multiple to allow reading or setting > multiple pins simultaneously. Pins in the same bank will all be switched at > the same time, improving synchronization and performances. Actually it won't 'improve synchronisation', instead it will lead to random synchronisation errors and potential metastability if one pin is used as a clock and another as data, or if the code is reading a free-flowing counter. It will improve performance though. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)