From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932364AbdKHHQW (ORCPT ); Wed, 8 Nov 2017 02:16:22 -0500 Received: from mail.free-electrons.com ([62.4.15.54]:35136 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751779AbdKHHQV (ORCPT ); Wed, 8 Nov 2017 02:16:21 -0500 Date: Wed, 8 Nov 2017 08:16:12 +0100 From: Alexandre Belloni To: Keerthy Cc: Sekhar Nori , linux-rtc@vger.kernel.org, linux-kernel@vger.kernel.org, Linux OMAP List Subject: Re: [PATCH] rtc: omap: Support scratch registers Message-ID: <20171108071612.65wrw7mhoip55lia@piout.net> References: <20171031162731.27019-1-alexandre.belloni@free-electrons.com> <600fd106-9f79-0f5a-a2fd-e6b067785c17@ti.com> <4741d4c7-d6f7-ecdb-1eed-1293175f38d9@ti.com> <9a383f74-e049-885b-4705-93968f4c75d4@ti.com> <20171108062738.cml7qaek324rvc4e@piout.net> <775d3cfc-95ca-1dff-d146-64efbdd71e1f@ti.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <775d3cfc-95ca-1dff-d146-64efbdd71e1f@ti.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/11/2017 at 12:38:05 +0530, Keerthy wrote: > > > On Wednesday 08 November 2017 11:57 AM, Alexandre Belloni wrote: > > Hi, > > > > On 08/11/2017 at 11:30:45 +0530, Keerthy wrote: > >>>>> +static int omap_rtc_scratch_read(void *priv, unsigned int offset, void *_val, > >>>>> + size_t bytes) > >>>>> +{ > >>>>> + struct omap_rtc *rtc = priv; > >>>>> + u32 *val = _val; > >>>>> + int i; > >>>>> + > >>>>> + for (i = 0; i < bytes / 4; i++) > >>>>> + val[i] = rtc_readl(rtc, > >>>>> + OMAP_RTC_SCRATCH0_REG + offset + (i * 4)); > >> > >> Can the offset be the Scratch register number instead of bytes offset? > >> More intuitive to me. > >> > >> So that one can request using offset as 0, 1, 2 instead of 0, 4, 8? > >> > > > > Well, the offset is coming from the nvmem core, itself getting it from > > the Linux file API (and it is in bytes). However, you have the guarantee > > that it will be aligned on a word, see: > > http://elixir.free-electrons.com/linux/latest/source/drivers/nvmem/core.c#L88 > > Okay Alexandre. Thanks for clarifying. Looks good to me. > I have tested on AM437X-GP-EVM. > If needed, you can define nvmem cells (and I guess that is what you want): http://elixir.free-electrons.com/linux/latest/source/Documentation/devicetree/bindings/nvmem/nvmem.txt -- Alexandre Belloni, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com