From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752591AbeERKEK (ORCPT ); Fri, 18 May 2018 06:04:10 -0400 Received: from mail-wm0-f66.google.com ([74.125.82.66]:34618 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752176AbeERKEF (ORCPT ); Fri, 18 May 2018 06:04:05 -0400 X-Google-Smtp-Source: AB8JxZrsanbUru9G8/Vk8P6WmPekNcuc6ORAKJLczxHrJ0p5JGpAid/5xk33P8WoQ7ga0BxOxfw7pA== Subject: Re: [PATCH] mtd: spi-nor: add support for Microchip 25LC256 To: Radu Pirea , Boris Brezillon Cc: linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org, Zhiqiang.Hou@nxp.com, pp@emlix.com, richard@nod.at, computersforpeace@gmail.com, dwmw2@infradead.org References: <20180504155404.5285-1-radu.pirea@microchip.com> <20180504204013.254d90cf@bbrezillon> <1db092c8-95fb-5747-f7b9-f6a215b1aa5b@gmail.com> <30ab9516-abc9-d2d5-79ea-266c682c5fa9@gmail.com> <1993151b-4434-c671-8498-b6488288f5f6@microchip.com> From: Marek Vasut Message-ID: Date: Fri, 18 May 2018 12:03:31 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: <1993151b-4434-c671-8498-b6488288f5f6@microchip.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 05/18/2018 11:50 AM, Radu Pirea wrote: > > > On 05/16/2018 04:47 PM, Marek Vasut wrote: >> On 05/16/2018 12:05 PM, Radu Pirea wrote: >>> On Wed, 2018-05-16 at 00:17 +0200, Marek Vasut wrote: >>>> On 05/15/2018 06:22 PM, Radu Pirea wrote: >>>>> On Fri, 2018-05-04 at 20:40 +0200, Boris Brezillon wrote: >>>>>> On Fri, 4 May 2018 18:54:04 +0300 >>>>>> Radu Pirea wrote: >>>>>> >>>>>>> Added geometry description for Microchip 25LC256 memory. >>>>>> >>>>>> Same as for the dataflash stuff you posted a few weeks ago: I >>>>>> don't >>>>>> think this device belongs in the SPI NOR framework. >>>>> >>>>> Hi Boris, >>>>> >>>>> 25lc256 memory is similar with mr25h256, the only difference is the >>>>> page size(64 vs 256). Because mr25h256 is already in SPI NOR >>>>> framework >>>>> I added here 25lc256. >>>> >>>> I think I must be reading the wrong datasheet, but can you show me >>>> how >>>> does it support things like READID opcode ? >>>> >>> Hi Marek, >>> >>> I read the datasheet for 25lc256 and for mr25h256 and none of them >>> supports READID. Is this required for a chip to be included in spi-nor >>> framework? I just followed the mr25h256 as an example. >> >> So I thought until you pointed out the MR25 devices. >> >> Does the 25LC device need erase or not ? I think the MR25s didn't, but I >> might be wrong. > > You are right. MR25s does not need erase and the same thing is true for > 25LC. Oh. And the command set is (except for readid) comparable to SPI NOR ? >> Maybe the framework could support the 25LC afterall. >> > Yes, this was my impression too. I am still thinking that the AT25 driver might be a better fit for such devices. Can you take a look ? -- Best regards, Marek Vasut