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=-3.9 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 5D709C04A6B for ; Mon, 6 May 2019 13:17:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 38072206A3 for ; Mon, 6 May 2019 13:17:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726348AbfEFNQ7 (ORCPT ); Mon, 6 May 2019 09:16:59 -0400 Received: from mx2.suse.de ([195.135.220.15]:56044 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725856AbfEFNQ6 (ORCPT ); Mon, 6 May 2019 09:16:58 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 9C509AC0C; Mon, 6 May 2019 13:16:57 +0000 (UTC) Date: Mon, 6 May 2019 15:16:56 +0200 From: Jean Delvare To: LKML Cc: Linux I2C , Arnd Bergmann , Greg Kroah-Hartman , Jarkko Nikula Subject: [PATCH 2/2] eeprom: ee1004: Deal with nack on page selection Message-ID: <20190506151656.47494e56@endymion> In-Reply-To: <20190506151539.69ee75e8@endymion> References: <20190506151539.69ee75e8@endymion> Organization: SUSE Linux X-Mailer: Claws Mail 3.13.2 (GTK+ 2.24.31; x86_64-suse-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some EE1004 implementations will not properly ack page selection commands. They still set the page correctly, so there is no actual error. Deal with this case gracefully by checking the currently selected page after we receive a nack. If the page is set right then we can continue. Signed-off-by: Jean Delvare Tested-by: Jarkko Nikula Cc: Arnd Bergmann Cc: Greg Kroah-Hartman --- drivers/misc/eeprom/ee1004.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- linux-5.0.orig/drivers/misc/eeprom/ee1004.c 2019-05-06 11:57:14.333572368 +0200 +++ linux-5.0/drivers/misc/eeprom/ee1004.c 2019-05-06 15:11:06.009718220 +0200 @@ -1,7 +1,7 @@ /* * ee1004 - driver for DDR4 SPD EEPROMs * - * Copyright (C) 2017 Jean Delvare + * Copyright (C) 2017-2019 Jean Delvare * * Based on the at24 driver: * Copyright (C) 2005-2007 David Brownell @@ -124,6 +124,16 @@ static ssize_t ee1004_read(struct file * /* Data is ignored */ status = i2c_smbus_write_byte(ee1004_set_page[page], 0x00); + if (status == -ENXIO) { + /* + * Don't give up just yet. Some memory + * modules will select the page but not + * ack the command. Check which page is + * selected now. + */ + if (ee1004_get_current_page() == page) + status = 0; + } if (status < 0) { dev_err(dev, "Failed to select page %d (%d)\n", page, status); -- Jean Delvare SUSE L3 Support