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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 E1E2FC43381 for ; Thu, 14 Mar 2019 10:38:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AA6CA21019 for ; Thu, 14 Mar 2019 10:38:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=synopsys.com header.i=@synopsys.com header.b="HnKhKe+f" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727398AbfCNKiA (ORCPT ); Thu, 14 Mar 2019 06:38:00 -0400 Received: from us01smtprelay-2.synopsys.com ([198.182.60.111]:34412 "EHLO smtprelay.synopsys.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726736AbfCNKh7 (ORCPT ); Thu, 14 Mar 2019 06:37:59 -0400 Received: from mailhost1.synopsys.com (mailhost1.synopsys.com [10.12.238.239]) by smtprelay.synopsys.com (Postfix) with ESMTP id 1B91010C25E5; Thu, 14 Mar 2019 03:37:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=synopsys.com; s=mail; t=1552559879; bh=zu3IXV2x1enxJJVP8oX8x9XRSshj58jSUHa/Lew54a0=; h=From:To:Cc:Subject:Date:From; b=HnKhKe+f7VYIeAwbvTLp2nHTxT2qBUoGNeDIm7geR7Gn7clApes2iAenOJ7G6/9br Rd/8Qep3e+8DybGOGsY71emxZP17cUydmWSauM8n7fRhketgP6CaJf+ALslRX04rpO pIszYCKFGM5IAYj3NkwNFZBFUI9jk10YgmiEJOVnYEMp5kuwfTmMUrpqE9BqRo+gCt QxjEwUiojwppLMKoi8yNEcHmtwh3xll2n3G15R+l1wVcW1YKRlJe1HNh6zXQOPDg/6 10uh7uNG9B0M0v/u4T53oipAPsRpM/y1pumH3fTZr/KFAhPagemn3u8vwKY29x6VLp t5udvTClsTBEw== Received: from de02dwia024.internal.synopsys.com (de02dwia024.internal.synopsys.com [10.225.19.81]) by mailhost1.synopsys.com (Postfix) with ESMTP id D07D45B41; Thu, 14 Mar 2019 03:37:25 -0700 (PDT) From: Jose Abreu To: netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Jose Abreu , Andrew Lunn , Florian Fainelli , "David S. Miller" , Joao Pinto Subject: [PATCH net] net: phy: Don't assume loopback is supported Date: Thu, 14 Mar 2019 11:37:21 +0100 Message-Id: X-Mailer: git-send-email 2.7.4 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Some PHYs may not support loopback mode so we need to check if register is read-only. Fixes: f0f9b4ed2338 ("net: phy: Add phy loopback support in net phy framework") Signed-off-by: Jose Abreu Cc: Andrew Lunn Cc: Florian Fainelli Cc: "David S. Miller" Cc: Joao Pinto --- drivers/net/phy/phy_device.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 49fdd1ee798e..a749639d98c3 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -1918,8 +1918,24 @@ EXPORT_SYMBOL(genphy_resume); int genphy_loopback(struct phy_device *phydev, bool enable) { - return phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK, - enable ? BMCR_LOOPBACK : 0); + int ret; + + ret = phy_modify(phydev, MII_BMCR, BMCR_LOOPBACK, + enable ? BMCR_LOOPBACK : 0); + if (ret < 0) + return ret; + + ret = phy_read(phydev, MII_BMCR); + if (ret < 0) + return ret; + + if (enable) { + if (ret & BMCR_LOOPBACK) + return 0; + return -EOPNOTSUPP; + } + + return 0; } EXPORT_SYMBOL(genphy_loopback); -- 2.7.4