Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752366AbbFEVKP (ORCPT ); Fri, 5 Jun 2015 17:10:15 -0400 Received: from mail-la0-f51.google.com ([209.85.215.51]:33148 "EHLO mail-la0-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752139AbbFEVKD (ORCPT ); Fri, 5 Jun 2015 17:10:03 -0400 Message-ID: <55721027.6030509@cogentembedded.com> Date: Sat, 06 Jun 2015 00:09:59 +0300 From: Sergei Shtylyov Organization: Cogent Embedded User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Jaeden Amero , Florian Fainelli , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 3/3] net/phy: micrel: Center FLP timing at 16ms References: <1433534130-16323-1-git-send-email-jaeden.amero@ni.com> <1433534130-16323-4-git-send-email-jaeden.amero@ni.com> In-Reply-To: <1433534130-16323-4-git-send-email-jaeden.amero@ni.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2813 Lines: 72 Hello. On 06/05/2015 10:55 PM, Jaeden Amero wrote: > Link failures have been observed when using the KSZ9031 with HP 1810-8G > and HP 1910-8G network switches. Center the FLP timing at 16ms to help > avoid intermittent link failures. > From the KSZ9031RNX and KSZ9031MNX data sheets revision 2.2, section > "Auto-Negotiation Timing": > The KSZ9031[RNX or MNX] Fast Link Pulse (FLP) burst-to-burst > transmit timing for Auto-Negotiation defaults to 8ms. IEEE 802.3 > Standard specifies this timing to be 16ms +/-8ms. Some PHY link > partners need to receive the FLP with 16ms centered timing; > otherwise, there can be intermittent link failures and long > link-up times. > After KSZ9031[RNX or MNX] power-up/reset, program the following > register sequence to set the FLP timing to 16ms > Write Register Dh = 0x0000 // Set up register address for MMD – Device Address 0h > Write Register Eh = 0x0004 // Select Register 4h of MMD – Device Address 0h > Write Register Dh = 0x4000 // Select register data for MMD – Device Address 0h, Register 4h > Write Register Eh = 0x0006 // Write value 0x0006 to MMD – Device Address 0h, Register 4h > Write Register Dh = 0x0000 // Set up register address for MMD – Device Address 0h > Write Register Eh = 0x0003 // Select Register 3h of MMD – Device Address 0h > Write Register Dh = 0x4000 // Select register data for MMD – Device Address 0h, Register 3h > Write Register Eh = 0x1A80 // Write value 0x1A80 to MMD – Device Address 0h, Register 3h > Write Register 0h, Bit [9] = 1 // Restart Auto-Negotiation > Signed-off-by: Jaeden Amero > --- > drivers/net/phy/micrel.c | 26 +++++++++++++++++++++++++- > 1 file changed, 25 insertions(+), 1 deletion(-) > diff --git a/drivers/net/phy/micrel.c b/drivers/net/phy/micrel.c > index f23765e..e156e36 100644 > --- a/drivers/net/phy/micrel.c > +++ b/drivers/net/phy/micrel.c [...] > @@ -441,6 +461,7 @@ static int ksz9031_config_init(struct phy_device *phydev) > "txd2-skew-ps", "txd3-skew-ps" > }; > static const char *control_skews[2] = {"txen-skew-ps", "rxdv-skew-ps"}; > + int result; You hardly need this variable... > > if (!of_node && dev->parent->of_node) > of_node = dev->parent->of_node; > @@ -462,7 +483,10 @@ static int ksz9031_config_init(struct phy_device *phydev) > MII_KSZ9031RN_TX_DATA_PAD_SKEW, 4, > tx_data_skews, 4); > } > - return 0; > + > + result = ksz9031_center_flp_timing(phydev); > + > + return result; Why not just return directly? [...] WBR, Sergei -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/