From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH v2 3/3] net/phy: micrel: Center FLP timing at 16ms Date: Sat, 06 Jun 2015 00:09:59 +0300 Message-ID: <55721027.6030509@cogentembedded.com> References: <1433534130-16323-1-git-send-email-jaeden.amero@ni.com> <1433534130-16323-4-git-send-email-jaeden.amero@ni.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE To: Jaeden Amero , Florian Fainelli , netdev@vger.kernel.org, linux-kernel@vger.kernel.org Return-path: In-Reply-To: <1433534130-16323-4-git-send-email-jaeden.amero@ni.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org 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 hel= p > 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 =3D 0x0000 // Set up register address for MMD =E2=80= =93 Device Address 0h > Write Register Eh =3D 0x0004 // Select Register 4h of MMD =E2=80=93 = Device Address 0h > Write Register Dh =3D 0x4000 // Select register data for MMD =E2=80=93= Device Address 0h, Register 4h > Write Register Eh =3D 0x0006 // Write value 0x0006 to MMD =E2=80=93 = Device Address 0h, Register 4h > Write Register Dh =3D 0x0000 // Set up register address for MMD =E2=80= =93 Device Address 0h > Write Register Eh =3D 0x0003 // Select Register 3h of MMD =E2=80=93 = Device Address 0h > Write Register Dh =3D 0x4000 // Select register data for MMD =E2=80=93= Device Address 0h, Register 3h > Write Register Eh =3D 0x1A80 // Write value 0x1A80 to MMD =E2=80=93 = Device Address 0h, Register 3h > Write Register 0h, Bit [9] =3D 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] =3D {"txen-skew-ps", "rxdv-ske= w-ps"}; > + int result; You hardly need this variable... > > if (!of_node && dev->parent->of_node) > of_node =3D 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 =3D ksz9031_center_flp_timing(phydev); > + > + return result; Why not just return directly? [...] WBR, Sergei