From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sebastian Frias Subject: Re: [PATCH 1/2] net: ethernet: nb8800: Do not apply TX delay at MAC level Date: Fri, 4 Nov 2016 16:36:50 +0100 Message-ID: <581CAB12.3030604@laposte.net> References: <581CA300.1060609@laposte.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Cc: "David S. Miller" , netdev , LKML , Mason , Andrew Lunn To: =?UTF-8?B?TcOlbnMgUnVsbGfDpXJk?= Return-path: Received: from smtpoutz300.laposte.net ([178.22.154.200]:57003 "EHLO smtp.laposte.net" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S935737AbcKDPgw (ORCPT ); Fri, 4 Nov 2016 11:36:52 -0400 Received: from smtp.laposte.net (localhost [127.0.0.1]) by lpn-prd-vrout012 (Postfix) with ESMTP id 6EA638CCE1 for ; Fri, 4 Nov 2016 16:36:51 +0100 (CET) Received: from lpn-prd-vrin002 (lpn-prd-vrin002.prosodie [10.128.63.3]) by lpn-prd-vrout012 (Postfix) with ESMTP id 68C358CADE for ; Fri, 4 Nov 2016 16:36:51 +0100 (CET) Received: from lpn-prd-vrin002 (localhost [127.0.0.1]) by lpn-prd-vrin002 (Postfix) with ESMTP id 5350C5BF2A5 for ; Fri, 4 Nov 2016 16:36:51 +0100 (CET) In-Reply-To: Sender: netdev-owner@vger.kernel.org List-ID: Hi Måns, On 11/04/2016 04:18 PM, Måns Rullgård wrote: > Sebastian Frias writes: > >> The delay can be applied at PHY or MAC level, but since >> PHY drivers will apply the delay at PHY level when using >> one of the "internal delay" declinations of RGMII mode >> (like PHY_INTERFACE_MODE_RGMII_TXID), applying it again >> at MAC level causes issues. > > The Broadcom GENET driver does the same thing. > Well, I don't know who uses that driver, or why they did it that way. However, with the current code and DT bindings, if one requires the delay, phy-connection-type="rgmii-txid" must be set. But when doing so, both the Atheros 8035 and the Aurora NB8800 drivers will apply the delay. I think a better way of dealing with this is that both, PHY and MAC drivers exchange information so that the delay is applied only once. I can see how to do that in another patch set. >> Signed-off-by: Sebastian Frias >> --- >> drivers/net/ethernet/aurora/nb8800.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/net/ethernet/aurora/nb8800.c b/drivers/net/ethernet/aurora/nb8800.c >> index b59aa35..d2855c9 100644 >> --- a/drivers/net/ethernet/aurora/nb8800.c >> +++ b/drivers/net/ethernet/aurora/nb8800.c >> @@ -1282,7 +1282,7 @@ static int nb8800_tangox_init(struct net_device *dev) >> break; >> >> case PHY_INTERFACE_MODE_RGMII_TXID: >> - pad_mode = PAD_MODE_RGMII | PAD_MODE_GTX_CLK_DELAY; >> + pad_mode = PAD_MODE_RGMII; >> break; >> >> default: >> -- >> 1.7.11.2 > > If this change is correct (and I'm not convinced it is), that case > should be merged with the one above it and PHY_INTERFACE_MODE_RGMII_RXID > added as well. > I can do a single patch. The reason I made two patches was that it was clear what this patch does, i.e.: do not apply the delay at MAC level, and what the subsequent patch does, i.e.: handle all RGMII declinations. Best regards, Sebastian