From mboxrd@z Thu Jan 1 00:00:00 1970 From: robh@kernel.org (Rob Herring) Date: Wed, 30 Nov 2016 15:44:29 -0600 Subject: [PATCH v2 1/7] net: dt-bindings: add RGMII TX delay configuration to meson8b-dwmac In-Reply-To: <20161125130156.17879-2-martin.blumenstingl@googlemail.com> References: <20161124143417.10178-1-martin.blumenstingl@googlemail.com> <20161125130156.17879-1-martin.blumenstingl@googlemail.com> <20161125130156.17879-2-martin.blumenstingl@googlemail.com> Message-ID: <20161130214429.albylffpoumbeugi@rob-hp-laptop> To: linus-amlogic@lists.infradead.org List-Id: linus-amlogic.lists.infradead.org On Fri, Nov 25, 2016 at 02:01:50PM +0100, Martin Blumenstingl wrote: > This allows configuring the RGMII TX clock delay. The RGMII clock is > generated by underlying hardware of the the Meson 8b / GXBB DWMAC glue. > The configuration depends on the actual hardware (no delay may be > needed due to the design of the actual circuit, the PHY might add this > delay, etc.). > > Signed-off-by: Martin Blumenstingl > --- > Documentation/devicetree/bindings/net/meson-dwmac.txt | 14 ++++++++++++++ > 1 file changed, 14 insertions(+) > > diff --git a/Documentation/devicetree/bindings/net/meson-dwmac.txt b/Documentation/devicetree/bindings/net/meson-dwmac.txt > index 89e62dd..f8bc540 100644 > --- a/Documentation/devicetree/bindings/net/meson-dwmac.txt > +++ b/Documentation/devicetree/bindings/net/meson-dwmac.txt > @@ -25,6 +25,20 @@ Required properties on Meson8b and newer: > - "clkin0" - first parent clock of the internal mux > - "clkin1" - second parent clock of the internal mux > > +Optional properties on Meson8b and newer: > +- amlogic,tx-delay-ns: The internal RGMII TX clock delay (provided > + by this driver) in nanoseconds. Allowed values > + are: 0ns, 2ns, 4ns, 6ns. > + This must be configured when the phy-mode is > + "rgmii" (typically a value of 2ns is used in > + this case). > + When phy-mode is set to "rgmii-id" or > + "rgmii-txid" the TX clock delay is already > + provided by the PHY. In that case this > + property should be set to 0ns (which disables > + the TX clock delay in the MAC to prevent the > + clock from going off because both PHY and MAC > + are adding a delay). What's the default? Why can't no property mean 0ns delay? > > Example for Meson6: > > -- > 2.10.2 >