Messages in this thread | | | Date | Wed, 16 Nov 2016 17:54:37 +0100 | From | Andrew Lunn <> | Subject | Re: [PATCH v2] net/phy/vitesse: Configure RGMII skew on VSC8601, if needed |
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On Wed, Nov 16, 2016 at 08:44:30AM -0800, Alex wrote: > > > On 11/16/2016 05:50 AM, Andrew Lunn wrote: > >On Wed, Nov 16, 2016 at 01:02:33AM -0800, Alexandru Gagniuc wrote: > >>With RGMII, we need a 1.5 to 2ns skew between clock and data lines. The > >>VSC8601 can handle this internally. While the VSC8601 can set more > >>fine-grained delays, the standard skew settings work out of the box. > >>The same heuristic is used to determine when this skew should be enabled > >>as in vsc824x_config_init(). > >> > >>+/* This adds a skew for both TX and RX clocks, so the skew should only be > >>+ * applied to "rgmii-id" interfaces. It may not work as expected > >>+ * on "rgmii-txid", "rgmii-rxid" or "rgmii" interfaces. */ > > > >Hi Alexandru > > > >You should be able to make "rgmii" work as expected. If that is the > >phy mode, disable the skew. > > And that's exactly the implemented behavior. See > vsc8601_config_init() below.
I don't think so. vsc8601_config_init() will not cause the skew to be cleared if the phy-mode is "rgmii" and something else like the bootloader could of set the skew. So saying that "rgmii" might not work as expected is true. But with a minor change, you can make it work as expected.
Andrew
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