Messages in this thread | | | Subject | Re: [PATCH v2] net/phy/vitesse: Configure RGMII skew on VSC8601, if needed | From | Alex <> | Date | Wed, 16 Nov 2016 09:10:02 -0800 |
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On 11/16/2016 08:54 AM, Andrew Lunn wrote: > 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.
That's not within the scope of this change. The scope is to make rgmii-id work. Any additional changes would be untested.
Alex
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