From mboxrd@z Thu Jan 1 00:00:00 1970 From: Grant Likely Subject: Re: [PATCH V3] net/dt: Add support for overriding phy configuration from device tree Date: Wed, 05 Feb 2014 09:47:03 +0000 Message-ID: <20140205094703.37C1EC40A89@trevor.secretlab.ca> References: <7510122.cayuQ6qt8r@wuerfel> < 1389999459-9483-1-git-send-email-matthew.garrett@nebula.com> < CAGVrzcZ4TFd=9KP+aoG47QbmqDJ1i23WBcEWDbzNRUfGmPvZHQ@mail.gmail.com> Cc: netdev , "devicetree@vger.kernel.org" , "linux-kernel@vger.kernel.org" , Kishon Vijay Abraham I To: Florian Fainelli , Matthew Garrett Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Tue, 4 Feb 2014 12:39:41 -0800, Florian Fainelli wrote: > 2014-01-17 Matthew Garrett : > > Some hardware may be broken in interesting and board-specific ways, such > > that various bits of functionality don't work. This patch provides a > > mechanism for overriding mii registers during init based on the contents of > > the device tree data, allowing board-specific fixups without having to > > pollute generic code. > > It would be good to explain exactly how your hardware is broken > exactly. I really do not think that such a fine-grained setting where > you could disable, e.g: 100BaseT_Full, but allow 100BaseT_Half to > remain usable makes that much sense. In general, Gigabit might be > badly broken, but 100 and 10Mbits/sec should work fine. How about the > MASTER-SLAVE bit, is overriding it really required? > > Is not a PHY fixup registered for a specific OUI the solution you are > looking for? I am also concerned that this creates PHY troubleshooting > issues much harder to debug than before as we may have no idea about > how much information has been put in Device Tree to override that. > > Finally, how about making this more general just like the BCM87xx PHY > driver, which is supplied value/reg pairs directly? There are 16 > common MII registers, and 16 others for vendor specific registers, > this is just covering for about 2% of the possible changes. I would be fine with that too. g.