From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Roese Date: Wed, 11 Feb 2015 09:26:06 +0100 Subject: [U-Boot] [PATCH 2/2] net: phy: Add ability to program the ksz9031 skew values from the uboot env In-Reply-To: References: <1423493073-9462-1-git-send-email-vbridger@opensource.altera.com> <201502092018.52128.marex@denx.de> <1423517501329.58727@opensource.altera.com> <201502101951.35515.marex@denx.de> <54DAFFF6.20003@denx.de> Message-ID: <54DB121E.8070800@denx.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On 11.02.2015 09:07, Joe Hershberger wrote: >>>> I agree it would make more sense to pull these from devicetree - I'm >>>> planning on adding that in a future patch. I thought it would be a good >>>> idea to pull these values from the environment first, overriding the >>>> devicetree (if present in the environment). This approach is helpful >>>> during bringup & debug since it doesn't require one to change the >>>> devicetree to try something quickly. I'm ok with any approach you think >>>> would work for the community. >>> >>> >>> You can do that with the 'mii' command as well I think, but I might be > wrong. >> >> >> Yes. For testing or board bringup this might really serve. Even though > this setting via environment as proposed from Vince is more elegant and > less hackish. And easier to adjust/tune for "normal users". >> >> The default values should come from the DT, once this is all in place. > But I think that for initial board bringup / testing such a method, to > override those values via environment variables can be quite helpful. >> >> Joe, whats your opinion on this? > > Do we really think this is a strong use-case? This seem like the type of > thing I would expect to tweak for testing through mii / mdio commands and > then configure the device tree based on that. This is pretty much a > one-time thing for a given board it seems to me. > > If we really want a polished interface to it, we should define a > sub-command / new command that phy drivers can implement. I'm not sure an > undiscoverable, un-"help"-able list of env vars will be apparent to users. > Do you have a feeling for how close to universal any of these parameters > are across phys? No. But with your comments above (which make total sense), I tend to NAK this ability to configure the PHY skew timings via environment variables. Thanks, Stefan