Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754445Ab3GaGQ2 (ORCPT ); Wed, 31 Jul 2013 02:16:28 -0400 Received: from comal.ext.ti.com ([198.47.26.152]:38775 "EHLO comal.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751559Ab3GaGQ0 (ORCPT ); Wed, 31 Jul 2013 02:16:26 -0400 Date: Wed, 31 Jul 2013 09:15:38 +0300 From: Felipe Balbi To: Kishon Vijay Abraham I CC: , Greg KH , Tomasz Figa , Alan Stern , , , , , , , , , , , , , , , , , , , , , Subject: Re: [PATCH 01/15] drivers: phy: add generic PHY framework Message-ID: <20130731061538.GC13289@radagast> Reply-To: References: <20130720220006.GA7977@kroah.com> <3839600.WiC1OLF35o@flatron> <51EBC0F5.70601@ti.com> <9748041.Qq1fWJBg6D@flatron> <20130721154653.GG16598@kroah.com> <20130730071106.GC16441@radagast> <51F8A440.8010803@ti.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="5QAgd0e35j3NYeGe" Content-Disposition: inline In-Reply-To: <51F8A440.8010803@ti.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4655 Lines: 113 --5QAgd0e35j3NYeGe Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Wed, Jul 31, 2013 at 11:14:32AM +0530, Kishon Vijay Abraham I wrote: > >>>>> IMHO we need a lookup method for PHYs, just like for clocks, > >>>>> regulators, PWMs or even i2c busses because there are complex cases > >>>>> when passing just a name using platform data will not work. I would > >>>>> second what Stephen said [1] and define a structure doing things in= a > >>>>> DT-like way. > >>>>> > >>>>> Example; > >>>>> > >>>>> [platform code] > >>>>> > >>>>> static const struct phy_lookup my_phy_lookup[] =3D { > >>>>> > >>>>> PHY_LOOKUP("s3c-hsotg.0", "otg", "samsung-usbphy.1", "phy.2"), > >>>> > >>>> The only problem here is that if *PLATFORM_DEVID_AUTO* is used while > >>>> creating the device, the ids in the device name would change and > >>>> PHY_LOOKUP wont be useful. > >>> > >>> I don't think this is a problem. All the existing lookup methods alre= ady=20 > >>> use ID to identify devices (see regulators, clkdev, PWMs, i2c, ...). = You=20 > >>> can simply add a requirement that the ID must be assigned manually,= =20 > >>> without using PLATFORM_DEVID_AUTO to use PHY lookup. > >> > >> And I'm saying that this idea, of using a specific name and id, is > >> frought with fragility and will break in the future in various ways wh= en > >> devices get added to systems, making these strings constantly have to = be > >> kept up to date with different board configurations. > >> > >> People, NEVER, hardcode something like an id. The fact that this > >> happens today with the clock code, doesn't make it right, it makes the > >> clock code wrong. Others have already said that this is wrong there as > >> well, as systems change and dynamic ids get used more and more. > >> > >> Let's not repeat the same mistakes of the past just because we refuse = to > >> learn from them... > >> > >> So again, the "find a phy by a string" functions should be removed, the > >> device id should be automatically created by the phy core just to make > >> things unique in sysfs, and no driver code should _ever_ be reliant on > >> the number that is being created, and the pointer to the phy structure > >> should be used everywhere instead. > >> > >> With those types of changes, I will consider merging this subsystem, b= ut > >> without them, sorry, I will not. > >=20 > > I'll agree with Greg here, the very fact that we see people trying to > > add a requirement of *NOT* using PLATFORM_DEVID_AUTO already points to a > > big problem in the framework. > >=20 > > The fact is that if we don't allow PLATFORM_DEVID_AUTO we will end up > > adding similar infrastructure to the driver themselves to make sure we > > don't end up with duplicate names in sysfs in case we have multiple > > instances of the same IP in the SoC (or several of the same PCIe card). > > I really don't want to go back to that. >=20 > If we are using PLATFORM_DEVID_AUTO, then I dont see any way we can give = the > correct binding information to the PHY framework. I think we can drop hav= ing > this non-dt support in PHY framework? I see only one platform (OMAP3) goi= ng to > be needing this non-dt support and we can use the USB PHY library for it. you shouldn't drop support for non-DT platform, in any case we lived without DT (and still do) for years. Gotta find a better way ;-) --=20 balbi --5QAgd0e35j3NYeGe Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) iQIcBAEBAgAGBQJR+KuKAAoJEIaOsuA1yqREE/MQAKN7wAutlqEQhh/2yyHsehtl jdfoMN8pAOKD1Fs5TUwItJKRs00jIggDrlU9rl1xet+ZaBykobKzILmF5HTsHaQc z4ku41vMrAbgCn4LXMtLQwVWSGPTXcic9a8HLyOwdzxNwkGG7bIo62TO/kPVCMKa wEmbdeSbq2DTtNX+cPwE0AmJlpTyNejD+f03xfG27qpNclbaxBZlQGAvq8xDlfuU rueYU+4xnEgdC8ZrhNF6RWkke/haJgoy3qQjOchYflSkjeyX9gKypaPKGaA87Bu+ z1NTYMZv6fLiCtAmpUYb05C13G2eoi2EXDVYYZg1OA9GaHDtg9J9+DiUzPpSD2Od fbF9ZH4EB8cwFN4SilLJjhn1ESJaMqCHuOugqXTgJD6md+k0nBX3yAkrnyCbbhIr 4/E7TnWFar+xXGDKu2DufWYZByn5/WtYG8K0T9QJyFZyMV+X67Qz02iIrBBORST3 3NnejtvQ84NMiy5N1Cp5M0ucHaBvoS4ic3uvhB33T8GIgZuSqr78dnWmbvsNpEI3 gv/9z1OvuvXNcvoFiLYmGhs0b5+4xbU2qmoxfDjdUEw/JNmksf+8QGS8JYSbgu9X PO+W2yI5+6rWvhWy14+x/aS7Ew613pYWYiA8j9W0X9Idby88cKbN346U8zWGNovP tj3EzocBdvt4pr9XngYP =5yv8 -----END PGP SIGNATURE----- --5QAgd0e35j3NYeGe-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/