From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH] i2c-qoriq: modified compatibility for correct prescaler Date: Tue, 25 Nov 2014 19:13:47 +0100 Message-ID: <20141125181347.GC9716@katana> References: <1413538026-15739-1-git-send-email-valentin.longchamp@keymile.com> <1414537731.23458.120.camel@snotra.buserror.net> <5450AC85.40302@keymile.com> <20141113003418.GE2062@katana> <5465B285.7070005@keymile.com> <20141114082832.GA2180@katana> <1416274083.15957.96.camel@freescale.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="MnLPg7ZWsaic7Fhd" Return-path: Content-Disposition: inline In-Reply-To: <1416274083.15957.96.camel-KZfg59tc24xl57MIdRCFDg@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Scott Wood Cc: Valentin Longchamp , Linux PowerPC Kernel , Linux device trees , Linux I2C , "Brunck, Holger" , "Boschung, Rainer" List-Id: devicetree@vger.kernel.org --MnLPg7ZWsaic7Fhd Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Nov 17, 2014 at 07:28:03PM -0600, Scott Wood wrote: > On Fri, 2014-11-14 at 09:28 +0100, Wolfram Sang wrote: > > > >=20 > > > > If we're going to change the device tree I'd rather just add a prop= erty > > > > to say what the prescaler is. > > >=20 > > > We would however, leave the boards' device trees that use things like > > > "fsl,mpc8543-i2c" as is and introduce the prescaler for the others re= quiring it. > > >=20 > > >=20 > > > Now the drawback is that the driver would require a change, to parse = this > > > prescaler new prescaler property. Would this be OK from your point of= view > > > Wolfram ? If yes, I will send the patches for it. > >=20 > > I don't think it is OK. >=20 > Why? Because I thought it could be deduced. Then, a seperate property would not be OK. > > I'd think it can be deduced from the compatible property. >=20 > For almost all existing device trees it cannot be. Pity :( If we do introduce a new property, it should probably be "clock-div". Grepping through binding documentation, that seems accepted. We should ask DT maintainers, too, to be safe. > If you want something that will work without changing device trees, > you'll need to use SVR to identify the SoC. The driver is doing that already, see mpc_i2c_get_sec_cfg_8xxx(). Dunno if it makes sense to add to it for consistency reasons? --MnLPg7ZWsaic7Fhd Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUdMbbAAoJEBQN5MwUoCm2BIsQAJ+N/XUWx2AclSWuY0H6ZtQD i5oOPHCbuu3GNjIqJlWjRRHYpMQb0wkl+u9Xbo8yzKULEeQ8cxb4FLOv70ylem/E kFkyecWGFdkRnLwTSk8FvywYayTmlb0ktNBeg83XJcx58ibN+Otwc0WzWNM0cLFX kKWhlNpKrz2LyNCJP4oFB7vhu5TClAo6VTdYBrN5bGY0BlEuhuRB7vx2RKTWvAWf VTIoMIBDVJAHbIYfMo1mFUgu0yK1j69/IAT8N1UZXttKlG0ZCbpeTXYrLds+n7ss DRChWvK9FH46gzzLmPbIAA/oUDAuetIcgyBwlwCt6xrW2MdncEML8YymhUjCF18p g739ZFA7Ukvn9J5NK/3+JfCy4Z5/aY1yiCHazwHVFK8wv7Asr994fl27HenDGjSq vupdCCv7cswoauVV4mydc0eZVovjFOijaVEwsFZLX6aXDLkw5OzEpA4xvh4lc9cm B/vr3iDYHn0+EuVpYUovh3Ob3vW+TGOObY2QV+Wh2R4jvBqZQ9sVNBomg4r0W/Nc 61CQzvM5TpmwOVXnI6cXz++P079js300Qy4oAG/q6luchyPWBUk1vujCnXP3iRh4 PvkUjdU0H7SbYYAd/LEFpwqv29go9dz6BLEoAB1P33XdOfAdXPGmtqQv3oFzXs91 5vfrkJBSvxVChwOphWJf =A8Vc -----END PGP SIGNATURE----- --MnLPg7ZWsaic7Fhd--