From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH v2] of: i2c: Add idle-disconnect DT property to PCA954x mux driver Date: Thu, 15 Jan 2015 14:19:35 +0100 Message-ID: <20150115131935.GE2549@katana> References: <5494599A.8050803@nsn.com> <20150115123237.GC2549@katana> <54B7BBF5.4010001@nsn.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="FEz7ebHBGB6b2e8X" Return-path: Content-Disposition: inline In-Reply-To: <54B7BBF5.4010001-OYasijW0DpE@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Alexander Sverdlin Cc: jdelvare-l3A5Bk7waGM@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Laurent Pinchart , Rob Herring , grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, Lawnick Michael 61283229 , Maxime Ripard , Stephen Warren List-Id: devicetree@vger.kernel.org --FEz7ebHBGB6b2e8X Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jan 15, 2015 at 02:09:09PM +0100, Alexander Sverdlin wrote: > Hi Wolfram! >=20 > On 15/01/15 13:32, ext Wolfram Sang wrote: > > On Fri, Dec 19, 2014 at 06:00:10PM +0100, Alexander Sverdlin wrote: > >> of: i2c: Add idle-disconnect DT property to PCA954x mux driver > >> > >> Add idle-disconnect device tree property to PCA954x mux driver. The ne= w property > >> forces the multiplexer to disconnect child buses in idle state. This i= s used, for > >> example, when there are several multiplexers on the same bus and the d= evices on > >> the underlying buses might have same I2C addresses. > >=20 > > Basically OK. Question to DT maintainers: "idle-disconnect", > > "i2c-mux-idle-disconnect", or is there another existing binding we could > > use? > >=20 > >> At the same time old (and not used in the tree) platform data binding > >> deselect_on_exit is removed to simplify the implementation. Old bindin= g has > >> different (per-channel) semantics and doesn't fit well in the new conc= ept. > >=20 > > I'd prefer to keep it. It should be only one || more. It is not really > > in the way IMO. >=20 > It complicates the implementation 3x times :) This is part of our discuss= ion with Laurent: Does it? I don't want DT and platform_data to behave equally. I just want to keep being backwards compatible. So, I'd suggest: (pdata && pdata->modes[num].deselect_on_exit) || idle_disconnect ? pca954x_= deselect_mux : NULL); > > I'm not keen to brake out-of-tree code (if any), but may be it will be > > decided to drop this per-channel deselect_on_exit, because it's not use= d at > > least in the kernel tree... I couldn't find a user of the platform_data, at all. But removing platform_data support is a seperate patch, and deprecating platform_data is a seperate and general issue IMO. --FEz7ebHBGB6b2e8X Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUt75nAAoJEBQN5MwUoCm2yrkQAI+LPukjVgpG/uc26gv3v1TI 7QzzHkTP+/IJnL1+fkgaShhAaYnxbKSiQpwzOg9o8/c3wV+MTEx/IAwGs+Oc6Wh8 ZDiL4KUODbIVxJTY1B8fOIb7syAu3onNRbygV+ebMmD17uZtdMme6XEE7OhwNn2f P0b93k+nxLvzdImDxCTO0DxDuhnjpOS3fM+hYHUj3F0laK5/+t2D7lCwcns4sfDl 2E0fpuM934lwtdGNAAGXuuF/S2DsEJzmigUshAABZI+YF7mWCpRoIH8hvqW3Bj0w ZXPDPtyGsjcME/zQHcJDo81kb9IbXM4YJ6H+Uz5Hxiu+EGf7U6co2JqTpJfG3+kL Ab/noPPJJfAWgPL8jmNwZsDJ8xJiIEAPWDBQb20VWxNqfxF5KAjLOq70WBwOSkBW ay9sMZaFvkJcTDadPPFlNs6Opr+PBRJj8c7AFks42mzPo2blmCmOjOueKKK+gLrr R3HZYd4Rz7/dt85m4JYATTriPbw4z1xI0ltqNFWOhgkEH6gIKPN78oL1h8n0ZKg9 ncZi0PKEeR51cQauM7HX826zf3ITsjMcu23D0Y4yeF+E30j3dUE+BCBwqV4ikaNB FBd9AegPsJsm84s33NUDjnrQt4neagITRYCQjq5/lXavDiDmXd3Y8eZ/bJRkr74o fe1U4q/EN1sDE+tuakjD =XXG0 -----END PGP SIGNATURE----- --FEz7ebHBGB6b2e8X--