From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wolfram Sang Subject: Re: [PATCH] i2c / ACPI: Pick the first address if device has multiple Date: Tue, 13 Jan 2015 17:48:29 +0100 Message-ID: <20150113164829.GO7660@katana> References: <1419860928-195404-1-git-send-email-mika.westerberg@linux.intel.com> <20150113155059.GN7660@katana> <1421167477.4459.229.camel@spandruv-desktop.jf.intel.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="+nG9yj4eE4W6Oba0" Return-path: Content-Disposition: inline In-Reply-To: <1421167477.4459.229.camel-hINH/TbAiWppyMZ9rn1DP+ejPoqOX1/hEvhb3Hwu1Ks@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Srinivas Pandruvada Cc: Mika Westerberg , linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org --+nG9yj4eE4W6Oba0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jan 13, 2015 at 08:44:37AM -0800, Srinivas Pandruvada wrote: > On Tue, 2015-01-13 at 16:50 +0100, Wolfram Sang wrote:=20 > > On Mon, Dec 29, 2014 at 03:48:48PM +0200, Mika Westerberg wrote: > > > ACPI specification allows I2C devices with multiple addresses. The cu= rrent > > > implementation goes over all addresses and assigns the last one to the > > > device. This is typically not the primary address of the device. > > >=20 > > > Instead of doing that we assign the first address to the device and t= hen > > > let the driver handle rest of the addresses as it wishes. > > >=20 > > > Signed-off-by: Mika Westerberg > > > Cc: Srinivas Pandruvada > >=20 > > Yes, seems better than what we do know. But maybe taking the lowest > > address is a bit better heuristic than taking the first address? > > Not sure, though... > The problem in taking lowest is that in many cases in current devices, > the lowest address may end being 0x0C, which is reserved address for > SMBUS (ARA). This will require different handling. Unfortunately ACPI > doesn't have a way to distinguish whether SMBUS support is desired or > not.=20 > The other option is to skip all reserved addresses for SMBUS also and > then create on the lowest. Well, this makes me think that Mika's approach is probably the sanest one... --+nG9yj4eE4W6Oba0 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBAgAGBQJUtUxcAAoJEBQN5MwUoCm2h6gQAKPX2S2zYcUK/yY8tufCA2+w 5Ev4vljd7wa7hemJd8cOV0rb5tv2kEMhoU9CUqdHuIfFkLMedA7CKvQOJTlhQGnT Qe1hak/3buESfhdQxmusuEsc6D5Djac0qLgE2pKYacwokNWus6vvjW3oF9zDQm0z GsBCFwvVeWp8OrruPDIVTeBeJP1TZx+xae5gcAPUeGfLJIAaiwRN8ct6e5GE1BSS rpzFxmG9Fa/zE1YcsnKj88jTHT6GHupNu9Eib0A4P7WOZrOgWlHNgyIFzmZqAwD+ XYtMayb7dWBzLslPr5X9RueTZ36y6SHTxSMslcJbC7aIpY7JHcmHRDstxqAq6R8G cDNS4J7UUJgcexJDiU6qrpUTtehMeZzK7GUaKwhanqbckJxVQdV5QEh6qDkd6F9K QpdNhTGDtostn4zf/ZC4XwfWT+0TdX5lamyk4J2D6tX+jUu+JFqqDd6FXZLCKH3u sFlRXO3FGPJkSm8hlhlx46VgmpFRfHtyVyTuDzUp4iXvvCRlOFfPnCB7TaJIClnj MBAm56NM8aulmwEsZH7Ys2VtBegPTyShqiaG2vhg004/0B0cQpXDZCFwoSABvkso gkqMQLSReab1Xk8hDssRoIhwYksiLWiLlG5OThuJyBLbO6pdXycH4MIFde4yPRNB OrbyYrDnxirqLbweKqOf =WO18 -----END PGP SIGNATURE----- --+nG9yj4eE4W6Oba0--