From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Brown Subject: Re: [PATCH] ASoC: tlv320aic31xx: Add MICBIAS off setting Date: Tue, 4 Sep 2018 16:56:55 +0100 Message-ID: <20180904155655.GJ12993@sirena.org.uk> References: <20180831180507.28867-1-afd@ti.com> <20180903112656.GF10302@sirena.org.uk> <701a066c-33e1-4476-7403-fdb9a3c366d8@ti.com> <20180904144159.GC12993@sirena.org.uk> <7163381a-ae09-ad3b-064d-990c98f13ccb@ti.com> <20180904145503.GD12993@sirena.org.uk> <85973bf4-1acb-1731-d93e-29c8141a3c53@ti.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="fU0UwhtRbpo05rnG" Return-path: Content-Disposition: inline In-Reply-To: <85973bf4-1acb-1731-d93e-29c8141a3c53@ti.com> Sender: linux-kernel-owner@vger.kernel.org To: "Andrew F. Davis" Cc: Liam Girdwood , Rob Herring , Mark Rutland , alsa-devel@alsa-project.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: alsa-devel@alsa-project.org --fU0UwhtRbpo05rnG Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Sep 04, 2018 at 10:10:24AM -0500, Andrew F. Davis wrote: > On 09/04/2018 09:55 AM, Mark Brown wrote: > > you get to keep the pieces" territory. If we really want to have a way > > of explicitly specifying that some widgets should never be turned on > > then it feels like rather than have something device and widget specific > > like this we should instead have a higher level way of doing that which > > can be applied to any widget, that is something that could be useful > > especially with things like speaker drivers where there's real potential > > for physical damage to the system. > Not sure how that could even look, it would need to be in DT as only > that layer knows the connections, but then the it would also have to > have internal knowledge of the widgets used in the driver.. We already have a bunch of DT code that knows about and uses the external widgets the device has (which are I'd guess the only ones where this is an issue)? I was thinking just have a property that lists the widgets that should never be turned on. > > Like I said in my original reply I'm also worried that this will break > > existing boards by causing them to change to a voltage of 0 when they > > had managed to end up with the default of 2V which happened to work for > > them. > Then only time this could happen is if they specified MICBIAS_OFF in DT > but got the default 2v instead. In which case, yes, the behavior would > change, but it would also be changing to the correct behavior. We can't > avoid fixing code on the off chance someone depended on the broken > behavior, no progress could ever be made. I'm really having a lot of trouble seeing MICBIAS_OFF as a useful voltage to specify in DT in the first place. --fU0UwhtRbpo05rnG Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAluOq0YACgkQJNaLcl1U h9CuhAf/dmux31fp+cI7rFVG+vbv4eJGv2tb02jeXVb0zMA4sOMbcdVzSDdFEkDj uczuKt63JFcvR/6VsoRhbVy7p1KgGLWH3eswLIPJLltgkMBpXlxzZWck7FpRHswH JWYa2kYtkygvORR4YNdtSzQWkbDCbhmGkSNriGKJo4tfkY+PLJCLjLohHynktlYt +Gon0wLd96yTMWWD8UJo9uJCDBdmXefqTd07IKuUFkQYNJThcBIzkSG2COO98VZD JvvtK97wm4SQW5ZQVNrRrCDB/h6jUrSjZxtqtBLswKYrOQNxbbe4e8tH0Q4aqQCO 4dzcmmQQ0rRNFpaeu5toGpTPycy7ew== =Ry/6 -----END PGP SIGNATURE----- --fU0UwhtRbpo05rnG--