From mboxrd@z Thu Jan 1 00:00:00 1970 From: Maxime Ripard Subject: Re: [PATCH RFC] arm64: dts: allwinner: a64: teres-i: Enable audio Date: Mon, 18 Feb 2019 11:24:42 +0100 Message-ID: <20190218102442.l3br2h3oqfe2atdv@flea> References: <20190212083850.7genwc6ipnxtl7eo@flea> <20190212100929.iqsxu443qrkl6myf@flea> <20190213094442.da2dy6d5bb527nft@flea> <20190213155311.ovkpim3lxwyvuhhj@flea> <20190215142029.GB32618@lst.de> Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============2050964039732922955==" Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Harald Geyer Cc: Mark Rutland , devicetree@vger.kernel.org, info@olimex.com, Mark Brown , Chen-Yu Tsai , Rob Herring , Torsten Duwe , ibu@radempa.de, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org --===============2050964039732922955== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="hokxk7gwa2n735je" Content-Disposition: inline --hokxk7gwa2n735je Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Sat, Feb 16, 2019 at 09:47:13PM +0100, Harald Geyer wrote: > Hi Torsten! >=20 > Torsten Duwe writes: >=20 > > > > > > > But we need a way to control the mux from userspace and aside= from > > > > > > > unbinding the ideas proposed thus far are: > > > > > > > > > > > > > > a) control the gpio directly > > > > > > > b) control the gpio via leds-gpio > > > > > > >=20 > > > > > > > (a) was dismissed because we can't set a default from DT > > > > > > > (b) was dismissed because some rogue app might try to blink it > >=20 > > Hey, this is a debugging hack. If some rogue app tries to blink it, so = be it. > >=20 > > > I suspect some distributions will pick up the patch I posted anyway, = if > > > it doesn't get merged mainline. (This is how I forgot missing backlig= ht > > > support - it just worked for too many people ...) If we ship > > > sun50i-a64-teres-i.dts with the proper nodes (but disabled), their > > > patches will be much easier to maintain as the official DT evolves. > >=20 > > As I wrote (held by the list admin), I consider the whole console mux > > GPIO an U-Boot hack, and would put it into sun50i-a64-teres-i-u-boot.dt= si. > > (As a LED, see above :-) >=20 > The thing is, one of the quite strict rules in kernel development is: > Never break userspace. That means: If we provide a way to userspace to > do something (ie switch between debug and audio), we are expected to > keep it around forever. So since there is a decent chance that someday > somebody might write a driver that handles this situation properly, we > don't want chain ourselves to some dirty hack. >=20 > (I'm not totally against writing such a driver myself, if there are > enough use cases. However, I think that TERES alone is not enough.) >=20 > > Would you care to submit a patch version without that GPIO handled? > > I think it's very useful and has the potential to be agreed upon. >=20 > That would enable audio from the internal speakers but select debug > output on the HP jack by default. I would be okay with that, despite > still thinking that audio on the head phones should be the default. >=20 > Maxime and Wens are the maintainers, so it's their call in the end. At this point, I'm not really convinced by the solution in that patch, but I don't have really good ideas either. I think it would be good to discuss this with Mark and Linus Walleij, they will probably have way better solutions than what I can come up with. Maxime --=20 Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com --hokxk7gwa2n735je Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRcEzekXsqa64kGDp7j7w1vZxhRxQUCXGqH6gAKCRDj7w1vZxhR xashAQDbjjYQHwqgbu1SqQX5qgkTWuLqt58lcPxbonZMhzMqJgEA5dOHZhZClyYd ea3rdkxNgaOI5DJ3GAwd3ALzXhycTwE= =n1ic -----END PGP SIGNATURE----- --hokxk7gwa2n735je-- --===============2050964039732922955== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel --===============2050964039732922955==--