From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751949AbdBMJy1 (ORCPT ); Mon, 13 Feb 2017 04:54:27 -0500 Received: from atrey.karlin.mff.cuni.cz ([195.113.26.193]:51206 "EHLO atrey.karlin.mff.cuni.cz" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751463AbdBMJyZ (ORCPT ); Mon, 13 Feb 2017 04:54:25 -0500 Date: Mon, 13 Feb 2017 10:54:20 +0100 From: Pavel Machek To: Sakari Ailus Cc: Rob Herring , "devicetree@vger.kernel.org" , Ivaylo Dimitrov , Sebastian Reichel , Pali =?iso-8859-1?Q?Roh=E1r?= , "linux-media@vger.kernel.org" , Kumar Gala , Mauro Carvalho Chehab , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] devicetree: Add video bus switch Message-ID: <20170213095420.GA7065@amd> References: <20161222100104.GA30917@amd> <20161222133938.GA30259@amd> <20161224152031.GA8420@amd> <20170203123508.GA10286@amd> <20170208213609.lnemfbzitee5iur2@rob-hp-laptop> <20170208223017.GA18807@amd> <20170210195435.GA1615@amd> <20170210221742.GI13854@valkosipuli.retiisi.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="1yeeQ81UyVL57Vl7" Content-Disposition: inline In-Reply-To: <20170210221742.GI13854@valkosipuli.retiisi.org.uk> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --1yeeQ81UyVL57Vl7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > Take a look at the wikipedia. If you do "one at a time" at 100Hz, you > > can claim it is time-domain multiplex. But we are plain switching the > > cameras. It takes second (or so) to setup the pipeline. > >=20 > > This is not multiplex. >=20 > The functionality is still the same, isn't it? Does it change what it is = if > the frequency might be 100 Hz or 0,01 Hz? Well. In your living your you can have a switch, which is switch at much less than 0.01Hz. You can also have a dimmer, which is a PWM, which is switch at 100Hz or so. So yes, I'd say switch and mux are different things. > I was a bit annoyed for having to have two drivers for switching the sour= ce > (one for GPIO, another for syscon / register), where both of the drivers > would be essentially the same with the minor exception of having a slight= ly > different means to toggle the mux setting. Well, most of the video-bus-switch is the video4linux glue. Actual switching is very very small part. So.. where is the other driver? Looks like we have the same problem. > The MUX framework adds an API for controlling the MUX. Thus we'll need on= ly > a single driver that uses the MUX framework API for V4L2. As an added bon= us, > V4L2 would be in line with the rest of the MUX usage in the kernel. >=20 > The set appears to already contain a GPIO MUX. What's needed would be to = use > the MUX API instead of direct GPIOs usage. If there's a driver that already does switching for video4linux devices? Do you have a pointer? Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --1yeeQ81UyVL57Vl7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlihgkwACgkQMOfwapXb+vKE6QCgiU3fHPC6AxTyWdxUdZygabqv 8+UAn03E4taDHUwumeZYXtg5hWQmZNoL =0MYv -----END PGP SIGNATURE----- --1yeeQ81UyVL57Vl7-- From mboxrd@z Thu Jan 1 00:00:00 1970 From: Pavel Machek Subject: Re: [PATCH] devicetree: Add video bus switch Date: Mon, 13 Feb 2017 10:54:20 +0100 Message-ID: <20170213095420.GA7065@amd> References: <20161222100104.GA30917@amd> <20161222133938.GA30259@amd> <20161224152031.GA8420@amd> <20170203123508.GA10286@amd> <20170208213609.lnemfbzitee5iur2@rob-hp-laptop> <20170208223017.GA18807@amd> <20170210195435.GA1615@amd> <20170210221742.GI13854@valkosipuli.retiisi.org.uk> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="1yeeQ81UyVL57Vl7" Return-path: Content-Disposition: inline In-Reply-To: <20170210221742.GI13854-S+BSfZ9RZZmRSg0ZkenSGLdO1Tsj/99ntUK59QYPAWc@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Sakari Ailus Cc: Rob Herring , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Ivaylo Dimitrov , Sebastian Reichel , Pali =?iso-8859-1?Q?Roh=E1r?= , "linux-media-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , Kumar Gala , Mauro Carvalho Chehab , "linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: devicetree@vger.kernel.org --1yeeQ81UyVL57Vl7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi! > > Take a look at the wikipedia. If you do "one at a time" at 100Hz, you > > can claim it is time-domain multiplex. But we are plain switching the > > cameras. It takes second (or so) to setup the pipeline. > >=20 > > This is not multiplex. >=20 > The functionality is still the same, isn't it? Does it change what it is = if > the frequency might be 100 Hz or 0,01 Hz? Well. In your living your you can have a switch, which is switch at much less than 0.01Hz. You can also have a dimmer, which is a PWM, which is switch at 100Hz or so. So yes, I'd say switch and mux are different things. > I was a bit annoyed for having to have two drivers for switching the sour= ce > (one for GPIO, another for syscon / register), where both of the drivers > would be essentially the same with the minor exception of having a slight= ly > different means to toggle the mux setting. Well, most of the video-bus-switch is the video4linux glue. Actual switching is very very small part. So.. where is the other driver? Looks like we have the same problem. > The MUX framework adds an API for controlling the MUX. Thus we'll need on= ly > a single driver that uses the MUX framework API for V4L2. As an added bon= us, > V4L2 would be in line with the rest of the MUX usage in the kernel. >=20 > The set appears to already contain a GPIO MUX. What's needed would be to = use > the MUX API instead of direct GPIOs usage. If there's a driver that already does switching for video4linux devices? Do you have a pointer? Pavel --=20 (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blo= g.html --1yeeQ81UyVL57Vl7 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iEYEARECAAYFAlihgkwACgkQMOfwapXb+vKE6QCgiU3fHPC6AxTyWdxUdZygabqv 8+UAn03E4taDHUwumeZYXtg5hWQmZNoL =0MYv -----END PGP SIGNATURE----- --1yeeQ81UyVL57Vl7-- -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html