From owner-freebsd-arm@freebsd.org Thu Mar 30 21:11:43 2017 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id BA7E3D24589 for ; Thu, 30 Mar 2017 21:11:43 +0000 (UTC) (envelope-from rj@obsigna.com) Received: from mo6-p00-ob.smtp.rzone.de (mo6-p00-ob.smtp.rzone.de [IPv6:2a01:238:20a:202:5300::7]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "*.smtp.rzone.de", Issuer "TeleSec ServerPass DE-2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 55918320 for ; Thu, 30 Mar 2017 21:11:42 +0000 (UTC) (envelope-from rj@obsigna.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; t=1490908299; l=2022; s=domk; d=obsigna.com; h=To:References:Content-Transfer-Encoding:Date:In-Reply-To:From: Subject:Mime-Version:Content-Type; bh=sigTRtfhSQMPHAYJQEUduFKiR1OKgWaJPRg1mQFWKEQ=; b=dkNFygDvNl1sEiiOr4BM7RJG6MD+oCd9fcFO1CSgWKUKN2X9x0iCMgeVUtpFhrto5+ Q4PZbGGFyMPWd19Du2WFkcV1W0NOgeuv7B35goVMK4fWdO75z9pls6CKT+coU9pSVJ9V DG0bGO1jakk896h2VNqXtU6eMjAopx0BMvH6c= X-RZG-AUTH: :O2kGeEG7b/pS1EK7WHa0hxqKZr4lnx6UhT0M0o35iAdWtoM07Gt3wQHFGh0i99LiI4M= X-RZG-CLASS-ID: mo00 Received: from mail.obsigna.com (bb02b5db.virtua.com.br [187.2.181.219]) by smtp.strato.de (RZmta 40.4 DYNA|AUTH) with ESMTPSA id 60bc88t2ULBcPHf (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (curve secp521r1 with 521 ECDH bits, eq. 15360 bits RSA)) (Client did not present a certificate) for ; Thu, 30 Mar 2017 23:11:38 +0200 (CEST) Received: from rolf.projectworld.net (rolf.projectworld.net [192.168.222.15]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mail.obsigna.com (Postfix) with ESMTPSA id 7F3ED7506DAD for ; Thu, 30 Mar 2017 18:11:35 -0300 (BRT) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Subject: Re: Enabling ADC on a Beaglebone Black running FreeBSD 12.0-CURRENT (BEAGLEBONE) From: "Dr. Rolf Jansen" In-Reply-To: <20170330202858.GA22253@bluezbox.com> Date: Thu, 30 Mar 2017 18:11:33 -0300 Content-Transfer-Encoding: quoted-printable Message-Id: <79EE9798-BCF0-4585-93F5-4E604142561F@obsigna.com> References: <0C4DCBB9-2642-4B0F-B15B-4139D5D8B249@obsigna.com> <271AFD8F-BD2C-445C-AB95-D7D07593E487@obsigna.com> <5D2FEB0D-64F3-488C-8458-85E7DF10EFB7@obsigna.com> <20170330202858.GA22253@bluezbox.com> To: freebsd-arm@FreeBSD.org X-Mailer: Apple Mail (2.1878.6) X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 30 Mar 2017 21:11:43 -0000 Am 30.03.2017 um 17:28 schrieb Oleksandr Tymoshenko = : > Dr. Rolf Jansen (rj@obsigna.com) wrote: >> Today I updated once again my Beaglebone Black by >> merging-in the latest FreeBSD 12.0-CURRENT (BEAGLEBONE) >> snapshot, and once again I enabled the ADCs on the >> Beaglebone in the device tree blob am335x-boneblack.dtb, >> and the ADC is still working fine. >>=20 >> Even if it is not that a big hassle to modify the device >> tree blob, I am curious on why the ADC has been disabled >> in the blob in the first place, end even more, given the >> fact that the device ti_adc driver is built-in to kernel >> and once enabled, the ADC is functional. >>=20 >> Didn't it work at some time in the past? Now it is. >>=20 >> What is missing to activate the ADC in the device tree >> blob by default? >=20 > Few months ago FreeBSD switched to using upstream DTB files > instead of custom-made ones. For some reason ADC is disabled > in upstream. If you're running recent FreeBSD you can use > dtb overlays to enable ADC without hassle of maintaining > custom dts file. You can do following: >=20 > 1. Create am335x-beaglebone-tscadc.dts with following > content: >=20 > /dts-v1/; > /plugin/; >=20 > / { > compatible =3D "ti,am335x-bone-green", "ti,am335x-bone-black", = "ti,am335x-bone", "ti,am33xx"; >=20 > fragment@0 { > target =3D <&tscadc>; > __overlay__ { > status =3D "okay"; > adc { > ti,adc-channels =3D <0 1 2 3 4 5 6>; > }; > }; > }; > }; >=20 > 2. Compile overlay: > $ dtc -I dts -O dtb -o am335x-beaglebone-tscadc.dtbo = am335x-beaglebone-tscadc.dts >=20 > 3. Copy it to /boot/dtb/ directory on your BBB >=20 > 4. Enable overlay in /boot/loader.conf by adding following line: >=20 > fdt_overlays=3D"am335x-beaglebone-tscadc.dtbo" Oleksandr, thank you very much for drawing my attention to the dtb = overlay facility. I created and enabled the adc-dtb-overlay file as you explained above, = and it works. Best regards Rolf