From owner-freebsd-arm@freebsd.org Tue Jun 2 15:08:46 2020 Return-Path: Delivered-To: freebsd-arm@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 92E8C2F1A35 for ; Tue, 2 Jun 2020 15:08:46 +0000 (UTC) (envelope-from oskar.holmlund@yahoo.com) Received: from sonic307-54.consmr.mail.ir2.yahoo.com (sonic307-54.consmr.mail.ir2.yahoo.com [87.248.110.31]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 49bwRJ0T31z44ww for ; Tue, 2 Jun 2020 15:08:43 +0000 (UTC) (envelope-from oskar.holmlund@yahoo.com) X-YMail-OSG: Z8.jKQ0VM1lkq_hsbFOtjJhO_Zlcm7cBwE2ke48Aw1b3cORBS.gEsegNJ4DfiAP uoLP8Mb8Ke3EsYB.meohjd5dQ1MWJNv7zqQddDGVFWQDDtxu3v731zLe4Czw.0OtP4Vx0eLrw.QN YHhkalAy5MyZ.wGS_.IcNIbaiFYoXxsBasTPeFqE0vVIsw_P8EQtGYMKski9CwSfzt3SxLJQ2ixO rVJwt4tf1vpDZ55.4_Z1GrgbtZOBo0uFXkC3xt4ydI_gyYxmYZ32aZIEl7UuO2Osk1tss6G6R4ui mvGRIgab9b.rVzS7jgYRNhSBstlxjtMwWcTkWKU8Lhinog_woBLpenx_0ITtpBsxlwCVDlZSv6fj UUI7mmUJ1Ld7QYpPmul4r4oxd6u1Bv.DfnhQpRb4kI1EwGORjTwxFnLSw5ZUiTcF4eBoOX5id4hd yWT8JGuhLVaayxqg0OuUIXp_Vfyg7jnge7nKLx99_PU0N9f3r8eUMf9MqHMqfPRtvdfB7DzRZBqS howfRndwN9QX77nbcYMFgkJpXtq48kRX1gcL78s8R54NimaKS1DCg1Imewimz2eymzDDVkt2Deon AX.MFHYjip1VZ8520uwghwEGvlvnPW5p3FKEAY7cx3SOBS..Yk_vwTXw1Pt26_ciB4D2SMsKlVU1 Q3OJbBQnx0TqomLvq_X5i5fUT7tDvjpnsJ2WM6rg4DPaDvDYY_H2YoLJJhXOlUKjbG7Q_gBh8Cmw 6SEWNe2DqFSXVkxuyAS7WihOy5kUY6Am7bToVXmJQ_LedsLyKwPabPlOcGKb1zF0WOnsP4r.byTt KcyVd_aARAKOunE4vi_YPrHW4EbNTe5jRWEqgI2lfI5rEIBSGwuT_nj6uOBVZpUR_OTUx7n8Eevr 3WOQl3yqT86yCsPBTMtVTWBXDIcn0aRE5k95kDlob7gvZE89oTCTrbC2kHG39wljrRP_pOpWqAuN 0YkXMesmlIFhRrPwejFcAwXUV1s3z49FoI2Zw08DEvcqwge.5EmExLv3bBwwkSX559IJWnWeK3gS q.2kmX38BUOeqK3ykvozKM.KQmm7V7vJUsVXGTXNJF6IiTpy2NFlmFhJfxhPvPvfKtbTbbtEEMLj MhEQOYZ47NplHD1YinazcRBlA1jfxPNlmqcOg5N8V3b4Cq2lvC3dda1Qfmk_lxNrC1vlhBIFgQ9D bJIAIvODmbM0CAwwIr8nltEliDDiolvL0ukiZRwG8TpUjJyhoCittC.wE5hIK0ZawKt9jFywo4Ny PJuWkc.uMq64P0tgqQJS6dBICj5nnYuop8LCYHksmSkMjTP2QIU0NfFTOpQ-- Received: from sonic.gate.mail.ne1.yahoo.com by sonic307.consmr.mail.ir2.yahoo.com with HTTP; Tue, 2 Jun 2020 15:08:41 +0000 Date: Tue, 2 Jun 2020 15:08:38 +0000 (UTC) From: Oskar Holmlund To: Ian Lepore , "Dr. Rolf Jansen" Cc: freebsd-arm@freebsd.org Message-ID: <479317334.2616392.1591110518765@mail.yahoo.com> In-Reply-To: <5299B3F7-1C95-4769-9701-F13699FE355C@cyclaero.com> References: <966c33ea1924c2cfab5d9e295a9239d134e03f8a.camel@freebsd.org> <3CA84BA5-FEA8-4BD8-A713-C794139170EE@cyclaero.com> <840faedfcf7c3c09a372cf566acddd8ad876ff2b.camel@freebsd.org> <5299B3F7-1C95-4769-9701-F13699FE355C@cyclaero.com> Subject: Re: BeagleBone AI MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Mailer: WebService/1.1.16037 YMailNorrin Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:76.0) Gecko/20100101 Firefox/76.0 X-Rspamd-Queue-Id: 49bwRJ0T31z44ww X-Spamd-Bar: --- X-Spamd-Result: default: False [-3.62 / 15.00]; RCVD_TLS_LAST(0.00)[]; ARC_NA(0.00)[]; R_DKIM_ALLOW(-0.20)[yahoo.com:s=s2048]; RWL_MAILSPIKE_POSSIBLE(0.00)[87.248.110.31:from]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[3]; FREEMAIL_FROM(0.00)[yahoo.com]; R_SPF_ALLOW(-0.20)[+ptr:yahoo.com]; MIME_GOOD(-0.10)[text/plain]; NEURAL_HAM_LONG(-1.01)[-1.008]; TO_DN_SOME(0.00)[]; TO_MATCH_ENVRCPT_SOME(0.00)[]; DKIM_TRACE(0.00)[yahoo.com:+]; DMARC_POLICY_ALLOW(-0.50)[yahoo.com,reject]; RCVD_IN_DNSWL_NONE(0.00)[87.248.110.31:from]; NEURAL_HAM_SHORT(-0.61)[-0.610]; NEURAL_HAM_MEDIUM(-1.01)[-1.006]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; FREEMAIL_ENVFROM(0.00)[yahoo.com]; ASN(0.00)[asn:34010, ipnet:87.248.110.0/24, country:GB]; RCVD_COUNT_TWO(0.00)[2]; DWL_DNSWL_NONE(0.00)[yahoo.com:dkim] X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.33 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 02 Jun 2020 15:08:46 -0000 Den tisdag 2 juni 2020 16:56:02 CEST, Dr. Rolf Jansen skrev:=20 > Am 02.06.2020 um 10:49 schrieb Ian Lepore : >=20 > On Sun, 2020-05-31 at 16:56 -0300, Dr. Rolf Jansen wrote: >>> Am 31.05.2020 um 14:11 schrieb Ian Lepore : >>>=20 >>> On Fri, 2020-05-29 at 23:21 -0300, Dr. Rolf Jansen wrote: >>>> ... >>>>=20 >>>> First Question: >>>>=20 >>>> What modern SBC with more than 1 I=C2=B2C bus and which can run >>>> FreeBSD 13++ would you suggest? >>>>=20 >>>> ... >>>>=20 >>>> Two more Questions: >>>>=20 >>>> Is it reasonable to assume that FreeBSD would run on a BBAI in >>>> the future, let=C2=B4s say in 2 to 3 years? >>>>=20 >>>> Perhaps I could help porting FreeBSD to a BBAI. What would be the >>>> general steps? >>>>=20 >>>>=20 >>>> Many thanks in advance for any suggestions, advices and >>>> clarifications. >>>>=20 >>>> Best regards >>>>=20 >>>> Rolf >>>=20 >>> BTW, if you need drivers for any new i2c devices just let me know >>> and >>> I'll see what I can do. >>=20 >> I am pretty comfortable with register level programming, and so far I >> came away with ioctl() calls for what I needed. So perhaps I won=C2=B4t >> need exactly a driver for new I=C2=B2C devices. However, I am far away >> from being a perfect I=C2=B2C expert, specially when it comes to timing >> and the best sequence of addressing different devices on the bus. >> Perhaps, I may ask some questions when I run into problems. >>=20 >>> Also, in my experience you can often get away with running an i2c >>> bus >>> faster than 400khz if you need more bandwidth.=C2=A0 I've never seen an= y >>> modern chip fail to work at 800khz, and most seem to work fine up >>> to >>> about 1mhz; above that they become pretty unreliable. >>=20 >> Does this =E2=80=9Eover clocking=E2=80=9C work for the ARM boards as wel= l? I just set >> the clock-frequency in the dts-overlay which activates I2C1 of the >> BBB from 400000 to 800000. The bus seems to work as usual, however, I >> did not yet come to check its speed. How again would I do that? >> Probably there are many more questions to come :-) >>=20 >> Best regards >>=20 >> Rolf >=20 > I suspect it works on some boards and maybe won't work on others.=C2=A0 S= ome > SOCs have very flexible clock settings in their i2c controllers, a few > just allow choosing between fixed low and high speeds. >=20 > For experimenting, there is a sysctl dev.iicbus.#.frequency that you > can change on the fly (it will override any value from the dts).=C2=A0 Th= e > value is the frequency in hz. >=20 > -- Ian Thank you very much for your response. I checked the sysctl setting, and th= e system accepts the values. The bus works at 800000, however, I can set it= as high as 10000000 (10 MHz) and it is still working. Perhaps, there is so= me sort of internal validation before the frequency value is actually appli= ed to the HW. In the moment this is more a matter of curiosity than an actu= al need. Once we equipped the bus with all I=C2=B2C devices, we will perhap= s run into some timing issues, and then I probably want to revisit changing= the clock frequency again. Best reagrds Rolf _______________________________________________ freebsd-arm@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/freebsd-arm To unsubscribe, send any mail to "freebsd-arm-unsubscribe@freebsd.org" Expect no more than 1MHz https://svnweb.freebsd.org/base/head/sys/arm/ti/ti_i2c.c?revision=3D355727&= view=3Dmarkup Line 127+ //Oskar