From owner-freebsd-arm@freebsd.org Fri Jun 7 15:22:37 2019 Return-Path: Delivered-To: freebsd-arm@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id C333B15AFB7B for ; Fri, 7 Jun 2019 15:22:36 +0000 (UTC) (envelope-from manu@bidouilliste.com) Received: from mail.blih.net (mail.blih.net [212.83.177.182]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "mail.blih.net", Issuer "mail.blih.net" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id E679776926; Fri, 7 Jun 2019 15:22:35 +0000 (UTC) (envelope-from manu@bidouilliste.com) Received: from mail.blih.net (mail.blih.net [212.83.177.182]) by mail.blih.net (OpenSMTPD) with ESMTP id 6210089f; Fri, 7 Jun 2019 17:22:33 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=bidouilliste.com; h=date :from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-type:content-transfer-encoding; s=mail; bh=3Me6U3c9EbTLzi9HhhIIDMMXfsY=; b=CgIymgbU/RiXn0WG1bnd5hqnNyNr iJzw25raADIDuoO/SDx85JNNmXrYVk8Pcl7a2HXqtpcALWOePGKvte0mOta57kHl KLtf1ZFvYo8SawiBA+jZvFi2r2Q8Y4SEMrRiwFcKeC533SjqQNrzHNugQENe06vY 00yzaDxXVoLBdIE= DomainKey-Signature: a=rsa-sha1; c=nofws; d=bidouilliste.com; h=date :from:to:cc:subject:message-id:in-reply-to:references :mime-version:content-type:content-transfer-encoding; q=dns; s= mail; b=nyPMReAyVDr8Wu6X6JGiS+gM+hEYr1jHnQiUZId3u5WpxGHLKVjcWBKo QkClCb1mU/bBHd09iuZ9Naf93xHGr0AA3xiVcbwZyyNAzKQ+wtNNsr6lBmzCwwns 7SHfKNCiG2Hmll6ytYU/SwfI0dHfsV+pi7K4oDC+aO71YnAoaSA= Received: from knuckles.blih.net (ip-9.net-89-3-105.rev.numericable.fr [89.3.105.9]) by mail.blih.net (OpenSMTPD) with ESMTPSA id 4a386bf4 TLS version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO; Fri, 7 Jun 2019 17:22:33 +0200 (CEST) Date: Fri, 7 Jun 2019 17:22:32 +0200 From: Emmanuel Vadot To: Warner Losh Cc: Ian Lepore , nmingott@gmail.com, "freebsd-arm@freebsd.org" Subject: Re: How to set PWM tunable name to ehrpwm.1 ? Message-Id: <20190607172232.c2fdc70e6ee8ef4dd5d70fa3@bidouilliste.com> In-Reply-To: References: <68790975-a5a5-2138-ca89-117878d6cf2d@gmail.com> <20190606220639.GE13546@eldorado> <8126fa4ae0ca650ca12f28dd538e6e8c4e81b432.camel@freebsd.org> <2852b9da-e647-69a7-3218-88cfa500eadc@gmail.com> <20190607171001.636efb2598ab9c88635973b6@bidouilliste.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.32; amd64-portbld-freebsd13.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: E679776926 X-Spamd-Bar: ++ Authentication-Results: mx1.freebsd.org; dkim=pass header.d=bidouilliste.com header.s=mail header.b=CgIymgbU; spf=pass (mx1.freebsd.org: domain of manu@bidouilliste.com designates 212.83.177.182 as permitted sender) smtp.mailfrom=manu@bidouilliste.com X-Spamd-Result: default: False [2.15 / 15.00]; ARC_NA(0.00)[]; TO_DN_EQ_ADDR_SOME(0.00)[]; R_DKIM_ALLOW(-0.20)[bidouilliste.com:s=mail]; RCVD_VIA_SMTP_AUTH(0.00)[]; FROM_HAS_DN(0.00)[]; RCPT_COUNT_THREE(0.00)[4]; R_SPF_ALLOW(-0.20)[+ip4:212.83.177.182/32]; MV_CASE(0.50)[]; MIME_GOOD(-0.10)[text/plain]; DMARC_NA(0.00)[bidouilliste.com]; TO_DN_SOME(0.00)[]; NEURAL_SPAM_MEDIUM(0.02)[0.016,0]; TO_MATCH_ENVRCPT_SOME(0.00)[]; NEURAL_SPAM_SHORT(0.60)[0.600,0]; DKIM_TRACE(0.00)[bidouilliste.com:+]; MX_GOOD(-0.01)[cached: mx-backup.blih.net]; NEURAL_SPAM_LONG(0.15)[0.152,0]; IP_SCORE(0.29)[ip: (-1.16), ipnet: 212.83.160.0/19(2.86), asn: 12876(-0.23), country: FR(-0.01)]; RCVD_NO_TLS_LAST(0.10)[]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; SUBJECT_ENDS_QUESTION(1.00)[]; ASN(0.00)[asn:12876, ipnet:212.83.160.0/19, country:FR]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-arm@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Porting FreeBSD to ARM processors." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 07 Jun 2019 15:22:37 -0000 On Fri, 7 Jun 2019 09:17:01 -0600 Warner Losh wrote: > On Fri, Jun 7, 2019 at 9:11 AM Emmanuel Vadot wrote: > > > On Fri, 07 Jun 2019 08:58:49 -0600 > > Ian Lepore wrote: > > > > > On Fri, 2019-06-07 at 02:08 -0700, Nicola Mingotti wrote: > > > > > > > > On 6/6/19 3:40 PM, Ian Lepore wrote: > > > > > On Thu, 2019-06-06 at 16:06 -0600, Sergey Manucharian wrote: > > > > > > Excerpts from Nicola Mingotti's message from Thu 06-Jun-19 12:33: > > > > > > > In my BeagleBone Black, FreeBSD-12 RELEASE, i created two > > > > > > > overlays, > > > > > > > pwm.dtso and pwm1.dtso. They enable the PWM pins p9.21, p9.22 > > > > > > > and > > > > > > > respectively p9.14, p9.16. DTSO files are below. > > > > > > > > > > > > > > If I load both the DTBO at boot I see > > > > > > > correctly|ehrpwm.0|and|ehrpwm.1|, > > > > > > > associated to the correct pins. But, if i remove the > > > > > > > overlay|pwm.dtbo|then i seen only|ehrpwm.0|in|sysctl -a|, which > > > > > > > is > > > > > > > not > > > > > > > what i want, i would like to see the name|ehrpwm.1|. > > > > > > > > > > > > > > This is important because i must be 100% sure a certain pin > > > > > > > corresponds > > > > > > > the a certain tunable.This must be true even if i remove non > > > > > > > relevant > > > > > > > overlays in the future. I guess there must be some parameter in > > > > > > > the > > > > > > > DTSO > > > > > > > which i don't know, i hope you can give me some directions > > > > > > > about > > > > > > > that. > > > > > > > > > > > > It is not related to your DTBO's. That's how everything works (at > > > > > > least > > > > > > by default). You will see the same naming issue with serial > > > > > > ports, > > > > > > for > > > > > > example. And not just in BBB. > > > > > > > > > > > > E.g. when I have enabled uart0 and uart2 they are named ttyu0 and > > > > > > ttyu1, > > > > > > if I have only uart2, it becomes ttyu0. > > > > > > > > > > > > It's easier if there is a device node in /dev, so you can create > > > > > > a > > > > > > symlink > > > > > > with a fixed name (I have a script called by devd for my multiple > > > > > > serial > > > > > > ports). However, that's not the case with PWM... > > > > > > > > > > > > Maybe there is an option to use persistent names for devices that > > > > > > somebody > > > > > > can point to. > > > > > > > > > > > > > > > > Nope, there's no magic thing you're missing that fixes > > > > > this. Devices > > > > > get named-and-numbered based on the order of instantiation. > > > > > > > > > > Since what really matters here is the sysctl names, we could change > > > > > the > > > > > driver to install the sysctl nodes using the fdt device node names > > > > > instead of the freebsd newbus device names. Hmm, actually, since > > > > > people may be relying on the current names, I guess what we'd have > > > > > to > > > > > do is install another set of sysctl names based on fdt name > > > > > (basically > > > > > a set of alias names). > > > > > > > > > > -- Ian > > > > > > > > > > > > > I see, I agree changing the default naming scheme may damage who is > > > > relaying on it. It is not a good idea. Maybe it could be implemented > > > > in > > > > release 13. > > > > > > > > To Sergey. I used devd in the past, it works well. But i would > > > > prefer > > > > not to use it in this case, even if I had a /dev/xyz file available. > > > > The > > > > reason is that the /dev/xyz file would appear before the the devd > > > > daemon > > > > starts up (i guess), so the case would not stricly be covered by > > > > what > > > > the devd man page says devd should do. > > > > $> man devd > > > > => " ... Whenever a device is added to or removed from the device > > > > tree ... " > > > > > > > > To Ian. The idea of the alias seems good. I don't know at all what > > > > you > > > > can manage to do at the kernel level with the tunables. I imagine > > > > something like |dev.alias.am335x_ehrpwm.1| which actually refers to > > > > > EHRPWM1| not the second |ehrpwm| that got plugged into the system > > > > > via > > > > > > > > overlay. > > > > > > > > Thank you for your answers > > > > > > > > > > > > > > The dev.* hierarchy is managed by newbus; what I was picturing was > > > something like hw.ehrpwm1.freq and so on, settable as either tunable or > > > sysctl. But it turns out ehrpwm1 is just a label in the dts, not > > > accessible at runtime. The actual node name is just 'pwm' and really, > > > nothing prevents upstream from changing that name on a whim next time > > > we import new dts files. (And linux sure seems to have a lot of > > > arbitrary whims when it comes to changing dts.) > > > > Relying on the name is clearly not a good idea, especially for TI > > since they change stuff A LOT. > > > > > Since an overlay is required to use this stuff anyway, I'm now thinking > > > a custom property in the overlay that names the sysctl nodes might be a > > > good option. So you'd add a property like: > > > > > > &ehrpwm0 { > > > status = "okay"; > > > pinctrl-names = "default"; > > > pinctrl-0 = <&ehrpwm0_AB_pins>; > > > freebsd,sysctl = "backlight"; > > > }; > > > > > > And that would make it install names like hw.backlight.freq and > > > hw.backlight.period and so on. If you don't add that property, it just > > > installs the names it uses now (dev.ehrpwm.*) for compatibility. > > > > > > -- Ian > > > > What would be better is to add support to the pwm(9) api for this > > driver and make the api and pwm(8) using the "pwm-names" property which > > is a standard one from the bindings. > > > > For this specific case, I think that's great. I'd go farther than say we > should have the FDT/OFW node name, if any, associated with something like > dev...node_name. > > Warner I like that idea too, I'll look at it this weekend, that should not be hard to do. -- Emmanuel Vadot