From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 15EEEC54E71 for ; Tue, 19 Mar 2024 18:20:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:Content-Type: List-Subscribe:List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id: In-Reply-To:MIME-Version:References:Message-ID:Subject:Cc:To:From:Date: Reply-To:Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date :Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=RfMwwwx6hl41dCUykMzBIo+jIgsUngPePfcU/EsBO9c=; b=2CYILHnUCRhayBonrJG2KtyssK 4FQF7hY4P3WjQEpoDRBzb8Rszckgrg4QzziaynVqb0HIe214sekmrOxuIb/1MFE6e7nzRHprTOORr dwfUAP0RxhDJOz6WJ9dhP8saXvXDKBRCjg3r0HYpdT7AlS9GGpZqppDlCAP5Shunrra1twuK2Gnyv HNUldvQulTh3TiGNR1SLy7T3gojMLXLb5eRJxy4Va5euxDcA/cjwV84/bVI+tBmIBzwXmAOV9jXe5 KCdJxUIE+o7iGJqaiouNp1QoFfqrdh7+JuxzylTcNbpGD1c8UkNI0xP0sWe+yxXJiWLRBktohcVrJ d6l9Az2Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rme47-0000000Dn3x-0JL1; Tue, 19 Mar 2024 18:19:59 +0000 Received: from sin.source.kernel.org ([2604:1380:40e1:4800::1]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rme43-0000000Dn2w-406n for linux-arm-kernel@lists.infradead.org; Tue, 19 Mar 2024 18:19:57 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id 02E6BCE0E4D; Tue, 19 Mar 2024 18:19:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5C136C433F1; Tue, 19 Mar 2024 18:19:48 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1710872393; bh=3jFdWHzKsF4y+RWYftyOChp9wyRVR2+1Jyzao9J/muI=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=nIEJ0skmTErXlhq63YSN5D57OCqU1RustN5tR4EY1/pK52948kRylXXe5xxfzTPbH BjBos5iV4bPo1FZlPqqzPo+Rfla3coQYbo7pCIeO5sCPqrbMRoOltMvSCUhUdB4VZo j0VsMBuKSHlQUf+d92El+tTVlv3sBBgOtNSX53Nx4nTGTWGwI6a6rHCyJM0S2fEu8T DzLCIn1d2hKJiMGD5pxOBXOvmZhJJ70ybh99rTx1CAAhIfNoYW91N30PR4o00qUT0l MJASIDi/MoTuMVINpHRJJIRAiZeqGSRG8a+amK1N5Fz1ntTqwHpf6N5pKVBCeMZauf cru8w/ccdu6YA== Date: Tue, 19 Mar 2024 18:19:46 +0000 From: Conor Dooley To: Vaishnav Achath Cc: Andrew Lunn , Ayush Singh , Michael Walle , open list , jkridner@beagleboard.org, robertcnelson@beagleboard.org, lorforlinux@beagleboard.org, Rob Herring , Krzysztof Kozlowski , Conor Dooley , Nishanth Menon , Vignesh Raghavendra , Tero Kristo , Derek Kiernan , Dragan Cvetic , Arnd Bergmann , Greg Kroah-Hartman , Mark Brown , Johan Hovold , Alex Elder , "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" , "moderated list:ARM/TEXAS INSTRUMENTS K3 ARCHITECTURE" , "open list:SPI SUBSYSTEM" , "moderated list:GREYBUS SUBSYSTEM" , Vaishnav M A Subject: Re: [PATCH v4 1/5] dt-bindings: misc: Add mikrobus-connector Message-ID: <20240319-unmoral-map-3ab9a467b637@spud> References: <20240317193714.403132-1-ayushdevel1325@gmail.com> <20240317193714.403132-2-ayushdevel1325@gmail.com> <4b319264-bff7-48e5-85e8-201ca0bafec6@ti.com> MIME-Version: 1.0 In-Reply-To: <4b319264-bff7-48e5-85e8-201ca0bafec6@ti.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240319_111956_493321_7FBEA741 X-CRM114-Status: GOOD ( 33.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: multipart/mixed; boundary="===============6890445816447621433==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============6890445816447621433== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="/GzH6Gz2jpHyJQ0B" Content-Disposition: inline --/GzH6Gz2jpHyJQ0B Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Mar 19, 2024 at 11:05:37PM +0530, Vaishnav Achath wrote: > Hi Andrew, >=20 > On 19/03/24 17:55, Andrew Lunn wrote: > > > The device tree defines the SPI controller associated with mikroBUS S= PI > > > pins. The driver on match queries and takes a reference to the SPI > > > controller but does nothing with it. Once a mikroBUS add-on board is > > > detected (by passing manifest using sysfs or reading from 1-wire EEPR= OM), > > > the driver parses the manifest, and if it detects an SPI device in ma= nifest, > > > it registers SPI device along with setting properties such as `chip_s= elect`, > > > `max_speed_hz`, `mode`, etc., > >=20 > > How complex can the description of the hardware be in the manifest? > >=20 > > Could i describe an SPI to I2C converter? And then a few temperature > > sensors, a fan controller, and a GPIO controller on that I2C bus? And > > the GPIO controller is then used for LEDs and a push button? DT > > overlays could describe that. Can the manifest? >=20 > No, it cannot describe such complex hardware, it can only describe simple > devices (sensors/displays .etc) on a standard mikroBUS add-on board, we d= id > a analysis on what mikroBUS add-on boards have driver support in Linux and > then noticed that most devices does not need this kind of complex > description to work: > https://elinux.org/MikroEClicks_with_Linux_Support What happens to the devices that fall outside of the "do not need a complex description" category? Do you expect that those would be described by a dt overlay? > The greybus manifest already is being used in the greybus susbystem for > describing an interface and there are already greybus controllers (SPI/I2C > .etc) being created according to the manifest contents, all this driver d= oes > is to extend that format to be able to instantiate devices on these buses. > The primary goals for introducing the driver for mikroBUS add-on boards a= re: >=20 > 1) A way to isolate platform specific information from add-on board speci= fic > information - so that each permutation of connecting the add-on board on > different ports on different board does not require a new overlay. > 2) A way to instantiate add-on boards on greybus created virtual mikroBUS > ports. > 3) Both 1 and 2 should use the same add-on board description format. >=20 > Standard device tree overlays did not help to achieve this and that is why > the standard interface discovery mechanism in greybus, the manifest was > extended even though it is not the most optimal way to describe hardware. >=20 > The greybus manifest extensions were made with the following things in mi= nd > and three new descriptor were introduced: > 1) mikrobus descriptor - pinmux/port state > 2) device descriptor - contains information which is a superset of struct > i2c_board_info , struct spi_board_info .etc > 3) property descriptor - to describe named properties of the types defined > under https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/= tree/include/linux/property.h#n22 >=20 > With these we were able to test around 150 add-on boards with correspondi= ng > drivers in Linux : > https://github.com/MikroElektronika/click_id/tree/main/manifests >=20 > The mechanism is not as robust a device tree and should not be compared, = the Why not? You're suggesting this as a method for describing devices and you seem to have extended the manifest to support more complex properties, why shouldn't someone question make that comparison? > intent was not to create a new hardware description format, but extend the > existing greybus manifest format to be able to instantiate devices on the > greybus SPI/I2C/GPIO/ (mikroBUS) --/GzH6Gz2jpHyJQ0B Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZfnXQgAKCRB4tDGHoIJi 0lYUAQC/cgPzxALFqs+2IGb37vdqN7kxtVGjYyGIxb1QrovmNQD/QGS0RjLRgZ8r Hi1rcx/ebRKdF7MmNmQ+2gyZuq/qyQE= =bX43 -----END PGP SIGNATURE----- --/GzH6Gz2jpHyJQ0B-- --===============6890445816447621433== 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 --===============6890445816447621433==--