From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.tq-group.com (mx1.tq-group.com [93.104.207.81]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 495011714B2; Mon, 11 Nov 2024 09:59:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=93.104.207.81 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731319157; cv=none; b=CngMn8Lki12hz5pTTbyMWuidUWFtAgWcwxnKqZpkI9u4RDpnPAqCEGUOWdV7R/UOgX13aKMZjveqleAxAkgV3JLhuWPDKRGo99G+coes0g+xRs+TzYlhuKBm1CLY2hKg6R4enXlbtwphmbEpkmaYx+TglTaVF37AiaAjk3rRjmw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1731319157; c=relaxed/simple; bh=oqchIAOV+ujAuuqGpj2VFndIG4Bf4mSoSDUOyVmgWy0=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=qFtpHfaZbJefGalnuc3qMxbyEb2JmSXdbuiyKxjygrgVWB62wx0Vt4PUAVuCdDjxOrOIIOcKJg3Ho5/pCkWi3DVZt/E7/AOJVq0YtJ5ALoaysVceBBX5ktKvJEKya56Ea29CZZKG38n40QmxT99zxqKRRyjX2RwS8sojJ5Fu1vE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ew.tq-group.com; spf=pass smtp.mailfrom=ew.tq-group.com; dkim=pass (2048-bit key) header.d=tq-group.com header.i=@tq-group.com header.b=PuCA/Y8B; dkim=fail (0-bit key) header.d=ew.tq-group.com header.i=@ew.tq-group.com header.b=K2zNtide reason="key not found in DNS"; arc=none smtp.client-ip=93.104.207.81 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=ew.tq-group.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=ew.tq-group.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=tq-group.com header.i=@tq-group.com header.b="PuCA/Y8B"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=ew.tq-group.com header.i=@ew.tq-group.com header.b="K2zNtide" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=tq-group.com; i=@tq-group.com; q=dns/txt; s=key1; t=1731319154; x=1762855154; h=message-id:subject:from:to:cc:date:in-reply-to: references:content-transfer-encoding:mime-version; bh=oqchIAOV+ujAuuqGpj2VFndIG4Bf4mSoSDUOyVmgWy0=; b=PuCA/Y8Boy6Je5SH6lPqNK7ey7Xc4gNXw5/M3mxRgFHUsqW47uRLF4Wm g5z8Sl4LQQRymaPXZKcQk53NXMGcZpq3bGyCNDgnnLYoNaKrjTXcLbH+k wd8nagAGQhrUyHAQCyDwS3BIF/Q6mFK54dQiwclVoRApW4MGdiHEnAA4q jAm1CuM6w+FT8jleelBxWAuduiC6mc2cDfpRIjt+ZSGfaimrmxc+1tO3X essB63JxJ6liRJvAONeQfWQ/XJTemih+2PSNxnJP7eyCNH6PTUazP2xt+ gY9efh+LzfB16Xrfp2QEWkTafwAuA61jlPnVrzVNpa0GmcJJnvuGFbB25 Q==; X-CSE-ConnectionGUID: bLzZoMNiTlC78uJSz6rOag== X-CSE-MsgGUID: fLtsWKQiRT+AHbmP2bbOBQ== X-IronPort-AV: E=Sophos;i="6.12,144,1728943200"; d="scan'208";a="39960460" Received: from vmailcow01.tq-net.de ([10.150.86.48]) by mx1.tq-group.com with ESMTP; 11 Nov 2024 10:59:04 +0100 X-CheckPoint: {6731D568-30-D31EDE1A-D52D6119} X-MAIL-CPID: 072718E0F89994E832C944FEBBA3E4C7_5 X-Control-Analysis: str=0001.0A682F25.6731D569.005A,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0 Received: from [127.0.0.1] (localhost [127.0.0.1]) by localhost (Mailerdaemon) with ESMTPSA id 01EFA165700; Mon, 11 Nov 2024 10:58:57 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ew.tq-group.com; s=dkim; t=1731319140; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=oqchIAOV+ujAuuqGpj2VFndIG4Bf4mSoSDUOyVmgWy0=; b=K2zNtideaFnscstKqfITpwJxPHlZA+t9kTzTL9KSiI52w4VBrqmDKo1sX/5+uHpgJMPpGi /KJV7gskuxM30VoCmQSkQEA3Ou/4t3wdza8k8GL2qQVfyBFSVPuIASlfHaIhBve4siYqcu o8Fe86VdngGAsIuOIqMy+NWrg+Ycj0tCDAMplZP8KRMjXOooVjmxHPt4QLUQF4uGR4fW33 Z0ycB9lqfIxhALVFWdHv6iNmmzcRKCGcSVEF89XxYZN35jJwpi+Wd/ExWPGdLjKRHfGagp d8XRWCbP7Zi94OJhOHMIgoXCtGZ8iWiyfwV53JxTFOQyARUUaJDOMbSWV9Qdgg== Message-ID: <068c22af19c07a7c79bb4abb0366a2505b4b1aae.camel@ew.tq-group.com> Subject: Re: [PATCH 2/5] dt-bindings: arm: ti: Add compatible for AM625-based TQMa62xx SOM family and carrier board From: Matthias Schiffer To: Conor Dooley Cc: Nishanth Menon , Vignesh Raghavendra , Tero Kristo , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Greg Kroah-Hartman , Kees Cook , Tony Luck , "Guilherme G. Piccoli" , Felipe Balbi , linux-arm-kernel@lists.infradead.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, linux-hardening@vger.kernel.org, Devarsh Thakkar , Hari Nagalla , linux@ew.tq-group.com Date: Mon, 11 Nov 2024 10:58:57 +0100 In-Reply-To: <20241106-happy-anything-46f7293f6aca@spud> References: <4f5ad877f44df35a3b2c7f336647f057c4e6377d.1730299760.git.matthias.schiffer@ew.tq-group.com> <20241104-floral-dexterous-7d3fee2ff616@spud> <20241105-tinsmith-countable-fbb51045bc98@spud> <7286141141fe4930cd2581dac7a1fb36a98e62c4.camel@ew.tq-group.com> <20241106-happy-anything-46f7293f6aca@spud> Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.44.4-0ubuntu2 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-Last-TLS-Session-Version: TLSv1.3 On Wed, 2024-11-06 at 16:40 +0000, Conor Dooley wrote: > On Wed, Nov 06, 2024 at 01:03:08PM +0100, Matthias Schiffer wrote: > > On Tue, 2024-11-05 at 18:55 +0000, Conor Dooley wrote: > > > On Tue, Nov 05, 2024 at 11:40:20AM +0100, Matthias Schiffer wrote: > > > > On Mon, 2024-11-04 at 18:47 +0000, Conor Dooley wrote: > > > > > On Mon, Nov 04, 2024 at 10:47:25AM +0100, Matthias Schiffer wrote= : > > > > > > The TQMa62xx is a SoM family with a pluggable connector. The MB= a62xx is > > > > > > the matching reference/starterkit carrier board. > > > > >=20 > > > > > Why all the wildcards? Why isn't there a compatible per device in= the > > > > > family? > >=20 > > Because all variants use the same Device Tree. There is also only one c= ompatible and one (main) DTSI > > for the AM62 SoC family, which our Device Trees are based on. >=20 > So what varies between the members of the family? There are currently 6 SoCs in the family: - AM6254 - AM6252 - AM6251 - AM6234 - AM6232 - AM6231 They differ in: - Existence of GPU (AM625 vs AM623) - Number of Cortex-A53 cores (last digit) =20 All of these use ti,am625 as their SoC-level compatible. The differences ar= e currently handled by U- Boot, which checks various feature flags in the SoC registers and patches t= he OS DTB accordingly by removing CPU nodes and disabling the GPU node if necessary. >=20 > > > > For the compatible string we've chosen the TQMa6254 as the represen= tative for the TQMa62xx family. > > >=20 > > > And all the boards in the family are the exact same? > >=20 > > There is a single TQMa62xx PCB, which has some AM62 family SoC installe= d (AM6254 in the case of the > > TQMa6254, but all AM62 are possible). TQMa62xx is also the name used fo= r marketing when not talking > > about a specific SoC variant: > > https://www.tq-group.com/en/products/tq-embedded/arm-architecture/tqma6= 2xx/ > >=20 > > Some SoM variants with different RAM/eMMC/SPI-NOR/... do exist, but the= y don't have separate device > > trees (firmware may patch some variant information into the DTB however= , like the correct RAM size). > >=20 > > Choosing one representative for the family including the SoC variant nu= mber, but not distinguishing > > minor variants matches the level of detail used for our other SOMs alre= ady supported by mainline > > Linux (like the TQMa64xxL and various i.MX-based platforms). >=20 > I don't like any of this wildcard stuff at all, who is to say that the > next soc you put on your SoM won't be an am62a7, which has a specific > compatible in the kernel? Your fallback then would be ti,am62a7 not > ti,am625. Probably someone will say "that's the am62a family not the > am62 family" - but that exact thing is why I hate all of this > wildcarding. It's barely any more effort to have a tqm6231 and a tqm6254 > compatible than what you're doing with wildcard but it is unambiguous. Our intention here is to have one SOM compatible string for each SoC compat= ible string. As all SoC variants use the same compatible ti,am625, we've chosen to do the same (usi= ng tq,am625-tqma6254 as the representative.) A hypothetical SOM using a ti,am62a7 would obviously n= ot use the tq,am625-tqma6254 compatible string. At no point we're including wildcards in our compatible strings - we're reu= sing a specific compatible string for multiple compatible variants. Or is what you're takin= g issue with the wildcard in the description string in the YAML? That one I don't have much of an opi= nion on. Best, Matthias >=20 >=20 > =C2=A0 --=20 TQ-Systems GmbH | M=C3=BChlstra=C3=9Fe 2, Gut Delling | 82229 Seefeld, Germ= any Amtsgericht M=C3=BCnchen, HRB 105018 Gesch=C3=A4ftsf=C3=BChrer: Detlef Schneider, R=C3=BCdiger Stahl, Stefan Sch= neider https://www.tq-group.com/