From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 CF53B3A168C; Mon, 16 Mar 2026 15:26:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773674817; cv=none; b=BSJ+5HEgDHXtyXPucaYnG27jFdS5QcafPdPyA/DAzt+f+Cr+3uXXoOzf/MJnVFnPrdIBaR94MM7/k98s6JwXGmGpKVMEJmyR4neuP65kMS2WpznN7ih5V/vGrZeOxFNEPGqC2+nLMDjDCxg/a3lFIrL+Oo7wRyUtGVtQj1jQJ4E= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773674817; c=relaxed/simple; bh=d0TF2Ekiy4goO/kVfRjEu+OZHQ0P1XPrJxN/o0O/eDs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=Dqob/IcU+MhQAfv6oc8BvJMbu9z4NuOplnY4hszPRvCQ5sTPJdAM+rUeeSv/qKHF0dphw66Pe26u8sX1MIxw3wE1LMzysm2W+MOgJ4IPOdVX8iMp7qmHrfgTlfrLGvTWP9cnETUeE2m6TkjLvgYY81sfxKH48+mdV7cVbZRjMmo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=ZarxGcIW; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="ZarxGcIW" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B9874C19421; Mon, 16 Mar 2026 15:26:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1773674817; bh=d0TF2Ekiy4goO/kVfRjEu+OZHQ0P1XPrJxN/o0O/eDs=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=ZarxGcIWjQWnViLSgd+P0qQ8SwDNqncly/um536rB74baBBf3ZF4eAba93fiZv1Sa NIbHhALNuoP7vgZ/T665mlccctc+Op5/xeMCqY7cDfT1Psfv043HT60twQ2J7mqQHZ jimmzQtCK+IYRwlNTB1t0FJ0vkRUCr1xZNX7uhXepgh6x9skQPi+kaKUGv2sbL3NLY Ba7ciGJptZ1tyTIYYfB8mGOwAgZT1ftw2jRAma8//ubQc7o2s2sLRIdNPNJcsg77xK 51ZRiX6y3TM8e2OyPIzPJNWk8sHj9Ifo5EL3Wjh16V/ezHpcbcA9NPBU4rwXWZFwG4 bb+i42SAx8ULQ== Message-ID: <60c29223-c703-44fe-9250-ae881eff57b6@kernel.org> Date: Mon, 16 Mar 2026 16:26:52 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 3/3] memory: renesas-rpc-if: Add support for RZ/T2H SoC To: Geert Uytterhoeven Cc: Wolfram Sang , Prabhakar , Rob Herring , Conor Dooley , Geert Uytterhoeven , Magnus Damm , Biju Das , linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Fabrizio Castro , Lad Prabhakar References: <20260310212927.3372410-1-prabhakar.mahadev-lad.rj@bp.renesas.com> <20260310212927.3372410-4-prabhakar.mahadev-lad.rj@bp.renesas.com> <69524a11-95bb-4dc9-b59c-1b5a9b70ae18@kernel.org> From: Krzysztof Kozlowski Content-Language: en-US Autocrypt: addr=krzk@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 16/03/2026 16:02, Geert Uytterhoeven wrote: > >>> a) The differences are not handled yet, because the extra features of >>> one variant (or both variants) are not yet supported by the supported by the driver >> So that's why I mentioned how DT understands compatibility. Above does >> not matter, sorry. >> >> Extra features means subset/superset. > > I haven't looked at the differences between the two variants here, > but I doubt one of them is a superset of the other. Probably both are > supersets of a common subvariant that doesn't really exist ;-) That could be the argument. Consider also that we don't care if superset/subset is a real, design decision. If you have two independent companies making something working with the same interface, they are compatible. If one adds one more feature, you have superset/subset. And we already have some examples of this for simpler devices in hwmon and/or iio. > >>> b) The differences are not handled explicitly, but implicitly, >>> or elsewhere. >>> E.g. the different number of resets is handled implicitly through >>> devm_reset_control_array_get_exclusive(). >> >> Still not an argument in meaning of DT compatibility. Implementation >> uses the same ABI (through devm_reset_control_array_get_exclusive), >> right? So devices are compatible for Linux kernel. > > Linux is not the only user of DT. With such argument (implied: "there is an user which cannot use that compatibility"), nothing would be ever compatible except devices being identical. If you cannot find such user, you can write a driver which on purpose will be incompatible and bring it as an argument. If there is known incompatible implementation, please mention it. Otherwise the implementation here kind of rules devices are compatible. Assuming implementation is working and to some extend usable, e.g. complete set of some features. Best regards, Krzysztof