From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794252955; b=yliMYeE94zLK9I9V8Z7UHWkisR+tLMYwxagp/HBe0V48QdzwMlRMAGPMKA0En06ArvAh bAOXaYxUiuAzWbRkDGyLy08liEJEOc9XqQj0sxXLzyZxY/EkOZn0uHAi0/xQ5HoMvFOTO dutFKbGi1mIRdPW09JMlmbS97Aa1MBNZ3kCRVRz1BU3lEDEYvseh68MAQ9PexpVfYWu7K vNpt3DjqtCfKzmwbAG8MaQ3hpHbgy+rjUt1V7kFsri88I/2+BQSyigLkUFPhC4n2zfknI RV27A5geqkpZkHzac+w4Le8Xmwm1LtNb/lRIWCV42Ya3AXhoXQhI+0LETz8x9XTnqzw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794252955; h=Received:DKIM-Signature:Date:From:To:Cc:Subject:Message-ID: References:MIME-Version:Content-Type:Content-Disposition:In-Reply-To; bh=GvJbX8tFvo6M8knK9lWgArZHC9iXmXi9MSIFfMGb9XA=; b=ToHJHRqAxGSC39GN7i+DOW7u9HsPxoEdzF941mysQG5Zfm9BsHiwbnLrIuqSuMrRhAnk MQpBvK04HowRLXVxvemOt9T0xJ4VY+kvzkjpTT+o/TsTItduKxuaTFBrKxTZXUP9eRhc+ t2WFSHS5BwsouOL0pxCnRknw6SmvRp2DFB8rDNzxUSM+aXvNyaRmj4PXuZH58OKJDDCpo ijWpruhL7uvLyvaNmKefD/H0jW/ybFIvu/aUqsuD7g4Qnue+1zIN6Cz4R08whyaCpHAvB 3/DkeGIaARiqzpw+N3PIbcGWpYJWqE7bJuSFVT1x9oOmoEw4FkFeopSwbvl74mo75EA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=HmVvzcKy; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 00406606A321; Mon, 9 Nov 2026 19:35:54 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=HmVvzcKy Received: by smtp.kernel.org (Postfix) with ESMTPSA id 602811F0089F; Mon, 9 Nov 2026 19:35:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1794252954; bh=GvJbX8tFvo6M8knK9lWgArZHC9iXmXi9MSIFfMGb9XA=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=HmVvzcKyyZYSYuEpcGH68C/7nyBvNxOyBaQVvhMISdKwW+YpdA+1Kjxjuor7HcxXp f7HDEoOL91u1jRv2JBFUNyMcw3x6M3sDW78TtDI2QxIzMcWtSxIWYOFTCzOyLVteXD NQdhoTn+MvEaIyCmZxGCCFyDQ0SEtC7dztX2Mv+oiBTGZCF2D6fYFI9MspIKCFMgKC 3OBMOqfwd1M8JxZxjnSpXeXQOBGMp59hlIgRISZibX2jOGrGJ9jIxU6SEArS2vt41m d9sH6E9YomHdAHFYSNu4pNZgnJx4zBXbEL7dFDEtI1udb8TCLqnJulwZ1YYrbO9F0w pnfCjx2Q2C+oQ== Date: Mon, 9 Nov 2026 19:35:50 +0000 From: Conor Dooley To: Kohei Otsuka Cc: Greg Kroah-Hartman , Jiri Slaby , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Lubomir Rintel , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org, conor.dooley@microchip.com Subject: Re: [PATCH 1/2] dt-bindings: serial: 8250: add Microchip Core16550 Message-ID: <20261109-sheath-companion-d7063fcbdbfa@spud> References: <20261103-core16550-rs485-v1-0-6d15ebe1e5b9@spacemachines.com> <20261103-core16550-rs485-v1-1-6d15ebe1e5b9@spacemachines.com> <20261104-zen-aloha-35da49a7e72c@spud> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Xk0qMBEm0ZJtSjIi" Content-Disposition: inline In-Reply-To: --Xk0qMBEm0ZJtSjIi Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, Nov 09, 2026 at 01:54:17PM +1100, Kohei Otsuka wrote: > On Thu, Nov 5, 2026 at 3:20=E2=80=AFAM Conor Dooley wr= ote: > > > > On Tue, Nov 03, 2026 at 11:11:31AM +1100, Kohei Otsuka wrote: > > > Core16550 is a 16550-compatible UART soft IP core for Microchip FPGAs, > > > including the fabric of PolarFire SoC. Its registers follow the 16550= A, > > > so ns16550a stays the fallback, but > > > > > it raises no interrupt on TEMT, > > > which the driver has to know about to support RS-485 on it. > > > > Doesn't this exclude using the fallback to ns16550a, since it requires > > specific interrupt handling? > > > Everything a plain ns16550a driver does works on > Core16550 including transmit, receive, FIFOs, modem control and the baud = rate > divisor. The only thing that needs the specific compatible string is > software RS-485 > (em485), which waits for a TEMT interrupt the core doesn=E2=80=99t raise. > Without the patch, RS-485 direction control is missing, but the UART > otherwise works. If you=E2=80=99d rather > not have the fallback, I can match the compatible in 8250_of directly. In my opinion, this is enough to invalidate the ns16550a fallback. --Xk0qMBEm0ZJtSjIi Content-Type: application/pgp-signature; name=signature.asc -----BEGIN PGP SIGNATURE----- iHUEABYKAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCavIglgAKCRB4tDGHoIJi 0t2WAQDr+SJzkU/53V56nypiHHoTlra6oqrdLRlSDdP/xbYZlQEAoYodUZrV5P8J rwEeTsutW32XJGvJzzg/+7yWStxKbg8= =yd+m -----END PGP SIGNATURE----- --Xk0qMBEm0ZJtSjIi--