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 6A02EC4828F for ; Fri, 9 Feb 2024 16:21:39 +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=se1S4URijlGZZj/RU1aqspiRq4MdAd7cG4MxNA1r2UE=; b=jGuYRirnzwBOMU4uvS+w70+VZH 37GWQHqp/aVpxIi49JqmiCBxbfLI9n5TEeFxtC/8sGyaqn92KXHM57HxGXvuqzJocHddO2gv7BkrB bHJjST7nvNEWQoV7AhKBJTSWmd6Jup/fs1ulLppXCFDpQ3v38rzBVCYN4Wh6kBIUUXblGW8tj4RR/ lRrG7gfNyUNqhfEnN6Mwip4njnA+g1/bs/LaJSNM1+s78jjS4AoSNv9o98YUWsRPNw5zW01hlrPg8 4S0fsJLgwD4lNM4ArVnTR+wleBpskk0V7u73xXknI5zZOn89NEbRI/EdaLThGjfRplYcIYhK907v5 0zo80aqw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.97.1 #2 (Red Hat Linux)) id 1rYTd1-0000000HVnE-3cEW; Fri, 09 Feb 2024 16:21:27 +0000 Received: from sin.source.kernel.org ([145.40.73.55]) by bombadil.infradead.org with esmtps (Exim 4.97.1 #2 (Red Hat Linux)) id 1rYTcy-0000000HVml-34aV for linux-arm-kernel@lists.infradead.org; Fri, 09 Feb 2024 16:21:26 +0000 Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by sin.source.kernel.org (Postfix) with ESMTP id B3DAACE1DA4; Fri, 9 Feb 2024 16:21:22 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4FEDAC433C7; Fri, 9 Feb 2024 16:21:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1707495682; bh=6P50JpMWtNawcrLYmSC8txcAEjCecYqddP8IbfkgA3c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=hF2EIiWrjPw+Pd13noyfJM2a0X3wBpj11gmQh5LXNvhwZuwyiaUALxiZPyJA3noAe SAyXo43AQs97YOuyh7+2k+q3sEej2tDUHKexse0N7KFS9AfyI23QEEO9tqqsbFYIKh rq7OdTgGF5FNILD6DMgYbltC0kmMHKxHuOdvgdZmMZo8s1fWBvg62sORYZW0bp8Msz io6TzO/hyZN/4jMNEy0vnTjt6Pjx62ZzL4dXSZl+aYkY8a15YwAUTvPAPdp45gaIxh fUPr+MaFUWlwdvSkXeiScC569n27Us+ziXK24iDYRBYUw9t9w42xY1Ne4c9q0BD/PH YiTiBj/THVklw== Date: Fri, 9 Feb 2024 16:21:16 +0000 From: Conor Dooley To: Tudor Ambarus Cc: Geert Uytterhoeven , broonie@kernel.org, robh@kernel.org, andi.shyti@kernel.org, semen.protsenko@linaro.org, krzysztof.kozlowski@linaro.org, alim.akhtar@samsung.com, linux-spi@vger.kernel.org, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, andre.draszik@linaro.org, peter.griffin@linaro.org, kernel-team@android.com, willmcvicker@google.com, conor+dt@kernel.org, devicetree@vger.kernel.org, arnd@arndb.de Subject: Re: [PATCH 01/12] spi: dt-bindings: introduce the ``fifo-depth`` property Message-ID: <20240209-chest-sleet-a119fc3d4243@spud> References: <20240208135045.3728927-1-tudor.ambarus@linaro.org> <20240208135045.3728927-2-tudor.ambarus@linaro.org> <20240208-grating-legwarmer-0a04cfb04d61@spud> MIME-Version: 1.0 In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20240209_082125_152414_60A4D7F0 X-CRM114-Status: GOOD ( 29.88 ) 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="===============3253966620421453042==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============3253966620421453042== Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="AYm2FyfJMLjy9NNH" Content-Disposition: inline --AYm2FyfJMLjy9NNH Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Feb 09, 2024 at 01:56:56PM +0000, Tudor Ambarus wrote: >=20 > + Geert >=20 > On 2/8/24 18:24, Conor Dooley wrote: > > On Thu, Feb 08, 2024 at 01:50:34PM +0000, Tudor Ambarus wrote: > >> There are instances of the same IP that are configured by the integrat= or > >> with different FIFO depths. Introduce the fifo-depth property to allow > >> such nodes to specify their FIFO depth. > >> > >> We haven't seen SPI IPs with different FIFO depths for RX and TX, thus > >> introduce a single property. > >=20 > > Some citation attached to this would be nice. "We haven't seen" offers > > no detail as to what IPs that allow this sort of configuration of FIFO > > size that you have actually checked. > >=20 > > I went and checked our IP that we use in FPGA fabric, which has a > > configurable fifo depth. It only has a single knob for both RX and TX > > FIFOs. The Xilinx xps spi core also has configurable FIFOs, but again RX > > and TX sizes are tied there. At least that's a sample size of three. > >=20 > > One of our guys is working on support for the IP I just mentioned and > > would be defining a vendor property for this, so > > Reviewed-by: Conor Dooley > >=20 >=20 > Thanks, Conor. I had in mind that SPI has a shift register and it's > improbable to have different FIFO depths for RX and TX. IDK, but I've learned to expect the unexpectable, especially when it comes to the IPs intended for use in FPGAs. > At least I don't > see how it would work, I guess it will use the minimum depth between the > two? I'm not really sure how it would work other than that in the general case, but some use case specific configuration could work, but I do agree that it is > I grepped by "fifo" in the spi bindings and I now see that renesas is > using dedicated properties for RX and TX, but I think that there too the > FIFOs have the same depths. Looking into drivers/spi/spi-sh-msiof.c I > see that the of_device_id.data contains 64 bytes FIFOs for RX and TX, > regardless of the compatible. >=20 > Geert, any idea if the FIFO depths can differ for RX and TX in > spi-sh-msiof.c? >=20 > Anyway, even if there are such imbalanced architectures, I guess we can > consider them when/if they appear? (add rx/tx-fifo-depth dt properties) I think so. > Documentation/devicetree/bindings/spi/renesas,sh-msiof.yaml: > Override the default TX fifo size. Unit is words. Ignored if 0. > Documentation/devicetree/bindings/spi/renesas,sh-msiof.yaml: > renesas,rx-fifo-size: > Documentation/devicetree/bindings/spi/renesas,sh-msiof.yaml: > Override the default RX fifo size. Unit is words. Ignored if 0. These renesas ones seemed interesting at first glance due to these comments, but what's missed by grep the is "deprecated" marking on these. They seem to have been replaced by soc-specific compatibles. --AYm2FyfJMLjy9NNH Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iHUEABYIAB0WIQRh246EGq/8RLhDjO14tDGHoIJi0gUCZcZQ+wAKCRB4tDGHoIJi 0tCHAQC+UahOjFrFh4KmlxoZGj3mhl0GhMgYnpK4Y008NNbSKwD7BWwhfjMZ1Zk1 UZE3Fa1Tubov+aQxuH2m9T+rmex3fQg= =PHwh -----END PGP SIGNATURE----- --AYm2FyfJMLjy9NNH-- --===============3253966620421453042== 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 --===============3253966620421453042==--