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 B29F0C5CFDB for ; Thu, 13 Aug 2026 21:34:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:In-Reply-To:Content-Type: 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=RJmCPul9jOqQ/QdYG0814B9QmndHxDgtfe+WTkVwZeo=; b=eUxkD7br4p9lUemE2VXiJ/wqkC 276RcYVmnu7d/j+pr+vA+3Ev/09B0hlDT9ZAWkc5v/I4FWZuofLXiPCOUj774aeGWGJ8ctmlm5ppt Fmqh5qfnSstt5xGj3U2RH8IbErlDQPn5HOfvhjbwzEM244GiCnfwcp0bXhkpbVZndxEacjplySadq 5fiNd3sWjrEBknMRovCJqFNmzwl6MPNzPRSGYRobiIHjqCzqBWCDlbPgKZOUU+TiTuYij1IzKZ3pZ 4Qve3SB3PCR0gxYxKV3VMlvsY+Hk8dd7uHU7HUuXAGmH7ILSmHy2p1DLxurflOwfbb1Wva7Xkh20T HcOiGNdw==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.99.1 #2 (Red Hat Linux)) id 1wud3p-00000001eVO-2PFl; Thu, 13 Aug 2026 21:34:01 +0000 Received: from sea.source.kernel.org ([2600:3c0a:e001:78e:0:1991:8:25]) by bombadil.infradead.org with esmtps (Exim 4.99.1 #2 (Red Hat Linux)) id 1wud3o-00000001eVH-13Ki for linux-arm-kernel@lists.infradead.org; Thu, 13 Aug 2026 21:34:00 +0000 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by sea.source.kernel.org (Postfix) with ESMTP id 8833A400FF; Thu, 13 Aug 2026 21:33:59 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id C6F621F000E9; Thu, 13 Aug 2026 21:33:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1786656839; bh=RJmCPul9jOqQ/QdYG0814B9QmndHxDgtfe+WTkVwZeo=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=KS0moFFF0rJITVVbOktfgUKvpVxgrVDDBPYx1NnyUMIWpFA2fym+YrnoXEcAFEC+z Pf6qZgmB1SojQqV3DbqFeyXjVm3MCCfEJc22VTTnCuvZYZlOuCZLCVt2jb8lXEmgn8 K0yzSb0lb8xZoJd/DBgG7za2GgvLuiVbnYzA8EGHQfeuFCJ8PN5IJuMiyneA1lrJDv frsXSzCGRjghvcb0q2rCwHNAxPcyzlqCzlkc1mWEvLJyvwTtIpObfbxDQwvPlkC+wk E+O9ST1kdCy8HpOptKG2YW8U3Izp3sprT8kEfqMoDK3FU9a8AbMUwnaogYxRAKykFd 35TIr6ysbh9WQ== Date: Thu, 13 Aug 2026 22:33:55 +0100 From: Mark Brown To: Miquel Raynal Cc: Jacky Huang , Shan-Chun Hung , Thomas Petazzoni , Steam Lin , linux-arm-kernel@lists.infradead.org, linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 4/5] spi: ma35d1-qspi: Add DTR support Message-ID: <09c3928f-4b58-4ac6-8e1a-84dfe3ff6b92@sirena.org.uk> References: <20260813-perso-ma35d1-upstream-qspi-v1-0-b217b9870eb1@bootlin.com> <20260813-perso-ma35d1-upstream-qspi-v1-4-b217b9870eb1@bootlin.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="Ofwh2gFKdI85BSw4" Content-Disposition: inline In-Reply-To: <20260813-perso-ma35d1-upstream-qspi-v1-4-b217b9870eb1@bootlin.com> X-Cookie: Immanuel doesn't pun, he Kant. 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: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --Ofwh2gFKdI85BSw4 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Aug 13, 2026 at 10:00:24AM +0200, Miquel Raynal wrote: > The controller has DTR support, a bit must be set for it. The behaviour > is interesting though, as the speed won't improve when enabled. This is > because there seems to be an internal divisor (/2) which keeps the rate > equal when DTR is enabled. As a result, this commit also doubles the > target bus speed, which in practice does not happen. This way, there is > a real gain: > @@ -567,7 +577,8 @@ static int nuvoton_qspi_transfer_one(struct spi_contr= oller *ctlr, > buswidth =3D 2; > } > =20 > - ret =3D nuvoton_qspi_configure_bus(spi, buswidth, dir, xfer->speed_hz); > + ret =3D nuvoton_qspi_configure_bus(spi, buswidth, dir, xfer->speed_hz, > + xfer->dtr_mode); > if (ret) > return ret; This needs ctlr->dtr_caps configuring, otherwise the validation will block it - only the _mem_caps were updated. --Ofwh2gFKdI85BSw4 Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmp+OEIACgkQJNaLcl1U h9DZ2Af+Nhsdzbp64ywAW88mtOuZ/FvF8klN/5pJZjRQzBM9u/Xw6tkIa1wfMTEa rubL4TJK2bNU7LG3vghKhkFZ9Z9E1GPYNHOPzQ42E0BWI/T+sCeMQdQKcCHWpiFq tADVc3oMY8vjymgRSzDU53flhddz6GREVOgoPy+LrRrjktCu84481I8YbMVjZqqh BXc4yo15EgqxKK/qckLVqpq1bNS133PJrA1xPT5gQSsPfr19uHRs22AGot0Vdd2y mSchqod0ciOlSQBQ+k9YfiYwpacrPZ9qIm9HJgULjKyk8vu2YZ9m8sK7BVAPSeAE cH4Wwpf6YPp6rElv0Wzo4CDGbtmTEA== =mY/B -----END PGP SIGNATURE----- --Ofwh2gFKdI85BSw4--