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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C16C0C00140 for ; Wed, 10 Aug 2022 12:38:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231804AbiHJMiF (ORCPT ); Wed, 10 Aug 2022 08:38:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33980 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230433AbiHJMhz (ORCPT ); Wed, 10 Aug 2022 08:37:55 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8D5417756F; Wed, 10 Aug 2022 05:37:54 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 2A0F561347; Wed, 10 Aug 2022 12:37:54 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2C7B5C433D6; Wed, 10 Aug 2022 12:37:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660135073; bh=ROHaIZk75ZgJisF7nTMLDJS9o0AxLi1V/y+T67/KwWQ=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Qg7V+bjI7lf3dzSN62yYr9g4pSgwDtQDJWcjI3dRgZRvMIoOD/bbKegaOJMO2MzWN SE+A3aKfjpe80HoF1s2lo5xVS6gIkpmA1DpXIUnW2aHmkkpf3RJ/y8dJotPeQecNET e5qc36Vnk3SFh2ixHl5EoVsn2FhJ3CmaaVXyK9sh5fVsJqfdHGFcit844ItnozYVb6 CGZ4Ma5LOKbVbJtmpUwe4+JSb49OOdw677rfq2XdN3V5GeorsO5RJZw/LAVbThEAK4 woyx4cJp5ybMTB/NJtCaI8FBAu4HmfiRtObEhNrpbt1GgSGGFejKux81LEpIDva+n8 xCEk6z1CseItQ== Date: Wed, 10 Aug 2022 13:37:48 +0100 From: Mark Brown To: Neil Armstrong Cc: linux-spi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-amlogic@lists.infradead.org, linux-kernel@vger.kernel.org, Da Xue Subject: Re: [PATCH] spi: meson-spicc: save pow2 datarate between messages Message-ID: References: <20220809152019.461741-1-narmstrong@baylibre.com> <39c2f53b-8f53-ceb1-ae0c-81e5e53d01aa@baylibre.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="2hd26sDiWQtv5ujx" Content-Disposition: inline In-Reply-To: <39c2f53b-8f53-ceb1-ae0c-81e5e53d01aa@baylibre.com> X-Cookie: First pull up, then pull down. Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org --2hd26sDiWQtv5ujx Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Wed, Aug 10, 2022 at 11:17:14AM +0200, Neil Armstrong wrote: > On 09/08/2022 17:27, Mark Brown wrote: > > On Tue, Aug 09, 2022 at 05:20:19PM +0200, Neil Armstrong wrote: > > When you say the value set by the clock framework does that mean that > > the clock driver is adjusting hardware inside the SPI controller IP > > block which is then getting reset by the SPI driver without the SPI > > driver knowing about it? That seems like a bad idea as you're finding > > here. > The SPI driver is explicitely triggering a reset at the end of each message > to get back to a clean HW state, but it does reset the content of the "legacy" > registers containing the power of 2 divider value, the new registers configuring > the new clock divider path (only on newer SoCs) doesn't get cleared. Sure, but that doesn't really address the concern - is this something that the clk driver programmed or is this the driver forgetting to restore a register that it programmed itself? The commit message sounds like the former which is a much bigger problem. --2hd26sDiWQtv5ujx Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmLzppwACgkQJNaLcl1U h9CP8Qf/cMQYM72jnQkNExfj6dskX5IIOlwCnAVUEnsbYrFpv3QL6BNLxgKx4eqx cjDy+gszIhOd4rr7/ayE4siN6fjOo/hWNIuydrrCsRWKrjvKTUInWB16AnVv5NrK JAjl3RZ9vrkKp2UcN/dsaU11B5Xce59ko2nuniDhKYZhubO9F2uYxOPiBLvufQyU Q20TDeHIgYaClQvbbnVnIBpjkeOYaZxhkpAjZmw/Btip07mzspkcC4ASnTbTKs2j cCeDY+xkSNPqT+Pie+GxbV0bOeAjLdUOwP7QoXIsrP4BJRzuoHk/aXWC8GzXo13a 3baxwuQr/bFzHeoJRT+a3zrpms9mLA== =yOBS -----END PGP SIGNATURE----- --2hd26sDiWQtv5ujx--