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 D62C2C19F2D for ; Tue, 9 Aug 2022 15:28:41 +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=i9KnKGiBnnHhRsBcpcWUKfWE2sa0OVWyLTZdq8JMW3U=; b=H/L0Faszh8zjrC7LOKJiGnFKDc Sk9GoK3xNEFfa9Hf1VX4WRdWkBs9nR5t0AGXB0ohpgrZr2YJ12/wGNcK9cmjA4PSNQO9WZrcLyhjR s6LFBzSrUFMzjjblhJDskoHTfZfJhiRd5SzYxPtybHvQLLQh/mrxzzdF0RxeHm6qHRqN8T+Rf5m7i nF/FRbB1iUac/aU0wJxPzJAAOYKfMnsvJflAsJmmoMf+8stxnX+Ca7MYSWtdHl5Pl3xMOCgUqry6g 0u8QCR3va4q0HFTqNOILwt3YA7eZbn9tvNE+ABgyXtsLNxTpfwfphlGzwNanY0weMd+JfUnDznswJ /qiVG8/A==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1oLR8x-004dEX-Ow; Tue, 09 Aug 2022 15:27:43 +0000 Received: from dfw.source.kernel.org ([2604:1380:4641:c500::1]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1oLR8r-004dAb-CL; Tue, 09 Aug 2022 15:27:38 +0000 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 52CB8611E6; Tue, 9 Aug 2022 15:27:36 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F63AC433D7; Tue, 9 Aug 2022 15:27:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1660058855; bh=fQ1vxx5hvw6lsWVefkUSI+jjDL0i6RgRtYeopmp59/c=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=XEnCGY9pciB+LdPdZXSY7FDJxCstebFVLJ4fGtjOLqcMK1FqJZFbkocRuXjrstDTC NtsI27Wrp/hcva7bVxlFQ0tsVd19dN4bIdo0O7BOo4nLmj2PeDDD62jgtVF5AhLFlt OP8ze/pzfmUui6nnuSM07hjug7DdXkM6MBxxPasRfgaBOo3YLBNCQP6OxAJamiKU67 dIvyIV5Ug9MBWPLdqoUVr9YASK3N8nEwLuLNgqAayiPYtyXVinMXS2vKz0DhDfGu4X GweuxDWrw09R9PoZ7U9fKl5wBGw4CY/Ryw2A5cyRmLfurwLQuWsp45cU8EWmlBbw7P 6M2eFOnGYudfw== Date: Tue, 9 Aug 2022 16:27:30 +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> MIME-Version: 1.0 In-Reply-To: <20220809152019.461741-1-narmstrong@baylibre.com> X-Cookie: A nuclear war can ruin your whole day. X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220809_082737_493370_14C4EF99 X-CRM114-Status: GOOD ( 16.18 ) 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="===============4342884173665602171==" Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org --===============4342884173665602171== Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="lBVgeDOGXQW0ujkF" Content-Disposition: inline --lBVgeDOGXQW0ujkF Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Aug 09, 2022 at 05:20:19PM +0200, Neil Armstrong wrote: > At the end of a message, the HW gets a reset in meson_spicc_unprepare_transfer(), > this resets the SPICC_CONREG register and notably the value set by the > Common Clock Framework. > This saves the datarate dividor value between message to keep the last > set value by the Common Clock Framework. 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. > This didn't appear before commit 3e0cf4d3fc29 ("spi: meson-spicc: add a linear clock divider support") > because we recalculated and wrote the rate for each xfer. Note that the rate might change per transfer. --lBVgeDOGXQW0ujkF Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmLyfOIACgkQJNaLcl1U h9Awagf+OUcsezR87epB5sRf0iUOehYNcaHJv9CU74vZ9hdz23rciUwHLGp+gGaO 6VTnFgYp20wC+Zxy/W0fT6WgbqQ9D+RujmabrST1jgVFd/ml24q/qCE7YL/GZ1pj Z7GGoe9GmrfRFUW7zRmKMrQsOFQtxXsZSR0rM8iMHlPm9lI8pVEBDY1AI1TFPL+0 U0ncLcbJ0pibxGz2cboKDEfRoU5OJu8a0F9EBJ4OVJeI+XgjEiRounhW+g9E1rc2 8XOrwsOdwFkRckIzeZqAuAECA4px79Fj24pJObWousC7M3x+1VkctwWe8SZHAUjq +FI09JvFwqg6AThV8fUxh5x8xxS/MA== =yNF+ -----END PGP SIGNATURE----- --lBVgeDOGXQW0ujkF-- --===============4342884173665602171== 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 --===============4342884173665602171==--