From patchwork Fri Aug 5 14:50:56 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Mark Brown X-Patchwork-Id: 9265471 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id F15CA60754 for ; Fri, 5 Aug 2016 14:51:10 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E313028441 for ; Fri, 5 Aug 2016 14:51:10 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D7B2128451; Fri, 5 Aug 2016 14:51:10 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 47C6A2844A for ; Fri, 5 Aug 2016 14:51:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161408AbcHEOvI (ORCPT ); Fri, 5 Aug 2016 10:51:08 -0400 Received: from mezzanine.sirena.org.uk ([106.187.55.193]:59236 "EHLO mezzanine.sirena.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759883AbcHEOvH (ORCPT ); Fri, 5 Aug 2016 10:51:07 -0400 Received: from debutante.sirena.org.uk ([2a01:348:6:8808:fab::3] helo=debutante) by mezzanine.sirena.org.uk with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.84_2) (envelope-from ) id 1bVgSi-0004FQ-29; Fri, 05 Aug 2016 14:51:02 +0000 Received: from broonie by debutante with local (Exim 4.87) (envelope-from ) id 1bVgSe-00058k-CZ; Fri, 05 Aug 2016 15:50:56 +0100 From: Mark Brown To: Chris Brandt Cc: Mark Brown , broonie@kernel.org, linux-spi@vger.kernel.org, linux-renesas-soc@vger.kernel.org, Geert Uytterhoeven , Daniel Palmer In-Reply-To: <1470404163-27427-1-git-send-email-chris.brandt@renesas.com> Message-Id: Date: Fri, 05 Aug 2016 15:50:56 +0100 X-SA-Exim-Connect-IP: 2a01:348:6:8808:fab::3 X-SA-Exim-Mail-From: broonie@sirena.org.uk Subject: Applied "spi: rspi: Increase accuracy of bit rate for RZ" to the spi tree X-SA-Exim-Version: 4.2.1 (built Mon, 26 Dec 2011 16:24:06 +0000) X-SA-Exim-Scanned: No (on mezzanine.sirena.org.uk); Unknown failure Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP The patch spi: rspi: Increase accuracy of bit rate for RZ has been applied to the spi tree at git://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git All being well this means that it will be integrated into the linux-next tree (usually sometime in the next 24 hours) and sent to Linus during the next merge window (or sooner if it is a bug fix), however if problems are discovered then the patch may be dropped or reverted. You may get further e-mails resulting from automated or manual testing and review of the tree, please engage with people reporting problems and send followup patches addressing any issues that are reported if needed. If any updates are required or you are submitting further changes they should be sent as incremental updates against current git, existing patches will not be replaced. Please add any relevant lists and maintainers to the CCs when replying to this mail. Thanks, Mark From ed66b659f95717432b7ede24efd8b2a34f479d32 Mon Sep 17 00:00:00 2001 From: Chris Brandt Date: Fri, 5 Aug 2016 09:36:03 -0400 Subject: [PATCH] spi: rspi: Increase accuracy of bit rate for RZ When you leave the clock divider at 0, 130kHz is the lowest you can go. Also, by adjusting the clock divider you can get more accurate resolutions for clock speeds lower than 16MHz. This patch uses the clock divider as part of the bit rate setup. Signed-off-by: Chris Brandt Signed-off-by: Mark Brown --- drivers/spi/spi-rspi.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c index 818843336932..a816f07e168e 100644 --- a/drivers/spi/spi-rspi.c +++ b/drivers/spi/spi-rspi.c @@ -295,14 +295,24 @@ static int rspi_set_config_register(struct rspi_data *rspi, int access_size) static int rspi_rz_set_config_register(struct rspi_data *rspi, int access_size) { int spbr; + int div = 0; + unsigned long clksrc; /* Sets output mode, MOSI signal, and (optionally) loopback */ rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR); + clksrc = clk_get_rate(rspi->clk); + while (div < 3) { + if (rspi->max_speed_hz >= clksrc/4) /* 4=(CLK/2)/2 */ + break; + div++; + clksrc /= 2; + } + /* Sets transfer bit rate */ - spbr = DIV_ROUND_UP(clk_get_rate(rspi->clk), - 2 * rspi->max_speed_hz) - 1; + spbr = DIV_ROUND_UP(clksrc, 2 * rspi->max_speed_hz) - 1; rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR); + rspi->spcmd |= div << 2; /* Disable dummy transmission, set byte access */ rspi_write8(rspi, SPDCR_SPLBYTE, RSPI_SPDCR);