From patchwork Wed Aug 19 12:59:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Geert Uytterhoeven X-Patchwork-Id: 11724045 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id CE429138C for ; Wed, 19 Aug 2020 13:00:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B45102054F for ; Wed, 19 Aug 2020 13:00:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728001AbgHSNAV (ORCPT ); Wed, 19 Aug 2020 09:00:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36262 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728536AbgHSM7q (ORCPT ); Wed, 19 Aug 2020 08:59:46 -0400 Received: from baptiste.telenet-ops.be (baptiste.telenet-ops.be [IPv6:2a02:1800:120:4::f00:13]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E8CEAC061346 for ; Wed, 19 Aug 2020 05:59:12 -0700 (PDT) Received: from ramsan ([84.195.186.194]) by baptiste.telenet-ops.be with bizsmtp id HQz62300F4C55Sk01Qz6y9; Wed, 19 Aug 2020 14:59:06 +0200 Received: from rox.of.borg ([192.168.97.57]) by ramsan with esmtp (Exim 4.90_1) (envelope-from ) id 1k8NgI-0002bq-31; Wed, 19 Aug 2020 14:59:06 +0200 Received: from geert by rox.of.borg with local (Exim 4.90_1) (envelope-from ) id 1k8NgI-0005Sm-2B; Wed, 19 Aug 2020 14:59:06 +0200 From: Geert Uytterhoeven To: Mark Brown Cc: Chris Brandt , linux-spi@vger.kernel.org, linux-renesas-soc@vger.kernel.org, linux-sh@vger.kernel.org, Geert Uytterhoeven Subject: [PATCH v2 5/7] spi: rspi: Increase bit rate range for QSPI Date: Wed, 19 Aug 2020 14:59:02 +0200 Message-Id: <20200819125904.20938-6-geert+renesas@glider.be> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20200819125904.20938-1-geert+renesas@glider.be> References: <20200819125904.20938-1-geert+renesas@glider.be> Sender: linux-sh-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sh@vger.kernel.org Increase bit rate range for QSPI by extending the range of supported dividers: 1. QSPI supports a divider of 1, by setting SPBR to zero, increasing the upper limit from 48.75 to 97.5 MHz on R-Car Gen2, 2. Make use of the Bit Rate Frequency Division Setting field in Command Registers, to decrease the lower limit from 191 to 24 kbps on R-Car Gen2. Signed-off-by: Geert Uytterhoeven --- v2: - No changes. drivers/spi/spi-rspi.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c index ea3f2680d3c13e02..38c0cd7febabf114 100644 --- a/drivers/spi/spi-rspi.c +++ b/drivers/spi/spi-rspi.c @@ -334,14 +334,26 @@ static int rspi_rz_set_config_register(struct rspi_data *rspi, int access_size) */ static int qspi_set_config_register(struct rspi_data *rspi, int access_size) { - int spbr; + unsigned long clksrc; + int brdv = 0, spbr; /* Sets output mode, MOSI signal, and (optionally) loopback */ rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR); /* Sets transfer bit rate */ - spbr = DIV_ROUND_UP(clk_get_rate(rspi->clk), 2 * rspi->speed_hz); - rspi_write8(rspi, clamp(spbr, 0, 255), RSPI_SPBR); + clksrc = clk_get_rate(rspi->clk); + if (rspi->speed_hz >= clksrc) { + spbr = 0; + } else { + spbr = DIV_ROUND_UP(clksrc, 2 * rspi->speed_hz); + while (spbr > 255 && brdv < 3) { + brdv++; + spbr = DIV_ROUND_UP(spbr, 2); + } + spbr = clamp(spbr, 0, 255); + } + rspi_write8(rspi, spbr, RSPI_SPBR); + rspi->spcmd |= SPCMD_BRDV(brdv); /* Disable dummy transmission, set byte access */ rspi_write8(rspi, 0, RSPI_SPDCR);