From patchwork Sat May 6 23:26:06 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maksim Kiselev X-Patchwork-Id: 679725 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 DB5E9C77B75 for ; Sat, 6 May 2023 23:27:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229837AbjEFX1o (ORCPT ); Sat, 6 May 2023 19:27:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39646 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229918AbjEFX1j (ORCPT ); Sat, 6 May 2023 19:27:39 -0400 Received: from mail-wm1-x336.google.com (mail-wm1-x336.google.com [IPv6:2a00:1450:4864:20::336]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 8CB8F1A1E6; Sat, 6 May 2023 16:27:31 -0700 (PDT) Received: by mail-wm1-x336.google.com with SMTP id 5b1f17b1804b1-3f19ab994ccso31812695e9.2; Sat, 06 May 2023 16:27:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1683415649; x=1686007649; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=Sz+u5N4kcArj/4/4O+XvKmG7yrDykhccEDf8daX3ZbA=; b=h0dREcW8aiCUpfPiBMA01W4AdvM5HxHH/X9SFFeYN3dxrTbGzf0w02Zj9XIrp0vhF+ g3ONrCGrCxn/6Y/0PXq0G3apgo70GDqhEV5N9hl5w2EMlZ5vK0JF3t4oRB0w+Xg/RdY7 /kF3K2gtDGYpZOse3BHg/uGTr+JO7kfEXw2cD3t6hhIciKANHnaxih6+xtIzMGJVUF8w b4N07hxDVc56sS/xQFJL7Kh+yYMbv+xV6uymxdH3V+ihcRno+wARarxt/Acjro2pDOPv PeI/CZF/SdhA0qynwWViNElbAupMJGd0LOCSWSsMXMasdCwzb4LGf/WtkxfYYWpBAHu3 hL3w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683415649; x=1686007649; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=Sz+u5N4kcArj/4/4O+XvKmG7yrDykhccEDf8daX3ZbA=; b=Eh+SZXCNvuB6pflHwfo4FFSjs+AOxrms0eoaneFmfYEjcs+JbUA9OKU/lMrYALNAyG 34zMVDwdhm365VOOluQwPp2MgiGeuzM3oxIj+FXccZVgSs/ypoXYUacZa8+tqzE7WPRP LGTFlw8NYtzQASya3eEkTpdv3048VZTH8XiQ2wcuOP5MRNn4g5KDv+X8hQn7RAo7riji J2JgoYbv+0OjzxOT2YSbGS09YD0LkgQiFbVFkPkN0sgvlqHQU4T1d+PJs/3ELuG3HoZA jjx6YfW5QifNvhyPnOF46vZg+mHOuOIP54L9THr7bMZz0azAaxuFZ6/tZOtmtukfSwWH CqBA== X-Gm-Message-State: AC+VfDzJW3AWdSFqdGEIxjPLgeMPGh7W8c675vyVv6RgwKP1ZtJOOLSK e97hDTOj82fJC/JqZCJHXJt8EZahgEAwIQ== X-Google-Smtp-Source: ACHHUZ558Vn2BHGt7HPcyoo/dxzfQ/bcKey8DMqGxSRedZ+6NdT67o63GCejna/hoVRU+xuhhRs00Q== X-Received: by 2002:a1c:7712:0:b0:3f4:1dd9:e9e0 with SMTP id t18-20020a1c7712000000b003f41dd9e9e0mr1526884wmi.7.1683415648950; Sat, 06 May 2023 16:27:28 -0700 (PDT) Received: from localhost.localdomain ([176.221.215.212]) by smtp.gmail.com with ESMTPSA id p4-20020a1c7404000000b003f1739a0116sm12098655wmc.33.2023.05.06.16.27.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sat, 06 May 2023 16:27:28 -0700 (PDT) From: Maksim Kiselev To: Andre Przywara Cc: Icenowy Zheng , Maksim Kiselev , Mark Brown , Rob Herring , Krzysztof Kozlowski , Conor Dooley , Chen-Yu Tsai , Jernej Skrabec , Samuel Holland , Paul Walmsley , Palmer Dabbelt , Albert Ou , Cristian Ciocaltea , Greg Kroah-Hartman , Maxime Ripard , linux-spi@vger.kernel.org, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-sunxi@lists.linux.dev, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org Subject: [PATCH v3 3/5] spi: sun6i: add quirk for in-controller clock divider Date: Sun, 7 May 2023 02:26:06 +0300 Message-Id: <20230506232616.1792109-4-bigunclemax@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230506232616.1792109-1-bigunclemax@gmail.com> References: <20230506232616.1792109-1-bigunclemax@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org Previously SPI controllers in Allwinner SoCs has a clock divider inside. However now the clock divider is removed and to set the transfer clock rate it's only needed to set the SPI module clock to the target value and configure a proper work mode. According to the datasheet there are three work modes: | SPI Sample Mode | SDM(bit13) | SDC(bit11) | Run Clock | |-------------------------|------------|------------|-----------| | normal sample | 1 | 0 | <= 24 MHz | | delay half cycle sample | 0 | 0 | <= 40 MHz | | delay one cycle sample | 0 | 1 | >= 80 MHz | Add a quirk for this kind of SPI controllers. Co-developed-by: Icenowy Zheng Signed-off-by: Maksim Kiselev --- drivers/spi/spi-sun6i.c | 92 +++++++++++++++++++++++++++-------------- 1 file changed, 62 insertions(+), 30 deletions(-) diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c index 01a01cd86db5..1e9e9a8159d9 100644 --- a/drivers/spi/spi-sun6i.c +++ b/drivers/spi/spi-sun6i.c @@ -42,7 +42,9 @@ #define SUN6I_TFR_CTL_CS_MANUAL BIT(6) #define SUN6I_TFR_CTL_CS_LEVEL BIT(7) #define SUN6I_TFR_CTL_DHB BIT(8) +#define SUN6I_TFR_CTL_SDC BIT(11) #define SUN6I_TFR_CTL_FBS BIT(12) +#define SUN6I_TFR_CTL_SDM BIT(13) #define SUN6I_TFR_CTL_XCH BIT(31) #define SUN6I_INT_CTL_REG 0x10 @@ -87,6 +89,7 @@ struct sun6i_spi_cfg { unsigned long fifo_depth; + bool has_clk_ctl; }; struct sun6i_spi { @@ -260,7 +263,7 @@ static int sun6i_spi_transfer_one(struct spi_master *master, struct spi_transfer *tfr) { struct sun6i_spi *sspi = spi_master_get_devdata(master); - unsigned int mclk_rate, div, div_cdr1, div_cdr2, timeout; + unsigned int div, div_cdr1, div_cdr2, timeout; unsigned int start, end, tx_time; unsigned int trig_level; unsigned int tx_len = 0, rx_len = 0; @@ -350,39 +353,66 @@ static int sun6i_spi_transfer_one(struct spi_master *master, sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg); - /* Ensure that we have a parent clock fast enough */ - mclk_rate = clk_get_rate(sspi->mclk); - if (mclk_rate < (2 * tfr->speed_hz)) { - clk_set_rate(sspi->mclk, 2 * tfr->speed_hz); - mclk_rate = clk_get_rate(sspi->mclk); - } + if (sspi->cfg->has_clk_ctl) { + unsigned int mclk_rate = clk_get_rate(sspi->mclk); - /* - * Setup clock divider. - * - * We have two choices there. Either we can use the clock - * divide rate 1, which is calculated thanks to this formula: - * SPI_CLK = MOD_CLK / (2 ^ cdr) - * Or we can use CDR2, which is calculated with the formula: - * SPI_CLK = MOD_CLK / (2 * (cdr + 1)) - * Wether we use the former or the latter is set through the - * DRS bit. - * - * First try CDR2, and if we can't reach the expected - * frequency, fall back to CDR1. - */ - div_cdr1 = DIV_ROUND_UP(mclk_rate, tfr->speed_hz); - div_cdr2 = DIV_ROUND_UP(div_cdr1, 2); - if (div_cdr2 <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) { - reg = SUN6I_CLK_CTL_CDR2(div_cdr2 - 1) | SUN6I_CLK_CTL_DRS; - tfr->effective_speed_hz = mclk_rate / (2 * div_cdr2); + /* Ensure that we have a parent clock fast enough */ + if (mclk_rate < (2 * tfr->speed_hz)) { + clk_set_rate(sspi->mclk, 2 * tfr->speed_hz); + mclk_rate = clk_get_rate(sspi->mclk); + } + + /* + * Setup clock divider. + * + * We have two choices there. Either we can use the clock + * divide rate 1, which is calculated thanks to this formula: + * SPI_CLK = MOD_CLK / (2 ^ cdr) + * Or we can use CDR2, which is calculated with the formula: + * SPI_CLK = MOD_CLK / (2 * (cdr + 1)) + * Whether we use the former or the latter is set through the + * DRS bit. + * + * First try CDR2, and if we can't reach the expected + * frequency, fall back to CDR1. + */ + div_cdr1 = DIV_ROUND_UP(mclk_rate, tfr->speed_hz); + div_cdr2 = DIV_ROUND_UP(div_cdr1, 2); + if (div_cdr2 <= (SUN6I_CLK_CTL_CDR2_MASK + 1)) { + reg = SUN6I_CLK_CTL_CDR2(div_cdr2 - 1) | SUN6I_CLK_CTL_DRS; + tfr->effective_speed_hz = mclk_rate / (2 * div_cdr2); + } else { + div = min(SUN6I_CLK_CTL_CDR1_MASK, order_base_2(div_cdr1)); + reg = SUN6I_CLK_CTL_CDR1(div); + tfr->effective_speed_hz = mclk_rate / (1 << div); + } + + sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg); } else { - div = min(SUN6I_CLK_CTL_CDR1_MASK, order_base_2(div_cdr1)); - reg = SUN6I_CLK_CTL_CDR1(div); - tfr->effective_speed_hz = mclk_rate / (1 << div); + clk_set_rate(sspi->mclk, tfr->speed_hz); + tfr->effective_speed_hz = clk_get_rate(sspi->mclk); + + /* + * Configure work mode. + * + * There are three work modes depending on the controller clock + * frequency: + * - normal sample mode : CLK <= 24MHz SDM=1 SDC=0 + * - delay half-cycle sample mode : CLK <= 40MHz SDM=0 SDC=0 + * - delay one-cycle sample mode : CLK >= 80MHz SDM=0 SDC=1 + */ + reg = sun6i_spi_read(sspi, SUN6I_TFR_CTL_REG); + + if (tfr->effective_speed_hz <= 24000000) + reg |= SUN6I_TFR_CTL_SDM; + else if (tfr->effective_speed_hz >= 80000000) + reg |= SUN6I_TFR_CTL_SDC; + else + reg &= ~(SUN6I_TFR_CTL_SDM | SUN6I_TFR_CTL_SDC); + + sun6i_spi_write(sspi, SUN6I_TFR_CTL_REG, reg); } - sun6i_spi_write(sspi, SUN6I_CLK_CTL_REG, reg); /* Finally enable the bus - doing so before might raise SCK to HIGH */ reg = sun6i_spi_read(sspi, SUN6I_GBL_CTL_REG); reg |= SUN6I_GBL_CTL_BUS_ENABLE; @@ -701,10 +731,12 @@ static void sun6i_spi_remove(struct platform_device *pdev) static const struct sun6i_spi_cfg sun6i_a31_spi_cfg = { .fifo_depth = SUN6I_FIFO_DEPTH, + .has_clk_ctl = true, }; static const struct sun6i_spi_cfg sun8i_h3_spi_cfg = { .fifo_depth = SUN8I_FIFO_DEPTH, + .has_clk_ctl = true, }; static const struct of_device_id sun6i_spi_match[] = {