From patchwork Wed May 10 08:11:10 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Maksim Kiselev X-Patchwork-Id: 13236604 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 4340DC77B7D for ; Wed, 10 May 2023 08:12:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236565AbjEJIMK (ORCPT ); Wed, 10 May 2023 04:12:10 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58866 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235952AbjEJIMI (ORCPT ); Wed, 10 May 2023 04:12:08 -0400 Received: from mail-wr1-x42b.google.com (mail-wr1-x42b.google.com [IPv6:2a00:1450:4864:20::42b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D90DB5258; Wed, 10 May 2023 01:12:04 -0700 (PDT) Received: by mail-wr1-x42b.google.com with SMTP id ffacd0b85a97d-3078cc99232so3873913f8f.3; Wed, 10 May 2023 01:12:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1683706323; x=1686298323; 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=T8Xbue+dZrUS0EtWBIjxZwNQ7G1HJWZPzEox+l8G5TM=; b=ilLqa4TIHk3vsCNzQPNPreZVusj7unaBLMLeM5ZUQEL7RYDEKZGyeg6Po5XgRyhIM9 NA1ZpzcrniOt2D/B7rIgjZ5dguaybhSBgQHaALXnjc5VlMDXyq0xs/QdKFcOys/TZGW4 vfwyqrnNqNV3tj35MYu03Fv6DvU1p7bjrEXFmXw1+gBOLB38BEy7zxp1A/8t6IMtVneX 1fyW66M5JjhJoef7SqkDgV5AxnoEz9lNfxDn+zaPZNrzgYid6uW6PUFiJKiOpuLgK5D+ SvsQKlIyiVtn8oUNmBLBVf831eKxd5n9Y6fIvgxxsq7gGZCdBGPMRWbwQuUNjQmFIUbM O71w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683706323; x=1686298323; 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=T8Xbue+dZrUS0EtWBIjxZwNQ7G1HJWZPzEox+l8G5TM=; b=dUh50OKmSzFrhWh7PTJ0iFa5ac7oTy6KyFd1nEx742S+UmCiP0xmN5QwMVZPozrW0N 2vg/8EExLIsn83ZD+s56zWtCGpCfKtMTJlqiFDPu73wbJs4k71W+A+3nfV81vFMBjdag kow8d/MzOvafKmvSsx/WBCK9Cjr4RxXe+Wo6wnXlrB6t9ZiBeZkmDige2ZHYeZzT8Aqr nvycDH4JGbaPEqOLoucJZD59mbuWYP4+et5Mzxs8faGFKd/rL38eiZ6L+840ng0PPyBO tY1dzO076XNumpm2XXHxUOmiH3b1xMjdyn1Mwg8AVP0faA7+l2HqiyKQP9j+DOve+OUt /QBA== X-Gm-Message-State: AC+VfDztj1jJHfm30RccwyCnOaWIQds8Ewg07R9iybf5kauZr42VkfZh 3ZnnFeqWeNldKrxRoMBO/H8= X-Google-Smtp-Source: ACHHUZ6U+cGMbulmj6nJrRqn5l5Tf1FQijCWZ80FeaYUifagQC6IDHhOU5heb6VUO5cb2bd5NXRAjg== X-Received: by 2002:a5d:4c82:0:b0:307:a77c:c167 with SMTP id z2-20020a5d4c82000000b00307a77cc167mr3678929wrs.57.1683706323286; Wed, 10 May 2023 01:12:03 -0700 (PDT) Received: from localhost.localdomain ([176.221.215.212]) by smtp.gmail.com with ESMTPSA id f16-20020a5d4dd0000000b003062ad45243sm16496375wru.14.2023.05.10.01.12.00 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 10 May 2023 01:12:02 -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 , 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 v5 3/5] spi: sun6i: add quirk for in-controller clock divider Date: Wed, 10 May 2023 11:11:10 +0300 Message-Id: <20230510081121.3463710-4-bigunclemax@gmail.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230510081121.3463710-1-bigunclemax@gmail.com> References: <20230510081121.3463710-1-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 Reviewed-by: Andre Przywara Reviewed-by: Jernej Skrabec --- drivers/spi/spi-sun6i.c | 91 +++++++++++++++++++++++++++-------------- 1 file changed, 61 insertions(+), 30 deletions(-) diff --git a/drivers/spi/spi-sun6i.c b/drivers/spi/spi-sun6i.c index 01a01cd86db5..e4efab310469 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 +353,65 @@ 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)) + * 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); + } 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); + reg &= ~(SUN6I_TFR_CTL_SDM | SUN6I_TFR_CTL_SDC); + + if (tfr->effective_speed_hz <= 24000000) + reg |= SUN6I_TFR_CTL_SDM; + else if (tfr->effective_speed_hz >= 80000000) + reg |= 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 +730,12 @@ 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[] = {