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 X-Spam-Level: X-Spam-Status: No, score=-10.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4DACAC10DCE for ; Mon, 16 Mar 2020 02:43:02 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id 006DC205C9 for ; Mon, 16 Mar 2020 02:43:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="np3paPXd"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="qc5aV2xM" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 006DC205C9 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=+uDNhYK20WOm+zm7b2IKWqTpDpZLrI/HaV9OYL5eJbo=; b=np3paPXdc0Qbyr TGhbXhhXReHsqLhAilVUOztdR/sCBCJXEovUcqFvdFIo+dw70+8YvxeWGb6zotgM0OG8L5zMUky27 PoRk+sqAY8tlDE3KN5yUXhUxp+QznuPqQ2/jOBsWFHqDnsEun3Fl+QHdO7/zApEDg1xqvu1q2DIw0 qN+u1/7iqB5hbNmUBBibUr79KJqejWijBWh8uDr09l1JuE9uTs4GAIyOzUivSNgr1Di20kyzrVM+W SQKFGflAhoP4SP/o3TpU/7HElGnEwG9qsV8F2XH/DQore5uoXfv6EtYTGheI5JBMlh8dS5rcWZKxA mb7Sh0nD5hRTIYUokdzw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1jDfiW-00058n-TV; Mon, 16 Mar 2020 02:43:01 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jDfaq-0003PW-Em for linux-arm-kernel@lists.infradead.org; Mon, 16 Mar 2020 02:35:07 +0000 Received: from sasha-vm.mshome.net (c-73-47-72-35.hsd1.nh.comcast.net [73.47.72.35]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id B813820736; Mon, 16 Mar 2020 02:35:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1584326101; bh=AJRa0n88DC2qgkWf2Ghqel9HmLvQSawbXMVKIWBG8R8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qc5aV2xMNfgNOngSlmycq3sdwYE/T6dUuSRk/TBIpiAbFQh3sUR14bxthITb2nu5f vVuzaOOuA7+PvBxQfvvJlRTCrilXwBhOxEapN3ug0t6RH0MbFYGhs0oyYCrWsa+rDx xnXivERVPurkdiCQLpjsgv+PRkIR4ivQu4gQCyGU= From: Sasha Levin To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Subject: [PATCH AUTOSEL 4.19 06/20] spi: pxa2xx: Add CS control clock quirk Date: Sun, 15 Mar 2020 22:34:39 -0400 Message-Id: <20200316023453.1800-6-sashal@kernel.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20200316023453.1800-1-sashal@kernel.org> References: <20200316023453.1800-1-sashal@kernel.org> MIME-Version: 1.0 X-stable: review X-Patchwork-Hint: Ignore X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20200315_193504_617974_ED9012D9 X-CRM114-Status: GOOD ( 13.00 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Sasha Levin , Evan Green , linux-spi@vger.kernel.org, Mark Brown , Rajat Jain , linux-arm-kernel@lists.infradead.org Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org From: Evan Green [ Upstream commit 683f65ded66a9a7ff01ed7280804d2132ebfdf7e ] In some circumstances on Intel LPSS controllers, toggling the LPSS CS control register doesn't actually cause the CS line to toggle. This seems to be failure of dynamic clock gating that occurs after going through a suspend/resume transition, where the controller is sent through a reset transition. This ruins SPI transactions that either rely on delay_usecs, or toggle the CS line without sending data. Whenever CS is toggled, momentarily set the clock gating register to "Force On" to poke the controller into acting on CS. Signed-off-by: Rajat Jain Signed-off-by: Evan Green Link: https://lore.kernel.org/r/20200211223700.110252-1-rajatja@google.com Signed-off-by: Mark Brown Signed-off-by: Sasha Levin --- drivers/spi/spi-pxa2xx.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+) diff --git a/drivers/spi/spi-pxa2xx.c b/drivers/spi/spi-pxa2xx.c index 525388126e260..e4482823d8d75 100644 --- a/drivers/spi/spi-pxa2xx.c +++ b/drivers/spi/spi-pxa2xx.c @@ -76,6 +76,10 @@ MODULE_ALIAS("platform:pxa2xx-spi"); #define LPSS_CAPS_CS_EN_SHIFT 9 #define LPSS_CAPS_CS_EN_MASK (0xf << LPSS_CAPS_CS_EN_SHIFT) +#define LPSS_PRIV_CLOCK_GATE 0x38 +#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK 0x3 +#define LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON 0x3 + struct lpss_config { /* LPSS offset from drv_data->ioaddr */ unsigned offset; @@ -92,6 +96,8 @@ struct lpss_config { unsigned cs_sel_shift; unsigned cs_sel_mask; unsigned cs_num; + /* Quirks */ + unsigned cs_clk_stays_gated : 1; }; /* Keep these sorted with enum pxa_ssp_type */ @@ -162,6 +168,7 @@ static const struct lpss_config lpss_platforms[] = { .tx_threshold_hi = 56, .cs_sel_shift = 8, .cs_sel_mask = 3 << 8, + .cs_clk_stays_gated = true, }, }; @@ -389,6 +396,22 @@ static void lpss_ssp_cs_control(struct spi_device *spi, bool enable) else value |= LPSS_CS_CONTROL_CS_HIGH; __lpss_ssp_write_priv(drv_data, config->reg_cs_ctrl, value); + if (config->cs_clk_stays_gated) { + u32 clkgate; + + /* + * Changing CS alone when dynamic clock gating is on won't + * actually flip CS at that time. This ruins SPI transfers + * that specify delays, or have no data. Toggle the clock mode + * to force on briefly to poke the CS pin to move. + */ + clkgate = __lpss_ssp_read_priv(drv_data, LPSS_PRIV_CLOCK_GATE); + value = (clkgate & ~LPSS_PRIV_CLOCK_GATE_CLK_CTL_MASK) | + LPSS_PRIV_CLOCK_GATE_CLK_CTL_FORCE_ON; + + __lpss_ssp_write_priv(drv_data, LPSS_PRIV_CLOCK_GATE, value); + __lpss_ssp_write_priv(drv_data, LPSS_PRIV_CLOCK_GATE, clkgate); + } } static void cs_assert(struct spi_device *spi) -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel