From patchwork Tue Feb 6 10:00:50 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Louis Chauvet X-Patchwork-Id: 770573 Received: from relay1-d.mail.gandi.net (relay1-d.mail.gandi.net [217.70.183.193]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 7297F12D76D; Tue, 6 Feb 2024 10:01:08 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.70.183.193 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707213671; cv=none; b=sxQgZ/anhhZ8fIQ2jHWN1uubm51RhaRUsqQQdF+5CQmsab5vvt53AKh3XTwGc4HviE2Ctg7/JhrCfDfkGdYQAR30SeBrF71CWZVoylpU/y6WmKPoB1Z7wQ3fw4xCjobWay+uVsrtGQhgaZrQ+pr2cwGJnA3OV0f83zin5RBPlTc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1707213671; c=relaxed/simple; bh=dLeoHdat5+2yokZ57ZMb1U/V1RdRR+uIGAJcxMGtu2w=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=tXMfIgqAv9PCADsR/RFCbEOQZ7U6oya9xcPZ3/cxWRtChTB707i05sqzQe1I1dU/Vx1xniMRhF8fZTpvK/m5vNTw1YjKTjTswx6o3o0NxfPAREfFmChIlzC+r5JbZM8/EukekvnaJtJbwEtOKrvuUezj/cY69xsw8kbBrFBtcBU= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com; spf=pass smtp.mailfrom=bootlin.com; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b=J+oeDK55; arc=none smtp.client-ip=217.70.183.193 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=bootlin.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=bootlin.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=bootlin.com header.i=@bootlin.com header.b="J+oeDK55" Received: by mail.gandi.net (Postfix) with ESMTPSA id 3893B240012; Tue, 6 Feb 2024 10:01:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bootlin.com; s=gm1; t=1707213661; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7ZyyNB/CZxx9/DUWNjxPsDT3HiAzuHwEEv/w7sNe/Cg=; b=J+oeDK55buHO+8CcYynTWmMMg+qfgizl8HUCfvSWyp4iSLtf04Hrv1xBFwTLYw7usBX6hW bxBKB0AAWZVRQJl0OFoTuTdayGkVo8gonZRhgf6MVdEBDnuAWxJAQv3cF6I7ORwJVnpCga GVbs1PyXfU/2cFsGuhwy4+f0mbQIXImEwfyEeI2Ng7dfIxDJpC8nWXcfyrRyv34ThBp3Yc 85Dv1RIAnDczpOLW7kaNqDFy+eYAQuT0ZRkwZuDln+TME8QSuQ05mYXu9aRfVSljWv9jWB WNaxMsrFcVh7GkKRze01RKD61HwtXvIG0ryznNkL5KfgCA4umFyR9BNR0eJtiA== From: Louis Chauvet Date: Tue, 06 Feb 2024 11:00:50 +0100 Subject: [PATCH 2/2] spi: omap2-mcspi: Add support for MULTI-mode Precedence: bulk X-Mailing-List: linux-spi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240126-spi-omap2-mcspi-multi-mode-v1-2-d143d33f0fe0@bootlin.com> References: <20240126-spi-omap2-mcspi-multi-mode-v1-0-d143d33f0fe0@bootlin.com> In-Reply-To: <20240126-spi-omap2-mcspi-multi-mode-v1-0-d143d33f0fe0@bootlin.com> To: Mark Brown Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org, thomas.petazzoni@bootlin.com, Miquel Raynal , yen-mei.goh@keysight.com, koon-kee.lie@keysight.com, Louis Chauvet X-Mailer: b4 0.12.1 X-Developer-Signature: v=1; a=openpgp-sha256; l=4015; i=louis.chauvet@bootlin.com; h=from:subject:message-id; bh=dLeoHdat5+2yokZ57ZMb1U/V1RdRR+uIGAJcxMGtu2w=; b=owEBbQKS/ZANAwAIASCtLsZbECziAcsmYgBlwgNc490SgPJdYZBCh8N73jiZS1KgRhcdKvOucQHs mmRLqHWJAjMEAAEIAB0WIQRPj7g/vng8MQxQWQQgrS7GWxAs4gUCZcIDXAAKCRAgrS7GWxAs4rhwD/ 9jG8LYFgLIO0pYCUnLTGlca5mn6PEjqk+gZKi2JAcQ5/p1YlnV6w3ZSuFqOY+FgNXAPc0voIN/P9T2 yJztrL12vfJf90d5D4SptCK0Ncmv+bJguUiY9ELbwqa6y67EoecbKnb3kIbGJ1foqbJaq1Qw3gZGtY WMF7Mkz2fngaQeAOctrnBT8Fs1y4am7TZ+bhD5ffr/b2v6Fi9vSPPXo6/nVk79OXkt1XYcktDlUvF4 3wHCDyeGfjw4E2sdmF3ZLXhC+SsEFbhqJZZ5m/gc3hItN9+pQ08jiYFX1QUjfx1SICnWL1j1Am5Moq qm82fjr/iekD3yBIYFYAQUojmR2PmGEXN2ieuwBMcRw1WXPX9bfaWj0wSzV70LNoNd4hmmLxu5C9MF KS8ydETXSG4HxoAtbLnLDc0+V+1YQUrIN0W63yX5fg6p1ZJ0NEGJfa8sRloViKKXBoqMqM/rYmVRnI i5St0q9kznSlgnBDDV8CR6cyu3EaDTbugGZz/yzoFQGyCALN+RaX7M1ELJMUl/9FiLF7Oo0rj5yJxr WA/ZCmfEs8jVNQhWeZwYPMHAgYRJ+762tML1CQBlFqbw3bdFbpAR1xziT3F1YsQL59zMKbPoNP+p60 0ZEr008aPriW0QFXDtNRTkFnap9K2598aoRc14UNYKJm4xkIavAj5M7JkNqQ== X-Developer-Key: i=louis.chauvet@bootlin.com; a=openpgp; fpr=8B7104AE9A272D6693F527F2EC1883F55E0B40A5 X-GND-Sasl: louis.chauvet@bootlin.com Introduce support for MULTI-mode in the OMAP2 MCSPI driver. Currently, the driver always uses SINGLE mode to handle the chip select (CS). With this enhancement, MULTI-mode is enabled for specific messages, allowing for a shorter delay between CS enable and the message (some FPGA devices are sensitive to this delay). The drawback of multi-mode is that it's not possible to keep the CS enabled between each words. Therefore, this patch enables multi-mode only for specific messages: the spi_message must contain only spi_transfer of 1 word (of any size) with cs_change enabled. A new member is introduced in the omap2_mcspi structure to keep track of the current used mode. Signed-off-by: Louis Chauvet --- drivers/spi/spi-omap2-mcspi.c | 57 ++++++++++++++++++++++++++++++++++++++----- 1 file changed, 51 insertions(+), 6 deletions(-) diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c index fc7f69973334..ab22b1b062f3 100644 --- a/drivers/spi/spi-omap2-mcspi.c +++ b/drivers/spi/spi-omap2-mcspi.c @@ -133,6 +133,8 @@ struct omap2_mcspi { unsigned int pin_dir:1; size_t max_xfer_len; u32 ref_clk_hz; + + bool use_multi_mode; }; struct omap2_mcspi_cs { @@ -258,10 +260,15 @@ static void omap2_mcspi_set_cs(struct spi_device *spi, bool enable) l = mcspi_cached_chconf0(spi); - if (enable) + /* Only enable chip select manually if single mode is used */ + if (mcspi->use_multi_mode) { l &= ~OMAP2_MCSPI_CHCONF_FORCE; - else - l |= OMAP2_MCSPI_CHCONF_FORCE; + } else { + if (enable) + l &= ~OMAP2_MCSPI_CHCONF_FORCE; + else + l |= OMAP2_MCSPI_CHCONF_FORCE; + } mcspi_write_chconf0(spi, l); @@ -285,7 +292,12 @@ static void omap2_mcspi_set_mode(struct spi_controller *ctlr) l |= (OMAP2_MCSPI_MODULCTRL_MS); } else { l &= ~(OMAP2_MCSPI_MODULCTRL_MS); - l |= OMAP2_MCSPI_MODULCTRL_SINGLE; + + /* Enable single mode if needed */ + if (mcspi->use_multi_mode) + l &= ~OMAP2_MCSPI_MODULCTRL_SINGLE; + else + l |= OMAP2_MCSPI_MODULCTRL_SINGLE; } mcspi_write_reg(ctlr, OMAP2_MCSPI_MODULCTRL, l); @@ -1371,15 +1383,48 @@ static int omap2_mcspi_prepare_message(struct spi_controller *ctlr, struct omap2_mcspi *mcspi = spi_controller_get_devdata(ctlr); struct omap2_mcspi_regs *ctx = &mcspi->ctx; struct omap2_mcspi_cs *cs; + struct spi_transfer *tr; + u8 bits_per_word; + u32 speed_hz; - /* Only a single channel can have the FORCE bit enabled + /* + * The conditions are strict, it is mandatory to check each transfer of the list to see if + * multi-mode is applicable. + */ + mcspi->use_multi_mode = true; + list_for_each_entry(tr, &msg->transfers, transfer_list) { + if (!tr->bits_per_word) + bits_per_word = msg->spi->bits_per_word; + else + bits_per_word = tr->bits_per_word; + + /* Check if the transfer content is only one word */ + if ((bits_per_word < 8 && tr->len > 1) || + (bits_per_word >= 8 && tr->len > bits_per_word / 8)) + mcspi->use_multi_mode = false; + + /* Check if transfer asks to change the CS status after the transfer */ + if (!tr->cs_change) + mcspi->use_multi_mode = false; + + /* If at least one message is not compatible, switch back to single mode */ + if (!mcspi->use_multi_mode) + break; + } + + omap2_mcspi_set_mode(master); + + /* In single mode only a single channel can have the FORCE bit enabled * in its chconf0 register. * Scan all channels and disable them except the current one. * A FORCE can remain from a last transfer having cs_change enabled + * + * In multi mode all FORCE bits must be disabled. */ list_for_each_entry(cs, &ctx->cs, node) { - if (msg->spi->controller_state == cs) + if (msg->spi->controller_state == cs && !mcspi->use_multi_mode) { continue; + } if ((cs->chconf0 & OMAP2_MCSPI_CHCONF_FORCE)) { cs->chconf0 &= ~OMAP2_MCSPI_CHCONF_FORCE;