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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Amelie Delaunay <amelie.delaunay@foss.st.com>,
        Alain Volmat <alain.volmat@foss.st.com>,
        Mark Brown <broonie@kernel.org>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.10 07/30] spi: stm32h7: fix full duplex irq handler handling
Date:   Fri,  6 Aug 2021 10:16:45 +0200
Message-Id: <20210806081113.374963345@linuxfoundation.org>
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From: Alain Volmat <alain.volmat@foss.st.com>

[ Upstream commit e4a5c19888a5f8a9390860ca493e643be58c8791 ]

In case of Full-Duplex mode, DXP flag is set when RXP and TXP flags are
set. But to avoid 2 different handlings, just add TXP and RXP flag in
the mask instead of DXP, and then keep the initial handling of TXP and
RXP events.
Also rephrase comment about EOTIE which is one of the interrupt enable
bits. It is not triggered by any event.

Signed-off-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>
Reviewed-by: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/1625042723-661-3-git-send-email-alain.volmat@foss.st.com
Signed-off-by: Mark Brown <broonie@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/spi/spi-stm32.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 8f91f8705eee..a6dfc8fef20c 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -917,15 +917,18 @@ static irqreturn_t stm32h7_spi_irq_thread(int irq, void *dev_id)
 	ier = readl_relaxed(spi->base + STM32H7_SPI_IER);
 
 	mask = ier;
-	/* EOTIE is triggered on EOT, SUSP and TXC events. */
+	/*
+	 * EOTIE enables irq from EOT, SUSP and TXC events. We need to set
+	 * SUSP to acknowledge it later. TXC is automatically cleared
+	 */
+
 	mask |= STM32H7_SPI_SR_SUSP;
 	/*
-	 * When TXTF is set, DXPIE and TXPIE are cleared. So in case of
-	 * Full-Duplex, need to poll RXP event to know if there are remaining
-	 * data, before disabling SPI.
+	 * DXPIE is set in Full-Duplex, one IT will be raised if TXP and RXP
+	 * are set. So in case of Full-Duplex, need to poll TXP and RXP event.
 	 */
-	if (spi->rx_buf && !spi->cur_usedma)
-		mask |= STM32H7_SPI_SR_RXP;
+	if ((spi->cur_comm == SPI_FULL_DUPLEX) && !spi->cur_usedma)
+		mask |= STM32H7_SPI_SR_TXP | STM32H7_SPI_SR_RXP;
 
 	if (!(sr & mask)) {
 		dev_warn(spi->dev, "spurious IT (sr=0x%08x, ier=0x%08x)\n",
-- 
2.30.2