Patch "spi: stm32: Revert change that enabled controller before asserting CS" has been added to the 6.9-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    spi: stm32: Revert change that enabled controller before asserting CS

to the 6.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     spi-stm32-revert-change-that-enabled-controller-befo.patch
and it can be found in the queue-6.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 27343412d1e6a6a47b03f4510e023796752f2ee7
Author: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
Date:   Thu May 23 12:33:25 2024 +0200

    spi: stm32: Revert change that enabled controller before asserting CS
    
    [ Upstream commit a827ad9b3c2fc243e058595533f91ce41a312527 ]
    
    On stm32mp157 enabling the controller before asserting CS makes the
    hardware trigger spurious interrupts in a tight loop and the transfers
    fail. Revert the commit that swapped the order of enable and CS. This
    reintroduces the problem that swapping was supposed to fix, which
    however is less grave.
    
    Reported-by: Leonard Göhrs <l.goehrs@xxxxxxxxxxxxxx>
    Link: https://lore.kernel.org/all/39033ed7-3e57-4339-80b4-fc8919e26aa7@xxxxxxxxxxxxxx/
    Fixes: 52b62e7a5d4f ("spi: stm32: enable controller before asserting CS")
    Signed-off-by: Uwe Kleine-König <u.kleine-koenig@xxxxxxxxxxxxxx>
    Link: https://msgid.link/r/20240523103326.792907-2-u.kleine-koenig@xxxxxxxxxxxxxx
    Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 4a68abcdcc353..e4e7ddb7524a9 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -1016,8 +1016,10 @@ static irqreturn_t stm32fx_spi_irq_event(int irq, void *dev_id)
 static irqreturn_t stm32fx_spi_irq_thread(int irq, void *dev_id)
 {
 	struct spi_controller *ctrl = dev_id;
+	struct stm32_spi *spi = spi_controller_get_devdata(ctrl);
 
 	spi_finalize_current_transfer(ctrl);
+	stm32fx_spi_disable(spi);
 
 	return IRQ_HANDLED;
 }
@@ -1185,8 +1187,6 @@ static int stm32_spi_prepare_msg(struct spi_controller *ctrl,
 			 ~clrb) | setb,
 			spi->base + spi->cfg->regs->cpol.reg);
 
-	stm32_spi_enable(spi);
-
 	spin_unlock_irqrestore(&spi->lock, flags);
 
 	return 0;
@@ -1204,6 +1204,7 @@ static void stm32fx_spi_dma_tx_cb(void *data)
 
 	if (spi->cur_comm == SPI_SIMPLEX_TX || spi->cur_comm == SPI_3WIRE_TX) {
 		spi_finalize_current_transfer(spi->ctrl);
+		stm32fx_spi_disable(spi);
 	}
 }
 
@@ -1218,6 +1219,7 @@ static void stm32_spi_dma_rx_cb(void *data)
 	struct stm32_spi *spi = data;
 
 	spi_finalize_current_transfer(spi->ctrl);
+	spi->cfg->disable(spi);
 }
 
 /**
@@ -1305,6 +1307,8 @@ static int stm32fx_spi_transfer_one_irq(struct stm32_spi *spi)
 
 	stm32_spi_set_bits(spi, STM32FX_SPI_CR2, cr2);
 
+	stm32_spi_enable(spi);
+
 	/* starting data transfer when buffer is loaded */
 	if (spi->tx_buf)
 		spi->cfg->write_tx(spi);
@@ -1341,6 +1345,8 @@ static int stm32h7_spi_transfer_one_irq(struct stm32_spi *spi)
 
 	spin_lock_irqsave(&spi->lock, flags);
 
+	stm32_spi_enable(spi);
+
 	/* Be sure to have data in fifo before starting data transfer */
 	if (spi->tx_buf)
 		stm32h7_spi_write_txfifo(spi);
@@ -1372,6 +1378,8 @@ static void stm32fx_spi_transfer_one_dma_start(struct stm32_spi *spi)
 		 */
 		stm32_spi_set_bits(spi, STM32FX_SPI_CR2, STM32FX_SPI_CR2_ERRIE);
 	}
+
+	stm32_spi_enable(spi);
 }
 
 /**
@@ -1405,6 +1413,8 @@ static void stm32h7_spi_transfer_one_dma_start(struct stm32_spi *spi)
 
 	stm32_spi_set_bits(spi, STM32H7_SPI_IER, ier);
 
+	stm32_spi_enable(spi);
+
 	if (STM32_SPI_HOST_MODE(spi))
 		stm32_spi_set_bits(spi, STM32H7_SPI_CR1, STM32H7_SPI_CR1_CSTART);
 }