linux-kernel - [PATCH 12/18] spi: stm32: move spi disable out of irq handler

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Date:   Wed, 5 Aug 2020 09:02:07 +0200
From:   Alain Volmat <alain.volmat@...com>
To:     <broonie@...nel.org>, <amelie.delaunay@...com>
CC:     <mcoquelin.stm32@...il.com>, <alexandre.torgue@...com>,
        <linux-spi@...r.kernel.org>,
        <linux-stm32@...md-mailman.stormreply.com>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>, <fabrice.gasnier@...com>,
        <alain.volmat@...com>
Subject: [PATCH 12/18] spi: stm32: move spi disable out of irq handler

From: Antonio Borneo <antonio.borneo@...com>

The spi disable could potentially require some time to finish.
It has to be executed at the end of a transfer, but there is
no reason to call it in the irq handler.

Simplify the irq handler by moving out the spi disable. The
synchronization through xfer_completion is used to defer the
execution of spi disable.

Signed-off-by: Antonio Borneo <antonio.borneo@...com>
Signed-off-by: Alain Volmat <alain.volmat@...com>
---
 drivers/spi/spi-stm32.c | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c
index 0eda9903e11e..1a703c4a65db 100644
--- a/drivers/spi/spi-stm32.c
+++ b/drivers/spi/spi-stm32.c
@@ -874,7 +874,6 @@ static irqreturn_t stm32f4_spi_irq_thread(int irq, void *dev_id)
 	struct spi_master *master = dev_id;
 	struct stm32_spi *spi = spi_master_get_devdata(master);
 
-	stm32f4_spi_disable(spi);
 	complete(&spi->xfer_completion);
 
 	return IRQ_HANDLED;
@@ -963,15 +962,18 @@ static irqreturn_t stm32h7_spi_irq_thread(int irq, void *dev_id)
 		if (!spi->cur_usedma && (spi->rx_buf && (spi->rx_len > 0)))
 			stm32h7_spi_read_rxfifo(spi);
 
-	writel_relaxed(ifcr, spi->base + STM32H7_SPI_IFCR);
-
-	spin_unlock_irqrestore(&spi->lock, flags);
-
 	if (end) {
-		stm32h7_spi_disable(spi);
+		/* Disable interrupts and clear status flags */
+		writel_relaxed(0, spi->base + STM32H7_SPI_IER);
+		writel_relaxed(STM32H7_SPI_IFCR_ALL,
+			       spi->base + STM32H7_SPI_IFCR);
+
 		complete(&spi->xfer_completion);
+	} else {
+		writel_relaxed(ifcr, spi->base + STM32H7_SPI_IFCR);
 	}
 
+	spin_unlock_irqrestore(&spi->lock, flags);
 	return IRQ_HANDLED;
 }
 
@@ -1039,10 +1041,8 @@ static void stm32f4_spi_dma_tx_cb(void *data)
 {
 	struct stm32_spi *spi = data;
 
-	if (spi->cur_comm == SPI_SIMPLEX_TX || spi->cur_comm == SPI_3WIRE_TX) {
-		stm32f4_spi_disable(spi);
+	if (spi->cur_comm == SPI_SIMPLEX_TX || spi->cur_comm == SPI_3WIRE_TX)
 		complete(&spi->xfer_completion);
-	}
 }
 
 /**
@@ -1055,7 +1055,6 @@ static void stm32f4_spi_dma_rx_cb(void *data)
 {
 	struct stm32_spi *spi = data;
 
-	stm32f4_spi_disable(spi);
 	complete(&spi->xfer_completion);
 }
 
@@ -1697,9 +1696,10 @@ static int stm32_spi_transfer_one(struct spi_master *master,
 	if (!ret) {
 		dev_err(spi->dev, "SPI transfer timeout (%u ms)\n", xfer_time);
 		spi->xfer_status = -ETIMEDOUT;
-		spi->cfg->disable(spi);
 	}
 
+	spi->cfg->disable(spi);
+
 	spi_finalize_current_transfer(master);
 
 	return spi->xfer_status;
-- 
2.7.4