linux-kernel - [PATCH v2] spi: atmel: Fix CS and initialization bug

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Message-ID: <20210629192218.32125-1-dan.sneddon@microchip.com>
Date:   Tue, 29 Jun 2021 12:22:18 -0700
From:   Dan Sneddon <dan.sneddon@...rochip.com>
To:     Dan Sneddon <dan.sneddon@...rochip.com>,
        Mark Brown <broonie@...nel.org>, <linux-spi@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
CC:     Tudor Ambarus <tudor.ambarus@...rochip.com>,
        Nicolas Ferre <nicolas.ferre@...rochip.com>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>,
        Ludovic Desroches <ludovic.desroches@...rochip.com>
Subject: [PATCH v2] spi: atmel: Fix CS and initialization bug

Commit 5fa5e6dec762 ("spi: atmel: Switch to transfer_one transfer
method") switched to using transfer_one and set_cs.  The
core doesn't call set_cs when the chip select lines are gpios.  Add the
SPI_MASTER_GPIO_SS flag to the driver to ensure the calls to set_cs
happen since the driver programs configuration registers there.

Fixes: 5fa5e6dec762 ("spi: atmel: Switch to transfer_one transfer method")

Signed-off-by: Dan Sneddon <dan.sneddon@...rochip.com>
---

Changes in v2:
- Updated commit message
- Dropped unnecessary change to enable variable in set_cs

 drivers/spi/spi-atmel.c | 9 ++-------
 1 file changed, 2 insertions(+), 7 deletions(-)

diff --git a/drivers/spi/spi-atmel.c b/drivers/spi/spi-atmel.c
index 2ef74885ffa2..788dcdf25f00 100644
--- a/drivers/spi/spi-atmel.c
+++ b/drivers/spi/spi-atmel.c
@@ -352,8 +352,6 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 		}
 
 		mr = spi_readl(as, MR);
-		if (spi->cs_gpiod)
-			gpiod_set_value(spi->cs_gpiod, 1);
 	} else {
 		u32 cpol = (spi->mode & SPI_CPOL) ? SPI_BIT(CPOL) : 0;
 		int i;
@@ -369,8 +367,6 @@ static void cs_activate(struct atmel_spi *as, struct spi_device *spi)
 
 		mr = spi_readl(as, MR);
 		mr = SPI_BFINS(PCS, ~(1 << chip_select), mr);
-		if (spi->cs_gpiod)
-			gpiod_set_value(spi->cs_gpiod, 1);
 		spi_writel(as, MR, mr);
 	}
 
@@ -400,8 +396,6 @@ static void cs_deactivate(struct atmel_spi *as, struct spi_device *spi)
 
 	if (!spi->cs_gpiod)
 		spi_writel(as, CR, SPI_BIT(LASTXFER));
-	else
-		gpiod_set_value(spi->cs_gpiod, 0);
 }
 
 static void atmel_spi_lock(struct atmel_spi *as) __acquires(&as->lock)
@@ -1483,7 +1477,8 @@ static int atmel_spi_probe(struct platform_device *pdev)
 	master->bus_num = pdev->id;
 	master->num_chipselect = 4;
 	master->setup = atmel_spi_setup;
-	master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX);
+	master->flags = (SPI_MASTER_MUST_RX | SPI_MASTER_MUST_TX |
+			SPI_MASTER_GPIO_SS);
 	master->transfer_one = atmel_spi_one_transfer;
 	master->set_cs = atmel_spi_set_cs;
 	master->cleanup = atmel_spi_cleanup;
-- 
2.17.1