[PATCH] spi: fsl-dspi: add cs-gpios support

[PATCH] spi: fsl-dspi: add cs-gpios support

[Vladimir Oltean]

From: "Radu Pirea (NXP OSS)" <radu-nicolae.pirea@oss.nxp.com>

Make the driver be able to bit-bang a GPIO for the Chip Select pin of
select peripherals.

The GPIO value is driven by the driver in that case, and none of the
hardware Chip Select bits will be populated in the PUSHR register for
the TX commands constructed for this peripheral.

Signed-off-by: Radu Pirea (NXP OSS) <radu-nicolae.pirea@oss.nxp.com>
Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com>
---
 drivers/spi/spi-fsl-dspi.c | 36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index a33e547b7d39..e419642eb10e 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -900,12 +900,31 @@ static irqreturn_t dspi_interrupt(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static void dspi_assert_cs(struct spi_device *spi, bool *cs)
+{
+	if (!spi->cs_gpiod || *cs)
+		return;
+
+	gpiod_set_value_cansleep(spi->cs_gpiod, true);
+	*cs = true;
+}
+
+static void dspi_deassert_cs(struct spi_device *spi, bool *cs)
+{
+	if (!spi->cs_gpiod || !*cs)
+		return;
+
+	gpiod_set_value_cansleep(spi->cs_gpiod, false);
+	*cs = false;
+}
+
 static int dspi_transfer_one_message(struct spi_controller *ctlr,
 				     struct spi_message *message)
 {
 	struct fsl_dspi *dspi = spi_controller_get_devdata(ctlr);
 	struct spi_device *spi = message->spi;
 	struct spi_transfer *transfer;
+	bool cs = false;
 	int status = 0;
 
 	message->actual_length = 0;
@@ -914,9 +933,14 @@ static int dspi_transfer_one_message(struct spi_controller *ctlr,
 		dspi->cur_transfer = transfer;
 		dspi->cur_msg = message;
 		dspi->cur_chip = spi_get_ctldata(spi);
+
+		dspi_assert_cs(spi, &cs);
+
 		/* Prepare command word for CMD FIFO */
-		dspi->tx_cmd = SPI_PUSHR_CMD_CTAS(0) |
-			       SPI_PUSHR_CMD_PCS(spi->chip_select);
+		dspi->tx_cmd = SPI_PUSHR_CMD_CTAS(0);
+		if (!spi->cs_gpiod)
+			dspi->tx_cmd |= SPI_PUSHR_CMD_PCS(spi->chip_select);
+
 		if (list_is_last(&dspi->cur_transfer->transfer_list,
 				 &dspi->cur_msg->transfers)) {
 			/* Leave PCS activated after last transfer when
@@ -964,6 +988,9 @@ static int dspi_transfer_one_message(struct spi_controller *ctlr,
 			break;
 
 		spi_transfer_delay_exec(transfer);
+
+		if (!(dspi->tx_cmd & SPI_PUSHR_CMD_CONT))
+			dspi_deassert_cs(spi, &cs);
 	}
 
 	message->status = status;
@@ -981,6 +1008,7 @@ static int dspi_setup(struct spi_device *spi)
 	unsigned char pasc = 0, asc = 0;
 	struct chip_data *chip;
 	unsigned long clkrate;
+	bool cs = true;
 
 	/* Only alloc on first setup */
 	chip = spi_get_ctldata(spi);
@@ -1030,6 +1058,9 @@ static int dspi_setup(struct spi_device *spi)
 			chip->ctar_val |= SPI_CTAR_LSBFE;
 	}
 
+	gpiod_direction_output(spi->cs_gpiod, false);
+	dspi_deassert_cs(spi, &cs);
+
 	spi_set_ctldata(spi, chip);
 
 	return 0;
@@ -1248,6 +1279,7 @@ static int dspi_probe(struct platform_device *pdev)
 	ctlr->cleanup = dspi_cleanup;
 	ctlr->slave_abort = dspi_slave_abort;
 	ctlr->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST;
+	ctlr->use_gpio_descriptors = true;
 
 	pdata = dev_get_platdata(&pdev->dev);
 	if (pdata) {
-- 
2.34.1

Re: [PATCH] spi: fsl-dspi: add cs-gpios support

[Mark Brown]

On Fri, 11 Nov 2022 23:13:56 +0200, Vladimir Oltean wrote:
> From: "Radu Pirea (NXP OSS)" <radu-nicolae.pirea@oss.nxp.com>
> 
> Make the driver be able to bit-bang a GPIO for the Chip Select pin of
> select peripherals.
> 
> The GPIO value is driven by the driver in that case, and none of the
> hardware Chip Select bits will be populated in the PUSHR register for
> the TX commands constructed for this peripheral.
> 
> [...]

Applied to

   broonie/spi.git for-next

Thanks!

[1/1] spi: fsl-dspi: add cs-gpios support
      commit: 84b60f2bce1f0416617c4dbc015b5da906b8e2ad

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark