[PATCH] spi: spi-fsl-dspi: Add GPIO chip select support

[Maxim Kiselev]

This patch allows use of GPIO for the chip select.
Because dSPI controller can't send transactions without hardware chip
selects, so first unused native CS will be set in SPI_PUSHR_CMD_PCS

Signed-off-by: Maxim Kiselev <bigunclemax@xxxxxxxxx>
---
 drivers/spi/spi-fsl-dspi.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 028736687488..d5fba34de740 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -913,9 +913,14 @@ 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);
+
+        if (spi->cs_gpiod)
+            gpiod_set_value(spi->cs_gpiod, 1);
+
         /* Prepare command word for CMD FIFO */
         dspi->tx_cmd = SPI_PUSHR_CMD_CTAS(0) |
-                   SPI_PUSHR_CMD_PCS(spi->chip_select);
+                   SPI_PUSHR_CMD_PCS(spi->cs_gpiod ?
+                         ctlr->unused_native_cs : spi->chip_select);
         if (list_is_last(&dspi->cur_transfer->transfer_list,
                  &dspi->cur_msg->transfers)) {
             /* Leave PCS activated after last transfer when
@@ -1240,6 +1245,7 @@ static int dspi_probe(struct platform_device *pdev)
     dspi->pdev = pdev;
     dspi->ctlr = ctlr;

+    ctlr->use_gpio_descriptors = true;
     ctlr->setup = dspi_setup;
     ctlr->transfer_one_message = dspi_transfer_one_message;
     ctlr->dev.of_node = pdev->dev.of_node;
-- 
2.27.0