diff mbox series

spi: spi-fsl-dspi: Add GPIO chip select support

Message ID CALHCpMgQPDqV1tB6v0sA0imwfZGkoG_j84NZCehOT1pf8MTuCA@mail.gmail.com
State New
Headers show
Series spi: spi-fsl-dspi: Add GPIO chip select support | expand

Commit Message

Maksim Kiselev Dec. 3, 2020, 5:12 p.m. UTC 
From: Maxim Kiselev <bigunclemax@gmail.com>
Date: Thu, 3 Dec 2020 18:56:12 +0300
Subject: [PATCH] spi: spi-fsl-dspi: Add GPIO chip select support

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@gmail.com>
---
 drivers/spi/spi-fsl-dspi.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

             /* 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;

Comments

Vladimir Oltean Dec. 4, 2020, 1:05 a.m. UTC | #1 
On Thu, Dec 03, 2020 at 09:50:04PM +0300, Maksim Kiselev wrote:
> In any case, I would like to add functionality for using GPIO as CS.
> Because I have a board which actually uses this.

I have absolutely nothing to object to that.
But the patches should still be as clean as possible, though.
diff mbox series

Patch

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)) {