Commit Message

Maksim Kiselev Dec. 3, 2020, 4:57 p.m. UTC

From 772007b92eda50186c2e420b5bd895d4e4006ae8 Mon Sep 17 00:00:00 2001
From: Maxim Kiselev <[e-mail]>
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 <[e-mail]>
---
 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;

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)) {