Applied "spi: spi-fsl-dspi: Provide support for DSPI slave mode operation (Vybryd vf610)" to the spi tree

[Mark Brown <broonie@xxxxxxxxxx>]

The patch

   spi: spi-fsl-dspi: Provide support for DSPI slave mode operation (Vybryd vf610)

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

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

>From 5ce3cc567471891be69a6f51146209560f132b83 Mon Sep 17 00:00:00 2001
From: Lukasz Majewski <lukma@xxxxxxx>
Date: Tue, 5 Feb 2019 23:13:49 +0100
Subject: [PATCH] spi: spi-fsl-dspi: Provide support for DSPI slave mode
 operation (Vybryd vf610)

The NXP's Vybryd vf610 can work as a SPI slave device (the CS and clock
signals are provided by master).

It is possible to specify a single device to work in that mode. As we do
use DMA for transferring data, the RX channel must be prepared for
incoming data.
Moreover, in slave mode we just set a subset of control fields in
configuration registers (CTAR0, PUSHR).

For testing the spidev_test program has been used.
Test script for this patch can be found here:
https://github.com/lmajewski/tests-spi/blob/master/tests/spi/spi_tests.sh

Signed-off-by: Lukasz Majewski <lukma@xxxxxxx>
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
---
 drivers/spi/spi-fsl-dspi.c | 40 ++++++++++++++++++++++++++++----------
 1 file changed, 30 insertions(+), 10 deletions(-)

diff --git a/drivers/spi/spi-fsl-dspi.c b/drivers/spi/spi-fsl-dspi.c
index 5e10dc5c93a5..348682be9dd5 100644
--- a/drivers/spi/spi-fsl-dspi.c
+++ b/drivers/spi/spi-fsl-dspi.c
@@ -233,6 +233,9 @@ static u32 dspi_pop_tx_pushr(struct fsl_dspi *dspi)
 {
 	u16 cmd = dspi->tx_cmd, data = dspi_pop_tx(dspi);
 
+	if (spi_controller_is_slave(dspi->master))
+		return data;
+
 	if (dspi->len > 0)
 		cmd |= SPI_PUSHR_CMD_CONT;
 	return cmd << 16 | data;
@@ -329,6 +332,11 @@ static int dspi_next_xfer_dma_submit(struct fsl_dspi *dspi)
 	dma_async_issue_pending(dma->chan_rx);
 	dma_async_issue_pending(dma->chan_tx);
 
+	if (spi_controller_is_slave(dspi->master)) {
+		wait_for_completion_interruptible(&dspi->dma->cmd_rx_complete);
+		return 0;
+	}
+
 	time_left = wait_for_completion_timeout(&dspi->dma->cmd_tx_complete,
 					DMA_COMPLETION_TIMEOUT);
 	if (time_left == 0) {
@@ -798,14 +806,18 @@ static int dspi_setup(struct spi_device *spi)
 	ns_delay_scale(&pasc, &asc, sck_cs_delay, clkrate);
 
 	chip->ctar_val = SPI_CTAR_CPOL(spi->mode & SPI_CPOL ? 1 : 0)
-		| SPI_CTAR_CPHA(spi->mode & SPI_CPHA ? 1 : 0)
-		| SPI_CTAR_LSBFE(spi->mode & SPI_LSB_FIRST ? 1 : 0)
-		| SPI_CTAR_PCSSCK(pcssck)
-		| SPI_CTAR_CSSCK(cssck)
-		| SPI_CTAR_PASC(pasc)
-		| SPI_CTAR_ASC(asc)
-		| SPI_CTAR_PBR(pbr)
-		| SPI_CTAR_BR(br);
+		| SPI_CTAR_CPHA(spi->mode & SPI_CPHA ? 1 : 0);
+
+	if (!spi_controller_is_slave(dspi->master)) {
+		chip->ctar_val |= SPI_CTAR_LSBFE(spi->mode &
+						 SPI_LSB_FIRST ? 1 : 0)
+			| SPI_CTAR_PCSSCK(pcssck)
+			| SPI_CTAR_CSSCK(cssck)
+			| SPI_CTAR_PASC(pasc)
+			| SPI_CTAR_ASC(asc)
+			| SPI_CTAR_PBR(pbr)
+			| SPI_CTAR_BR(br);
+	}
 
 	spi_set_ctldata(spi, chip);
 
@@ -970,8 +982,13 @@ static const struct regmap_config dspi_xspi_regmap_config[] = {
 
 static void dspi_init(struct fsl_dspi *dspi)
 {
-	regmap_write(dspi->regmap, SPI_MCR, SPI_MCR_MASTER | SPI_MCR_PCSIS |
-		     (dspi->devtype_data->xspi_mode ? SPI_MCR_XSPI : 0));
+	unsigned int mcr = SPI_MCR_PCSIS |
+		(dspi->devtype_data->xspi_mode ? SPI_MCR_XSPI : 0);
+
+	if (!spi_controller_is_slave(dspi->master))
+		mcr |= SPI_MCR_MASTER;
+
+	regmap_write(dspi->regmap, SPI_MCR, mcr);
 	regmap_write(dspi->regmap, SPI_SR, SPI_SR_CLEAR);
 	if (dspi->devtype_data->xspi_mode)
 		regmap_write(dspi->regmap, SPI_CTARE(0),
@@ -1027,6 +1044,9 @@ static int dspi_probe(struct platform_device *pdev)
 		}
 		master->bus_num = bus_num;
 
+		if (of_property_read_bool(np, "spi-slave"))
+			master->slave = true;
+
 		dspi->devtype_data = of_device_get_match_data(&pdev->dev);
 		if (!dspi->devtype_data) {
 			dev_err(&pdev->dev, "can't get devtype_data\n");
-- 
2.20.1