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From: Lukasz Majewski <lukma@denx.de>
To: Mark Brown <broonie@kernel.org>
Cc: "Mark Rutland" <mark.rutland@arm.com>,
	linux-spi@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, "Esben Haabendal" <eha@deif.com>,
	"Martin Hundebøll" <martin@geanix.com>,
	"Andrey Smirnov" <andrew.smirnov@gmail.com>,
	"Lukasz Majewski" <lukma@denx.de>
Subject: [PATCHv3] ARM: dspi: Provide support for DSPI slave mode operation (Vybryd vf610)
Date: Tue, 13 Nov 2018 13:06:31 +0100	[thread overview]
Message-ID: <20181113120631.13514-1-lukma@denx.de> (raw)
In-Reply-To: <20180927150709.17010-1-lukma@denx.de>

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@denx.de>
---
Changes for v3:

- Rebase to v4.20-rc2 (no code changes needed)

Changes for v2:

- Remove patch which adds extra NXP specific DTS property to support slave
mode and reuse the generic one (spi-slave)
- Remove patch which brings back the mcr_register local copy. It is not
needed as generic SPI slave infrastructure is used.
- Rewrite the code to use spi_controller_is_slave() helper functions
---
 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 3082e72e4f6c..94b6a9690062 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");
-- 
2.11.0


  parent reply	other threads:[~2018-11-13 12:06 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-09-27 15:07 [PATCH v2] ARM: dspi: Provide support for DSPI slave more " Lukasz Majewski
2018-10-08 12:23 ` Lukasz Majewski
2018-10-23  9:13 ` [RESEND PATCHv2] " Lukasz Majewski
2018-11-13 12:06 ` Lukasz Majewski [this message]
2018-12-02  8:47   ` [PATCHv3] ARM: dspi: Provide support for DSPI slave mode " Lukasz Majewski
2018-12-09 21:57 ` [PATCHv4] " Lukasz Majewski
2019-01-09  8:26 ` [PATCH v5] " Lukasz Majewski
2019-02-04 10:30   ` Lukasz Majewski
2019-02-04 10:57     ` Mark Brown
2019-02-04 12:52       ` Lukasz Majewski
2019-02-04 13:03         ` Mark Brown
2019-02-04 13:12           ` Lukasz Majewski
2019-02-05 22:13 ` [PATCH v6] spi: spi-fsl-dspi: " Lukasz Majewski

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