spi: rspi: Add support for loopback mode

Add support for specifying loopback mode.

Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

1 files changed, 14 insertions, 8 deletions

diff --git a/drivers/spi/spi-rspi.c b/drivers/spi/spi-rspi.c
index 0c7556978d2e..28db8770aaf3 100644
--- a/drivers/spi/spi-rspi.c
+++ b/drivers/spi/spi-rspi.c
@@ -183,8 +183,9 @@ struct rspi_data {
         struct spi_master *master;
         wait_queue_head_t wait;
         struct clk *clk;
-        u8 spsr;
         u16 spcmd;
+        u8 spsr;
+        u8 sppcr;
         int rx_irq, tx_irq;
         const struct spi_ops *ops;
 
@@ -252,8 +253,8 @@ static int rspi_set_config_register(struct rspi_data *rspi, int access_size)
 {
         int spbr;
 
-        /* Sets output mode(CMOS) and MOSI signal(from previous transfer) */
-        rspi_write8(rspi, 0x00, RSPI_SPPCR);
+        /* Sets output mode, MOSI signal, and (optionally) loopback */
+        rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR);
 
         /* Sets transfer bit rate */
         spbr = clk_get_rate(rspi->clk) / (2 * rspi->max_speed_hz) - 1;
@@ -288,8 +289,8 @@ static int rspi_rz_set_config_register(struct rspi_data *rspi, int access_size)
 {
         int spbr;
 
-        /* Sets output mode */
-        rspi_write8(rspi, 0x00, RSPI_SPPCR);
+        /* Sets output mode, MOSI signal, and (optionally) loopback */
+        rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR);
 
         /* Sets transfer bit rate */
         spbr = clk_get_rate(rspi->clk) / (2 * rspi->max_speed_hz) - 1;
@@ -322,8 +323,8 @@ static int qspi_set_config_register(struct rspi_data *rspi, int access_size)
         u16 spcmd;
         int spbr;
 
-        /* Sets output mode(CMOS) and MOSI signal(from previous transfer) */
-        rspi_write8(rspi, 0x00, RSPI_SPPCR);
+        /* Sets output mode, MOSI signal, and (optionally) loopback */
+        rspi_write8(rspi, rspi->sppcr, RSPI_SPPCR);
 
         /* Sets transfer bit rate */
         spbr = clk_get_rate(rspi->clk) / (2 * rspi->max_speed_hz);
@@ -829,6 +830,11 @@ static int rspi_setup(struct spi_device *spi)
         if (spi->mode & SPI_CPHA)
                 rspi->spcmd |= SPCMD_CPHA;
 
+        /* CMOS output mode and MOSI signal from previous transfer */
+        rspi->sppcr = 0;
+        if (spi->mode & SPI_LOOP)
+                rspi->sppcr |= SPPCR_SPLP;
+
         set_config_register(rspi, 8);
 
         return 0;
@@ -1050,7 +1056,7 @@ static int rspi_probe(struct platform_device *pdev)
         master->cleanup = rspi_cleanup;
         master->prepare_message = rspi_prepare_message;
         master->unprepare_message = rspi_unprepare_message;
-        master->mode_bits = SPI_CPHA | SPI_CPOL;
+        master->mode_bits = SPI_CPHA | SPI_CPOL | SPI_LOOP;
 
         ret = platform_get_irq_byname(pdev, "rx");
         if (ret < 0) {