1 files changed, 26 insertions, 0 deletions

diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index 323c66c5db50..55afdcee7d2b 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -12,6 +12,7 @@
 #include <linux/delay.h>
 #include <linux/slab.h>
 #include <linux/spi/spi.h>
+#include <linux/of.h>
 
 #include "spi-dw.h"
 
@@ -26,6 +27,8 @@ struct chip_data {
 
 	u16 clk_div;		/* baud rate divider */
 	u32 speed_hz;		/* baud rate */
+
+	u32 rx_sample_dly;	/* RX sample delay */
 };
 
 #ifdef CONFIG_DEBUG_FS
@@ -52,6 +55,7 @@ static const struct debugfs_reg32 dw_spi_dbgfs_regs[] = {
 	DW_SPI_DBGFS_REG("DMACR", DW_SPI_DMACR),
 	DW_SPI_DBGFS_REG("DMATDLR", DW_SPI_DMATDLR),
 	DW_SPI_DBGFS_REG("DMARDLR", DW_SPI_DMARDLR),
+	DW_SPI_DBGFS_REG("RX_SAMPLE_DLY", DW_SPI_RX_SAMPLE_DLY),
 };
 
 static int dw_spi_debugfs_init(struct dw_spi *dws)
@@ -328,6 +332,12 @@ static int dw_spi_transfer_one(struct spi_controller *master,
 	if (master->can_dma && master->can_dma(master, spi, transfer))
 		dws->dma_mapped = master->cur_msg_mapped;
 
+	/* Update RX sample delay if required */
+	if (dws->cur_rx_sample_dly != chip->rx_sample_dly) {
+		dw_writel(dws, DW_SPI_RX_SAMPLE_DLY, chip->rx_sample_dly);
+		dws->cur_rx_sample_dly = chip->rx_sample_dly;
+	}
+
 	/* For poll mode just disable all interrupts */
 	spi_mask_intr(dws, 0xff);
 
@@ -380,10 +390,22 @@ static int dw_spi_setup(struct spi_device *spi)
 	/* Only alloc on first setup */
 	chip = spi_get_ctldata(spi);
 	if (!chip) {
+		struct dw_spi *dws = spi_controller_get_devdata(spi->controller);
+		u32 rx_sample_dly_ns;
+
 		chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
 		if (!chip)
 			return -ENOMEM;
 		spi_set_ctldata(spi, chip);
+		/* Get specific / default rx-sample-delay */
+		if (device_property_read_u32(&spi->dev,
+					     "rx-sample-delay-ns",
+					     &rx_sample_dly_ns) != 0)
+			/* Use default controller value */
+			rx_sample_dly_ns = dws->def_rx_sample_dly_ns;
+		chip->rx_sample_dly = DIV_ROUND_CLOSEST(rx_sample_dly_ns,
+							NSEC_PER_SEC /
+							dws->max_freq);
 	}
 
 	chip->tmode = SPI_TMOD_TR;
@@ -472,6 +494,10 @@ int dw_spi_add_host(struct device *dev, struct dw_spi *dws)
 	if (dws->set_cs)
 		master->set_cs = dws->set_cs;
 
+	/* Get default rx sample delay */
+	device_property_read_u32(dev, "rx-sample-delay-ns",
+				 &dws->def_rx_sample_dly_ns);
+
 	/* Basic HW init */
 	spi_hw_init(dev, dws);