[PATCH 06/11] spi: dw: update SPI_CTRLR0 register

[Sudip Mukherjee <sudip.mukherjee@sifive.com>]

If the controller supports enhanced SPI modes then update the register
or reset the register if the transfer is not using dual/quad/octal mode.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@sifive.com>
---
 drivers/spi/spi-dw-core.c | 29 +++++++++++++++++++++++++++++
 1 file changed, 29 insertions(+)

diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index 8e624620864f..9d499bdf2ce6 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -676,6 +676,32 @@ static void dw_spi_stop_mem_op(struct dw_spi *dws, struct spi_device *spi)
 	dw_spi_enable_chip(dws, 1);
 }
 
+static void update_spi_ctrl0(struct dw_spi *dws, const struct spi_mem_op *op, bool enable)
+{
+	u32 spi_ctrlr0;
+
+	spi_ctrlr0 = dw_readl(dws, DW_HSSI_SPI_CTRLR0);
+	if (enable) {
+		spi_ctrlr0 |= FIELD_PREP(DW_HSSI_SPI_CTRLR0_WAIT_CYCLE_MASK,
+					 op->dummy.nbytes * BITS_PER_BYTE);
+		/* 8 bit instruction length */
+		spi_ctrlr0 |= FIELD_PREP(DW_HSSI_SPI_CTRLR0_INST_L_MASK,
+					 DW_HSSI_SPI_CTRLR0_INST_L8);
+		/* 32 bit address length */
+		spi_ctrlr0 |= FIELD_PREP(DW_HSSI_SPI_CTRLR0_ADDR_L_MASK,
+					 DW_HSSI_SPI_CTRLR0_ADDR_L32);
+		/* Enable clock stretching */
+		spi_ctrlr0 |= DW_HSSI_SPI_CTRLR0_CLK_STRETCH_EN;
+	} else {
+		spi_ctrlr0 &= ~DW_HSSI_SPI_CTRLR0_WAIT_CYCLE_MASK;
+		spi_ctrlr0 &= ~DW_HSSI_SPI_CTRLR0_INST_L_MASK;
+		spi_ctrlr0 &= ~DW_HSSI_SPI_CTRLR0_ADDR_L_MASK;
+		spi_ctrlr0 &= ~DW_HSSI_SPI_CTRLR0_CLK_STRETCH_EN;
+	}
+
+	dw_writel(dws, DW_HSSI_SPI_CTRLR0, spi_ctrlr0);
+}
+
 /*
  * The SPI memory operation implementation below is the best choice for the
  * devices, which are selected by the native chip-select lane. It's
@@ -738,6 +764,9 @@ static int dw_spi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
 
 	dw_spi_enable_chip(dws, 0);
 
+	if (dws->caps & DW_SPI_CAP_EXT_SPI)
+		update_spi_ctrl0(dws, op, enhanced_spi);
+
 	dw_spi_update_config(dws, mem->spi, &cfg);
 
 	dw_spi_mask_intr(dws, 0xff);
-- 
2.30.2