[PATCH v1 03/11] spi: dw: update SPI_CTRLR0 register

[Changhuang Liang <changhuang.liang@starfivetech.com>]

From: Sudip Mukherjee <sudip.mukherjee@sifive.com>

If the SPI transfer is being done in enhanced mode then SPI_CTRLR0
register needs to be updated to mention the instruction length, address
length, address and instruction transfer format, wait cycles. And, we
also need to enable clock stretching.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@sifive.com>
Co-developed-by: Changhuang Liang <changhuang.liang@starfivetech.com>
Signed-off-by: Changhuang Liang <changhuang.liang@starfivetech.com>
---
 drivers/spi/spi-dw-core.c | 15 ++++++++++++---
 drivers/spi/spi-dw.h      | 17 ++++++++++++++++-
 2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index bd41e1b4dba7..fabfdf4ef604 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -313,7 +313,7 @@ static u32 dw_spi_prepare_cr0(struct dw_spi *dws, struct spi_device *spi)
 }
 
 void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
-			  struct dw_spi_cfg *cfg)
+			  struct dw_spi_cfg *cfg, struct dw_spi_enh_cfg *enh_cfg)
 {
 	struct dw_spi_chip_data *chip = spi_get_ctldata(spi);
 	u32 cr0 = chip->cr0;
@@ -366,6 +366,15 @@ void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
 		dw_writel(dws, DW_SPI_RX_SAMPLE_DLY, chip->rx_sample_dly);
 		dws->cur_rx_sample_dly = chip->rx_sample_dly;
 	}
+
+	if (enh_cfg) {
+		cr0 = DW_SPI_ENH_CTRLR0_CLK_STRETCH_EN;
+		cr0 |= FIELD_PREP(DW_SPI_ENH_CTRLR0_WAIT_CYCLE_MASK, enh_cfg->wait_c);
+		cr0 |= FIELD_PREP(DW_SPI_ENH_CTRLR0_INST_L_MASK, enh_cfg->inst_l);
+		cr0 |= FIELD_PREP(DW_SPI_ENH_CTRLR0_ADDR_L_MASK, enh_cfg->addr_l);
+		cr0 |= FIELD_PREP(DW_SPI_ENH_CTRLR0_TRANS_TYPE_MASK, enh_cfg->trans_t);
+		dw_writel(dws, DW_SPI_SPI_CTRLR0, cr0);
+	}
 }
 EXPORT_SYMBOL_NS_GPL(dw_spi_update_config, "SPI_DW_CORE");
 
@@ -451,7 +460,7 @@ static int dw_spi_transfer_one(struct spi_controller *ctlr,
 
 	dw_spi_enable_chip(dws, 0);
 
-	dw_spi_update_config(dws, spi, &cfg);
+	dw_spi_update_config(dws, spi, &cfg, NULL);
 
 	transfer->effective_speed_hz = dws->current_freq;
 
@@ -718,7 +727,7 @@ static int dw_spi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
 
 	dw_spi_enable_chip(dws, 0);
 
-	dw_spi_update_config(dws, mem->spi, &cfg);
+	dw_spi_update_config(dws, mem->spi, &cfg, NULL);
 
 	dw_spi_mask_intr(dws, 0xff);
 
diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h
index 19cf1b1a5d4f..16a8c7ab7364 100644
--- a/drivers/spi/spi-dw.h
+++ b/drivers/spi/spi-dw.h
@@ -63,6 +63,7 @@
 #define DW_SPI_VERSION			0x5c
 #define DW_SPI_DR			0x60
 #define DW_SPI_RX_SAMPLE_DLY		0xf0
+#define DW_SPI_SPI_CTRLR0		0xf4
 #define DW_SPI_CS_OVERRIDE		0xf4
 
 /* Bit fields in CTRLR0 (DWC APB SSI) */
@@ -127,6 +128,13 @@
 #define DW_SPI_DMACR_RDMAE			BIT(0)
 #define DW_SPI_DMACR_TDMAE			BIT(1)
 
+/* Bit fields in SPI_CTRLR0 */
+#define DW_SPI_ENH_CTRLR0_CLK_STRETCH_EN	BIT(30)
+#define DW_SPI_ENH_CTRLR0_WAIT_CYCLE_MASK	GENMASK(15, 11)
+#define DW_SPI_ENH_CTRLR0_INST_L_MASK		GENMASK(9, 8)
+#define DW_SPI_ENH_CTRLR0_ADDR_L_MASK		GENMASK(5, 2)
+#define DW_SPI_ENH_CTRLR0_TRANS_TYPE_MASK	GENMASK(1, 0)
+
 /* Mem/DMA operations helpers */
 #define DW_SPI_WAIT_RETRIES			5
 #define DW_SPI_BUF_SIZE \
@@ -144,6 +152,13 @@ struct dw_spi_cfg {
 	u8 spi_frf;
 };
 
+struct dw_spi_enh_cfg {
+	u8 wait_c;
+	u8 inst_l;
+	u8 addr_l;
+	u8 trans_t;
+};
+
 struct dw_spi;
 struct dw_spi_dma_ops {
 	int (*dma_init)(struct device *dev, struct dw_spi *dws);
@@ -294,7 +309,7 @@ static inline void dw_spi_shutdown_chip(struct dw_spi *dws)
 
 extern void dw_spi_set_cs(struct spi_device *spi, bool enable);
 extern void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
-				 struct dw_spi_cfg *cfg);
+				 struct dw_spi_cfg *cfg, struct dw_spi_enh_cfg *enh_cfg);
 extern int dw_spi_check_status(struct dw_spi *dws, bool raw);
 extern int dw_spi_add_controller(struct device *dev, struct dw_spi *dws);
 extern void dw_spi_remove_controller(struct dw_spi *dws);
-- 
2.25.1