[PATCH 16/30] spi: dw: Add DW SPI controller config structure

[Serge Semin <Sergey.Semin@baikalelectronics.ru>]

DW APB SSI controller can be used by the two SPI core interfaces:
traditional SPI transfers and SPI memory operations. The controller needs
to be accordingly configured at runtime when the corresponding operations
are executed. In order to do that for the both interfaces from a single
function we introduce a new data wrapper for the transfer mode, data
width, number of data frames (for the automatic data transfer) and the bus
frequency. It will be used by the update_config() method to tune the DW
APB SSI up.

The update_config() method is made exported to be used not only by the DW
SPI core driver, but by the glue layer drivers too. This will be required
in a coming further commit.

Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
---
 drivers/spi/spi-dw-core.c | 29 +++++++++++++++++------------
 drivers/spi/spi-dw.h      | 10 ++++++++++
 2 files changed, 27 insertions(+), 12 deletions(-)

diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index f00fc4828480..9102685c1523 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -20,10 +20,8 @@
 #include <linux/debugfs.h>
 #endif
 
-/* Slave spi_dev related */
+/* Slave spi_device related */
 struct chip_data {
-	u8 tmode;		/* TR/TO/RO/EEPROM */
-
 	u32 cr0;
 	u32 rx_sample_dly;	/* RX sample delay */
 };
@@ -248,25 +246,28 @@ static u32 dw_spi_get_cr0(struct dw_spi *dws, struct spi_device *spi)
 	return cr0;
 }
 
-static void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
-				 struct spi_transfer *transfer)
+void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
+			  struct dw_spi_cfg *cfg)
 {
 	struct chip_data *chip = spi_get_ctldata(spi);
 	u32 cr0 = chip->cr0;
 	u32 speed_hz;
 	u16 clk_div;
 
-	cr0 |= (transfer->bits_per_word - 1);
+	cr0 |= (cfg->dfs - 1);
 
 	if (!(dws->caps & DW_SPI_CAP_DWC_SSI))
-		cr0 |= chip->tmode << SPI_TMOD_OFFSET;
+		cr0 |= cfg->tmode << SPI_TMOD_OFFSET;
 	else
-		cr0 |= chip->tmode << DWC_SSI_CTRLR0_TMOD_OFFSET;
+		cr0 |= cfg->tmode << DWC_SSI_CTRLR0_TMOD_OFFSET;
 
 	dw_writel(dws, DW_SPI_CTRLR0, cr0);
 
+	if (cfg->tmode == SPI_TMOD_EPROMREAD || cfg->tmode == SPI_TMOD_RO)
+		dw_writel(dws, DW_SPI_CTRLR1, cfg->ndf ? cfg->ndf - 1 : 0);
+
 	/* Note DW APB SSI clock divider doesn't support odd numbers */
-	clk_div = (DIV_ROUND_UP(dws->max_freq, transfer->speed_hz) + 1) & 0xfffe;
+	clk_div = (DIV_ROUND_UP(dws->max_freq, cfg->freq) + 1) & 0xfffe;
 	speed_hz = dws->max_freq / clk_div;
 
 	if (dws->current_freq != speed_hz) {
@@ -280,11 +281,17 @@ static void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
 		dws->cur_rx_sample_dly = chip->rx_sample_dly;
 	}
 }
+EXPORT_SYMBOL_GPL(dw_spi_update_config);
 
 static int dw_spi_transfer_one(struct spi_controller *master,
 		struct spi_device *spi, struct spi_transfer *transfer)
 {
 	struct dw_spi *dws = spi_controller_get_devdata(master);
+	struct dw_spi_cfg cfg = {
+		.tmode = SPI_TMOD_TR,
+		.dfs = transfer->bits_per_word,
+		.freq = transfer->speed_hz,
+	};
 	u8 imask = 0;
 	u16 txlevel = 0;
 	int ret;
@@ -302,7 +309,7 @@ static int dw_spi_transfer_one(struct spi_controller *master,
 
 	spi_enable_chip(dws, 0);
 
-	dw_spi_update_config(dws, spi, transfer);
+	dw_spi_update_config(dws, spi, &cfg);
 
 	transfer->effective_speed_hz = dws->current_freq;
 
@@ -388,8 +395,6 @@ static int dw_spi_setup(struct spi_device *spi)
 	 */
 	chip->cr0 = dw_spi_get_cr0(dws, spi);
 
-	chip->tmode = SPI_TMOD_TR;
-
 	return 0;
 }
 
diff --git a/drivers/spi/spi-dw.h b/drivers/spi/spi-dw.h
index c02351cf2f99..2a2346438564 100644
--- a/drivers/spi/spi-dw.h
+++ b/drivers/spi/spi-dw.h
@@ -111,6 +111,14 @@ enum dw_ssi_type {
 #define DW_SPI_CAP_KEEMBAY_MST		BIT(1)
 #define DW_SPI_CAP_DWC_SSI		BIT(2)
 
+/* Slave spi_transfer/spi_mem_op related */
+struct dw_spi_cfg {
+	u8 tmode;
+	u8 dfs;
+	u32 ndf;
+	u32 freq;
+};
+
 struct dw_spi;
 struct dw_spi_dma_ops {
 	int (*dma_init)(struct device *dev, struct dw_spi *dws);
@@ -249,6 +257,8 @@ static inline void 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);
 extern int dw_spi_add_host(struct device *dev, struct dw_spi *dws);
 extern void dw_spi_remove_host(struct dw_spi *dws);
 extern int dw_spi_suspend_host(struct dw_spi *dws);
-- 
2.27.0