spi: dw: Update SPI bus speed in a config function

The SPI bus speed update functionality will be useful in another parts of
the driver too (like to implement the SPI memory operations and from the
DW SPI glue layers). Let's move it to the update_cr0() method then and
since the later is now updating not only the CTRLR0 register alter its
prototype to have a generic function name not related to CR0.

Leave the too long line with the chip->clk_div setting as is for now,
since it's going to be changed later anyway.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Link: https://lore.kernel.org/r/20201007235511.4935-5-Sergey.Semin@baikalelectronics.ruSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-dw-core.c

@@ -269,8 +269,8 @@ static u32 dw_spi_prepare_cr0(struct dw_spi *dws, struct spi_device *spi)
 	return cr0;
 }
 
-static void dw_spi_update_cr0(struct dw_spi *dws, struct spi_device *spi,
-			      struct spi_transfer *transfer)
+static void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi,
+				 struct spi_transfer *transfer)
 {
 	struct chip_data *chip = spi_get_ctldata(spi);
 	u32 cr0 = chip->cr0;
@@ -286,6 +286,17 @@ static void dw_spi_update_cr0(struct dw_spi *dws, struct spi_device *spi,
 		cr0 |= chip->tmode << DWC_SSI_CTRLR0_TMOD_OFFSET;
 
 	dw_writel(dws, DW_SPI_CTRLR0, cr0);
+
+	/* Handle per transfer options for bpw and speed */
+	if (transfer->speed_hz != dws->current_freq) {
+		if (transfer->speed_hz != chip->speed_hz) {
+			/* clk_div doesn't support odd number */
+			chip->clk_div = (DIV_ROUND_UP(dws->max_freq, transfer->speed_hz) + 1) & 0xfffe;
+			chip->speed_hz = transfer->speed_hz;
+		}
+		dws->current_freq = transfer->speed_hz;
+		spi_set_clk(dws, chip->clk_div);
+	}
 }
 
 static int dw_spi_transfer_one(struct spi_controller *master,
@@ -310,21 +321,10 @@ static int dw_spi_transfer_one(struct spi_controller *master,
 
 	spi_enable_chip(dws, 0);
 
-	/* Handle per transfer options for bpw and speed */
-	if (transfer->speed_hz != dws->current_freq) {
-		if (transfer->speed_hz != chip->speed_hz) {
-			/* clk_div doesn't support odd number */
-			chip->clk_div = (DIV_ROUND_UP(dws->max_freq, transfer->speed_hz) + 1) & 0xfffe;
-			chip->speed_hz = transfer->speed_hz;
-		}
-		dws->current_freq = transfer->speed_hz;
-		spi_set_clk(dws, chip->clk_div);
-	}
+	dw_spi_update_config(dws, spi, transfer);
 
 	transfer->effective_speed_hz = dws->max_freq / chip->clk_div;
 
-	dw_spi_update_cr0(dws, spi, transfer);
-
 	/* Check if current transfer is a DMA transaction */
 	if (master->can_dma && master->can_dma(master, spi, transfer))
 		dws->dma_mapped = master->cur_msg_mapped;