spi: mxic: Create a helper to configure the controller before an operation

Create the mxic_spi_set_hc_cfg() helper to configure the HC_CFG
register. This helper will soon be used by the dirmap implementation and
having this code factorized out earlier will clarify this addition.
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Reviewed-by: Mark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/linux-mtd/20220127091808.1043392-11-miquel.raynal@bootlin.com

drivers/spi/spi-mxic.c

@@ -280,6 +280,22 @@ static void mxic_spi_hw_init(struct mxic_spi *mxic)
 	       mxic->regs + HC_CFG);
 }
 
+static u32 mxic_spi_prep_hc_cfg(struct spi_device *spi, u32 flags)
+{
+	int nio = 1;
+
+	if (spi->mode & (SPI_TX_OCTAL | SPI_RX_OCTAL))
+		nio = 8;
+	else if (spi->mode & (SPI_TX_QUAD | SPI_RX_QUAD))
+		nio = 4;
+	else if (spi->mode & (SPI_TX_DUAL | SPI_RX_DUAL))
+		nio = 2;
+
+	return flags | HC_CFG_NIO(nio) |
+	       HC_CFG_TYPE(spi->chip_select, HC_CFG_TYPE_SPI_NOR) |
+	       HC_CFG_SLV_ACT(spi->chip_select) | HC_CFG_IDLE_SIO_LVL(1);
+}
+
 static int mxic_spi_data_xfer(struct mxic_spi *mxic, const void *txbuf,
 			      void *rxbuf, unsigned int len)
 {
@@ -349,7 +365,7 @@ static int mxic_spi_mem_exec_op(struct spi_mem *mem,
 				const struct spi_mem_op *op)
 {
 	struct mxic_spi *mxic = spi_master_get_devdata(mem->spi->master);
-	int nio = 1, i, ret;
+	int i, ret;
 	u32 ss_ctrl;
 	u8 addr[8], cmd[2];
 
@@ -357,18 +373,9 @@ static int mxic_spi_mem_exec_op(struct spi_mem *mem,
 	if (ret)
 		return ret;
 
-	if (mem->spi->mode & (SPI_TX_OCTAL | SPI_RX_OCTAL))
-		nio = 8;
-	else if (mem->spi->mode & (SPI_TX_QUAD | SPI_RX_QUAD))
-		nio = 4;
-	else if (mem->spi->mode & (SPI_TX_DUAL | SPI_RX_DUAL))
-		nio = 2;
-
-	writel(HC_CFG_NIO(nio) |
-	       HC_CFG_TYPE(mem->spi->chip_select, HC_CFG_TYPE_SPI_NOR) |
-	       HC_CFG_SLV_ACT(mem->spi->chip_select) | HC_CFG_IDLE_SIO_LVL(1) |
-	       HC_CFG_MAN_CS_EN,
+	writel(mxic_spi_prep_hc_cfg(mem->spi, HC_CFG_MAN_CS_EN),
 	       mxic->regs + HC_CFG);
+
 	writel(HC_EN_BIT, mxic->regs + HC_EN);
 
 	ss_ctrl = OP_CMD_BYTES(op->cmd.nbytes) |