spi: sh-msiof: SITMDR2 and SIRMDR2 bitfield conversion

Convert MSIOF Transmit and Receive Mode Register 2 field accesses to use
the FIELD_PREP() bitfield access macro.

This gets rid of explicit shifts and custom field preparation macros.

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Link: https://patch.msgid.link/135b92d010a71e2c224feab3a5792724b4e60ff1.1747401908.git.geert+renesas@glider.be
Signed-off-by: Mark Brown <broonie@kernel.org>

Author: geertu

drivers/spi/spi-sh-msiof.c

@@ -100,8 +100,8 @@ struct sh_msiof_spi_priv {
 						/* 0=MSIOF_SYNC, 1=MSIOF_SS1, 2=MSIOF_SS2 */
 
 /* SITMDR2 and SIRMDR2 */
-#define SIMDR2_BITLEN1(i)	(((i) - 1) << 24) /* Data Size (8-32 bits) */
-#define SIMDR2_WDLEN1(i)	(((i) - 1) << 16) /* Word Count (1-64/256 (SH, A1))) */
+#define SIMDR2_BITLEN1		GENMASK(28, 24)	/* Data Size (8-32 bits) */
+#define SIMDR2_WDLEN1		GENMASK(23, 16)	/* Word Count (1-64/256 (SH, A1))) */
 #define SIMDR2_GRPMASK1		BIT(0)		/* Group Output Mask 1 (SH, A1) */
 
 /* SITSCR and SIRSCR */
@@ -397,7 +397,8 @@ static void sh_msiof_spi_set_mode_regs(struct sh_msiof_spi_priv *p,
 				       const void *tx_buf, void *rx_buf,
 				       u32 bits, u32 words)
 {
-	u32 dr2 = SIMDR2_BITLEN1(bits) | SIMDR2_WDLEN1(words);
+	u32 dr2 = FIELD_PREP(SIMDR2_BITLEN1, bits - 1) |
+		  FIELD_PREP(SIMDR2_WDLEN1, words - 1);
 
 	if (tx_buf || (p->ctlr->flags & SPI_CONTROLLER_MUST_TX))
 		sh_msiof_write(p, SITMDR2, dr2);
@@ -931,6 +932,7 @@ static int sh_msiof_transfer_one(struct spi_controller *ctlr,
 				 struct spi_transfer *t)
 {
 	struct sh_msiof_spi_priv *p = spi_controller_get_devdata(ctlr);
+	unsigned int max_wdlen = FIELD_MAX(SIMDR2_WDLEN1) + 1;
 	void (*copy32)(u32 *, const u32 *, unsigned int);
 	void (*tx_fifo)(struct sh_msiof_spi_priv *, const void *, unsigned int,
 			unsigned int);
@@ -940,7 +942,6 @@ static int sh_msiof_transfer_one(struct spi_controller *ctlr,
 	void *rx_buf = t->rx_buf;
 	unsigned int len = t->len;
 	unsigned int bits = t->bits_per_word;
-	unsigned int max_wdlen = 256;
 	unsigned int bytes_per_word;
 	unsigned int words;
 	int n;