mtd: spi-nor: micron-st: Rework spi_nor_micron_octal_dtr_enable()

Introduce template operation to remove code duplication.
Split spi_nor_micron_octal_dtr_enable() in spi_nor_micron_octal_dtr_en()
and spi_nor_micron_octal_dtr_dis() as it no longer made sense to try to
keep everything alltogether: too many "if (enable)" throughout the code,
which made the code difficult to follow. Add dev_dbg messages in case
spi_nor_read_id() fails.

Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Michael Walle <michael@walle.cc>
Link: https://lore.kernel.org/r/20220420103427.47867-8-tudor.ambarus@microchip.com

drivers/mtd/spi-nor/micron-st.c

@@ -28,75 +28,43 @@
 #define FSR_P_ERR		BIT(4)	/* Program operation status */
 #define FSR_PT_ERR		BIT(1)	/* Protection error bit */
 
-static int micron_st_nor_octal_dtr_enable(struct spi_nor *nor, bool enable)
+/* Micron ST SPI NOR flash operations. */
+#define MICRON_ST_NOR_WR_ANY_REG_OP(naddr, addr, ndata, buf)		\
+	SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_MT_WR_ANY_REG, 0),		\
+		   SPI_MEM_OP_ADDR(naddr, addr, 0),			\
+		   SPI_MEM_OP_NO_DUMMY,					\
+		   SPI_MEM_OP_DATA_OUT(ndata, buf, 0))
+
+static int micron_st_nor_octal_dtr_en(struct spi_nor *nor)
 {
 	struct spi_mem_op op;
 	u8 *buf = nor->bouncebuf;
 	int ret;
 
-	if (enable) {
+	/* Use 20 dummy cycles for memory array reads. */
-		/* Use 20 dummy cycles for memory array reads. */
+	*buf = 20;
-		ret = spi_nor_write_enable(nor);
+	op = (struct spi_mem_op)
-		if (ret)
+		MICRON_ST_NOR_WR_ANY_REG_OP(3, SPINOR_REG_MT_CFR1V, 1, buf);
-			return ret;
+	ret = spi_nor_write_any_volatile_reg(nor, &op, nor->reg_proto);
-
+	if (ret)
-		*buf = 20;
+		return ret;
-		op = (struct spi_mem_op)
+	ret = spi_nor_wait_till_ready(nor);
-			SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_MT_WR_ANY_REG, 1),
-				   SPI_MEM_OP_ADDR(3, SPINOR_REG_MT_CFR1V, 1),
-				   SPI_MEM_OP_NO_DUMMY,
-				   SPI_MEM_OP_DATA_OUT(1, buf, 1));
-
-		ret = spi_mem_exec_op(nor->spimem, &op);
-		if (ret)
-			return ret;
-
-		ret = spi_nor_wait_till_ready(nor);
-		if (ret)
-			return ret;
-	}
-
-	ret = spi_nor_write_enable(nor);
 	if (ret)
 		return ret;
 
-	if (enable) {
+	buf[0] = SPINOR_MT_OCT_DTR;
-		buf[0] = SPINOR_MT_OCT_DTR;
-	} else {
-		/*
-		 * The register is 1-byte wide, but 1-byte transactions are not
-		 * allowed in 8D-8D-8D mode. The next register is the dummy
-		 * cycle configuration register. Since the transaction needs to
-		 * be at least 2 bytes wide, set the next register to its
-		 * default value. This also makes sense because the value was
-		 * changed when enabling 8D-8D-8D mode, it should be reset when
-		 * disabling.
-		 */
-		buf[0] = SPINOR_MT_EXSPI;
-		buf[1] = SPINOR_REG_MT_CFR1V_DEF;
-	}
-
 	op = (struct spi_mem_op)
-		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_MT_WR_ANY_REG, 1),
+		MICRON_ST_NOR_WR_ANY_REG_OP(3, SPINOR_REG_MT_CFR0V, 1, buf);
-			   SPI_MEM_OP_ADDR(enable ? 3 : 4,
+	ret = spi_nor_write_any_volatile_reg(nor, &op, nor->reg_proto);
-					   SPINOR_REG_MT_CFR0V, 1),
-			   SPI_MEM_OP_NO_DUMMY,
-			   SPI_MEM_OP_DATA_OUT(enable ? 1 : 2, buf, 1));
-
-	if (!enable)
-		spi_nor_spimem_setup_op(nor, &op, SNOR_PROTO_8_8_8_DTR);
-
-	ret = spi_mem_exec_op(nor->spimem, &op);
 	if (ret)
 		return ret;
 
 	/* Read flash ID to make sure the switch was successful. */
-	if (enable)
+	ret = spi_nor_read_id(nor, 0, 8, buf, SNOR_PROTO_8_8_8_DTR);
-		ret = spi_nor_read_id(nor, 0, 8, buf, SNOR_PROTO_8_8_8_DTR);
+	if (ret) {
-	else
+		dev_dbg(nor->dev, "error %d reading JEDEC ID after enabling 8D-8D-8D mode\n", ret);
-		ret = spi_nor_read_id(nor, 0, 0, buf, SNOR_PROTO_1_1_1);
-	if (ret)
 		return ret;
+	}
 
 	if (memcmp(buf, nor->info->id, nor->info->id_len))
 		return -EINVAL;
@@ -104,6 +72,47 @@ static int micron_st_nor_octal_dtr_enable(struct spi_nor *nor, bool enable)
 	return 0;
 }
 
+static int micron_st_nor_octal_dtr_dis(struct spi_nor *nor)
+{
+	struct spi_mem_op op;
+	u8 *buf = nor->bouncebuf;
+	int ret;
+
+	/*
+	 * The register is 1-byte wide, but 1-byte transactions are not allowed
+	 * in 8D-8D-8D mode. The next register is the dummy cycle configuration
+	 * register. Since the transaction needs to be at least 2 bytes wide,
+	 * set the next register to its default value. This also makes sense
+	 * because the value was changed when enabling 8D-8D-8D mode, it should
+	 * be reset when disabling.
+	 */
+	buf[0] = SPINOR_MT_EXSPI;
+	buf[1] = SPINOR_REG_MT_CFR1V_DEF;
+	op = (struct spi_mem_op)
+		MICRON_ST_NOR_WR_ANY_REG_OP(4, SPINOR_REG_MT_CFR0V, 2, buf);
+	ret = spi_nor_write_any_volatile_reg(nor, &op, SNOR_PROTO_8_8_8_DTR);
+	if (ret)
+		return ret;
+
+	/* Read flash ID to make sure the switch was successful. */
+	ret = spi_nor_read_id(nor, 0, 0, buf, SNOR_PROTO_1_1_1);
+	if (ret) {
+		dev_dbg(nor->dev, "error %d reading JEDEC ID after disabling 8D-8D-8D mode\n", ret);
+		return ret;
+	}
+
+	if (memcmp(buf, nor->info->id, nor->info->id_len))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int micron_st_nor_octal_dtr_enable(struct spi_nor *nor, bool enable)
+{
+	return enable ? micron_st_nor_octal_dtr_en(nor) :
+			micron_st_nor_octal_dtr_dis(nor);
+}
+
 static void mt35xu512aba_default_init(struct spi_nor *nor)
 {
 	nor->params->octal_dtr_enable = micron_st_nor_octal_dtr_enable;