mtd: spi-nor: Merge spansion Quad Enable methods

Merge
    spansion_no_read_cr_quad_enable()
    spansion_read_cr_quad_enable()
into
    spi_nor_sr2_bit1_quad_enable().

Reduce code duplication by introducing spi_nor_write_16bit_cr_and_check().
The Configuration Register contains bits that can be updated in future:
FREEZE, CMP. Provide a generic method that allows updating all bits
of the Configuration Register.
Signed-off-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Reviewed-by: Vignesh Raghavendra <vigneshr@ti.com>

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

@@ -1054,6 +1054,59 @@ static int spi_nor_write_16bit_sr_and_check(struct spi_nor *nor, u8 sr1)
 	return 0;
 }
 
+/**
+ * spi_nor_write_16bit_cr_and_check() - Write the Status Register 1 and the
+ * Configuration Register in one shot. Ensure that the byte written in the
+ * Configuration Register match the received value, and that the 16-bit Write
+ * did not affect what was already in the Status Register 1.
+ * @nor:	pointer to a 'struct spi_nor'.
+ * @cr:		byte value to be written to the Configuration Register.
+ *
+ * Return: 0 on success, -errno otherwise.
+ */
+static int spi_nor_write_16bit_cr_and_check(struct spi_nor *nor, u8 cr)
+{
+	int ret;
+	u8 *sr_cr = nor->bouncebuf;
+	u8 sr_written;
+
+	/* Keep the current value of the Status Register 1. */
+	ret = spi_nor_read_sr(nor, sr_cr);
+	if (ret)
+		return ret;
+
+	sr_cr[1] = cr;
+
+	ret = spi_nor_write_sr(nor, sr_cr, 2);
+	if (ret)
+		return ret;
+
+	sr_written = sr_cr[0];
+
+	ret = spi_nor_read_sr(nor, sr_cr);
+	if (ret)
+		return ret;
+
+	if (sr_written != sr_cr[0]) {
+		dev_dbg(nor->dev, "SR: Read back test failed\n");
+		return -EIO;
+	}
+
+	if (nor->flags & SNOR_F_NO_READ_CR)
+		return 0;
+
+	ret = spi_nor_read_cr(nor, &sr_cr[1]);
+	if (ret)
+		return ret;
+
+	if (cr != sr_cr[1]) {
+		dev_dbg(nor->dev, "CR: read back test failed\n");
+		return -EIO;
+	}
+
+	return 0;
+}
+
 /**
  * spi_nor_write_sr_and_check() - Write the Status Register 1 and ensure that
  * the byte written match the received value without affecting other bits in the
@@ -2051,111 +2104,29 @@ static int macronix_quad_enable(struct spi_nor *nor)
 }
 
 /**
- * spansion_no_read_cr_quad_enable() - set QE bit in Configuration Register.
- * @nor:	pointer to a 'struct spi_nor'
+ * spi_nor_sr2_bit1_quad_enable() - set the Quad Enable BIT(1) in the Status
+ * Register 2.
+ * @nor:       pointer to a 'struct spi_nor'.
  *
- * Set the Quad Enable (QE) bit in the Configuration Register.
- * This function should be used with QSPI memories not supporting the Read
- * Configuration Register (35h) instruction.
- *
- * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
- * memories.
+ * Bit 1 of the Status Register 2 is the QE bit for Spansion like QSPI memories.
  *
  * Return: 0 on success, -errno otherwise.
  */
-static int spansion_no_read_cr_quad_enable(struct spi_nor *nor)
+static int spi_nor_sr2_bit1_quad_enable(struct spi_nor *nor)
 {
-	u8 *sr_cr = nor->bouncebuf;
 	int ret;
-	u8 sr_written;
-
-	/* Keep the current value of the Status Register. */
-	ret = spi_nor_read_sr(nor, sr_cr);
-	if (ret)
-		return ret;
-
-	sr_cr[1] = SR2_QUAD_EN_BIT1;
-
-	ret = spi_nor_write_sr(nor, sr_cr, 2);
-	if (ret)
-		return ret;
 
-	sr_written = sr_cr[0];
-
-	ret = spi_nor_read_sr(nor, sr_cr);
-	if (ret)
-		return ret;
-
-	if (sr_cr[0] != sr_written) {
-		dev_err(nor->dev, "SR: Read back test failed\n");
-		return -EIO;
-	}
-
-	return 0;
-}
-
-/**
- * spansion_read_cr_quad_enable() - set QE bit in Configuration Register.
- * @nor:	pointer to a 'struct spi_nor'
- *
- * Set the Quad Enable (QE) bit in the Configuration Register.
- * This function should be used with QSPI memories supporting the Read
- * Configuration Register (35h) instruction.
- *
- * bit 1 of the Configuration Register is the QE bit for Spansion like QSPI
- * memories.
- *
- * Return: 0 on success, -errno otherwise.
- */
-static int spansion_read_cr_quad_enable(struct spi_nor *nor)
-{
-	u8 *sr_cr = nor->bouncebuf;
-	int ret;
-	u8 sr_written;
+	if (nor->flags & SNOR_F_NO_READ_CR)
+		return spi_nor_write_16bit_cr_and_check(nor, SR2_QUAD_EN_BIT1);
 
-	/* Check current Quad Enable bit value. */
-	ret = spi_nor_read_cr(nor, &sr_cr[1]);
+	ret = spi_nor_read_cr(nor, nor->bouncebuf);
 	if (ret)
 		return ret;
 
-	if (sr_cr[1] & SR2_QUAD_EN_BIT1)
+	if (nor->bouncebuf[0] & SR2_QUAD_EN_BIT1)
 		return 0;
 
-	sr_cr[1] |= SR2_QUAD_EN_BIT1;
-
-	/* Keep the current value of the Status Register. */
-	ret = spi_nor_read_sr(nor, sr_cr);
-	if (ret)
-		return ret;
-
-	ret = spi_nor_write_sr(nor, sr_cr, 2);
-	if (ret)
-		return ret;
-
-	sr_written = sr_cr[0];
-
-	ret = spi_nor_read_sr(nor, sr_cr);
-	if (ret)
-		return ret;
-
-	if (sr_written != sr_cr[0]) {
-		dev_err(nor->dev, "SR: Read back test failed\n");
-		return -EIO;
-	}
-
-	sr_written = sr_cr[1];
-
-	/* Read back and check it. */
-	ret = spi_nor_read_cr(nor, &sr_cr[1]);
-	if (ret)
-		return ret;
-
-	if (sr_cr[1] != sr_written) {
-		dev_dbg(nor->dev, "CR: Read back test failed\n");
-		return -EIO;
-	}
-
-	return 0;
+	return spi_nor_write_16bit_cr_and_check(nor, nor->bouncebuf[0]);
 }
 
 /**
@@ -3685,7 +3656,7 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
 		 * supported.
 		 */
 		nor->flags |= SNOR_F_HAS_16BIT_SR | SNOR_F_NO_READ_CR;
-		params->quad_enable = spansion_no_read_cr_quad_enable;
+		params->quad_enable = spi_nor_sr2_bit1_quad_enable;
 		break;
 
 	case BFPT_DWORD15_QER_SR1_BIT6:
@@ -3707,7 +3678,7 @@ static int spi_nor_parse_bfpt(struct spi_nor *nor,
 		 */
 		nor->flags |= SNOR_F_HAS_16BIT_SR;
 
-		params->quad_enable = spansion_read_cr_quad_enable;
+		params->quad_enable = spi_nor_sr2_bit1_quad_enable;
 		break;
 
 	default:
@@ -4697,7 +4668,7 @@ static void spi_nor_info_init_params(struct spi_nor *nor)
 	u8 i, erase_mask;
 
 	/* Initialize legacy flash parameters and settings. */
-	params->quad_enable = spansion_read_cr_quad_enable;
+	params->quad_enable = spi_nor_sr2_bit1_quad_enable;
 	params->set_4byte = spansion_set_4byte;
 	params->setup = spi_nor_default_setup;
 	/* Default to 16-bit Write Status (01h) Command */