[PATCH v3 4/5] mtd: spinand: micron: Add M70A series Micron SPI NAND devices

[shiva . linuxworks]

From: Shivamurthy Shastri <sshivamurthy@xxxxxxxxxx>

Add device table for M70A series Micron SPI NAND devices.

As opposed to the M79A and M78A series already supported, M70A parts
have the "Continuous Read" feature enabled by default, which does not fit
the subsystem needs.

In this mode, the READ CACHE command doesn't require the starting column
address. The device always output the data starting from the first
column of the cache register, and once the end of the cache register
reached, the data output continues through the next page. With the
continuous read mode, it is possible to read out the entire block using
a single READ command, and once the end of the block reached, the output
pins become High-Z state. However, during this mode the read command
doesn't output the OOB area.

Hence, we disable the feature at probe time.

Signed-off-by: Shivamurthy Shastri <sshivamurthy@xxxxxxxxxx>
---
 drivers/mtd/nand/spi/micron.c | 36 +++++++++++++++++++++++++++++++++++
 1 file changed, 36 insertions(+)

diff --git a/drivers/mtd/nand/spi/micron.c b/drivers/mtd/nand/spi/micron.c
index 5fd1f921ef12..3d3734afc35e 100644
--- a/drivers/mtd/nand/spi/micron.c
+++ b/drivers/mtd/nand/spi/micron.c
@@ -18,6 +18,8 @@
 #define MICRON_STATUS_ECC_4TO6_BITFLIPS	(3 << 4)
 #define MICRON_STATUS_ECC_7TO8_BITFLIPS	(5 << 4)
 
+#define MICRON_CFG_CONTI_READ		BIT(0)
+
 static SPINAND_OP_VARIANTS(read_cache_variants,
 		SPINAND_PAGE_READ_FROM_CACHE_QUADIO_OP(0, 2, NULL, 0),
 		SPINAND_PAGE_READ_FROM_CACHE_X4_OP(0, 1, NULL, 0),
@@ -131,6 +133,26 @@ static const struct spinand_info micron_spinand_table[] = {
 		     0,
 		     SPINAND_ECCINFO(&micron_8_ooblayout,
 				     micron_8_ecc_get_status)),
+	/* M70A 4Gb 3.3V */
+	SPINAND_INFO("MT29F4G01ABAFD", 0x34,
+		     NAND_MEMORG(1, 4096, 256, 64, 2048, 40, 1, 1, 1),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
+					      &write_cache_variants,
+					      &update_cache_variants),
+		     SPINAND_HAS_CR_FEAT_BIT,
+		     SPINAND_ECCINFO(&micron_8_ooblayout,
+				     micron_8_ecc_get_status)),
+	/* M70A 4Gb 1.8V */
+	SPINAND_INFO("MT29F4G01ABBFD", 0x35,
+		     NAND_MEMORG(1, 4096, 256, 64, 2048, 40, 1, 1, 1),
+		     NAND_ECCREQ(8, 512),
+		     SPINAND_INFO_OP_VARIANTS(&read_cache_variants,
+					      &write_cache_variants,
+					      &update_cache_variants),
+		     SPINAND_HAS_CR_FEAT_BIT,
+		     SPINAND_ECCINFO(&micron_8_ooblayout,
+				     micron_8_ecc_get_status)),
 };
 
 static int micron_spinand_detect(struct spinand_device *spinand)
@@ -153,8 +175,22 @@ static int micron_spinand_detect(struct spinand_device *spinand)
 	return 1;
 }
 
+static int micron_spinand_init(struct spinand_device *spinand)
+{
+	/*
+	 * M70A device series enable Continuous Read feature at Power-up,
+	 * which is not supported. Disable this bit to avoid any possible
+	 * failure.
+	 */
+	if (spinand->flags == SPINAND_HAS_CR_FEAT_BIT)
+		return spinand_upd_cfg(spinand, MICRON_CFG_CONTI_READ, 0);
+
+	return 0;
+}
+
 static const struct spinand_manufacturer_ops micron_spinand_manuf_ops = {
 	.detect = micron_spinand_detect,
+	.init = micron_spinand_init,
 };
 
 const struct spinand_manufacturer micron_spinand_manufacturer = {
-- 
2.17.1