[PATCH RFC 2/4] mtd: spi-nor: Add post_sfdp() callback

[Biju Das]

Some generic flash devices such as Renesas AT25QL128A serial nor
flash requires the IO pins must be in high-impedance before the
falling edge of the first data out clock for the Fast Read Quad
IO.

Add post_sfdp() callback for generic flash devices and then call
spi_mem_set_iofv() to configure IO fixed value to control the pin
state.

Signed-off-by: Biju Das <biju.das.jz at bp.renesas.com>
---
 drivers/mtd/spi-nor/core.c | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
index 1c443fe568cf..eef3c286b174 100644
--- a/drivers/mtd/spi-nor/core.c
+++ b/drivers/mtd/spi-nor/core.c
@@ -1997,6 +1997,21 @@ int spi_nor_sr2_bit7_quad_enable(struct spi_nor *nor)
 	return 0;
 }
 
+static int spi_nor_generic_post_sfdp_fixup(struct spi_nor *nor)
+{
+	struct spi_device *spi = nor->spimem->spi;
+	const u8 *id = nor->id;
+
+	if (spi->mode & SPI_TX_QUAD && nor->spimem) {
+		const struct spi_nor_id *at25ql128a_id = SNOR_ID(0x1f, 0x42, 0x18);
+
+		if (!memcmp(id, at25ql128a_id->bytes, at25ql128a_id->len))
+			return spi_mem_set_iofv(nor->spimem, 0xff);
+	}
+
+	return 0;
+}
+
 static const struct spi_nor_manufacturer *manufacturers[] = {
 	&spi_nor_atmel,
 	&spi_nor_eon,
@@ -2015,8 +2030,13 @@ static const struct spi_nor_manufacturer *manufacturers[] = {
 	&spi_nor_xmc,
 };
 
+static const struct spi_nor_fixups spi_nor_generic_fixups = {
+	.post_sfdp = spi_nor_generic_post_sfdp_fixup,
+};
+
 static const struct flash_info spi_nor_generic_flash = {
 	.name = "spi-nor-generic",
+	.fixups = &spi_nor_generic_fixups,
 };
 
 static const struct flash_info *spi_nor_match_id(struct spi_nor *nor,
-- 
2.25.1