[PATCH 3/9] mtd: spi-nor-core: Rework spansion_read_any_reg() to support Octal DTR mode

[tkuw584924 at gmail.com]

From: Takahiro Kuwano <Takahiro.Kuwano at infineon.com>

In Infineon multi-die package parts, we need to use Read Any Register op
to read status register in 2nd or further die. Infineon S28HS02GT is
dual-die package and supports Octal DTR interface. To support this,
spansion_read_any_reg() needs to be reworked. Implementation is similar
to existing read_sr() that already supports Octal DTR mode.

Signed-off-by: Takahiro Kuwano <Takahiro.Kuwano at infineon.com>
---
 drivers/mtd/spi/spi-nor-core.c | 34 +++++++++++++++++++++++++++++-----
 1 file changed, 29 insertions(+), 5 deletions(-)

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 2f0f24a41ee9..b7f0f3343dd4 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -330,12 +330,36 @@ static int spansion_read_any_reg(struct spi_nor *nor, u32 addr, u8 dummy,
 				 u8 *val)
 {
 	struct spi_mem_op op =
-		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RD_ANY_REG, 1),
-			   SPI_MEM_OP_ADDR(nor->addr_mode_nbytes, addr, 1),
-			   SPI_MEM_OP_DUMMY(dummy / 8, 1),
-			   SPI_MEM_OP_DATA_IN(1, NULL, 1));
+		SPI_MEM_OP(SPI_MEM_OP_CMD(SPINOR_OP_RD_ANY_REG, 0),
+			   SPI_MEM_OP_ADDR(nor->addr_mode_nbytes, addr, 0),
+			   SPI_MEM_OP_DUMMY(dummy, 0),
+			   SPI_MEM_OP_DATA_IN(1, NULL, 0));
+	u8 buf[2];
+	int ret;
+
+	spi_nor_setup_op(nor, &op, nor->reg_proto);
+
+	/*
+	 * In Octal DTR mode, the number of address bytes is always 4 regardless
+	 * of addressing mode setting.
+	 */
+	if (nor->reg_proto == SNOR_PROTO_8_8_8_DTR)
+		op.addr.nbytes = 4;
+
+	/*
+	 * We don't want to read only one byte in DTR mode. So, read 2 and then
+	 * discard the second byte.
+	 */
+	if (spi_nor_protocol_is_dtr(nor->reg_proto))
+		op.data.nbytes = 2;
 
-	return spi_nor_read_write_reg(nor, &op, val);
+	ret = spi_nor_read_write_reg(nor, &op, buf);
+	if (ret)
+		return ret;
+
+	*val = buf[0];
+
+	return 0;
 }
 
 static int spansion_write_any_reg(struct spi_nor *nor, u32 addr, u8 val)
-- 
2.25.1