[PATCH 7/9] mtd: spi-nor: use dummy cycle and address width info from SFDP

[Pratyush Yadav <p.yadav-l0cyMroinI0@public.gmane.org>]

The xSPI Profile 1.0 table specifies how many dummy cycles and address
bytes are needed for the Read Status Register command in octal DTR mode.
Use that information to send the correct Read SR command.

Signed-off-by: Pratyush Yadav <p.yadav-l0cyMroinI0@public.gmane.org>
---
 drivers/mtd/spi-nor/spi-nor.c | 17 +++++++++++++++--
 1 file changed, 15 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/spi-nor/spi-nor.c b/drivers/mtd/spi-nor/spi-nor.c
index eefde5abff8a..8c5d7bfa4f16 100644
--- a/drivers/mtd/spi-nor/spi-nor.c
+++ b/drivers/mtd/spi-nor/spi-nor.c
@@ -525,6 +525,8 @@ static int spi_nor_write_disable(struct spi_nor *nor)
 static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
 {
 	int ret;
+	u8 addr_bytes = nor->params.rdsr_addr_nbytes;
+	u8 dummy = nor->params.rdsr_dummy;
 
 	if (nor->spimem) {
 		struct spi_mem_op op =
@@ -533,10 +535,21 @@ static int spi_nor_read_sr(struct spi_nor *nor, u8 *sr)
 				   SPI_MEM_OP_NO_DUMMY,
 				   SPI_MEM_OP_DATA_IN(1, sr, 1));
 
+		if (spi_nor_protocol_is_dtr(nor->reg_proto)) {
+			op.addr.nbytes = addr_bytes;
+			op.addr.val = 0;
+			op.dummy.nbytes = dummy;
+		}
+
+		spi_nor_spimem_setup_op(nor, &op, nor->reg_proto);
+
 		ret = spi_mem_exec_op(nor->spimem, &op);
 	} else {
-		ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDSR,
-						    sr, 1);
+		if (spi_nor_protocol_is_dtr(nor->reg_proto))
+			ret = -ENOTSUPP;
+		else
+			ret = nor->controller_ops->read_reg(nor, SPINOR_OP_RDSR,
+							    sr, 1);
 	}
 
 	if (ret)
-- 
2.25.0