[PATCH v2 02/30] mtd: spi-nor-core: Set dummy buswidth equal to data buswidth

[Tejas Bhumkar]

From: T Karthik Reddy <t.karthik.reddy at xilinx.com>

In current implementation dummy buswidth is set equal to address
buswidth. In case of quad spi (mode 1-1-4), where address width is 1
the dummy bytes will be calculated to 1(8 dummy cycles) and dummy
buswidth is set to 1. Due to this, the controller driver will introduce
8 dummy cycles on data line(D0) during read operation.

But since we are using 4 data lines in case of qspi, we need to change
this dummy bus width to 4. This will make dummy bytes to 4 inplace of 1.
This will be taken care in controller driver by dividing with dummy
buswidth again as in below code, which makes dummy cycles to 8 as
earlier.

dummy_cycles = op->dummy.nbytes * 8 / op->dummy.buswidth;

So with this change dummy cycles will be on all data lines(D0-D3) and it
is taken care for all the configurations(single, dual, quad and octal).

Signed-off-by: Ashok Reddy Soma <ashok.reddy.soma at xilinx.com>
Signed-off-by: T Karthik Reddy <t.karthik.reddy at xilinx.com>
Signed-off-by: Tejas Bhumkar <tejas.arvind.bhumkar at amd.com>
---
 drivers/mtd/spi/spi-nor-core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/mtd/spi/spi-nor-core.c b/drivers/mtd/spi/spi-nor-core.c
index 473d9f41f3..8949dab548 100644
--- a/drivers/mtd/spi/spi-nor-core.c
+++ b/drivers/mtd/spi/spi-nor-core.c
@@ -260,7 +260,7 @@ void spi_nor_setup_op(const struct spi_nor *nor,
 		op->addr.buswidth = spi_nor_get_protocol_addr_nbits(proto);
 
 	if (op->dummy.nbytes)
-		op->dummy.buswidth = spi_nor_get_protocol_addr_nbits(proto);
+		op->dummy.buswidth = spi_nor_get_protocol_data_nbits(proto);
 
 	if (op->data.nbytes)
 		op->data.buswidth = spi_nor_get_protocol_data_nbits(proto);
-- 
2.27.0