Currently there are 3 different variants of read_id implementation:
1. opcode only. Found in GD5FxGQ4xF.
2. opcode + 1 addr byte. Found in GD5GxGQ4xA/E
3. opcode + 1 dummy byte. Found in other currently supported chips.
Original implementation was for variant 1 and let detect function
of chips with variant 2 and 3 to ignore the first byte. This isn't
robust:
1. For chips of variant 2, if SPI master doesn't keep MOSI low
during read, chip will get a random id offset, and the entire id
buffer will shift by that offset, causing detect failure.
2. For chips of variant 1, if it happens to get a devid that equals
to manufacture id of variant 2 or 3 chips, it'll get incorrectly
detected.
This patch reworks detect procedure to address problems above. New
logic do detection for all variants separatedly, in 1-2-3 order.
Since all current detect methods do exactly the same id matching
procedure, unify them into core.c and remove detect method from
manufacture_ops.
Tested on GD5F1GQ4UAYIG and W25N01GVZEIG.
Signed-off-by: Chuanhong Guo <gch981213@gmail.com>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://lore.kernel.org/linux-mtd/20200208074439.146296-1-gch981213@gmail.com
