spi: spi-mem: Limit octal DTR constraints to octal DTR situations

In this helper, any operation with a single DTR cycle (like 1S-1S-8D) is
considered requiring a duplicated command opcode. This is wrong as this
constraint only applies to octal DTR operations (8D-8D-8D).

Narrow the application of this constraint to the concerned bus
interface.

Note: none of the possible XD-XD-XD pattern, with X being one of {1, 2,
4} would benefit from this check either as there is only in octal DTR
mode that a single clock edge would be enough to transmit the full
opcode.

Make sure the constraint of expecting two bytes for the command is
applied to the relevant bus interface.

Reviewed-by: Tudor Ambarus <tudor.ambarus@linaro.org>
Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com>
Link: https://patch.msgid.link/20260109-winbond-v6-17-rc1-oddr-v2-3-1fff6a2ddb80@bootlin.com
Signed-off-by: Mark Brown <broonie@kernel.org>

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index c8b2add2640e553c1791bd22cab76920b3ad72b4..6c7921469b90b1ea6c39fd24d9b702f7cfeb18c0 100644 (file)
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -178,8 +178,19 @@ bool spi_mem_default_supports_op(struct spi_mem *mem,
                if (op->data.swap16 && !spi_mem_controller_is_capable(ctlr, swap16))
                        return false;
 
-               if (op->cmd.nbytes != 2)
-                       return false;
+               /* Extra 8D-8D-8D limitations */
+               if (op->cmd.dtr && op->cmd.buswidth == 8) {
+                       if (op->cmd.nbytes != 2)
+                               return false;
+
+                       if ((op->addr.nbytes % 2) ||
+                           (op->dummy.nbytes % 2) ||
+                           (op->data.nbytes % 2)) {
+                               dev_err(&ctlr->dev,
+                                       "Even byte numbers not allowed in octal DTR operations\n");
+                               return false;
+                       }
+               }
        } else {
                if (op->cmd.nbytes != 1)
                        return false;