spi: spi-mem: Kill the spi_mem_dtr_supports_op() helper

Now that spi_mem_default_supports_op() has access to the static
controller capabilities (relating to memory operations), and now that
these capabilities have been filled by the relevant controllers, there
is no need for a specific helper checking only DTR operations, so let's
just kill spi_mem_dtr_supports_op() and simply use
spi_mem_default_supports_op() instead.

Signed-off-by: Miquel Raynal <[e-mail]>
Reviewed-by: Pratyush Yadav <[e-mail]>
Reviewed-by: Boris Brezillon <[e-mail]>
Reviewed-by: Tudor Ambarus <[e-mail]>
Link: https://lore.kernel.org/linux-mtd/[e-mail]

drivers/spi/spi-cadence-quadspi.c

···
 	if (!(all_true || all_false))
 		return false;
 
-	if (all_true)
-		return spi_mem_dtr_supports_op(mem, op);
-	else
-		return spi_mem_default_supports_op(mem, op);
+	return spi_mem_default_supports_op(mem, op);
 }
 
 static int cqspi_of_get_flash_pdata(struct platform_device *pdev,

drivers/spi/spi-mem.c

···
 	return true;
 }
 
-bool spi_mem_dtr_supports_op(struct spi_mem *mem,
-			     const struct spi_mem_op *op)
-{
-	if (op->cmd.nbytes != 2)
-		return false;
-
-	return spi_mem_check_buswidth(mem, op);
-}
-EXPORT_SYMBOL_GPL(spi_mem_dtr_supports_op);
-
 bool spi_mem_default_supports_op(struct spi_mem *mem,
 				 const struct spi_mem_op *op)
 {

drivers/spi/spi-mxic.c

···
 static bool mxic_spi_mem_supports_op(struct spi_mem *mem,
 				     const struct spi_mem_op *op)
 {
-	bool all_false;
-
 	if (op->data.buswidth > 8 || op->addr.buswidth > 8 ||
 	    op->dummy.buswidth > 8 || op->cmd.buswidth > 8)
 		return false;
···
 	if (op->addr.nbytes > 7)
 		return false;
 
-	all_false = !op->cmd.dtr && !op->addr.dtr && !op->dummy.dtr &&
-		    !op->data.dtr;
-
-	if (all_false)
-		return spi_mem_default_supports_op(mem, op);
-	else
-		return spi_mem_dtr_supports_op(mem, op);
+	return spi_mem_default_supports_op(mem, op);
 }
 
 static int mxic_spi_mem_exec_op(struct spi_mem *mem,

include/linux/spi/spi-mem.h

···
 
 bool spi_mem_default_supports_op(struct spi_mem *mem,
 				 const struct spi_mem_op *op);
-
-bool spi_mem_dtr_supports_op(struct spi_mem *mem,
-			     const struct spi_mem_op *op);
-
 #else
 static inline int
 spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
···
 static inline
 bool spi_mem_default_supports_op(struct spi_mem *mem,
 				 const struct spi_mem_op *op)
-{
-	return false;
-}
-
-static inline
-bool spi_mem_dtr_supports_op(struct spi_mem *mem,
-			     const struct spi_mem_op *op)
 {
 	return false;
 }