[PATCH v4 03/12] spi: spi-mem: Create a helper to gather all the supports_op checks

[Miquel Raynal <miquel.raynal@xxxxxxxxxxx>]

So far we check the support for:
- regular operations
- dtr operations
Soon, we will also need to check the support for ECC operations.

As the combinatorial will increase exponentially, let's gather all the
checks in a single generic function. This new helper will be called by
the exported functions, directly used by the different drivers.

Then, in a second time, we will add an ECC check and allow this new
helper to be directly used to avoid increasing dramatically the number
of new helpers needed to cover the {dtr-on/dtr-off, ecc-on/ecc-off}
situations, and perhaps others too. It will always be possible to create
abstraction helpers in the future if a particular combination is
regularly used.

Signed-off-by: Miquel Raynal <miquel.raynal@xxxxxxxxxxx>
---
 drivers/spi/spi-mem.c | 32 +++++++++++++++++++++-----------
 1 file changed, 21 insertions(+), 11 deletions(-)

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index 37f4443ce9a0..013efaaaac75 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -160,26 +160,36 @@ static bool spi_mem_check_buswidth(struct spi_mem *mem,
 	return true;
 }
 
+static bool spi_mem_generic_supports_op(struct spi_mem *mem,
+					const struct spi_mem_op *op,
+					bool dtr)
+{
+	if (!dtr) {
+		if (op->cmd.dtr || op->addr.dtr ||
+		    op->dummy.dtr || op->data.dtr)
+			return false;
+
+		if (op->cmd.nbytes != 1)
+			return false;
+	} else {
+		if (op->cmd.nbytes != 2)
+			return false;
+	}
+
+	return spi_mem_check_buswidth(mem, op);
+}
+
 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);
+	return spi_mem_generic_supports_op(mem, op, true);
 }
 EXPORT_SYMBOL_GPL(spi_mem_dtr_supports_op);
 
 bool spi_mem_default_supports_op(struct spi_mem *mem,
 				 const struct spi_mem_op *op)
 {
-	if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
-		return false;
-
-	if (op->cmd.nbytes != 1)
-		return false;
-
-	return spi_mem_check_buswidth(mem, op);
+	return spi_mem_generic_supports_op(mem, op, false);
 }
 EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
 
-- 
2.27.0