[PATCH RFC 04/18] spi: spi-mem: Prepare things for dual bytes opcodes support

[Boris Brezillon <boris.brezillon@xxxxxxxxxxx>]

Some SPI NORs are using 2bytes opcodes when operated in OPI (Octo
Peripheral Interface). Make opcode an u16 and add an nbytes field to
specify the number of opcode bytes.

Also add the SPI_MEM_OP_[DTR_]CMD_16B() to declare 2bytes opcodes and
update spi_mem_default_supports_op() to reject operations with 2 bytes
opcodes.

Signed-off-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
---
 drivers/spi/spi-mem.c       |  5 ++++-
 include/linux/spi/spi-mem.h | 21 ++++++++++++++++++++-
 2 files changed, 24 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index 3da57219b539..10bb852cfaea 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -157,6 +157,9 @@ static bool spi_mem_default_supports_op(struct spi_mem *mem,
 	if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
 		return false;
 
+	if (op->cmd.nbytes != 1)
+		return false;
+
 	return true;
 }
 EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
@@ -171,7 +174,7 @@ static bool spi_mem_buswidth_is_valid(u8 buswidth)
 
 static int spi_mem_check_op(const struct spi_mem_op *op)
 {
-	if (!op->cmd.buswidth)
+	if (!op->cmd.buswidth || op->cmd.nbytes < 1 || op->cmd.nbytes > 2)
 		return -EINVAL;
 
 	if ((op->addr.nbytes && !op->addr.buswidth) ||
diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
index cad116005034..af54a1c91f93 100644
--- a/include/linux/spi/spi-mem.h
+++ b/include/linux/spi/spi-mem.h
@@ -17,12 +17,29 @@
 	{							\
 		.buswidth = __buswidth,				\
 		.opcode = __opcode,				\
+		.nbytes = 1,					\
 	}
 
 #define SPI_MEM_OP_DTR_CMD(__opcode, __buswidth)		\
 	{							\
 		.buswidth = __buswidth,				\
 		.opcode = __opcode,				\
+		.nbytes = 1,					\
+		.dtr = true,					\
+	}
+
+#define SPI_MEM_OP_CMD_16B(__opcode, __buswidth)		\
+	{							\
+		.buswidth = __buswidth,				\
+		.opcode = __opcode,				\
+		.nbytes = 2,					\
+	}
+
+#define SPI_MEM_OP_DTR_CMD_16B(__opcode, __buswidth)		\
+	{							\
+		.buswidth = __buswidth,				\
+		.opcode = __opcode,				\
+		.nbytes = 2,					\
 		.dtr = true,					\
 	}
 
@@ -107,6 +124,7 @@ enum spi_mem_data_dir {
 
 /**
  * struct spi_mem_op - describes a SPI memory operation
+ * @cmd.nbytes: number of opcode bytes (only 1 or 2 are valid)
  * @cmd.buswidth: number of IO lines used to transmit the command
  * @cmd.dtr: set true to transfer opcode in double transfer rate mode
  * @cmd.opcode: operation opcode
@@ -132,9 +150,10 @@ enum spi_mem_data_dir {
  */
 struct spi_mem_op {
 	struct {
+		u8 nbytes;
 		u8 buswidth;
 		bool dtr;
-		u8 opcode;
+		u16 opcode;
 	} cmd;
 
 	struct {
-- 
2.14.1