spi: spi-mem: allow specifying whether an op is DTR or not

Each phase is given a separate 'dtr' field so mixed protocols like
4S-4D-4D can be supported.
Signed-off-by: Pratyush Yadav <p.yadav@ti.com>
Reviewed-by: Tudor Ambarus <tudor.ambarus@microchip.com>
Link: https://lore.kernel.org/r/20200623183030.26591-2-p.yadav@ti.comSigned-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi-mem.c

@@ -156,6 +156,9 @@ bool spi_mem_default_supports_op(struct spi_mem *mem,
 				   op->data.dir == SPI_MEM_DATA_OUT))
 		return false;
 
+	if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
+		return false;
+
 	return true;
 }
 EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);

include/linux/spi/spi-mem.h

@@ -71,9 +71,11 @@ enum spi_mem_data_dir {
  * struct spi_mem_op - describes a SPI memory operation
  * @cmd.buswidth: number of IO lines used to transmit the command
  * @cmd.opcode: operation opcode
+ * @cmd.dtr: whether the command opcode should be sent in DTR mode or not
  * @addr.nbytes: number of address bytes to send. Can be zero if the operation
  *		 does not need to send an address
  * @addr.buswidth: number of IO lines used to transmit the address cycles
+ * @addr.dtr: whether the address should be sent in DTR mode or not
  * @addr.val: address value. This value is always sent MSB first on the bus.
  *	      Note that only @addr.nbytes are taken into account in this
  *	      address value, so users should make sure the value fits in the
@@ -81,7 +83,9 @@ enum spi_mem_data_dir {
  * @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
  *		  be zero if the operation does not require dummy bytes
  * @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
+ * @dummy.dtr: whether the dummy bytes should be sent in DTR mode or not
  * @data.buswidth: number of IO lanes used to send/receive the data
+ * @data.dtr: whether the data should be sent in DTR mode or not
  * @data.dir: direction of the transfer
  * @data.nbytes: number of data bytes to send/receive. Can be zero if the
  *		 operation does not involve transferring data
@@ -91,22 +95,26 @@ enum spi_mem_data_dir {
 struct spi_mem_op {
 	struct {
 		u8 buswidth;
+		u8 dtr : 1;
 		u8 opcode;
 	} cmd;
 
 	struct {
 		u8 nbytes;
 		u8 buswidth;
+		u8 dtr : 1;
 		u64 val;
 	} addr;
 
 	struct {
 		u8 nbytes;
 		u8 buswidth;
+		u8 dtr : 1;
 	} dummy;
 
 	struct {
 		u8 buswidth;
+		u8 dtr : 1;
 		enum spi_mem_data_dir dir;
 		unsigned int nbytes;
 		union {