[PATCH 1/9] spi: spi-mem: allow specifying whether an op is DTR or not

[Pratyush Yadav <p.yadav@xxxxxx>]

Each phase is given a separate 'is_dtr' field so mixed protocols like
4S-4D-4D can be supported.

Also add the mode bits SPI_RX_DTR and SPI_TX_DTR so controllers can
specify whether they support DTR modes or not.

Signed-off-by: Pratyush Yadav <p.yadav@xxxxxx>
---
 drivers/spi/spi-mem.c       | 25 +++++++++++++++++++++++++
 include/linux/spi/spi-mem.h |  8 ++++++++
 include/linux/spi/spi.h     |  2 ++
 3 files changed, 35 insertions(+)

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
index e5a46f0eb93b..8c52ecc41a0e 100644
--- a/drivers/spi/spi-mem.c
+++ b/drivers/spi/spi-mem.c
@@ -99,6 +99,17 @@ void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
 }
 EXPORT_SYMBOL_GPL(spi_controller_dma_unmap_mem_op_data);
 
+static int spi_check_dtr_req(struct spi_mem *mem, bool is_dtr, bool tx)
+{
+	u32 mode = mem->spi->mode;
+
+	if (is_dtr &&
+	    ((tx && (mode & SPI_TX_DTR)) || (!tx && (mode & SPI_RX_DTR))))
+			return 0;
+
+	return -ENOTSUPP;
+}
+
 static int spi_check_buswidth_req(struct spi_mem *mem, u8 buswidth, bool tx)
 {
 	u32 mode = mem->spi->mode;
@@ -154,6 +165,20 @@ bool spi_mem_default_supports_op(struct spi_mem *mem,
 				   op->data.dir == SPI_MEM_DATA_OUT))
 		return false;
 
+	if (op->cmd.is_dtr && spi_check_dtr_req(mem, op->cmd.is_dtr, true))
+		return false;
+
+	if (op->addr.is_dtr && spi_check_dtr_req(mem, op->addr.is_dtr, true))
+		return false;
+
+	if (op->dummy.is_dtr && spi_check_dtr_req(mem, op->dummy.is_dtr, true))
+		return false;
+
+	if (op->data.dir != SPI_MEM_NO_DATA &&
+	    spi_check_dtr_req(mem, op->data.is_dtr,
+			      op->data.dir == SPI_MEM_DATA_OUT))
+		return false;
+
 	return true;
 }
 EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h
index af9ff2f0f1b2..4669082b4e3b 100644
--- a/include/linux/spi/spi-mem.h
+++ b/include/linux/spi/spi-mem.h
@@ -71,6 +71,7 @@ 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.is_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
@@ -78,10 +79,13 @@ enum spi_mem_data_dir {
  *	      Note that only @addr.nbytes are taken into account in this
  *	      address value, so users should make sure the value fits in the
  *	      assigned number of bytes.
+ * @addr.is_dtr: whether the address should be sent in DTR mode or not
  * @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.is_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.is_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
@@ -92,21 +96,25 @@ struct spi_mem_op {
 	struct {
 		u8 buswidth;
 		u8 opcode;
+		bool is_dtr;
 	} cmd;
 
 	struct {
 		u8 nbytes;
 		u8 buswidth;
 		u64 val;
+		bool is_dtr;
 	} addr;
 
 	struct {
 		u8 nbytes;
 		u8 buswidth;
+		bool is_dtr;
 	} dummy;
 
 	struct {
 		u8 buswidth;
+		bool is_dtr;
 		enum spi_mem_data_dir dir;
 		unsigned int nbytes;
 		union {
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index 6d16ba01ff5a..bf1108318389 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -183,6 +183,8 @@ struct spi_device {
 #define	SPI_TX_OCTAL	0x2000			/* transmit with 8 wires */
 #define	SPI_RX_OCTAL	0x4000			/* receive with 8 wires */
 #define	SPI_3WIRE_HIZ	0x8000			/* high impedance turnaround */
+#define SPI_RX_DTR	0x10000			/* receive in DTR mode */
+#define SPI_TX_DTR	0x20000			/* transmit in DTR mode */
 	int			irq;
 	void			*controller_state;
 	void			*controller_data;
-- 
2.25.0