[PATCH 22/30] spi: cadence_qspi: Add spi mem dtr support ops

[Tejas Bhumkar]

From: T Karthik Reddy <t.karthik.reddy at xilinx.com>

In DDR mode, current default spi_mem_dtr_supports_op() function does
not allow mixed DTR operation functionality. So implement cadence
specific cadence_spi_mem_dtr_supports_op() function to verifying only
the command buswidth and command opcode bytes which satisfies the DTR
protocol.

Signed-off-by: T Karthik Reddy <t.karthik.reddy at xilinx.com>
Signed-off-by: Tejas Bhumkar <tejas.arvind.bhumkar at amd.com>
---
 drivers/spi/cadence_qspi.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/cadence_qspi.c b/drivers/spi/cadence_qspi.c
index 710c4a532d..282028c845 100644
--- a/drivers/spi/cadence_qspi.c
+++ b/drivers/spi/cadence_qspi.c
@@ -718,6 +718,21 @@ static int cadence_spi_mem_exec_op(struct spi_slave *spi,
 	return err;
 }
 
+static bool cadence_spi_mem_dtr_supports_op(struct spi_slave *slave,
+					    const struct spi_mem_op *op)
+{
+	/*
+	 * In DTR mode, except op->cmd all other parameters like address,
+	 * dummy and data could be 0.
+	 * So lets only check if the cmd buswidth and number of opcode bytes
+	 * are true for DTR to support.
+	 */
+	if (op->cmd.buswidth == 8 && op->cmd.nbytes % 2)
+		return false;
+
+	return true;
+}
+
 static bool cadence_spi_mem_supports_op(struct spi_slave *slave,
 					const struct spi_mem_op *op)
 {
@@ -740,7 +755,7 @@ static bool cadence_spi_mem_supports_op(struct spi_slave *slave,
 		return false;
 
 	if (all_true)
-		return spi_mem_dtr_supports_op(slave, op);
+		return cadence_spi_mem_dtr_supports_op(slave, op);
 	else
 		return spi_mem_default_supports_op(slave, op);
 }
-- 
2.27.0