[PATCH 5/7] spi: cadence-quadspi: Implement a simple supports_op hook

[Pratyush Yadav]

The default SPI MEM supports_op hook rejects DTR ops by default. Add a
simple supports_op hook that very closely imitates the SPI MEM one. It
will be extended in later commits to allow DTR ops.

Signed-off-by: Pratyush Yadav <p.ya...@ti.com>
---
 drivers/spi/spi-cadence-quadspi.c | 61 +++++++++++++++++++++++++++++++
 1 file changed, 61 insertions(+)

diff --git a/drivers/spi/spi-cadence-quadspi.c 
b/drivers/spi/spi-cadence-quadspi.c
index 376abef43530..1781d4e94ebd 100644
--- a/drivers/spi/spi-cadence-quadspi.c
+++ b/drivers/spi/spi-cadence-quadspi.c
@@ -1031,6 +1031,66 @@ static int cqspi_exec_mem_op(struct spi_mem *mem, const 
struct spi_mem_op *op)
        return ret;
 }
 
+static int cqspi_check_buswidth_req(struct spi_mem *mem, u8 buswidth, bool tx)
+{
+       u32 mode = mem->spi->mode;
+
+       switch (buswidth) {
+       case 1:
+               return 0;
+
+       case 2:
+               if ((tx &&
+                    (mode & (SPI_TX_DUAL | SPI_TX_QUAD | SPI_TX_OCTAL))) ||
+                   (!tx &&
+                    (mode & (SPI_RX_DUAL | SPI_RX_QUAD | SPI_RX_OCTAL))))
+                       return 0;
+
+               break;
+
+       case 4:
+               if ((tx && (mode & (SPI_TX_QUAD | SPI_TX_OCTAL))) ||
+                   (!tx && (mode & (SPI_RX_QUAD | SPI_RX_OCTAL))))
+                       return 0;
+
+               break;
+
+       case 8:
+               if ((tx && (mode & SPI_TX_OCTAL)) ||
+                   (!tx && (mode & SPI_RX_OCTAL)))
+                       return 0;
+
+               break;
+
+       default:
+               break;
+       }
+
+       return -EOPNOTSUPP;
+}
+
+static bool cqspi_supports_mem_op(struct spi_mem *mem,
+                                 const struct spi_mem_op *op)
+{
+       if (cqspi_check_buswidth_req(mem, op->cmd.buswidth, true))
+               return false;
+
+       if (op->addr.nbytes &&
+           cqspi_check_buswidth_req(mem, op->addr.buswidth, true))
+               return false;
+
+       if (op->dummy.nbytes &&
+           cqspi_check_buswidth_req(mem, op->dummy.buswidth, true))
+               return false;
+
+       if (op->data.nbytes &&
+           cqspi_check_buswidth_req(mem, op->data.buswidth,
+                                    op->data.dir == SPI_MEM_DATA_OUT))
+               return false;
+
+       return true;
+}
+
 static int cqspi_of_get_flash_pdata(struct platform_device *pdev,
                                    struct cqspi_flash_pdata *f_pdata,
                                    struct device_node *np)
@@ -1159,6 +1219,7 @@ static const char *cqspi_get_name(struct spi_mem *mem)
 static const struct spi_controller_mem_ops cqspi_mem_ops = {
        .exec_op = cqspi_exec_mem_op,
        .get_name = cqspi_get_name,
+       .supports_op = cqspi_supports_mem_op,
 };
 
 static int cqspi_setup_flash(struct cqspi_st *cqspi)
-- 
2.28.0