[PATCH v2 12/15] spi: dw: Add retry for enhanced spi mode

[Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxx>]

If the connection to the spi device is not stable then the transfer can
fail. Add retry for DW_SPI_WAIT_RETRIES times and print error if it still
fails.

Signed-off-by: Sudip Mukherjee <sudip.mukherjee@xxxxxxxxxx>
---
 drivers/spi/spi-dw-core.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
index dff7b419af304..cef56acd8d8fd 100644
--- a/drivers/spi/spi-dw-core.c
+++ b/drivers/spi/spi-dw-core.c
@@ -906,7 +906,7 @@ static void dw_spi_enh_write_cmd_addr(struct dw_spi *dws, const struct spi_mem_o
 	}
 }
 
-static int dw_spi_exec_enh_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
+static int dw_spi_try_enh_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
 {
 	struct spi_controller *ctlr = mem->spi->controller;
 	struct dw_spi *dws = spi_controller_get_devdata(ctlr);
@@ -991,6 +991,21 @@ static int dw_spi_exec_enh_mem_op(struct spi_mem *mem, const struct spi_mem_op *
 	return ret;
 }
 
+static int dw_spi_exec_enh_mem_op(struct spi_mem *mem, const struct spi_mem_op *op)
+{
+	struct spi_controller *ctlr = mem->spi->controller;
+	struct dw_spi *dws = spi_controller_get_devdata(ctlr);
+	int retry, ret = -EIO;
+
+	for (retry = 0; retry < DW_SPI_WAIT_RETRIES && ret != 0; retry++)
+		ret = dw_spi_try_enh_mem_op(mem, op);
+
+	if (retry == DW_SPI_WAIT_RETRIES)
+		dev_err(&dws->master->dev, "Retry of enh_mem_op failed\n");
+
+	return ret;
+}
+
 /*
  * Initialize the default memory operations if a glue layer hasn't specified
  * custom ones. Direct mapping operations will be preserved anyway since DW SPI
-- 
2.30.2