spi: Update multi-die info in spi_device structure

Added multi-die member in spi_device structure.
Scan for multi-die property in the device tree, if
present then set the multi_die member of spi_device
structure variable to true.

If the multi_die member of spi_device structure variable
is set, then a read transaction that spans across multiple
banks is split into one read per bank. This resolves the
die crossover issue.

Signed-off-by: Amit Kumar Mahapatra <amit.kumar-mahapatra@xilinx.com>
Reviewed-by: Naga Sureshkumar Relli <naga.sureshkumar.relli@xilinx.com>
Signed-off-by: Radhey Shyam Pandey <radhey.shyam.pandey@xilinx.com>

drivers/spi/spi.c

@@ -1632,6 +1632,10 @@ static int of_spi_parse_dt(struct spi_controller *ctlr, struct spi_device *spi,
 	}
 	spi->max_speed_hz = value;
 
+	/* Multi die flash */
+	if (of_property_read_bool(nc, "multi-die"))
+		spi->multi_die = true;
+
 	return 0;
 }
 

include/linux/spi/spi.h

@@ -127,6 +127,7 @@ void spi_statistics_add_transfer_stats(struct spi_statistics *stats,
  *	for driver coldplugging, and in uevents used for hotplugging
  * @cs_gpio: gpio number of the chipselect line (optional, -ENOENT when
  *	not using a GPIO line)
+ * @multi_die: Flash device with multiple dies.
  *
  * @statistics: statistics for the spi_device
  *
@@ -171,6 +172,7 @@ struct spi_device {
 	void			*controller_data;
 	char			modalias[SPI_NAME_SIZE];
 	int			cs_gpio;	/* chip select gpio */
+	bool			multi_die;	/* flash with multiple dies*/
 
 	/* the statistics */
 	struct spi_statistics	statistics;