spi: export spi_transfer_cs_change_delay_exec function

For SPI controller that implements transfer_one_message, it needs to
insert the delay that required by cs change event between the transfers.
Add a wrapper for the local function _spi_transfer_cs_change_delay_exec
and export it for SPI controller driver to use.

Signed-off-by: William Zhang <william.zhang@broadcom.com>
Link: https://lore.kernel.org/r/20230209200246.141520-9-william.zhang@broadcom.com
Signed-off-by: Mark Brown <broonie@kernel.org>

drivers/spi/spi.c

@@ -1483,6 +1483,13 @@ static void _spi_transfer_cs_change_delay(struct spi_message *msg,
 	}
 }
 
+void spi_transfer_cs_change_delay_exec(struct spi_message *msg,
+						  struct spi_transfer *xfer)
+{
+	_spi_transfer_cs_change_delay(msg, xfer);
+}
+EXPORT_SYMBOL_GPL(spi_transfer_cs_change_delay_exec);
+
 /*
  * spi_transfer_one_message - Default implementation of transfer_one_message()
  *

include/linux/spi/spi.h

@@ -26,6 +26,7 @@ struct spi_controller;
 struct spi_transfer;
 struct spi_controller_mem_ops;
 struct spi_controller_mem_caps;
+struct spi_message;
 
 /*
  * INTERFACES between SPI master-side drivers and SPI slave protocol handlers,
@@ -119,6 +120,8 @@ struct spi_delay {
 
 extern int spi_delay_to_ns(struct spi_delay *_delay, struct spi_transfer *xfer);
 extern int spi_delay_exec(struct spi_delay *_delay, struct spi_transfer *xfer);
+extern void spi_transfer_cs_change_delay_exec(struct spi_message *msg,
+						  struct spi_transfer *xfer);
 
 /**
  * struct spi_device - Controller side proxy for an SPI slave device
@@ -283,8 +286,6 @@ static inline void spi_set_csgpiod(struct spi_device *spi, u8 idx, struct gpio_d
 	spi->cs_gpiod = csgpiod;
 }
 
-struct spi_message;
-
 /**
  * struct spi_driver - Host side "protocol" driver
  * @id_table: List of SPI devices supported by this driver