[PATCH v10 1/3] spi: export of_find_spi_controller_by_node()

[Oder Chiou <oder_chiou@realtek.com>]

Some devices are primarily described on another bus (e.g. I2C) but also
have an additional SPI connection that serves as a transport for
firmware loading. Export of_find_spi_controller_by_node() so drivers can
obtain the SPI controller referenced by a DT phandle.

Signed-off-by: Oder Chiou <oder_chiou@realtek.com>
---
 drivers/spi/spi.c       |  3 ++-
 include/linux/spi/spi.h | 11 +++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index e25df9990f82..ecb5281b04a2 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -4771,7 +4771,7 @@ static struct spi_device *of_find_spi_device_by_node(struct device_node *node)
 }
 
 /* The spi controllers are not using spi_bus, so we find it with another way */
-static struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
+struct spi_controller *of_find_spi_controller_by_node(struct device_node *node)
 {
 	struct device *dev;
 
@@ -4784,6 +4784,7 @@ static struct spi_controller *of_find_spi_controller_by_node(struct device_node
 	/* Reference got in class_find_device */
 	return container_of(dev, struct spi_controller, dev);
 }
+EXPORT_SYMBOL_GPL(of_find_spi_controller_by_node);
 
 static int of_spi_notify(struct notifier_block *nb, unsigned long action,
 			 void *arg)
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index cb2c2df31089..1eb04a96cc1c 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -882,6 +882,17 @@ extern int devm_spi_register_controller(struct device *dev,
 					struct spi_controller *ctlr);
 extern void spi_unregister_controller(struct spi_controller *ctlr);
 
+#if IS_ENABLED(CONFIG_OF_DYNAMIC)
+extern struct spi_controller *of_find_spi_controller_by_node(
+	struct device_node *node);
+#else
+static inline struct spi_controller *of_find_spi_controller_by_node(
+	struct device_node *node)
+{
+	return NULL;
+}
+#endif
+
 #if IS_ENABLED(CONFIG_ACPI) && IS_ENABLED(CONFIG_SPI_MASTER)
 extern struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev);
 extern struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
-- 
2.52.0