[PATCH v2 1/3] spi: Add empty versions of ACPI functions

[Richard Fitzgerald <rf@opensource.cirrus.com>]

Provide empty versions of acpi_spi_count_resources(),
acpi_spi_device_alloc() and acpi_spi_find_controller_by_adev()
if the real functions are not being built.

This commit fixes two problems with the original definitions:

1) There wasn't an empty version of these functions
2) The #if only depended on CONFIG_ACPI. But the functions are implemented
   in the core spi.c so CONFIG_SPI_MASTER must also be enabled for the real
   functions to exist.

Signed-off-by: Richard Fitzgerald <rf@opensource.cirrus.com>
---
Changes since V1:
- This patch is new in V2.

 include/linux/spi/spi.h | 19 ++++++++++++++++++-
 1 file changed, 18 insertions(+), 1 deletion(-)

diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h
index e4f3f3d30a03..d47d5f14ff99 100644
--- a/include/linux/spi/spi.h
+++ b/include/linux/spi/spi.h
@@ -902,12 +902,29 @@ 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_ACPI)
+#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,
 						struct acpi_device *adev,
 						int index);
 int acpi_spi_count_resources(struct acpi_device *adev);
+#else
+static inline struct spi_controller *acpi_spi_find_controller_by_adev(struct acpi_device *adev)
+{
+	return NULL;
+}
+
+static inline struct spi_device *acpi_spi_device_alloc(struct spi_controller *ctlr,
+						       struct acpi_device *adev,
+						       int index)
+{
+	return ERR_PTR(-ENODEV);
+}
+
+static inline int acpi_spi_count_resources(struct acpi_device *adev)
+{
+	return 0;
+}
 #endif
 
 /*
-- 
2.39.2