[PATCH v4 2/4] soundwire: Provide build stubs for common functions

[Charles Keepax <ckeepax@opensource.cirrus.com>]

Provide stub functions when CONFIG_SOUNDWIRE is not set for functions
that are quite likely to be used from common code on devices supporting
multiple control buses.

Reviewed-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Charles Keepax <ckeepax@opensource.cirrus.com>
---

Changes since v3:
 - Return error code and add WARN_ONCE in build stubs. Note I returned
   EINVAL rather than the discussed ENOSYS since it turns out checkpatch
   informs me I really shouldn't be returning ENOSYS :-)

Thanks,
Charles

 include/linux/soundwire/sdw.h | 105 ++++++++++++++++++++++++++++++----
 1 file changed, 95 insertions(+), 10 deletions(-)

diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index 902ed46f76c80..132a0ee97b804 100644
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -4,6 +4,7 @@
 #ifndef __SOUNDWIRE_H
 #define __SOUNDWIRE_H
 
+#include <linux/bug.h>
 #include <linux/mod_devicetable.h>
 #include <linux/bitfield.h>
 
@@ -1021,15 +1022,8 @@ int sdw_stream_add_master(struct sdw_bus *bus,
 		struct sdw_port_config *port_config,
 		unsigned int num_ports,
 		struct sdw_stream_runtime *stream);
-int sdw_stream_add_slave(struct sdw_slave *slave,
-		struct sdw_stream_config *stream_config,
-		struct sdw_port_config *port_config,
-		unsigned int num_ports,
-		struct sdw_stream_runtime *stream);
 int sdw_stream_remove_master(struct sdw_bus *bus,
 		struct sdw_stream_runtime *stream);
-int sdw_stream_remove_slave(struct sdw_slave *slave,
-		struct sdw_stream_runtime *stream);
 int sdw_startup_stream(void *sdw_substream);
 int sdw_prepare_stream(struct sdw_stream_runtime *stream);
 int sdw_enable_stream(struct sdw_stream_runtime *stream);
@@ -1040,8 +1034,20 @@ int sdw_bus_prep_clk_stop(struct sdw_bus *bus);
 int sdw_bus_clk_stop(struct sdw_bus *bus);
 int sdw_bus_exit_clk_stop(struct sdw_bus *bus);
 
-/* messaging and data APIs */
+int sdw_compare_devid(struct sdw_slave *slave, struct sdw_slave_id id);
+void sdw_extract_slave_id(struct sdw_bus *bus, u64 addr, struct sdw_slave_id *id);
 
+#if IS_ENABLED(CONFIG_SOUNDWIRE)
+
+int sdw_stream_add_slave(struct sdw_slave *slave,
+			 struct sdw_stream_config *stream_config,
+			 struct sdw_port_config *port_config,
+			 unsigned int num_ports,
+			 struct sdw_stream_runtime *stream);
+int sdw_stream_remove_slave(struct sdw_slave *slave,
+			    struct sdw_stream_runtime *stream);
+
+/* messaging and data APIs */
 int sdw_read(struct sdw_slave *slave, u32 addr);
 int sdw_write(struct sdw_slave *slave, u32 addr, u8 value);
 int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value);
@@ -1053,7 +1059,86 @@ int sdw_nwrite_no_pm(struct sdw_slave *slave, u32 addr, size_t count, const u8 *
 int sdw_update(struct sdw_slave *slave, u32 addr, u8 mask, u8 val);
 int sdw_update_no_pm(struct sdw_slave *slave, u32 addr, u8 mask, u8 val);
 
-int sdw_compare_devid(struct sdw_slave *slave, struct sdw_slave_id id);
-void sdw_extract_slave_id(struct sdw_bus *bus, u64 addr, struct sdw_slave_id *id);
+#else
+
+static inline int sdw_stream_add_slave(struct sdw_slave *slave,
+				       struct sdw_stream_config *stream_config,
+				       struct sdw_port_config *port_config,
+				       unsigned int num_ports,
+				       struct sdw_stream_runtime *stream)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+static inline int sdw_stream_remove_slave(struct sdw_slave *slave,
+					  struct sdw_stream_runtime *stream)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+/* messaging and data APIs */
+static inline int sdw_read(struct sdw_slave *slave, u32 addr)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+static inline int sdw_write(struct sdw_slave *slave, u32 addr, u8 value)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+static inline int sdw_write_no_pm(struct sdw_slave *slave, u32 addr, u8 value)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+static inline int sdw_read_no_pm(struct sdw_slave *slave, u32 addr)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+static inline int sdw_nread(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+static inline int sdw_nread_no_pm(struct sdw_slave *slave, u32 addr, size_t count, u8 *val)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+static inline int sdw_nwrite(struct sdw_slave *slave, u32 addr, size_t count, const u8 *val)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+static inline int sdw_nwrite_no_pm(struct sdw_slave *slave, u32 addr, size_t count, const u8 *val)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+static inline int sdw_update(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+static inline int sdw_update_no_pm(struct sdw_slave *slave, u32 addr, u8 mask, u8 val)
+{
+	WARN_ONCE(1, "SoundWire API is disabled");
+	return -EINVAL;
+}
+
+#endif /* CONFIG_SOUNDWIRE */
 
 #endif /* __SOUNDWIRE_H */
-- 
2.30.2