--- zzzz-none-000/linux-4.4.271/include/linux/spi/spi_bitbang.h	2021-06-03 06:22:09.000000000 +0000
+++ hawkeye-5590-750/linux-4.4.271/include/linux/spi/spi_bitbang.h	2023-04-19 10:22:30.000000000 +0000
@@ -39,6 +39,7 @@
 extern void spi_bitbang_cleanup(struct spi_device *spi);
 extern int spi_bitbang_setup_transfer(struct spi_device *spi,
 				      struct spi_transfer *t);
+extern int spi_bitbang_bufs(struct spi_device *spi, struct spi_transfer *t);
 
 /* start or stop queue processing */
 extern int spi_bitbang_start(struct spi_bitbang *spi);