diff --git a/drivers/staging/fbtft/fbtft-core.c b/drivers/staging/fbtft/fbtft-core.c
index f2684d2d6851..6dc77895a87c 100644
--- a/drivers/staging/fbtft/fbtft-core.c
+++ b/drivers/staging/fbtft/fbtft-core.c
@@ -49,7 +49,7 @@ int fbtft_write_buf_dc(struct fbtft_par *par, void *buf, size_t len, int dc)
 EXPORT_SYMBOL(fbtft_write_buf_dc);
 
 void fbtft_dbg_hex(const struct device *dev, int groupsize,
-		   void *buf, size_t len, const char *fmt, ...)
+		   const void *buf, size_t len, const char *fmt, ...)
 {
 	va_list args;
 	static char textbuf[512];
diff --git a/drivers/staging/fbtft/fbtft.h b/drivers/staging/fbtft/fbtft.h
index 6a7545b5bcd2..473523dea838 100644
--- a/drivers/staging/fbtft/fbtft.h
+++ b/drivers/staging/fbtft/fbtft.h
@@ -240,7 +240,7 @@ struct fbtft_par {
 int fbtft_write_buf_dc(struct fbtft_par *par, void *buf, size_t len, int dc);
 __printf(5, 6)
 void fbtft_dbg_hex(const struct device *dev, int groupsize,
-		   void *buf, size_t len, const char *fmt, ...);
+		   const void *buf, size_t len, const char *fmt, ...);
 struct fb_info *fbtft_framebuffer_alloc(struct fbtft_display *display,
 					struct device *dev,
 					struct fbtft_platform_data *pdata);