USB: gadget: added a saner gadget downloader registration API

Preprocessor definitions and hardcoded implementation selection in
g_dnl core were replaced by a linker list made of (usb_function_name,
bind_callback) pairs.

Signed-off-by: Mateusz Zalega <m.zalega@samsung.com>
Acked-by: Lukasz Majewski <l.majewski@samsung.com>
Acked-by: Marek Vasut <marex@denx.de>

1 files changed, 23 insertions, 0 deletions

diff --git a/include/g_dnl.h b/include/g_dnl.h
index f4e8d1089e..1b1b35e0e1 100644
--- a/include/g_dnl.h
+++ b/include/g_dnl.h
@@ -10,6 +10,29 @@
 
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
+#include <linux/usb/composite.h>
+#include <linker_lists.h>
+
+/*
+ * @usb_fname: unescaped USB function name
+ * @callback_ptr: bind callback, one per function name
+ */
+#define DECLARE_GADGET_BIND_CALLBACK(usb_fname, callback_ptr) \
+	ll_entry_declare(struct g_dnl_bind_callback, \
+			__usb_function_name_##usb_fname, \
+			g_dnl_bind_callbacks) = { \
+				.usb_function_name = #usb_fname, \
+				.fptr = callback_ptr \
+			}
+
+typedef int (*g_dnl_bind_callback_f)(struct usb_configuration *);
+
+/* used in Gadget downloader callback linker list */
+struct g_dnl_bind_callback {
+	const char *usb_function_name;
+	g_dnl_bind_callback_f fptr;
+};
+
 int g_dnl_bind_fixup(struct usb_device_descriptor *, const char *);
 int g_dnl_board_usb_cable_connected(void);
 int g_dnl_register(const char *s);