usb: gadget: acm_ms: use function framework for ACM

This patch converts the acm_ms gadget to make use of the function
framework to request the ACM function.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Felipe Balbi <balbi@ti.com>

drivers/usb/gadget/Kconfig

@@ -844,6 +844,7 @@ config USB_G_ACM_MS
 	depends on BLOCK
 	select USB_LIBCOMPOSITE
 	select USB_U_SERIAL
+	select USB_F_ACM
 	help
 	  This driver provides two functions in one configuration:
 	  a mass storage, and a CDC ACM (serial port) link.

drivers/usb/gadget/acm_ms.c

@@ -40,8 +40,6 @@
  * the runtime footprint, and giving us at least some parts of what
  * a "gcc --combine ... part1.c part2.c part3.c ... " build would.
  */
-#define USB_FACM_INCLUDED
-#include "f_acm.c"
 #include "f_mass_storage.c"
 
 /*-------------------------------------------------------------------------*/
@@ -112,29 +110,50 @@ static struct fsg_common fsg_common;
 
 /*-------------------------------------------------------------------------*/
 static unsigned char tty_line;
-
+static struct usb_function *f_acm;
+static struct usb_function_instance *f_acm_inst;
 /*
  * We _always_ have both ACM and mass storage functions.
  */
 static int __init acm_ms_do_config(struct usb_configuration *c)
 {
+	struct f_serial_opts *opts;
 	int	status;
 
 	if (gadget_is_otg(c->cdev->gadget)) {
 		c->descriptors = otg_desc;
 		c->bmAttributes |= USB_CONFIG_ATT_WAKEUP;
 	}
 
+	f_acm_inst = usb_get_function_instance("acm");
+	if (IS_ERR(f_acm_inst))
+		return PTR_ERR(f_acm_inst);
+
+	opts = container_of(f_acm_inst, struct f_serial_opts, func_inst);
+	opts->port_num = tty_line;
+
+	f_acm = usb_get_function(f_acm_inst);
+	if (IS_ERR(f_acm)) {
+		status = PTR_ERR(f_acm);
+		goto err_func;
+	}
 
-	status = acm_bind_config(c, tty_line);
+	status = usb_add_function(c, f_acm);
 	if (status < 0)
-		return status;
+		goto err_conf;
 
 	status = fsg_bind_config(c->cdev, c, &fsg_common);
 	if (status < 0)
-		return status;
+		goto err_fsg;
 
 	return 0;
+err_fsg:
+	usb_remove_function(c, f_acm);
+err_conf:
+	usb_put_function(f_acm);
+err_func:
+	usb_put_function_instance(f_acm_inst);
+	return status;
 }
 
 static struct usb_configuration acm_ms_config_driver = {
@@ -195,6 +214,8 @@ static int __init acm_ms_bind(struct usb_composite_dev *cdev)
 
 static int __exit acm_ms_unbind(struct usb_composite_dev *cdev)
 {
+	usb_put_function(f_acm);
+	usb_put_function_instance(f_acm_inst);
 	gserial_free_line(tty_line);
 	return 0;
 }