usb: gadget: f_acm: convert to new function interface with backwards compatibility

This patch converts f_acm into a module which uses the new function
interface. It also converts one of its users that is g_serial to make
use of it. The other users of it (g_nokia for instance) are still using
the old include file system and should not notice the change at all. So
they can be converter later independently.

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

drivers/usb/gadget/f_acm.c

@@ -16,7 +16,9 @@
 
 #include <linux/slab.h>
 #include <linux/kernel.h>
+#include <linux/module.h>
 #include <linux/device.h>
+#include <linux/err.h>
 
 #include "u_serial.h"
 #include "gadget_chips.h"
@@ -608,6 +610,22 @@ acm_bind(struct usb_configuration *c, struct usb_function *f)
 	int			status;
 	struct usb_ep		*ep;
 
+	/* REVISIT might want instance-specific strings to help
+	 * distinguish instances ...
+	 */
+
+	/* maybe allocate device-global string IDs, and patch descriptors */
+	if (acm_string_defs[0].id == 0) {
+		status = usb_string_ids_tab(c->cdev, acm_string_defs);
+		if (status < 0)
+			return status;
+		acm_control_interface_desc.iInterface =
+			acm_string_defs[ACM_CTRL_IDX].id;
+		acm_data_interface_desc.iInterface =
+			acm_string_defs[ACM_DATA_IDX].id;
+		acm_iad_descriptor.iFunction = acm_string_defs[ACM_IAD_IDX].id;
+	}
+
 	/* allocate instance-specific interface IDs, and patch descriptors */
 	status = usb_interface_id(c, f);
 	if (status < 0)
@@ -700,14 +718,41 @@ fail:
 	return status;
 }
 
+static struct f_acm *acm_alloc_basic_func(void)
+{
+	struct f_acm	*acm;
+
+	acm = kzalloc(sizeof(*acm), GFP_KERNEL);
+	if (!acm)
+		return NULL;
+
+	spin_lock_init(&acm->lock);
+
+	acm->port.connect = acm_connect;
+	acm->port.disconnect = acm_disconnect;
+	acm->port.send_break = acm_send_break;
+
+	acm->port.func.name = "acm";
+	acm->port.func.strings = acm_strings;
+	/* descriptors are per-instance copies */
+	acm->port.func.bind = acm_bind;
+	acm->port.func.set_alt = acm_set_alt;
+	acm->port.func.setup = acm_setup;
+	acm->port.func.disable = acm_disable;
+
+	return acm;
+}
+
+#ifdef USB_FACM_INCLUDED
 static void
-acm_unbind(struct usb_configuration *c, struct usb_function *f)
+acm_old_unbind(struct usb_configuration *c, struct usb_function *f)
 {
 	struct f_acm		*acm = func_to_acm(f);
 
 	acm_string_defs[0].id = 0;
 	usb_free_all_descriptors(f);
-	gs_free_req(acm->notify, acm->notify_req);
+	if (acm->notify_req)
+		gs_free_req(acm->notify, acm->notify_req);
 	kfree(acm);
 }
 
@@ -725,46 +770,74 @@ int acm_bind_config(struct usb_configuration *c, u8 port_num)
 	struct f_acm	*acm;
 	int		status;
 
-	/* REVISIT might want instance-specific strings to help
-	 * distinguish instances ...
-	 */
-
-	/* maybe allocate device-global string IDs, and patch descriptors */
-	if (acm_string_defs[0].id == 0) {
-		status = usb_string_ids_tab(c->cdev, acm_string_defs);
-		if (status < 0)
-			return status;
-		acm_control_interface_desc.iInterface =
-			acm_string_defs[ACM_CTRL_IDX].id;
-		acm_data_interface_desc.iInterface =
-			acm_string_defs[ACM_DATA_IDX].id;
-		acm_iad_descriptor.iFunction = acm_string_defs[ACM_IAD_IDX].id;
-	}
-
 	/* allocate and initialize one new instance */
-	acm = kzalloc(sizeof *acm, GFP_KERNEL);
+	acm = acm_alloc_basic_func();
 	if (!acm)
 		return -ENOMEM;
 
-	spin_lock_init(&acm->lock);
-
 	acm->port_num = port_num;
-
-	acm->port.connect = acm_connect;
-	acm->port.disconnect = acm_disconnect;
-	acm->port.send_break = acm_send_break;
-
-	acm->port.func.name = "acm";
-	acm->port.func.strings = acm_strings;
-	/* descriptors are per-instance copies */
-	acm->port.func.bind = acm_bind;
-	acm->port.func.unbind = acm_unbind;
-	acm->port.func.set_alt = acm_set_alt;
-	acm->port.func.setup = acm_setup;
-	acm->port.func.disable = acm_disable;
+	acm->port.func.unbind = acm_old_unbind;
 
 	status = usb_add_function(c, &acm->port.func);
 	if (status)
 		kfree(acm);
 	return status;
 }
+
+#else
+
+static void acm_unbind(struct usb_configuration *c, struct usb_function *f)
+{
+	struct f_acm		*acm = func_to_acm(f);
+
+	acm_string_defs[0].id = 0;
+	usb_free_all_descriptors(f);
+	if (acm->notify_req)
+		gs_free_req(acm->notify, acm->notify_req);
+}
+
+static void acm_free_func(struct usb_function *f)
+{
+	struct f_acm		*acm = func_to_acm(f);
+
+	kfree(acm);
+}
+
+static struct usb_function *acm_alloc_func(struct usb_function_instance *fi)
+{
+	struct f_serial_opts *opts;
+	struct f_acm *acm;
+
+	acm = acm_alloc_basic_func();
+	if (!acm)
+		return ERR_PTR(-ENOMEM);
+
+	opts = container_of(fi, struct f_serial_opts, func_inst);
+	acm->port_num = opts->port_num;
+	acm->port.func.unbind = acm_unbind;
+	acm->port.func.free_func = acm_free_func;
+
+	return &acm->port.func;
+}
+
+static void acm_free_instance(struct usb_function_instance *fi)
+{
+	struct f_serial_opts *opts;
+
+	opts = container_of(fi, struct f_serial_opts, func_inst);
+	kfree(opts);
+}
+
+static struct usb_function_instance *acm_alloc_instance(void)
+{
+	struct f_serial_opts *opts;
+
+	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
+	if (!opts)
+		return ERR_PTR(-ENOMEM);
+	opts->func_inst.free_func_inst = acm_free_instance;
+	return &opts->func_inst;
+}
+DECLARE_USB_FUNCTION_INIT(acm, acm_alloc_instance, acm_alloc_func);
+MODULE_LICENSE("GPL");
+#endif