usb: gadget: f_phonet: add configfs support

f_phonet learns about configfs so we can remove
in-kernel gadget drivers.

Signed-off-by: Andrzej Pietrasiewicz <andrzej.p@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

3 files changed, 74 insertions, 0 deletions

diff --git a/Documentation/ABI/testing/configfs-usb-gadget-phonet b/Documentation/ABI/testing/configfs-usb-gadget-phonet
new file mode 100644
index 000000000000..19b67d3eab94
--- /dev/null
+++ b/Documentation/ABI/testing/configfs-usb-gadget-phonet
@@ -0,0 +1,8 @@
+What:           /config/usb-gadget/gadget/functions/phonet.name
+Date:           May 2013
+KenelVersion:   3.11
+Description:
+
+                This item contains just one readonly attribute: ifname.
+                It contains the network interface name assigned during
+                network device registration.
diff --git a/drivers/usb/gadget/Kconfig b/drivers/usb/gadget/Kconfig
index 5022c2d3e365..d6c4e601d711 100644
--- a/drivers/usb/gadget/Kconfig
+++ b/drivers/usb/gadget/Kconfig
@@ -541,6 +541,16 @@ choice
 
 # this first set of drivers all depend on bulk-capable hardware.
 
+config USB_CONFIGFS_PHONET
+        boolean "Phonet protocol"
+        depends on USB_CONFIGFS
+        depends on NET
+        depends on PHONET
+        select USB_U_ETHER
+        select USB_F_PHONET
+        help
+          The Phonet protocol implementation for USB device.
+
 config USB_ZERO
         tristate "Gadget Zero (DEVELOPMENT)"
         select USB_LIBCOMPOSITE
diff --git a/drivers/usb/gadget/f_phonet.c b/drivers/usb/gadget/f_phonet.c
index 5dd774876168..7944fb0efe3b 100644
--- a/drivers/usb/gadget/f_phonet.c
+++ b/drivers/usb/gadget/f_phonet.c
@@ -26,6 +26,7 @@
 #include <linux/usb/composite.h>
 
 #include "u_phonet.h"
+#include "u_ether.h"
 
 #define PN_MEDIA_USB    0x1B
 #define MAXPACKET       512
@@ -581,6 +582,58 @@ err:
         return status;
 }
 
+static inline struct f_phonet_opts *to_f_phonet_opts(struct config_item *item)
+{
+        return container_of(to_config_group(item), struct f_phonet_opts,
+                        func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(f_phonet_opts);
+static ssize_t f_phonet_attr_show(struct config_item *item,
+                                struct configfs_attribute *attr,
+                                char *page)
+{
+        struct f_phonet_opts *opts = to_f_phonet_opts(item);
+        struct f_phonet_opts_attribute *f_phonet_opts_attr =
+                container_of(attr, struct f_phonet_opts_attribute, attr);
+        ssize_t ret = 0;
+
+        if (f_phonet_opts_attr->show)
+                ret = f_phonet_opts_attr->show(opts, page);
+        return ret;
+}
+
+static void phonet_attr_release(struct config_item *item)
+{
+        struct f_phonet_opts *opts = to_f_phonet_opts(item);
+
+        usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations phonet_item_ops = {
+        .release                = phonet_attr_release,
+        .show_attribute         = f_phonet_attr_show,
+};
+
+static ssize_t f_phonet_ifname_show(struct f_phonet_opts *opts, char *page)
+{
+        return gether_get_ifname(opts->net, page, PAGE_SIZE);
+}
+
+static struct f_phonet_opts_attribute f_phonet_ifname =
+        __CONFIGFS_ATTR_RO(ifname, f_phonet_ifname_show);
+
+static struct configfs_attribute *phonet_attrs[] = {
+        &f_phonet_ifname.attr,
+        NULL,
+};
+
+static struct config_item_type phonet_func_type = {
+        .ct_item_ops    = &phonet_item_ops,
+        .ct_attrs       = phonet_attrs,
+        .ct_owner       = THIS_MODULE,
+};
+
 static void phonet_free_inst(struct usb_function_instance *f)
 {
         struct f_phonet_opts *opts;
@@ -606,6 +659,9 @@ static struct usb_function_instance *phonet_alloc_inst(void)
         if (IS_ERR(opts->net))
                 return ERR_PTR(PTR_ERR(opts->net));
 
+        config_group_init_type_name(&opts->func_inst.group, "",
+                        &phonet_func_type);
+
         return &opts->func_inst;
 }