usb: gadget: printer: add configfs support

[linux.git] / drivers / usb / gadget / function / f_printer.c

diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c
index 7afe17d76f17c2cdfb0acad0dfab3beb38447c00..757fcf070013c27e01cdd2e2a523b2daa0250cee 100644 (file)
--- a/drivers/usb/gadget/function/f_printer.c
+++ b/drivers/usb/gadget/function/f_printer.c
@@ -1140,6 +1140,117 @@ static void printer_func_disable(struct usb_function *f)
        spin_unlock_irqrestore(&dev->lock, flags);
 }
 
+static inline struct f_printer_opts
+*to_f_printer_opts(struct config_item *item)
+{
+       return container_of(to_config_group(item), struct f_printer_opts,
+                           func_inst.group);
+}
+
+CONFIGFS_ATTR_STRUCT(f_printer_opts);
+CONFIGFS_ATTR_OPS(f_printer_opts);
+
+static void printer_attr_release(struct config_item *item)
+{
+       struct f_printer_opts *opts = to_f_printer_opts(item);
+
+       usb_put_function_instance(&opts->func_inst);
+}
+
+static struct configfs_item_operations printer_item_ops = {
+       .release        = printer_attr_release,
+       .show_attribute = f_printer_opts_attr_show,
+       .store_attribute = f_printer_opts_attr_store,
+};
+
+static ssize_t f_printer_opts_pnp_string_show(struct f_printer_opts *opts,
+                                             char *page)
+{
+       int result;
+
+       mutex_lock(&opts->lock);
+       result = strlcpy(page, opts->pnp_string + 2, PNP_STRING_LEN - 2);
+       mutex_unlock(&opts->lock);
+
+       return result;
+}
+
+static ssize_t f_printer_opts_pnp_string_store(struct f_printer_opts *opts,
+                                              const char *page, size_t len)
+{
+       int result, l;
+
+       mutex_lock(&opts->lock);
+       result = strlcpy(opts->pnp_string + 2, page, PNP_STRING_LEN - 2);
+       l = strlen(opts->pnp_string + 2) + 2;
+       opts->pnp_string[0] = (l >> 8) & 0xFF;
+       opts->pnp_string[1] = l & 0xFF;
+       mutex_unlock(&opts->lock);
+
+       return result;
+}
+
+static struct f_printer_opts_attribute f_printer_opts_pnp_string =
+       __CONFIGFS_ATTR(pnp_string, S_IRUGO | S_IWUSR,
+                       f_printer_opts_pnp_string_show,
+                       f_printer_opts_pnp_string_store);
+
+static ssize_t f_printer_opts_q_len_show(struct f_printer_opts *opts,
+                                        char *page)
+{
+       int result;
+
+       mutex_lock(&opts->lock);
+       result = sprintf(page, "%d\n", opts->q_len);
+       mutex_unlock(&opts->lock);
+
+       return result;
+}
+
+static ssize_t f_printer_opts_q_len_store(struct f_printer_opts *opts,
+                                         const char *page, size_t len)
+{
+       int ret;
+       u16 num;
+
+       mutex_lock(&opts->lock);
+       if (opts->refcnt) {
+               ret = -EBUSY;
+               goto end;
+       }
+
+       ret = kstrtou16(page, 0, &num);
+       if (ret)
+               goto end;
+
+       if (num > 65535) {
+               ret = -EINVAL;
+               goto end;
+       }
+
+       opts->q_len = (unsigned)num;
+       ret = len;
+end:
+       mutex_unlock(&opts->lock);
+       return ret;
+}
+
+static struct f_printer_opts_attribute f_printer_opts_q_len =
+       __CONFIGFS_ATTR(q_len, S_IRUGO | S_IWUSR, f_printer_opts_q_len_show,
+                       f_printer_opts_q_len_store);
+
+static struct configfs_attribute *printer_attrs[] = {
+       &f_printer_opts_pnp_string.attr,
+       &f_printer_opts_q_len.attr,
+       NULL,
+};
+
+static struct config_item_type printer_func_type = {
+       .ct_item_ops    = &printer_item_ops,
+       .ct_attrs       = printer_attrs,
+       .ct_owner       = THIS_MODULE,
+};
+
 static inline int gprinter_get_minor(void)
 {
        return ida_simple_get(&printer_ida, 0, 0, GFP_KERNEL);
@@ -1180,6 +1291,7 @@ static struct usb_function_instance *gprinter_alloc_inst(void)
        if (!opts)
                return ERR_PTR(-ENOMEM);
 
+       mutex_init(&opts->lock);
        opts->func_inst.free_func_inst = gprinter_free_inst;
        ret = &opts->func_inst;
 
@@ -1201,6 +1313,8 @@ static struct usb_function_instance *gprinter_alloc_inst(void)
                if (idr_is_empty(&printer_ida.idr))
                        gprinter_cleanup();
        }
+       config_group_init_type_name(&opts->func_inst.group, "",
+                                   &printer_func_type);
 
 unlock:
        mutex_unlock(&printer_ida_lock);
@@ -1210,8 +1324,13 @@ static struct usb_function_instance *gprinter_alloc_inst(void)
 static void gprinter_free(struct usb_function *f)
 {
        struct printer_dev *dev = func_to_printer(f);
+       struct f_printer_opts *opts;
 
+       opts = container_of(f->fi, struct f_printer_opts, func_inst);
        kfree(dev);
+       mutex_lock(&opts->lock);
+       --opts->refcnt;
+       mutex_unlock(&opts->lock);
 }
 
 static void printer_func_unbind(struct usb_configuration *c,
@@ -1265,16 +1384,23 @@ static struct usb_function *gprinter_alloc(struct usb_function_instance *fi)
 
        opts = container_of(fi, struct f_printer_opts, func_inst);
 
-       if (opts->minor >= minors)
+       mutex_lock(&opts->lock);
+       if (opts->minor >= minors) {
+               mutex_unlock(&opts->lock);
                return ERR_PTR(-ENOENT);
+       }
 
        dev = kzalloc(sizeof(*dev), GFP_KERNEL);
-       if (!dev)
+       if (!dev) {
+               mutex_unlock(&opts->lock);
                return ERR_PTR(-ENOMEM);
+       }
 
+       ++opts->refcnt;
        dev->minor = opts->minor;
        dev->pnp_string = opts->pnp_string;
        dev->q_len = opts->q_len;
+       mutex_unlock(&opts->lock);
 
        dev->function.name = "printer";
        dev->function.bind = printer_func_bind;