am7xxx: mention open_device() in the comment about scan_devices()

[libam7xxx.git] / src / am7xxx.c

diff --git a/src/am7xxx.c b/src/am7xxx.c
index 7122658..8837e41 100644 (file)
--- a/src/am7xxx.c
+++ b/src/am7xxx.c
@@ -1,6 +1,6 @@
 /* am7xxx - communication with AM7xxx based USB Pico Projectors and DPFs
  *
- * Copyright (C) 2012  Antonio Ospite <ospite@studenti.unina.it>
+ * Copyright (C) 2012-2014  Antonio Ospite <ao2@ao2.it>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -702,6 +702,62 @@ static am7xxx_device *find_device(am7xxx_context *ctx,
        return current;
 }
 
+static int open_device(am7xxx_context *ctx,
+                      unsigned int device_index,
+                      libusb_device* usb_dev,
+                      am7xxx_device **dev)
+{
+       int ret;
+
+       *dev = find_device(ctx, device_index);
+       if (*dev == NULL) {
+               ret = -ENODEV;
+               goto out;
+       }
+
+       /* the usb device has already been opened */
+       if ((*dev)->usb_device) {
+               debug(ctx, "(*dev)->usb_device already set\n");
+               ret = 1;
+               goto out;
+       }
+
+       ret = libusb_open(usb_dev, &((*dev)->usb_device));
+       if (ret < 0) {
+               debug(ctx, "libusb_open failed\n");
+               goto out;
+       }
+
+       /* XXX, the device is now open, if any of the calls below fail we need
+        * to close it again before bailing out.
+        */
+
+       ret = libusb_set_configuration((*dev)->usb_device,
+                                      (*dev)->desc->configuration);
+       if (ret < 0) {
+               debug(ctx, "libusb_set_configuration failed\n");
+               debug(ctx, "Cannot set configuration %hhu\n",
+                     (*dev)->desc->configuration);
+               goto out_libusb_close;
+       }
+
+       ret = libusb_claim_interface((*dev)->usb_device,
+                                    (*dev)->desc->interface_number);
+       if (ret < 0) {
+               debug(ctx, "libusb_claim_interface failed\n");
+               debug(ctx, "Cannot claim interface %hhu\n",
+                     (*dev)->desc->interface_number);
+               goto out_libusb_close;
+       }
+out:
+       return ret;
+
+out_libusb_close:
+       libusb_close((*dev)->usb_device);
+       (*dev)->usb_device = NULL;
+       return ret;
+}
+
 typedef enum {
        SCAN_OP_BUILD_DEVLIST,
        SCAN_OP_OPEN_DEVICE,
@@ -716,8 +772,9 @@ typedef enum {
  *
  * When 'op' == SCAN_OP_OPEN_DEVICE the function opens the supported USB
  * device with index 'open_device_index' and returns the correspondent
- * am7xxx_device in the 'dev' parameter; the function returns 0 on success,
- * 1 if the device was already open and a negative value on error.
+ * am7xxx_device in the 'dev' parameter; the function returns the value from
+ * open_device(), which is 0 on success, 1 if the device was already open and
+ * a negative value on error.
  *
  * NOTES:
  * if scan_devices() fails when called with 'op' == SCAN_OP_BUILD_DEVLIST,
@@ -780,51 +837,16 @@ static int scan_devices(am7xxx_context *ctx, scan_op op,
                                } else if (op == SCAN_OP_OPEN_DEVICE &&
                                           current_index == open_device_index) {
 
-                                       *dev = find_device(ctx, open_device_index);
-                                       if (*dev == NULL) {
-                                               ret = -ENODEV;
-                                               goto out;
-                                       }
-
-                                       /* the usb device has already been opened */
-                                       if ((*dev)->usb_device) {
-                                               debug(ctx, "(*dev)->usb_device already set\n");
-                                               ret = 1;
-                                               goto out;
-                                       }
-
-                                       ret = libusb_open(list[i], &((*dev)->usb_device));
-                                       if (ret < 0) {
-                                               debug(ctx, "libusb_open failed\n");
-                                               goto out;
-                                       }
-
-                                       /* XXX, the device is now open, if any
-                                        * of the calls below fail we need to
-                                        * close it again before bailing out.
-                                        */
-
-                                       ret = libusb_set_configuration((*dev)->usb_device,
-                                                                      (*dev)->desc->configuration);
-                                       if (ret < 0) {
-                                               debug(ctx, "libusb_set_configuration failed\n");
-                                               debug(ctx, "Cannot set configuration %hhu\n",
-                                                     (*dev)->desc->configuration);
-                                               goto out_libusb_close;
-                                       }
-
-                                       ret = libusb_claim_interface((*dev)->usb_device,
-                                                                    (*dev)->desc->interface_number);
-                                       if (ret < 0) {
-                                               debug(ctx, "libusb_claim_interface failed\n");
-                                               debug(ctx, "Cannot claim interface %hhu\n",
-                                                     (*dev)->desc->interface_number);
-out_libusb_close:
-                                               libusb_close((*dev)->usb_device);
-                                               (*dev)->usb_device = NULL;
-                                               goto out;
-                                       }
+                                       ret = open_device(ctx,
+                                                         open_device_index,
+                                                         list[i],
+                                                         dev);
+                                       if (ret < 0)
+                                               debug(ctx, "open_device failed\n");
 
+                                       /* exit the loop unconditionally after
+                                        * attempting to open the device
+                                        * requested by the user */
                                        goto out;
                                }
                                current_index++;
@@ -832,7 +854,8 @@ out_libusb_close:
                }
        }
 
-       /* if we made it up to here we didn't find any device to open */
+       /* if we made it up to here when op == SCAN_OP_OPEN_DEVICE,
+        * no devices to open had been found. */
        if (op == SCAN_OP_OPEN_DEVICE) {
                error(ctx, "Cannot find any device to open\n");
                ret = -ENODEV;