+ unsigned int i = 0;
+ am7xxx_device *current;
+
+ if (ctx == NULL) {
+ fatal("context must not be NULL!\n");
+ return NULL;
+ }
+
+ current = ctx->devices_list;
+ while (current && i++ < device_index)
+ current = current->next;
+
+ return current;
+}
+
+typedef enum {
+ SCAN_OP_BUILD_DEVLIST,
+ SCAN_OP_OPEN_DEVICE,
+} scan_op;
+
+/**
+ * This is where the central logic of multi-device support is.
+ *
+ * When 'op' == SCAN_OP_BUILD_DEVLIST the parameters 'open_device_index' and
+ * 'dev' are ignored; the function returns 0 on success and a negative value
+ * on error.
+ *
+ * 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.
+ *
+ * NOTES:
+ * if scan_devices() fails when called with 'op' == SCAN_OP_BUILD_DEVLIST,
+ * the caller might want to call am7xxx_shutdown() in order to remove
+ * devices possibly added before the failure.
+ */
+static int scan_devices(am7xxx_context *ctx, scan_op op,
+ unsigned int open_device_index, am7xxx_device **dev)
+{
+ ssize_t num_devices;
+ libusb_device** list;
+ unsigned int current_index;
+ int i;
+ int ret;
+
+ if (ctx == NULL) {
+ fatal("context must not be NULL!\n");
+ return -EINVAL;
+ }
+ if (op == SCAN_OP_BUILD_DEVLIST && ctx->devices_list != NULL) {
+ error(ctx, "device scan done already? Abort!\n");
+ return -EINVAL;
+ }
+
+ num_devices = libusb_get_device_list(ctx->usb_context, &list);
+ if (num_devices < 0) {
+ ret = -ENODEV;
+ goto out;
+ }
+
+ current_index = 0;
+ for (i = 0; i < num_devices; i++) {
+ struct libusb_device_descriptor desc;
+ unsigned int j;
+
+ ret = libusb_get_device_descriptor(list[i], &desc);
+ if (ret < 0)
+ continue;
+
+ for (j = 0; j < ARRAY_SIZE(supported_devices); j++) {
+ if (desc.idVendor == supported_devices[j].vendor_id &&
+ desc.idProduct == supported_devices[j].product_id) {
+
+ if (op == SCAN_OP_BUILD_DEVLIST) {
+ am7xxx_device *new_device;
+ info(ctx, "am7xxx device found, index: %d, name: %s\n",
+ current_index,
+ supported_devices[j].name);
+ new_device = add_new_device(ctx, &supported_devices[j]);
+ if (new_device == NULL) {
+ /* XXX, the caller may want
+ * to call am7xxx_shutdown() if
+ * we fail here, as we may have
+ * added some devices already
+ */
+ debug(ctx, "Cannot create a new device\n");
+ ret = -ENODEV;
+ goto out;
+ }
+ } 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;
+ }
+
+ goto out;
+ }
+ current_index++;
+ }
+ }
+ }
+
+ /* if we made it up to here we didn't find any device to open */
+ if (op == SCAN_OP_OPEN_DEVICE) {
+ error(ctx, "Cannot find any device to open\n");
+ ret = -ENODEV;
+ goto out;
projects / libam7xxx.git / blobdiff