Linux/TRF7970A: Unable to power off through neard.

Tool/software: Linux

Hi there,

I'm currently interfacing with the TRF7970a in a C++ application using Neard. I am using the low-level dbus api for communicating with the nfc bus. As of right now I can do everything that I need to (start/stop polling, read/write from tags), with the exception of powering off the adapter (I can read the adapter power state fine and can power it on, I just can't power it off).

The adapter NFC API has a Powered property for the adapters, so I am using the Set method of the org.freedesktop.DBus interface to set the power on/off over the nfc bus.

The code used to do so is below:

int setBoolProperty(DBusConnection *connection, const char* property, const int value, DBusError *error)
{
    DBusMessage *queryMessage = NULL;
    DBusMessage *replyMessage = NULL;
    DBusMessageIter iter;
    DBusMessageIter sub;

    if (value != 0 && value != 1)
    {
        printf("Not a valid boolean type.\n");
        return -1;
    }

    queryMessage = dbus_message_new_method_call("org.neard",
                "/org/neard/nfc0", 
                "org.freedesktop.DBus.Properties",
                "Set");

    // append arguments to the Set() method. (string interface, string property, value)
    dbus_message_iter_init_append(queryMessage, &iter);

    dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &adapterName);
    dbus_message_iter_append_basic(&iter, DBUS_TYPE_STRING, &property);

    dbus_message_iter_open_container(&iter, DBUS_TYPE_VARIANT, DBUS_TYPE_BOOLEAN_AS_STRING, &sub);
    // Set the bool value.
    dbus_message_iter_append_basic(&sub, DBUS_TYPE_BOOLEAN, &value);

    dbus_message_iter_close_container(&iter, &sub);

    replyMessage = dbus_connection_send_with_reply_and_block(connection,
                          queryMessage,
                          1000,
                          error);

    dbus_message_unref(queryMessage);
    abort_on_error(error);
    dbus_message_unref(replyMessage);

    return 0;
}

Whenever I attempt to power off I first stop polling (using the StopPollLoop method on the org.neard.Adapter interface). I then set the Powered property to a 0. When the message gets received I get an "Unknown error -16" back from dbus and the power state doesn't change. I'm hoping that I'm missing something simple and that someone has some insight into what might be causing this problem.

-Ben