pbio/drv/legodev/pup_uart: Fix power requirement check.

If a device was busy on program exit, the check for power requirements returns ERROR_AGAIN as expected. But this caused the device capabilities not to be read, thus turning off the power to the ultrasonic sensor if the light was being set.

Author: laurensvalk

lib/pbio/drv/legodev/legodev_pup.c

@@ -604,9 +604,10 @@ bool pbdrv_legodev_needs_permanent_power(pbdrv_legodev_dev_t *legodev) {
         return false;
     }
 
-    // Get device information, and check if device is ready.
+    // Get device information as test for device presence and to read properties.
     pbdrv_legodev_info_t *info;
-    if (pbdrv_legodev_get_info(legodev, &info) != PBIO_SUCCESS) {
+    pbio_error_t err = pbdrv_legodev_get_info(legodev, &info);
+    if (err != PBIO_SUCCESS && err != PBIO_ERROR_AGAIN) {
         return false;
     }
 

lib/pbio/drv/legodev/legodev_pup_uart.c

@@ -1356,14 +1356,10 @@ pbio_error_t pbdrv_legodev_get_info(pbdrv_legodev_dev_t *legodev, pbdrv_legodev_
     if (!port_data) {
         return PBIO_ERROR_NO_DEV;
     }
-
-    pbio_error_t err = pbdrv_legodev_is_ready(legodev);
-    if (err != PBIO_SUCCESS) {
-        return err;
-    }
-
+    // Info is set even in case of error. Caller can decide what values apply
+    // based on the error code.
     *info = &port_data->device_info;
-    return PBIO_SUCCESS;
+    return pbdrv_legodev_is_ready(legodev);
 }
 
 #endif // PBDRV_CONFIG_LEGODEV_PUP_UART