host/common: Added MIT-licensed DC calibration routines

This code is a re-designed set of DC calibration functionality
built atop of libbladeRF.

This functionality provides the ability to:
    - Run LMS6002D DC calibrations per module (or all at once)

    - Search for nominal RX/TX DC correction values for a single
      frequencies or a range of frequencies.

To avoid inducing issue #408 by utilizing a single stream,
rather than repeatedly starting and stopping streams.

No TX thread is used, as this is uneccessary; it is sufficient to
flush 0+0j samples through the TX path at the start of calibration
and allow the DAC to remain held in this state as the FPGA
(intentionally) underruns.

host/CMakeLists.txt

@@ -191,6 +191,7 @@ endif()
 add_subdirectory(libraries)
 add_subdirectory(misc)
 add_subdirectory(utilities)
+add_subdirectory(common)
 
 ################################################################################
 # Create uninstall target

host/common/CMakeLists.txt

@@ -0,0 +1 @@
+add_subdirectory(test)

host/common/include/dc_calibration.h

@@ -0,0 +1,144 @@
+/**
+ * This file is part of the bladeRF project:
+ *   http://www.github.com/nuand/bladeRF
+ *
+ * Copyright (c) 2015 Nuand LLC
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+/* This file provides DC calibration routines that utilize libbladeRF */
+
+#ifndef DC_CALIBRATION_H_
+#define DC_CALIBRATION_H_
+
+#include <libbladeRF.h>
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+struct dc_calibration_params {
+    unsigned int frequency;
+    int16_t corr_i;
+    int16_t corr_q;
+    float error_i;
+    float error_q;
+};
+
+/**
+ * Calibrate the specified LMS6002D module.
+ *
+ * Generally, one should run all of these calibrations prior to executing the RX
+ * and TX auto calibration routines.
+ *
+ * Streams should not be running when attempting to call this function.
+ *
+ * Below are the case-insensitive options for the LMS6002D `module` string:
+ *  - LPF Tuning: "lpf_tuning", "lpftuning", "tuning"
+ *  - TX LPF: "tx_lpf", "txlpf"
+ *  - RX LPF: "rx_lpf", "rxlpf"
+ *  - RX VGA2 "rx_vga2", "rxvga2"
+ *  - All of the above: "all"
+ *
+ * @param   dev     bladeRF device handle
+ * @param   module  LMS6002D module to calibrate. Passing NULL is synonymous
+ *                  with specifying "ALL".
+ *
+ * @return 0 on success or libbladeRF return value on failure.
+ *         BLADERF_ERR_INVAL is returned if `module` is invalid.
+ */
+int dc_calibration_lms6(struct bladerf *dev, const char *module);
+
+/**
+ * Perform DC offset calbration of the RX path. Neither RX or TX should be
+ * used during this procedure, as the TX frequency may be adjusted to ensure
+ * good results are obtained.
+ *
+ * The RX input should be disconected from any input sources or antennas when
+ * performing this calibration.
+ *
+ * @pre dc_calibration_lms6() should have been called for all modules prior to
+ *      using this function.
+ *
+ * @param[in]       dev         bladeRF device handle
+ *
+ * @param[inout]    params      DC calibration input and output parameters. This
+ *                              list should be populated to describe the
+ *                              frequencies over which to calibrate. The
+ *                              `corr_i` and `corr_q` fields will be filled in
+ *                              for each entry.
+ *
+ * @param[in]       num_params  Number of entries in the `params` list.
+ *
+ * @param[in]       show_status Print status information to stdout
+ *
+ * @return 0 on success or libbladeRF return value on failure.
+ */
+int dc_calibration_rx(struct bladerf *dev,
+                      struct dc_calibration_params *params,
+                      size_t num_params, bool show_status);
+
+/**
+ * Perform DC offset calbration of the TX path.
+ *
+ * This requires use of both RX and TX modules in an internal loopback mode;
+ * neither should be in use when this function is called. It should not
+ * be neccessary to disconnect the RX and TX ports, but it is still recommended,
+ * just to err on the side of caution.
+ *
+ * @pre dc_calibration_lms6() should have been called for all modules prior to
+ *      using this function.
+ *
+ * @param   dev     bladeRF device handle
+ *
+ * @return 0 on success or libbladeRF return value on failure.
+ */
+int dc_calibration_tx(struct bladerf *dev,
+                      struct dc_calibration_params *params,
+                      size_t num_params, bool show_status);
+
+/**
+ * Convenience wrapper around dc_cal_rx() and dc_cal_tx()
+ *
+ * @pre dc_calibration_lms6() should have been called for all modules prior to
+ *      using this function.
+ *
+ * @param[in]       dev         Device handle
+ * @param[in]       module      BLADERF_MODULE_RX or BLADERF_MODULE_TX
+ * @param[inout]    params      DC calibration input and output parameters. This
+ *                              list should be populated to describe the
+ *                              frequencies over which to calibrate. The
+ *                              `corr_i` and `corr_q` fields will be filled in
+ *                              for each entry.
+ *
+ * @param[in]       num_params  Number of entries in the `params` list.
+ * @param[in]       show_status Print status information to stdout
+ *
+ * @return 0 on success or libbladeRF return value on failure.
+ */
+int dc_calibration(struct bladerf *dev, bladerf_module module,
+                   struct dc_calibration_params *params,
+                   size_t num_params, bool show_status);
+
+#ifdef __cplusplus
+} /* extern "C" */
+#endif
+
+#endif