gps: gpsd: Adding gpsd_iface to interface with gpsd.

The gpsd_iface class might be useful for more than just e3x0,
it therefore belongs into lib/usrp instead of lib/usrp/e300.

A new UHD component is being registered, to cope with the additional
dependency. If libgps is not found, UHD and E300 will be compiled
without GPS support.

This has several consequences:
- The E310 GPSDO should now work transparently over network
- Users can use the GPS through gpsd for other applications
  *while* running UHD applications
- We now have a dependency on libgps

We need currently at least version 3.11 (while running 3.14),
on the device. Older versions do work if 3.10 runs on both
sides e.g

Reviewed-by: Martin Braun <martin.braun@ettus.com>
Reviewed-by: Ashish Chaudhari <ashish.chaudhari@ettus.com>
Signed-off-by: Moritz Fischer <moritz.fischer@ettus.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/host/cmake/Modules/FindGPSD.cmake b/host/cmake/Modules/FindGPSD.cmake
new file mode 100644
index 000000000..0d56a5380
--- /dev/null
+++ b/host/cmake/Modules/FindGPSD.cmake
@@ -0,0 +1,62 @@
+#
+# Copyright 2015 Ettus Research LLC
+#
+# 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
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+# - Find libgps
+# Find the Gpsd includes and client library
+# This module defines
+#  LIBGPS_INCLUDE_DIR, where to find gps.h
+#  LIBGPS_LIBRARIES, the libraries needed by a GPSD client.
+#  LIBGPS_FOUND, If false, do not try to use GPSD.
+# also defined, but not for general use are
+#  LIBGPS_LIBRARY, where to find the GPSD library.
+
+INCLUDE(FindPkgConfig)
+PKG_CHECK_MODULES(PC_GPSD "libgps")
+PKG_CHECK_MODULES(PC_GPSD_V3_11 "libgps > 3.11")
+
+IF(PC_GPSD_FOUND AND NOT PC_GPSD_V3_11_FOUND)
+    MESSAGE(WARNING "GPSD version found is too old")
+ENDIF(PC_GPSD_FOUND AND NOT PC_GPSD_V3_11_FOUND)
+
+IF(PC_GPSD_V3_11_FOUND)
+  FIND_PATH(
+      LIBGPS_INCLUDE_DIR
+      NAMES gps.h
+      HINTS ${PC_GPSD_INCLUDE_DIR}
+  )
+
+  SET(
+      LIBGPS_NAMES
+      ${LIBGPS_NAMES} gps
+  )
+
+  FIND_LIBRARY(
+      LIBGPS_LIBRARY
+      NAMES ${LIBGPS_NAMES}
+      HINTS ${PC_GPSD_LIBDIR}
+  )
+ENDIF(PC_GPSD_V3_11_FOUND)
+
+# handle the QUIETLY and REQUIRED arguments and set LIBGPS_FOUND to TRUE if
+# all listed variables are TRUE
+INCLUDE(FindPackageHandleStandardArgs)
+FIND_PACKAGE_HANDLE_STANDARD_ARGS(LIBGPS DEFAULT_MSG LIBGPS_LIBRARY LIBGPS_INCLUDE_DIR)
+
+IF(LIBGPS_FOUND)
+  SET(LIBGPS_LIBRARIES ${LIBGPS_LIBRARY})
+ENDIF(LIBGPS_FOUND)
+
+MARK_AS_ADVANCED(LIBGPS_LIBRARY LIBGPS_INCLUDE_DIR)