linuxgpio: add gpiod_line_set_direction_input helper for libgpiod v1.4 support (refs #1782)

This ancient libgpiod version is still shipped on Ubuntu 20.04 LTS. Add support for it by adding another helper. Signed-off-by: Michael Heimpold <mhei@heimpold.de>
2026-06-02 09:46:34 +03:00 · 2024-04-22 23:11:33 +02:00
parent db2580d17b
commit 6a75ac7057
4 changed files with 66 additions and 15 deletions
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -240,6 +240,7 @@ if(HAVE_LINUXGPIO)
    # defaults/fallbacks
    set(HAVE_LIBGPIOD 0)
    set(HAVE_LIBGPIOD_V2 0)
+    set(HAVE_LIBGPIOD_V1_6 0)

    find_package(PkgConfig)
    if(PKG_CONFIG_FOUND)
@@ -251,12 +252,21 @@ if(HAVE_LINUXGPIO)
            set(CMAKE_REQUIRED_LIBRARIES ${LIBGPIODV2_LIBRARIES})
            set(LIB_LIBGPIOD ${LIBGPIODV2_LINK_LIBRARIES})
        else()
-            # check whether we have at least an older version
-            pkg_check_modules(LIBGPIOD libgpiod)
-            if(LIBGPIOD_FOUND)
+            # check whether we have version >= 1.6
+            pkg_check_modules(LIBGPIODV1_6 libgpiod>=1.6)
+            if(LIBGPIODV1_6_FOUND)
                set(HAVE_LIBGPIOD 1)
-                set(CMAKE_REQUIRED_LIBRARIES ${LIBGPIOD_LIBRARIES})
-                set(LIB_LIBGPIOD ${LIBGPIOD_LINK_LIBRARIES})
+                set(HAVE_LIBGPIOD_V1_6 1)
+                set(CMAKE_REQUIRED_LIBRARIES ${LIBGPIODV1_6_LIBRARIES})
+                set(LIB_LIBGPIOD ${LIBGPIODV1_6_LINK_LIBRARIES})
+            else()
+                # check whether we have at least an older version
+                pkg_check_modules(LIBGPIOD libgpiod)
+                if(LIBGPIOD_FOUND)
+                    set(HAVE_LIBGPIOD 1)
+                    set(CMAKE_REQUIRED_LIBRARIES ${LIBGPIOD_LIBRARIES})
+                    set(LIB_LIBGPIOD ${LIBGPIOD_LINK_LIBRARIES})
+                endif()
            endif()
        endif()
    else()
@@ -358,6 +368,7 @@ if (DEBUG_CMAKE)
    message(STATUS "HAVE_HIDAPI_HIDAPI_H: ${HAVE_HIDAPI_HIDAPI_H}")
    message(STATUS "LIBUSB_COMPAT_DIR: ${LIBUSB_COMPAT_DIR}")
    message(STATUS "LIBGPIODV2_FOUND: ${LIBGPIODV2_FOUND}")
+    message(STATUS "LIBGPIODV1_6_FOUND: ${LIBGPIODV1_6_FOUND}")
    message(STATUS "LIBGPIOD_FOUND: ${LIBGPIOD_FOUND}")
    message(STATUS "----------------------")
 endif()
@@ -429,7 +440,9 @@ endif()
 if(HAVE_LINUXGPIO)
    message(STATUS "ENABLED    linuxgpio")
    if (LIBGPIODV2_FOUND)
-        message(STATUS "DO HAVE    libgpiod (v2.x)")
+        message(STATUS "DO HAVE    libgpiod (>=2.0)")
+    elseif(LIBGPIODV1_6_FOUND)
+        message(STATUS "DO HAVE    libgpiod (>=1.6)")
    elseif(LIBGPIOD_FOUND)
        message(STATUS "DO HAVE    libgpiod")
    else()
--- a/src/cmake_config.h.in
+++ b/src/cmake_config.h.in
@@ -30,8 +30,11 @@
 /* Let linuxgpio know if libgpiod is available. */
 #cmakedefine HAVE_LIBGPIOD

-/* Let linuxgpio know whether v2 of libgpiod is available. */
-#cmakedefine HAVE_LIBGPIOD_V2
+/* Let linuxgpio know whether libgpiod is available in version >= v1.6 but < v2.0. */
+#cmakedefine01 HAVE_LIBGPIOD_V1_6
+
+/* Let linuxgpio know whether v2.0 or higher of libgpiod is available. */
+#cmakedefine01 HAVE_LIBGPIOD_V2

 /* Linux SPI support enabled */
 #cmakedefine HAVE_LINUXSPI 1
--- a/src/configure.ac
+++ b/src/configure.ac
@@ -529,17 +529,26 @@ if test "x$enabled_linuxgpio" = xyes; then
 		have_libgpiod=yes
 		have_libgpiodv2=yes
 		AC_DEFINE([HAVE_LIBGPIOD], [1], [Linux libgpiod available])
-		AC_DEFINE([HAVE_LIBGPIOD_V2], [1], [Linux libgpiod (v2.x) available])
+		AC_DEFINE([HAVE_LIBGPIOD_V1_6], [0], [Linux libgpiod >= v1.6 but < 2.0 available])
+		AC_DEFINE([HAVE_LIBGPIOD_V2], [1], [Linux libgpiod >= 2.0 available])
 	], [
-		PKG_CHECK_MODULES([LIBGPIOD], [libgpiod], [
+		PKG_CHECK_MODULES([LIBGPIOD], [libgpiod >= 1.6], [
 			have_libgpiod=yes
-			have_libgpiodv2=no
+			have_libgpiodv1_6=yes
 			AC_DEFINE([HAVE_LIBGPIOD], [1], [Linux libgpiod available])
+			AC_DEFINE([HAVE_LIBGPIOD_V1_6], [1], [Linux libgpiod >= v1.6 but < 2.0 available])
+			AC_DEFINE([HAVE_LIBGPIOD_V2], [0], [Linux libgpiod >= 2.0 available])
 		], [
-			have_libgpiod=no
-			have_libgpiodv2=no
+			PKG_CHECK_MODULES([LIBGPIOD], [libgpiod], [
+				have_libgpiod=yes
+				AC_DEFINE([HAVE_LIBGPIOD_V1_6], [0], [Linux libgpiod >= v1.6 but < 2.0 available])
+				AC_DEFINE([HAVE_LIBGPIOD_V2], [0], [Linux libgpiod >= 2.0 available])
+			], [
+				have_libgpiod=no
+			])
 		])
 	])
+
 else
 	confsubst="$confsubst -e /^@HAVE_LINUXGPIO_BEGIN@/,/^@HAVE_LINUXGPIO_END@/d"
 fi
@@ -748,7 +757,9 @@ fi
 if test "x$enabled_linuxgpio" = xyes; then
   echo "ENABLED    linuxgpio"
   if test "x$have_libgpiodv2" = xyes; then
-       echo "DO HAVE    libgpiod (v2.x)"
+       echo "DO HAVE    libgpiod (>=2.0)"
+   elif test "x$have_libgpiodv1_6" = xyes; then
+       echo "DO HAVE    libgpiod (>=1.6)"
   elif test "x$have_libgpiod" = xyes; then
       echo "DO HAVE    libgpiod"
   else
--- a/src/linuxgpio.c
+++ b/src/linuxgpio.c
@@ -344,7 +344,23 @@ void linuxgpio_teardown(PROGRAMMER *pgm) {

 #ifdef HAVE_LIBGPIOD

-#ifdef HAVE_LIBGPIOD_V2
+#if !HAVE_LIBGPIOD_V1_6 && !HAVE_LIBGPIOD_V2
+
+int gpiod_line_set_direction_input(struct gpiod_line **gpio_line) {
+  struct gpiod_chip *chip = gpiod_line_get_chip(*gpio_line);
+  unsigned int gpio_num = gpiod_line_offset(*gpio_line);
+
+  // release to pin first...
+  gpiod_line_release(*gpio_line);
+
+  // so that we can re-acquire it as input
+  *gpio_line = gpiod_chip_get_line(chip, gpio_num);
+  return gpiod_line_request_input(*gpio_line, "avrdude");
+}
+
+#endif
+
+#if HAVE_LIBGPIOD_V2

 struct gpiod_line {
  struct gpiod_chip *chip;
@@ -565,7 +581,11 @@ static void linuxgpio_libgpiod_close(PROGRAMMER *pgm) {
  // This should avoid possible conflicts when AVR firmware starts.
  for (i = 0; i < N_PINS; ++i) {
    if (linuxgpio_libgpiod_lines[i] != NULL && i != PIN_AVR_RESET) {
+#if HAVE_LIBGPIOD_V1_6 || HAVE_LIBGPIOD_V2
      int r = gpiod_line_set_direction_input(linuxgpio_libgpiod_lines[i]);
+#else
+      int r = gpiod_line_set_direction_input(&linuxgpio_libgpiod_lines[i]);
+#endif
      if (r != 0) {
        msg_error("failed to set pin %u to input: %s\n",
          linuxgpio_libgpiod_lines[i]->gpio_num, strerror(errno));
@@ -577,7 +597,11 @@ static void linuxgpio_libgpiod_close(PROGRAMMER *pgm) {

  // Configure RESET as input.
  if (linuxgpio_libgpiod_lines[PIN_AVR_RESET] != NULL) {
+#if HAVE_LIBGPIOD_V1_6 || HAVE_LIBGPIOD_V2
    int r = gpiod_line_set_direction_input(linuxgpio_libgpiod_lines[PIN_AVR_RESET]);
+#else
+    int r = gpiod_line_set_direction_input(&linuxgpio_libgpiod_lines[PIN_AVR_RESET]);
+#endif
    if (r != 0) {
      msg_error("failed to set pin %u to input: %s\n",
        linuxgpio_libgpiod_lines[PIN_AVR_RESET]->gpio_num, strerror(errno));