[libgpiod,5/6] treewide: kill line updating

diff --git a/bindings/cxx/gpiod.hpp b/bindings/cxx/gpiod.hpp
index 189a133..003acdd 100644
--- a/bindings/cxx/gpiod.hpp
+++ b/bindings/cxx/gpiod.hpp
@@ -412,11 +412,6 @@  public:
 	 */
 	GPIOD_API const chip get_chip(void) const;
 
-	/**
-	 * @brief Re-read the line info from the kernel.
-	 */
-	GPIOD_API void update(void) const;
-
 	/**
 	 * @brief Reset the state of this object.
 	 *
diff --git a/bindings/cxx/line.cpp b/bindings/cxx/line.cpp
index 058f7ce..bf84867 100644
--- a/bindings/cxx/line.cpp
+++ b/bindings/cxx/line.cpp
@@ -278,18 +278,6 @@  const chip line::get_chip(void) const
 	return chip(this->_m_owner);
 }
 
-void line::update(void) const
-{
-	this->throw_if_null();
-	line::chip_guard lock_chip(*this);
-
-	int ret = ::gpiod_line_update(this->_m_line);
-
-	if (ret < 0)
-		throw ::std::system_error(errno, ::std::system_category(),
-					  "unable to update the line info");
-}
-
 void line::reset(void)
 {
 	this->_m_line = nullptr;
diff --git a/bindings/cxx/tests/tests-line.cpp b/bindings/cxx/tests/tests-line.cpp
index 17fdd89..ababf8b 100644
--- a/bindings/cxx/tests/tests-line.cpp
+++ b/bindings/cxx/tests/tests-line.cpp
@@ -139,11 +139,6 @@  TEST_CASE("Line information can be correctly retrieved", "[line]")
 		REQUIRE(line.drive() == ::gpiod::line::DRIVE_PUSH_PULL);
 		REQUIRE(line.bias() == ::gpiod::line::BIAS_PULL_UP);
 	}
-
-	SECTION("update line info")
-	{
-		REQUIRE_NOTHROW(line.update());
-	}
 }
 
 TEST_CASE("Line values can be set and read", "[line]")
diff --git a/bindings/python/gpiodmodule.c b/bindings/python/gpiodmodule.c
index 12a6867..8bfb4c4 100644
--- a/bindings/python/gpiodmodule.c
+++ b/bindings/python/gpiodmodule.c
@@ -721,23 +721,6 @@  static PyObject *gpiod_Line_release(gpiod_LineObject *self,
 	return ret;
 }
 
-PyDoc_STRVAR(gpiod_Line_update_doc,
-"update() -> None\n"
-"\n"
-"Re-read the line information from the kernel.");
-
-static PyObject *gpiod_Line_update(gpiod_LineObject *self,
-				   PyObject *Py_UNUSED(ignored))
-{
-	int ret;
-
-	ret = gpiod_line_update(self->line);
-	if (ret)
-		return PyErr_SetFromErrno(PyExc_OSError);
-
-	Py_RETURN_NONE;
-}
-
 PyDoc_STRVAR(gpiod_Line_event_wait_doc,
 "event_wait([sec[ ,nsec]]) -> boolean\n"
 "\n"
@@ -1008,12 +991,6 @@  static PyMethodDef gpiod_Line_methods[] = {
 		.ml_flags = METH_NOARGS,
 		.ml_doc = gpiod_Line_release_doc,
 	},
-	{
-		.ml_name = "update",
-		.ml_meth = (PyCFunction)gpiod_Line_update,
-		.ml_flags = METH_NOARGS,
-		.ml_doc = gpiod_Line_update_doc,
-	},
 	{
 		.ml_name = "event_wait",
 		.ml_meth = (PyCFunction)(void (*)(void))gpiod_Line_event_wait,
diff --git a/bindings/python/tests/gpiod_py_test.py b/bindings/python/tests/gpiod_py_test.py
index d448776..f93c72c 100755
--- a/bindings/python/tests/gpiod_py_test.py
+++ b/bindings/python/tests/gpiod_py_test.py
@@ -315,11 +315,6 @@  class LineInfo(MockupTestCase):
             self.assertEqual(line.drive(), gpiod.Line.DRIVE_PUSH_PULL)
             self.assertEqual(line.bias(), gpiod.Line.BIAS_PULL_UP)
 
-    def test_update_line_info(self):
-        with gpiod.Chip(mockup.chip_path(0)) as chip:
-            line = chip.get_line(3)
-            line.update()
-
 class LineValues(MockupTestCase):
 
     chip_sizes = ( 8, )
diff --git a/include/gpiod.h b/include/gpiod.h
index a5e09e2..0ee9778 100644
--- a/include/gpiod.h
+++ b/include/gpiod.h
@@ -358,28 +358,6 @@  bool gpiod_line_is_used(struct gpiod_line *line) GPIOD_API;
  */
 int gpiod_line_drive(struct gpiod_line *line) GPIOD_API;
 
-/**
- * @brief Re-read the line info.
- * @param line GPIO line object.
- * @return 0 if the operation succeeds. In case of an error this routine
- *         returns -1 and sets the last error number.
- *
- * The line info is initially retrieved from the kernel by
- * gpiod_chip_get_line() and is later re-read after every successful request.
- * Users can use this function to manually re-read the line info when needed.
- *
- * We currently have no mechanism provided by the kernel for keeping the line
- * info synchronized and for the sake of speed and simplicity of this low-level
- * library we don't want to re-read the line info automatically everytime
- * a property is retrieved. Any daemon using this library must track the state
- * of lines on its own and call this routine if needed.
- *
- * The state of requested lines is kept synchronized (or rather cannot be
- * changed by external agents while the ownership of the line is taken) so
- * there's no need to call this function in that case.
- */
-int gpiod_line_update(struct gpiod_line *line) GPIOD_API;
-
 /**
  * @brief Get the handle to the GPIO chip controlling this line.
  * @param line The GPIO line object.
diff --git a/lib/core.c b/lib/core.c
index 8e3d8a7..8fdc503 100644
--- a/lib/core.c
+++ b/lib/core.c
@@ -373,6 +373,8 @@  unsigned int gpiod_chip_num_lines(struct gpiod_chip *chip)
 	return chip->num_lines;
 }
 
+static int line_update(struct gpiod_line *line);
+
 struct gpiod_line *
 gpiod_chip_get_line(struct gpiod_chip *chip, unsigned int offset)
 {
@@ -406,7 +408,7 @@  gpiod_chip_get_line(struct gpiod_chip *chip, unsigned int offset)
 		line = chip->lines[offset];
 	}
 
-	rv = gpiod_line_update(line);
+	rv = line_update(line);
 	if (rv < 0)
 		return NULL;
 
@@ -535,7 +537,7 @@  static int line_info_v2_to_info_flags(struct gpio_v2_line_info *info)
 	return iflags;
 }
 
-int gpiod_line_update(struct gpiod_line *line)
+static int line_update(struct gpiod_line *line)
 {
 	struct gpio_v2_line_info info;
 	int rv;
@@ -766,7 +768,7 @@  static int line_request_values(struct gpiod_line_bulk *bulk,
 				req.config.attrs[0].attr.values, i);
 		line_set_fd(line, line_fd);
 
-		rv = gpiod_line_update(line);
+		rv = line_update(line);
 		if (rv) {
 			gpiod_line_release_bulk(bulk);
 			return rv;
@@ -805,7 +807,7 @@  static int line_request_event_single(struct gpiod_line *line,
 	line->req_flags = config->flags;
 	line_set_fd(line, line_fd);
 
-	rv = gpiod_line_update(line);
+	rv = line_update(line);
 	if (rv) {
 		gpiod_line_release(line);
 		return rv;
@@ -1036,7 +1038,7 @@  int gpiod_line_set_config_bulk(struct gpiod_line_bulk *bulk,
 			line->output_value = lines_bitmap_test_bit(
 				hcfg.attrs[0].attr.values, i);
 
-		rv = gpiod_line_update(line);
+		rv = line_update(line);
 		if (rv < 0)
 			return rv;
 	}