bindings: python: tests: add coverage of kernel reconfigure as-is behaviour

The kernel's handling of reconfigure with default values, as is the
case for providing a None value as the settings to the Python bindings'
reconfigure_lines(), resets any flags set to non-default values when the
line is requested to their default values.  While the flags are cleared,
the kernel makes no corresponding change to the electrical settings -
though subsequent calls to get and set values will apply the updated
flags.

The tests for missing or None settings are extended to demonstrate the
issue for active_low and drive flags, though the issue applies to all
flags.

The tests fail unless the kernel is patched to ignore reconfiguration
of lines without direction set.

Signed-off-by: Kent Gibson <warthog618@gmail.com>
Link: https://lore.kernel.org/r/20240626053808.179457-4-warthog618@gmail.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

diff --git a/bindings/python/tests/tests_line_request.py b/bindings/python/tests/tests_line_request.py
index 2f375d63172389d540b3acc1e51e6a215b131589..79167f12312a82e69f4b3c7374400fb2ddd54af3 100644 (file)
--- a/bindings/python/tests/tests_line_request.py
+++ b/bindings/python/tests/tests_line_request.py
@@ -5,7 +5,7 @@ import errno
 import gpiod
 
 from . import gpiosim
-from gpiod.line import Direction, Edge, Value
+from gpiod.line import Direction, Drive, Edge, Value
 from unittest import TestCase
 
 Pull = gpiosim.Chip.Pull
@@ -462,7 +462,9 @@ class ReconfigureRequestedLines(TestCase):
         self.sim = gpiosim.Chip(num_lines=8, line_names={3: "foo", 4: "bar", 6: "baz"})
         self.chip = gpiod.Chip(self.sim.dev_path)
         self.req = self.chip.request_lines(
-            {(0, 2, "foo", "baz"): gpiod.LineSettings(direction=Direction.OUTPUT)}
+            {(0, 2, "foo", "baz"): gpiod.LineSettings(direction=Direction.OUTPUT,
+                                                      active_low=True,
+                                                      drive=Drive.OPEN_DRAIN)}
         )
 
     def tearDown(self):
@@ -511,6 +513,8 @@ class ReconfigureRequestedLines(TestCase):
     def test_reconfigure_with_default(self):
         info = self.chip.get_line_info(2)
         self.assertEqual(info.direction, Direction.OUTPUT)
+        self.assertTrue(info.active_low)
+        self.assertEqual(info.drive, Drive.OPEN_DRAIN)
         self.req.reconfigure_lines({
             0: gpiod.LineSettings(direction=Direction.INPUT),
             2: None,
@@ -520,10 +524,14 @@ class ReconfigureRequestedLines(TestCase):
         self.assertEqual(info.direction, Direction.INPUT)
         info = self.chip.get_line_info(2)
         self.assertEqual(info.direction, Direction.OUTPUT)
+        self.assertTrue(info.active_low)
+        self.assertEqual(info.drive, Drive.OPEN_DRAIN)
 
     def test_reconfigure_missing_offsets(self):
         info = self.chip.get_line_info(2)
         self.assertEqual(info.direction, Direction.OUTPUT)
+        self.assertTrue(info.active_low)
+        self.assertEqual(info.drive, Drive.OPEN_DRAIN)
         self.req.reconfigure_lines(
                 {(6, 0): gpiod.LineSettings(direction=Direction.INPUT)}
             )
@@ -531,6 +539,8 @@ class ReconfigureRequestedLines(TestCase):
         self.assertEqual(info.direction, Direction.INPUT)
         info = self.chip.get_line_info(2)
         self.assertEqual(info.direction, Direction.OUTPUT)
+        self.assertTrue(info.active_low)
+        self.assertEqual(info.drive, Drive.OPEN_DRAIN)
 
     def test_reconfigure_extra_offsets(self):
         info = self.chip.get_line_info(2)