[PULL 54/83] tests/qtest: pca9554: test polarity inversion

From: Emmanuel Blot <[email protected]>

Verify that the polarity register inverts the value read back from the
INPUT register, both on pulled-up inputs and on output-driven pins, while
leaving the OUTPUT register itself unchanged.

Signed-off-by: Emmanuel Blot <[email protected]>
Reviewed-by: Glenn Miles <[email protected]>
Link: https://lore.kernel.org/qemu-devel/[email protected]
Signed-off-by: Cédric Le Goater <[email protected]>
---
 tests/qtest/pca9554-test.c | 39 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/tests/qtest/pca9554-test.c b/tests/qtest/pca9554-test.c
index ce6e90f3f881..74237df611ea 100644
--- a/tests/qtest/pca9554-test.c
+++ b/tests/qtest/pca9554-test.c
@@ -67,6 +67,41 @@ static void test_input_pullup(void *obj, void *data, QGuestAllocator *alloc)
     g_assert_cmphex(i2c_get8(dev, PCA9554_INPUT), ==, 0x00);
 }
 
+/*
+ * Polarity inversion: reading INPUT returns the XOR of the pin levels and the
+ * polarity register.
+ */
+static void test_polarity_inversion(void *obj, void *data,
+                                    QGuestAllocator *alloc)
+{
+    QI2CDevice *dev = (QI2CDevice *)obj;
+
+    g_assert_cmphex(i2c_get8(dev, PCA9554_INPUT), ==, 0xFF);
+
+    i2c_set8(dev, PCA9554_POLARITY, 0xFF);
+    g_assert_cmphex(i2c_get8(dev, PCA9554_INPUT), ==, 0x00);
+
+    i2c_set8(dev, PCA9554_POLARITY, 0x0F);
+    g_assert_cmphex(i2c_get8(dev, PCA9554_INPUT), ==, 0xF0);
+}
+
+/* Polarity inversion combined with output-driven pins. */
+static void test_polarity_with_output(void *obj, void *data,
+                                      QGuestAllocator *alloc)
+{
+    QI2CDevice *dev = (QI2CDevice *)obj;
+
+    i2c_set8(dev, PCA9554_CONFIG, 0x00);
+    i2c_set8(dev, PCA9554_OUTPUT, 0xA5);
+    g_assert_cmphex(i2c_get8(dev, PCA9554_INPUT), ==, 0xA5);
+
+    i2c_set8(dev, PCA9554_POLARITY, 0xFF);
+    g_assert_cmphex(i2c_get8(dev, PCA9554_INPUT), ==, 0x5A);
+
+    /* Inversion only affects the INPUT read, not the OUTPUT register. */
+    g_assert_cmphex(i2c_get8(dev, PCA9554_OUTPUT), ==, 0xA5);
+}
+
 static void pca9554_register_nodes(void)
 {
     QOSGraphEdgeOptions opts = {
@@ -81,6 +116,10 @@ static void pca9554_register_nodes(void)
     qos_add_test("output-drives-input", "pca9554", test_output_drives_input,
                  NULL);
     qos_add_test("input-pullup", "pca9554", test_input_pullup, NULL);
+    qos_add_test("polarity-inversion", "pca9554", test_polarity_inversion,
+                 NULL);
+    qos_add_test("polarity-with-output", "pca9554", test_polarity_with_output,
+                 NULL);
 }
 
 libqos_init(pca9554_register_nodes);
-- 
2.55.0