[PULL 44/83] tests/qtest: pca9555: test output-to-input reflection and pull-ups

From: Emmanuel Blot <[email protected]>

Add tests covering the pin I/O semantics of the expander: output-driven
pins reflected in the input register, the pull-up seen on input-configured
pins, and the independence of the two 8-bit ports.

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/pca9555-test.c | 75 ++++++++++++++++++++++++++++++++++++++
 1 file changed, 75 insertions(+)

diff --git a/tests/qtest/pca9555-test.c b/tests/qtest/pca9555-test.c
index 5945c3441e92..6b085702c3c8 100644
--- a/tests/qtest/pca9555-test.c
+++ b/tests/qtest/pca9555-test.c
@@ -28,6 +28,77 @@ static void test_reset_defaults(void *obj, void *data, QGuestAllocator *alloc)
     g_assert_cmphex(i2c_get8(dev, PCA9535_CONFIG1), ==, 0xFF);
 }
 
+/*
+ * When a pin is configured as output and driven low (output=0, config=0),
+ * the input register should reflect 0 for that pin.
+ * When driven high (output=1, config=0), input should reflect 1.
+ * When configured as input (config=1), PCA5555 pull-up makes it read 1.
+ */
+static void test_output_drives_input(void *obj, void *data,
+                                     QGuestAllocator *alloc)
+{
+    QI2CDevice *dev = (QI2CDevice *)obj;
+
+    i2c_set8(dev, PCA9535_CONFIG0, 0xF0);
+    i2c_set8(dev, PCA9535_OUTPUT0, 0xFA);
+
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT0), ==, 0xFA);
+
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT1), ==, 0xFF);
+
+    i2c_set8(dev, PCA9535_CONFIG0, 0x00);
+    i2c_set8(dev, PCA9535_OUTPUT0, 0x00);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT0), ==, 0x00);
+
+    i2c_set8(dev, PCA9535_OUTPUT0, 0xFF);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT0), ==, 0xFF);
+}
+
+/*
+ * When all pins are inputs (config=0xFF) and no external driver,
+ * PCA9555 pull-ups should make the input register read all ones.
+ * Switching a pin to output mode with output=0 should drive it low.
+ */
+static void test_input_pullup(void *obj, void *data, QGuestAllocator *alloc)
+{
+    QI2CDevice *dev = (QI2CDevice *)obj;
+
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT0), ==, 0xFF);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT1), ==, 0xFF);
+
+    i2c_set8(dev, PCA9535_OUTPUT0, 0x00);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT0), ==, 0xFF);
+
+    i2c_set8(dev, PCA9535_CONFIG0, 0x00);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT0), ==, 0x00);
+}
+
+/*
+ * Test that both ports are independent: changing port 0 registers
+ * should not affect port 1 and vice versa.
+ */
+static void test_port_independence(void *obj, void *data,
+                                   QGuestAllocator *alloc)
+{
+    QI2CDevice *dev = (QI2CDevice *)obj;
+
+    i2c_set8(dev, PCA9535_CONFIG0, 0x00);
+    i2c_set8(dev, PCA9535_OUTPUT0, 0x00);
+
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT0), ==, 0x00);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT1), ==, 0xFF);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_CONFIG1), ==, 0xFF);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_OUTPUT1), ==, 0xFF);
+
+    i2c_set8(dev, PCA9535_CONFIG1, 0x00);
+    i2c_set8(dev, PCA9535_OUTPUT1, 0xAA);
+
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT0), ==, 0x00);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_INPUT1), ==, 0xAA);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_OUTPUT0), ==, 0x00);
+    g_assert_cmphex(i2c_get8(dev, PCA9535_OUTPUT1), ==, 0xAA);
+}
+
 static void pca9555_register_nodes(void)
 {
     QOSGraphEdgeOptions opts = {
@@ -39,6 +110,10 @@ static void pca9555_register_nodes(void)
     qos_node_consumes("pca9555", "i2c-bus", &opts);
 
     qos_add_test("reset-defaults", "pca9555", test_reset_defaults, NULL);
+    qos_add_test("output-drives-input", "pca9555", test_output_drives_input,
+                 NULL);
+    qos_add_test("input-pullup", "pca9555", test_input_pullup, NULL);
+    qos_add_test("port-independence", "pca9555", test_port_independence, NULL);
 }
 
 libqos_init(pca9555_register_nodes);
-- 
2.55.0