zephyr test: SYV682 VCONN_OC interrupt

Simulate VCONN OC and verify that the driver handles it as expected.
Increase syv682x.c line coverage 65.4% -> 68.8%.

BUG=b:190519131
TEST=zmake configure --test zephyr/test/drivers
BRANCH=none

Signed-off-by: Abe Levkoy <alevkoy@chromium.org>
Change-Id: Ifa9ff4129ef0f158e2f59314dbf62ee53b6180e8
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3219870
Reviewed-by: Yuval Peress <peress@google.com>

3 files changed, 75 insertions, 3 deletions

diff --git a/zephyr/emul/emul_syv682x.c b/zephyr/emul/emul_syv682x.c
index 2148851b56..2bc18b7089 100644
--- a/zephyr/emul/emul_syv682x.c
+++ b/zephyr/emul/emul_syv682x.c
@@ -82,6 +82,26 @@ void syv682x_emul_set_status(struct i2c_emul *emul, uint8_t val)
 	 */
 }
 
+void syv682x_emul_set_control_4(struct i2c_emul *emul, uint8_t val)
+{
+	struct syv682x_emul_data *data;
+	uint8_t val_interrupt = val & SYV682X_CONTROL_4_INT_MASK;
+
+	data = CONTAINER_OF(emul, struct syv682x_emul_data, emul);
+	data->control_4_cond = val_interrupt;
+	/* Only update the interrupting bits. */
+	data->reg[SYV682X_CONTROL_4_REG] &= ~SYV682X_CONTROL_4_INT_MASK;
+	data->reg[SYV682X_CONTROL_4_REG] |= val_interrupt;
+
+	/*
+	 * Note: The description of CONTROL_4 suggests that setting VCONN_OC
+	 * will turn off the VCONN channel. The "VCONN Channel Over Current
+	 * Response" plot shows that VCONN the device will merely throttle VCONN
+	 * current. The latter behavior is observed in practice, and this
+	 * emulator does not currently model it.
+	 */
+}
+
 int syv682x_emul_get_reg(struct i2c_emul *emul, int reg, uint8_t *val)
 {
 	struct syv682x_emul_data *data;
@@ -142,6 +162,10 @@ static int syv682x_emul_transfer(struct i2c_emul *emul, struct i2c_msg *msgs,
 						SYV682X_STATUS_OVP))
 				val |= SYV682X_CONTROL_1_PWR_ENB;
 			break;
+		case SYV682X_CONTROL_4_REG:
+			/* Interrupt bits are read-only. */
+			val &= ~SYV682X_CONTROL_4_INT_MASK;
+			break;
 		default:
 			break;
 		}
@@ -167,14 +191,16 @@ static int syv682x_emul_transfer(struct i2c_emul *emul, struct i2c_msg *msgs,
 
 		switch (reg) {
 		/*
-		 * These registers are clear-on-read (if the underlying
-		 * condition has cleared).
+		 * STATUS and the interrupt bits of CONTROL_4 are clear-on-read
+		 * (if the underlying condition has cleared).
 		 */
 		case SYV682X_STATUS_REG:
 			syv682x_emul_set_reg(emul, reg, data->status_cond);
 			break;
 		case SYV682X_CONTROL_4_REG:
-			syv682x_emul_set_reg(emul, reg, data->control_4_cond);
+			syv682x_emul_set_reg(emul, reg,
+					(*buf & ~SYV682X_CONTROL_4_INT_MASK) |
+					data->control_4_cond);
 			break;
 		default:
 			break;
diff --git a/zephyr/include/emul/emul_syv682x.h b/zephyr/include/emul/emul_syv682x.h
index aa0d8840f7..46580e8257 100644
--- a/zephyr/include/emul/emul_syv682x.h
+++ b/zephyr/include/emul/emul_syv682x.h
@@ -119,6 +119,17 @@ struct i2c_emul *syv682x_emul_get(int ord);
 void syv682x_emul_set_status(struct i2c_emul *emul, uint8_t val);
 
 /**
+ * @brief Set the underlying interrupt conditions affecting the control 4
+ *        register
+ *
+ * @param emul SYV682x emulator
+ * @param val  A control 4 register value corresponding to the underlying
+ *             conditions; only the bits in SYV682X_CONTROL_4_INT_MASK have an
+ *             effect.
+ */
+void syv682x_emul_set_control_4(struct i2c_emul *emul, uint8_t val);
+
+/**
  * @brief Set value of a register of SYV682x
  *
  * @param emul SYV682x emulator
diff --git a/zephyr/test/drivers/src/ppc.c b/zephyr/test/drivers/src/ppc.c
index 7f736c4938..82b0aeb6c9 100644
--- a/zephyr/test/drivers/src/ppc.c
+++ b/zephyr/test/drivers/src/ppc.c
@@ -121,6 +121,41 @@ static void test_ppc_syv682x_interrupt(void)
 			SYV682X_CONTROL_1_PWR_ENB,
 			"Power path enabled after HV_OC handled 3 times");
 	syv682x_emul_set_status(emul, 0);
+
+	/*
+	 * A VCONN OC event less than 100 ms should not cause the driver to turn
+	 * VCONN off.
+	 */
+	ppc_set_vconn(syv682x_port, true);
+	syv682x_emul_set_control_4(emul, SYV682X_CONTROL_4_VCONN_OCP);
+	syv682x_interrupt(syv682x_port);
+	msleep(1);
+	zassert_ok(syv682x_emul_get_reg(emul, SYV682X_CONTROL_4_REG, &reg),
+			"Reading CONTROL_4 failed");
+	zassert_true(reg &
+			(SYV682X_CONTROL_4_VCONN1 | SYV682X_CONTROL_4_VCONN2),
+			"VCONN disabled after initial VCONN OC");
+	msleep(50);
+	syv682x_interrupt(syv682x_port);
+	msleep(1);
+	zassert_ok(syv682x_emul_get_reg(emul, SYV682X_CONTROL_4_REG, &reg),
+			"Reading CONTROL_4 failed");
+	zassert_true(reg &
+			(SYV682X_CONTROL_4_VCONN1 | SYV682X_CONTROL_4_VCONN2),
+			"VCONN disabled after short VCONN OC");
+	/*
+	 * But if the event keeps going for over 100 ms continuously, the driver
+	 * should turn VCONN off.
+	 */
+	msleep(60);
+	syv682x_interrupt(syv682x_port);
+	msleep(1);
+	zassert_ok(syv682x_emul_get_reg(emul, SYV682X_CONTROL_4_REG, &reg),
+			"Reading CONTROL_4 failed");
+	zassert_false(reg &
+			(SYV682X_CONTROL_4_VCONN1 | SYV682X_CONTROL_4_VCONN2),
+			"VCONN enabled after long VCONN OC");
+	syv682x_emul_set_control_4(emul, 0x0);
 }
 
 static void test_ppc_syv682x(void)