zephyr: test: sn5s330 dead battery boot init

Verify sn5s330 PP2 are force enabled.

BRANCH=none
BUG=b:203364783
TEST=zmake configure --test zephyr/test/drivers

Signed-off-by: Aaron Massey <aaronmassey@google.com>
Change-Id: I118b05140228b89d27790863a3c8ddc62793fedc
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/3271367
Reviewed-by: Abe Levkoy <alevkoy@chromium.org>

2 files changed, 80 insertions, 1 deletions

diff --git a/driver/ppc/sn5s330.c b/driver/ppc/sn5s330.c
index 1aac04af02..3fa44ae803 100644
--- a/driver/ppc/sn5s330.c
+++ b/driver/ppc/sn5s330.c
@@ -464,7 +464,14 @@ static int sn5s330_init(int port)
 		i2c_write8(i2c_port, i2c_addr_flags,
 			   SN5S330_INT_STATUS_REG4, regval);
 
-		/* Turn on PP2 FET. */
+		/*
+		 * Turn on PP2 FET.
+		 * Although PP2 FET is already enabled during dead batter boot
+		 * by the spec, we force that state here.
+		 *
+		 * TODO(207034759): Verify need or remove redundant PP2 set.
+		 */
+
 		status = sn5s330_pp_fet_enable(port, SN5S330_PP2, 1);
 		if (status) {
 			ppc_prints("Failed to turn on PP2 FET!", port);
diff --git a/zephyr/test/drivers/src/ppc_sn5s330.c b/zephyr/test/drivers/src/ppc_sn5s330.c
index 95556e28cf..aa06cf3bd9 100644
--- a/zephyr/test/drivers/src/ppc_sn5s330.c
+++ b/zephyr/test/drivers/src/ppc_sn5s330.c
@@ -23,6 +23,39 @@
  * to avoid test flakiness
  */
 
+struct intercept_write_data {
+	int reg_to_intercept;
+	uint8_t val_intercepted;
+};
+
+struct intercept_read_data {
+	int reg_to_intercept;
+	bool replace_reg_val;
+	uint8_t replacement_val;
+};
+
+static int intercept_read_func(struct i2c_emul *emul, int reg, uint8_t *val,
+			       int bytes, void *data)
+{
+	struct intercept_read_data *test_data = data;
+
+	if (test_data->reg_to_intercept && test_data->replace_reg_val)
+		*val = test_data->replacement_val;
+
+	return EC_SUCCESS;
+}
+
+static int intercept_write_func(struct i2c_emul *emul, int reg, uint8_t val,
+				int bytes, void *data)
+{
+	struct intercept_write_data *test_data = data;
+
+	if (test_data->reg_to_intercept == reg)
+		test_data->val_intercepted = val;
+
+	return 1;
+}
+
 static int fail_until_write_func(struct i2c_emul *emul, int reg, uint8_t val,
 				 int bytes, void *data)
 {
@@ -53,8 +86,44 @@ static void test_fail_once_func_set1(void)
 	i2c_common_emul_set_write_func(i2c_emul, NULL, NULL);
 }
 
+static void test_dead_battery_boot_force_pp2_fets_set(void)
+{
+	const struct emul *emul = EMUL;
+	struct i2c_emul *i2c_emul = sn5s330_emul_to_i2c_emul(emul);
+	struct intercept_write_data test_write_data = {
+		.reg_to_intercept = SN5S330_FUNC_SET3,
+		.val_intercepted = 0,
+	};
+	struct intercept_read_data test_read_data = {
+		.reg_to_intercept = SN5S330_INT_STATUS_REG4,
+		.replace_reg_val = true,
+		.replacement_val = SN5S330_DB_BOOT,
+	};
+
+	i2c_common_emul_set_write_func(i2c_emul, intercept_write_func,
+				       &test_write_data);
+	i2c_common_emul_set_read_func(i2c_emul, intercept_read_func,
+				      &test_read_data);
+
+	zassert_ok(sn5s330_drv.init(SN5S330_PORT), NULL);
+
+	/*
+	 * Although the device enables PP2_FET on dead battery boot by setting
+	 * the PP2_EN bit, the driver also force sets this bit during dead
+	 * battery boot by writing that bit to the FUNC_SET3 reg.
+	 *
+	 * TODO(207034759): Verify need or remove redundant PP2 set.
+	 */
+	zassert_true(test_write_data.val_intercepted & SN5S330_PP2_EN, NULL);
+	zassert_false(sn5s330_drv.is_sourcing_vbus(SN5S330_PORT), NULL);
+}
+
 static void reset_sn5s330_state(void)
 {
+	struct i2c_emul *i2c_emul = sn5s330_emul_to_i2c_emul(EMUL);
+
+	i2c_common_emul_set_write_func(i2c_emul, NULL, NULL);
+	i2c_common_emul_set_read_func(i2c_emul, NULL, NULL);
 	sn5s330_emul_reset(EMUL);
 }
 
@@ -62,6 +131,9 @@ void test_suite_ppc_sn5s330(void)
 {
 	ztest_test_suite(ppc_sn5s330,
 			 ztest_unit_test_setup_teardown(
+				 test_dead_battery_boot_force_pp2_fets_set,
+				 reset_sn5s330_state, reset_sn5s330_state),
+			 ztest_unit_test_setup_teardown(
 				 test_fail_once_func_set1, reset_sn5s330_state,
 				 reset_sn5s330_state));
 	ztest_run_test_suite(ppc_sn5s330);