modem: modem_cellular: delay after reset de-assert

Add a delay after de-asserting the reset pin before pulsing the power on
pin, if both are enabled.

Signed-off-by: Jordan Yates <[email protected]>

Author: JordanYates

drivers/modem/Kconfig.cellular

@@ -74,6 +74,10 @@ config MODEM_CELLULAR_NEW_BAUDRATE_DELAY
 	default 100 if DT_HAS_U_BLOX_LARA_R6_ENABLED
 	default 300
 
+config MODEM_CELLULAR_RESET_POWER_ON_DELAY_MS
+	int "Delay between de-asserting the reset pin and pulsing the power pin"
+	default 500
+
 if DT_HAS_U_BLOX_LARA_R6_ENABLED
 
 choice MODEM_CELLULAR_RAT

drivers/modem/modem_cellular.c

@@ -58,6 +58,7 @@ BUILD_ASSERT(sizeof(CONFIG_MODEM_CELLULAR_APN) - 1 < MODEM_CELLULAR_DATA_APN_LEN
 enum modem_cellular_state {
 	MODEM_CELLULAR_STATE_IDLE = 0,
 	MODEM_CELLULAR_STATE_RESET_PULSE,
+	MODEM_CELLULAR_STATE_AWAIT_RESET,
 	MODEM_CELLULAR_STATE_POWER_ON_PULSE,
 	MODEM_CELLULAR_STATE_AWAIT_POWER_ON,
 	MODEM_CELLULAR_STATE_SET_BAUDRATE,
@@ -206,6 +207,8 @@ static const char *modem_cellular_state_str(enum modem_cellular_state state)
 		return "idle";
 	case MODEM_CELLULAR_STATE_RESET_PULSE:
 		return "reset pulse";
+	case MODEM_CELLULAR_STATE_AWAIT_RESET:
+		return "await reset";
 	case MODEM_CELLULAR_STATE_POWER_ON_PULSE:
 		return "power pulse";
 	case MODEM_CELLULAR_STATE_AWAIT_POWER_ON:
@@ -288,6 +291,7 @@ static bool modem_cellular_apn_change_allowed(enum modem_cellular_state st)
 	switch (st) {
 	case MODEM_CELLULAR_STATE_IDLE:
 	case MODEM_CELLULAR_STATE_RESET_PULSE:
+	case MODEM_CELLULAR_STATE_AWAIT_RESET:
 	case MODEM_CELLULAR_STATE_POWER_ON_PULSE:
 	case MODEM_CELLULAR_STATE_AWAIT_POWER_ON:
 	case MODEM_CELLULAR_STATE_SET_BAUDRATE:
@@ -876,9 +880,16 @@ static int modem_cellular_on_reset_pulse_state_enter(struct modem_cellular_data
 static void modem_cellular_reset_pulse_event_handler(struct modem_cellular_data *data,
 							enum modem_cellular_event evt)
 {
+	const struct modem_cellular_config *config =
+		(const struct modem_cellular_config *)data->dev->config;
+
 	switch (evt) {
 	case MODEM_CELLULAR_EVENT_TIMEOUT:
-		modem_cellular_enter_state(data, MODEM_CELLULAR_STATE_AWAIT_POWER_ON);
+		if (modem_cellular_gpio_is_enabled(&config->power_gpio)) {
+			modem_cellular_enter_state(data, MODEM_CELLULAR_STATE_AWAIT_RESET);
+		} else {
+			modem_cellular_enter_state(data, MODEM_CELLULAR_STATE_AWAIT_POWER_ON);
+		}
 		break;
 
 	case MODEM_CELLULAR_EVENT_SUSPEND:
@@ -905,6 +916,41 @@ static int modem_cellular_on_reset_pulse_state_leave(struct modem_cellular_data
 	return 0;
 }
 
+static int modem_cellular_on_await_reset_state_enter(struct modem_cellular_data *data)
+{
+	modem_cellular_start_timer(data, K_MSEC(CONFIG_MODEM_CELLULAR_RESET_POWER_ON_DELAY_MS));
+	return 0;
+}
+
+static void modem_cellular_await_reset_event_handler(struct modem_cellular_data *data,
+							enum modem_cellular_event evt)
+{	const struct modem_cellular_config *config =
+		(const struct modem_cellular_config *)data->dev->config;
+
+	switch (evt) {
+	case MODEM_CELLULAR_EVENT_TIMEOUT:
+		if (modem_cellular_gpio_is_enabled(&config->power_gpio)) {
+			modem_cellular_enter_state(data, MODEM_CELLULAR_STATE_POWER_ON_PULSE);
+		} else {
+			modem_cellular_enter_state(data, MODEM_CELLULAR_STATE_AWAIT_POWER_ON);
+		}
+		break;
+
+	case MODEM_CELLULAR_EVENT_SUSPEND:
+		modem_cellular_enter_state(data, MODEM_CELLULAR_STATE_IDLE);
+		break;
+
+	default:
+		break;
+	}
+}
+
+static int modem_cellular_on_await_reset_state_leave(struct modem_cellular_data *data)
+{
+	modem_cellular_stop_timer(data);
+	return 0;
+}
+
 static int modem_cellular_on_power_on_pulse_state_enter(struct modem_cellular_data *data)
 {
 	const struct modem_cellular_config *config =
@@ -1551,6 +1597,10 @@ static int modem_cellular_on_state_enter(struct modem_cellular_data *data)
 		ret = modem_cellular_on_reset_pulse_state_enter(data);
 		break;
 
+	case MODEM_CELLULAR_STATE_AWAIT_RESET:
+		ret = modem_cellular_on_await_reset_state_enter(data);
+		break;
+
 	case MODEM_CELLULAR_STATE_POWER_ON_PULSE:
 		ret = modem_cellular_on_power_on_pulse_state_enter(data);
 		break;
@@ -1636,6 +1686,10 @@ static int modem_cellular_on_state_leave(struct modem_cellular_data *data)
 		ret = modem_cellular_on_reset_pulse_state_leave(data);
 		break;
 
+	case MODEM_CELLULAR_STATE_AWAIT_RESET:
+		ret = modem_cellular_on_await_reset_state_leave(data);
+		break;
+
 	case MODEM_CELLULAR_STATE_POWER_ON_PULSE:
 		ret = modem_cellular_on_power_on_pulse_state_leave(data);
 		break;
@@ -1723,6 +1777,10 @@ static void modem_cellular_event_handler(struct modem_cellular_data *data,
 		modem_cellular_reset_pulse_event_handler(data, evt);
 		break;
 
+	case MODEM_CELLULAR_STATE_AWAIT_RESET:
+		modem_cellular_await_reset_event_handler(data, evt);
+		break;
+
 	case MODEM_CELLULAR_STATE_POWER_ON_PULSE:
 		modem_cellular_power_on_pulse_event_handler(data, evt);
 		break;