modem: hl7800: fix PSM

Fix power-save-mode (PSM) operation.
When in PSM, do not bring the networking interface down
when an out-of-coverage event occurs.
When PSM goes into hibernate, this will cause an
out-of-coverage event to occur, even though the device
still has access to service.
Keeping the networking interface in the up state
allows an app to send data whenever it needs to.

Signed-off-by: Ryan Erickson <[email protected]>

Author: rerickson1

drivers/modem/hl7800.c

@@ -130,6 +130,12 @@ enum socket_state {
 	SOCK_CONNECTED,
 };
 
+enum hl7800_lpm {
+	HL7800_LPM_NONE,
+	HL7800_LPM_EDRX,
+	HL7800_LPM_PSM,
+};
+
 struct mdm_control_pinconfig {
 	char *dev_name;
 	gpio_pin_t pin;
@@ -515,6 +521,7 @@ struct hl7800_iface_ctx {
 	bool allow_sleep;
 	bool uart_on;
 	enum mdm_hl7800_sleep_state sleep_state;
+	enum hl7800_lpm low_power_mode;
 	enum mdm_hl7800_network_state network_state;
 	enum net_operator_status operator_status;
 	void (*event_callback)(enum mdm_hl7800_event event, void *event_data);
@@ -2901,14 +2908,17 @@ static void iface_status_work_cb(struct k_work *work)
 		break;
 	case HL7800_OUT_OF_COVERAGE:
 	default:
-		if (ictx.iface && net_if_is_up(ictx.iface)) {
+		if (ictx.iface && net_if_is_up(ictx.iface) &&
+		    (ictx.low_power_mode != HL7800_LPM_PSM)) {
 			LOG_DBG("HL7800 iface DOWN");
 			net_if_down(ictx.iface);
 		}
 		break;
 	}
 
-	if (ictx.iface && !net_if_is_up(ictx.iface)) {
+	if ((ictx.iface && !net_if_is_up(ictx.iface)) ||
+	    (ictx.low_power_mode == HL7800_LPM_PSM &&
+	     ictx.network_state == HL7800_OUT_OF_COVERAGE)) {
 		hl7800_stop_rssi_work();
 		notify_all_tcp_sockets_closed();
 	} else if (ictx.iface && net_if_is_up(ictx.iface)) {
@@ -3516,7 +3526,8 @@ static void sockreadrecv_cb_work(struct k_work *work)
 
 	sock = CONTAINER_OF(work, struct hl7800_socket, recv_cb_work);
 
-	LOG_DBG("Sock %d RX CB", sock->socket_id);
+	LOG_DBG("Sock %d RX CB (size: %zd)", sock->socket_id,
+		(sock->recv_pkt != NULL) ? net_pkt_get_len(sock->recv_pkt) : 0);
 	/* return data */
 	pkt = sock->recv_pkt;
 	sock->recv_pkt = NULL;
@@ -4311,8 +4322,8 @@ static void mdm_vgpio_work_cb(struct k_work *item)
 		if (ictx.sleep_state != HL7800_SLEEP_STATE_ASLEEP) {
 			set_sleep_state(HL7800_SLEEP_STATE_ASLEEP);
 		}
-		if (ictx.iface && ictx.initialized &&
-		    net_if_is_up(ictx.iface)) {
+		if (ictx.iface && ictx.initialized && net_if_is_up(ictx.iface) &&
+		    ictx.low_power_mode != HL7800_LPM_PSM) {
 			net_if_down(ictx.iface);
 		}
 	}
@@ -4736,20 +4747,22 @@ static int modem_reset_and_configure(void)
 	}
 #endif
 
+	ictx.low_power_mode = HL7800_LPM_NONE;
 #ifdef CONFIG_MODEM_HL7800_LOW_POWER_MODE
-
 	/* enable GPIO6 low power monitoring */
 	SEND_AT_CMD_EXPECT_OK("AT+KHWIOCFG=3,1,6");
 
 	/* Turn on sleep mode */
 	SEND_AT_CMD_EXPECT_OK("AT+KSLEEP=1,2,10");
 
 #if CONFIG_MODEM_HL7800_PSM
+	ictx.low_power_mode = HL7800_LPM_PSM;
 	/* Turn off eDRX */
 	SEND_AT_CMD_EXPECT_OK("AT+CEDRXS=0");
 
 	SEND_AT_CMD_EXPECT_OK(TURN_ON_PSM);
 #elif CONFIG_MODEM_HL7800_EDRX
+	ictx.low_power_mode = HL7800_LPM_EDRX;
 	/* Turn off PSM */
 	SEND_AT_CMD_EXPECT_OK("AT+CPSMS=0");