lib: modem_slm: Stop triggering indicate multiple times

When indicate handler is registered and indicate pin configured,
thousands of callback calls were executed because the GPIO cannot
be triggering on an edge due to Hw issues increasing power consumption
Now there will be one callback call for one instance of
incoming data or AT notifications in SLM idle state.

This solution is not perfect but better than currently with
thousands of callbacks.

Jira: LRCS-82

Signed-off-by: Tommi Rantanen <[email protected]>

Author: trantanen

lib/modem_slm/modem_slm.c

@@ -60,13 +60,67 @@ static const char at_usage_str[] = "Usage: slm <at_command>";
 /* global functions defined in different files */
 void slm_monitor_dispatch(const char *notif);
 
+#if (CONFIG_MODEM_SLM_INDICATE_PIN >= 0)
+static bool indicate_pin_enabled;
+
+static void gpio_cb_func(const struct device *dev, struct gpio_callback *gpio_cb, uint32_t pins);
+static struct gpio_callback gpio_cb;
+#endif
+
+static int indicate_pin_enable(void)
+{
+#if (CONFIG_MODEM_SLM_INDICATE_PIN >= 0)
+	int err = 0;
+
+	if (!indicate_pin_enabled) {
+		err = gpio_pin_configure(gpio_dev, CONFIG_MODEM_SLM_INDICATE_PIN,
+					 GPIO_INPUT | GPIO_PULL_UP | GPIO_ACTIVE_LOW);
+		if (err) {
+			LOG_ERR("GPIO config error: %d", err);
+			return err;
+		}
+
+		gpio_init_callback(&gpio_cb, gpio_cb_func, BIT(CONFIG_MODEM_SLM_INDICATE_PIN));
+		err = gpio_add_callback(gpio_dev, &gpio_cb);
+		if (err) {
+			LOG_WRN("GPIO add callback error: %d", err);
+		}
+		err = gpio_pin_interrupt_configure(gpio_dev, CONFIG_MODEM_SLM_INDICATE_PIN,
+						   GPIO_INT_LEVEL_LOW);
+		if (err) {
+			LOG_WRN("GPIO interrupt configure error: %d", err);
+		}
+		indicate_pin_enabled = true;
+		LOG_DBG("Indicate pin enabled");
+	}
+#endif
+	return 0;
+}
+
+static void indicate_pin_disable(void)
+{
+#if (CONFIG_MODEM_SLM_INDICATE_PIN >= 0)
+	if (indicate_pin_enabled) {
+		gpio_remove_callback(gpio_dev, &gpio_cb);
+		gpio_pin_interrupt_configure(gpio_dev, CONFIG_MODEM_SLM_INDICATE_PIN,
+					     GPIO_INT_DISABLE);
+		gpio_pin_configure(gpio_dev, CONFIG_MODEM_SLM_INDICATE_PIN, GPIO_DISCONNECTED);
+		indicate_pin_enabled = false;
+		LOG_DBG("Indicate pin disabled");
+	}
+#endif
+}
+
 static void gpio_wakeup_wk(struct k_work *work)
 {
 	ARG_UNUSED(work);
 
 	if (gpio_pin_set(gpio_dev, CONFIG_MODEM_SLM_WAKEUP_PIN, 0) != 0) {
 		LOG_WRN("GPIO set error");
 	}
+	/* When SLM is woken up, indicate pin must be enabled */
+	(void)indicate_pin_enable();
+
 	LOG_INF("Stop wake-up");
 }
 
@@ -323,11 +377,16 @@ static void gpio_cb_func(const struct device *dev, struct gpio_callback *gpio_cb
 	if (k_work_delayable_is_pending(&gpio_wakeup_work)) {
 		(void)k_work_cancel_delayable(&gpio_wakeup_work);
 		(void)gpio_pin_set(gpio_dev, CONFIG_MODEM_SLM_WAKEUP_PIN, 0);
+	} else {
+		/* Disable indicate pin so that callbacks doesn't keep on coming. */
+		indicate_pin_disable();
 	}
 
 	LOG_INF("Remote indication");
 	if (ind_handler) {
 		ind_handler();
+	} else {
+		LOG_WRN("Indicate PIN configured but slm_ind_handler_t not defined");
 	}
 }
 #endif  /* CONFIG_MODEM_SLM_INDICATE_PIN */
@@ -348,27 +407,9 @@ static int gpio_init(void)
 		return err;
 	}
 
-#if (CONFIG_MODEM_SLM_INDICATE_PIN >= 0)
-	err = gpio_pin_configure(gpio_dev, CONFIG_MODEM_SLM_INDICATE_PIN,
-				 GPIO_INPUT | GPIO_PULL_UP | GPIO_ACTIVE_LOW);
-	if (err) {
-		LOG_ERR("GPIO config error: %d", err);
-		return err;
-	}
+	err = indicate_pin_enable();
 
-	gpio_init_callback(&gpio_cb, gpio_cb_func, BIT(CONFIG_MODEM_SLM_INDICATE_PIN));
-	err = gpio_add_callback(gpio_dev, &gpio_cb);
-	if (err) {
-		LOG_WRN("GPIO add callback error: %d", err);
-	}
-	err = gpio_pin_interrupt_configure(gpio_dev, CONFIG_MODEM_SLM_INDICATE_PIN,
-					   GPIO_INT_LEVEL_LOW);
-	if (err) {
-		LOG_WRN("GPIO enable callback error: %d", err);
-	}
-#endif
-
-	return 0;
+	return err;
 }
 
 int modem_slm_init(slm_data_handler_t handler)
@@ -415,11 +456,8 @@ int modem_slm_uninit(void)
 	k_sleep(K_MSEC(10));
 
 	gpio_pin_configure(gpio_dev, CONFIG_MODEM_SLM_WAKEUP_PIN, GPIO_DISCONNECTED);
-#if (CONFIG_MODEM_SLM_INDICATE_PIN >= 0)
-	gpio_remove_callback(gpio_dev, &gpio_cb);
-	gpio_pin_interrupt_configure(gpio_dev, CONFIG_MODEM_SLM_INDICATE_PIN, GPIO_INT_DISABLE);
-	gpio_pin_configure(gpio_dev, CONFIG_MODEM_SLM_INDICATE_PIN, GPIO_DISCONNECTED);
-#endif
+
+	indicate_pin_disable();
 
 	data_handler = NULL;
 	ind_handler = NULL;
@@ -485,6 +523,11 @@ int modem_slm_send_cmd(const char *const command, uint32_t timeout)
 {
 	int ret;
 
+	/* Enable indicate pin when command is sent. This should not be needed but is made
+	 * currently to make sure it wouldn't be disabled forever.
+	 */
+	(void)indicate_pin_enable();
+
 	slm_at_state = AT_CMD_PENDING;
 	ret = uart_send(command, strlen(command));
 	if (ret < 0) {