chore: Various soft-off review fixes

* Code style to avoid goto.
* Enable pm.c compilation via dedicated Kconfig flag.
* Comment wakeup trigger PM behavior.

app/CMakeLists.txt

@@ -31,7 +31,7 @@ target_sources_ifdef(CONFIG_ZMK_WPM app PRIVATE src/wpm.c)
 target_sources(app PRIVATE src/event_manager.c)
 target_sources_ifdef(CONFIG_ZMK_GPIO_KEY_BEHAVIOR_TRIGGER app PRIVATE src/gpio_key_behavior_trigger.c)
 target_sources_ifdef(CONFIG_ZMK_GPIO_SCANNED_KEY_BEHAVIOR_TRIGGER app PRIVATE src/gpio_scanned_key_behavior_trigger.c)
-target_sources_ifdef(CONFIG_ZMK_PM_SOFT_OFF app PRIVATE src/pm.c)
+target_sources_ifdef(CONFIG_ZMK_PM app PRIVATE src/pm.c)
 target_sources_ifdef(CONFIG_ZMK_EXT_POWER app PRIVATE src/ext_power_generic.c)
 target_sources_ifdef(CONFIG_ZMK_GPIO_KEY_WAKEUP_TRIGGER app PRIVATE src/gpio_key_wakeup_trigger.c)
 target_sources(app PRIVATE src/events/activity_state_changed.c)

app/Kconfig

@@ -423,8 +423,12 @@ config ZMK_EXT_POWER
     bool "Enable support to control external power output"
     default y
 
+config ZMK_PM
+    bool
+
 config ZMK_PM_SOFT_OFF
     bool "Soft-off support"
+    select ZMK_PM
     select PM_DEVICE
 
 config ZMK_GPIO_KEY_WAKEUP_TRIGGER

app/module/drivers/kscan/kscan_gpio_direct.c

@@ -324,11 +324,9 @@ static int kscan_direct_init(const struct device *dev) {
 static int kscan_direct_pm_action(const struct device *dev, enum pm_device_action action) {
     switch (action) {
     case PM_DEVICE_ACTION_SUSPEND:
-        kscan_direct_disable(dev);
-        break;
+        return kscan_direct_disable(dev);
     case PM_DEVICE_ACTION_RESUME:
-        kscan_direct_enable(dev);
-        break;
+        return kscan_direct_enable(dev);
     default:
         return -ENOTSUP;
     }

app/module/drivers/kscan/kscan_gpio_matrix.c

@@ -427,11 +427,9 @@ static int kscan_matrix_init(const struct device *dev) {
 static int kscan_matrix_pm_action(const struct device *dev, enum pm_device_action action) {
     switch (action) {
     case PM_DEVICE_ACTION_SUSPEND:
-        kscan_matrix_disable(dev);
-        break;
+        return kscan_matrix_disable(dev);
     case PM_DEVICE_ACTION_RESUME:
-        kscan_matrix_enable(dev);
-        break;
+        return kscan_matrix_enable(dev);
     default:
         return -ENOTSUP;
     }

app/src/gpio_key_wakeup_trigger.c

@@ -39,18 +39,17 @@ static int gpio_key_wakeup_trigger_pm_resume(const struct device *dev) {
     int ret = gpio_pin_interrupt_configure_dt(&config->trigger, GPIO_INT_LEVEL_ACTIVE);
     if (ret < 0) {
         LOG_ERR("Failed to configure wakeup trigger key GPIO pin interrupt (%d)", ret);
-        goto exit;
+        return ret;
     }
 
     for (int i = 0; i < config->extra_gpios_count; i++) {
         ret = gpio_pin_configure_dt(&config->extra_gpios[i], GPIO_OUTPUT_ACTIVE);
         if (ret < 0) {
             LOG_WRN("Failed to set extra GPIO pin active for waker (%d)", ret);
-            goto exit;
+            return ret;
         }
     }
 
-exit:
     return ret;
 }
 
@@ -62,9 +61,20 @@ static int gpio_key_wakeup_trigger_pm_suspend(const struct device *dev) {
         LOG_ERR("Failed to configure wakeup trigger key GPIO pin interrupt (%d)", ret);
     }
 
+    for (int i = 0; i < config->extra_gpios_count; i++) {
+        ret = gpio_pin_configure_dt(&config->extra_gpios[i], GPIO_DISCONNECTED);
+        if (ret < 0) {
+            LOG_WRN("Failed to set extra GPIO pin disconnected for waker (%d)", ret);
+            return ret;
+        }
+    }
+
     return ret;
 }
 
+// The waker is "backwards", in as much as it is designed to be resumed/enabled immediately
+// before a soft-off state is entered, so it can wake the device from that state later.
+// So this waker correctly resumes and is ready to wake the device later.
 static int gpio_key_wakeup_trigger_pm_action(const struct device *dev,
                                              enum pm_device_action action) {
     switch (action) {

app/src/pm.c

@@ -15,6 +15,8 @@ LOG_MODULE_DECLARE(zmk, CONFIG_ZMK_LOG_LEVEL);
 
 #include <zmk/endpoints.h>
 
+#if IS_ENABLED(CONFIG_ZMK_PM_SOFT_OFF)
+
 #define HAS_WAKERS DT_HAS_COMPAT_STATUS_OKAY(zmk_soft_off_wakeup_sources)
 
 #if HAS_WAKERS
@@ -63,3 +65,5 @@ int zmk_pm_soft_off(void) {
     LOG_DBG("soft-off: go to sleep");
     return pm_state_force(0U, &(struct pm_state_info){PM_STATE_SOFT_OFF, 0, 0});
 }
+
+#endif // IS_ENABLED(CONFIG_ZMK_PM_SOFT_OFF)