button: allow disabling software poweroff

On some devices, the button driver allows a "software poweroff" by long-
pressing a certain key. This behavior is inconvnient when that button needs
to be held down for other purposes, such as moving the cursor in rockpaint
or sgt-untangle.

This patch allows selectively disabling the software poweroff (enabled by
default) from both core and plugin code.

Change-Id: I7580752888ae5c7c7c5eb1be5966e3d67f17d4b4

apps/plugin.c

@@ -387,6 +387,10 @@ static const struct plugin_api rockbox_api = {
 #ifdef HAS_BUTTON_HOLD
     button_hold,
 #endif
+#ifdef HAVE_SW_POWEROFF
+    button_set_sw_poweroff_state,
+    button_get_sw_poweroff_state,
+#endif
 #ifdef HAVE_TOUCHSCREEN
     touchscreen_set_mode,
     touchscreen_get_mode,

apps/plugin.h

@@ -161,12 +161,12 @@ void* plugin_get_buffer(size_t *buffer_size);
 #define PLUGIN_MAGIC 0x526F634B /* RocK */
 
 /* increase this every time the api struct changes */
-#define PLUGIN_API_VERSION 237
+#define PLUGIN_API_VERSION 238
 
 /* update this to latest version if a change to the api struct breaks
    backwards compatibility (and please take the opportunity to sort in any
    new function which are "waiting" at the end of the function table) */
-#define PLUGIN_MIN_API_VERSION 237
+#define PLUGIN_MIN_API_VERSION 238
 
 /* plugin return codes */
 /* internal returns start at 0x100 to make exit(1..255) work */
@@ -435,6 +435,10 @@ struct plugin_api {
 #ifdef HAS_BUTTON_HOLD
     bool (*button_hold)(void);
 #endif
+#ifdef HAVE_SW_POWEROFF
+    void (*button_set_sw_poweroff_state)(bool enable);
+    bool (*button_get_sw_poweroff_state)(void);
+#endif
 #ifdef HAVE_TOUCHSCREEN
     void (*touchscreen_set_mode)(enum touchscreen_mode);
     enum touchscreen_mode (*touchscreen_get_mode)(void);

apps/plugins/lib/helper.c

@@ -66,6 +66,21 @@ void backlight_use_settings(void)
 #endif /* CONFIG_CHARGING */
 }
 
+#ifdef HAVE_SW_POWEROFF
+static bool original_sw_poweroff_state = true;
+
+void sw_poweroff_disable(void)
+{
+    original_sw_poweroff_state = rb->button_get_sw_poweroff_state();
+    rb->button_set_sw_poweroff_state(false);
+}
+
+void sw_poweroff_restore(void)
+{
+    rb->button_set_sw_poweroff_state(original_sw_poweroff_state);
+}
+#endif
+
 #ifdef HAVE_REMOTE_LCD
 /*  Force the backlight on */
 void remote_backlight_force_on(void)

apps/plugins/lib/helper.h

@@ -29,6 +29,16 @@
 void backlight_force_on(void);
 void backlight_ignore_timeout(void);
 void backlight_use_settings(void);
+
+#ifdef HAVE_SW_POWEROFF
+/**
+ * Disable and restore software poweroff (i.e. holding PLAY on iPods).
+ * Only call _restore() if _disable() was called earlier!
+ */
+void sw_poweroff_disable(void);
+void sw_poweroff_restore(void);
+#endif
+
 #ifdef HAVE_REMOTE_LCD
 void remote_backlight_force_on(void);
 void remote_backlight_ignore_timeout(void);

firmware/drivers/button.c

@@ -65,6 +65,9 @@ static bool phones_present = false;
 #ifdef HAVE_LINEOUT_DETECTION
 static bool lineout_present = false;
 #endif
+#ifdef HAVE_SW_POWEROFF
+static bool enable_sw_poweroff = true;
+#endif
 
 /* how long until repeat kicks in, in centiseconds */
 #define REPEAT_START      (30*HZ/100)
@@ -280,7 +283,8 @@ static void button_tick(void)
                            which doesn't shut down easily with the OFF
                            key */
 #ifdef HAVE_SW_POWEROFF
-                        if ((btn & POWEROFF_BUTTON
+                        if (enable_sw_poweroff &&
+                            (btn & POWEROFF_BUTTON
 #ifdef RC_POWEROFF_BUTTON
                                     || btn == RC_POWEROFF_BUTTON
 #endif
@@ -773,3 +777,13 @@ void button_enable_touch(bool en)
 #endif
 }
 #endif
+
+#ifdef HAVE_SW_POWEROFF
+void button_set_sw_poweroff_state(bool en) {
+    enable_sw_poweroff = en;
+}
+
+bool button_get_sw_poweroff_state() {
+    return enable_sw_poweroff;
+}
+#endif

firmware/export/button.h

@@ -130,4 +130,9 @@ int touchscreen_last_touch(void);
 void button_enable_touch(bool en);
 #endif
 
+#ifdef HAVE_SW_POWEROFF
+void button_set_sw_poweroff_state(bool en);
+bool button_get_sw_poweroff_state(void);
+#endif
+
 #endif /* _BUTTON_H_ */