usb: Add ability to prompt user about what to do upon usb insertion

 v3: Add in config option
 v4: Bugfixes
 v5: Force a redraw upon exiting
 v6: keypress-in-chargeonly mode enables mass storage (and vice versa)
 v7: Fix bootloader builds
 v8: Update manual, and have bootloader respect keypresses
 v9: Change default to mass storage (ie no change in behavior)

 todo:
  * test-build dx50/dx90
  * Switch from yes/no to proper menu?
  * prevent WPS progress bar from drawing over us

Change-Id: I82e0ccb08497b7a5aa756ce77f1332ee963703a7

...

Change-Id: I7946cf240b18a4fa8ace5e25e1eb6e97b8b12d7c

2 files changed, 13 insertions, 4 deletions

diff --git a/manual/configure_rockbox/system_options.tex b/manual/configure_rockbox/system_options.tex
index 4faeafb895..f9e09a91b1 100755
--- a/manual/configure_rockbox/system_options.tex
+++ b/manual/configure_rockbox/system_options.tex
@@ -851,6 +851,12 @@ therefore result in better runtime.
     }}
     \end{description}
 }
+\opt{usb_power}{
+  \subsection{USB Mode}
+    This controls what happens with the \dap{}'s USB port is connected.
+    \setting{Charge Only} and \setting{Mass Storage} will automatically enter
+    that mode, and \setting{Ask} will prompt the user each time.
+}
 \opt{multidrive_usb}{
   \subsection{USB Hide Internal Drive}
     If this option is turned \setting{On}, the internal storage drive will not
diff --git a/manual/rockbox_interface/main.tex b/manual/rockbox_interface/main.tex
index ec76ce4ed5..33dae2f62f 100644
--- a/manual/rockbox_interface/main.tex
+++ b/manual/rockbox_interface/main.tex
@@ -827,10 +827,13 @@ properly.}
 
   \opt{usb_power}{
     \section{USB Charging}
-    To charge your \dap{} over USB, hold any button while plugging it
-    in. This will prevent it from connecting to your computer and let you
-    continue to use it normally. Your \dap{} must already be in Rockbox for this
-    to function.
+    Whenever your \dap{} is connected to USB, it will automatically charge.
+    However, depending on the \config{usb\_mode} setting, the \dap{} may also
+    enter mass storage mode or prompt the user for what action to take.
+    When the \dap{} is configured to enter mass storage mode or automatically
+    charge, you may trigger the opposite behaivor by holding down any button
+    while plugging it in.  Your \dap{} must already be in Rockbox for this to
+    function.
     \nopt{fuzeplus}{
     \note{Be aware that this button may still perform its normal function, so
     it is recommended to use a button without harmful side effects, such as