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               Linux for the Dingoo A320

	Ignacio Garcia Perez <iggarpe@gmail.com>

                (updated 2009-06-14)


----------------
** Quickstart **
----------------

Use "make a320_defconfig" for a default configuration (LCD driver ILI9325).

If your A320 is one of the newer models, you must change the LCD driver
to ILI9331:

    Device drivers
    |---Graphics support
        |---Support for framebuffer devices
            |---SLCD panel

--------------
** Keyboard **
--------------

The keyboard driver has been completely rewritten now using the polled
input device code. The standard keyboard map is as follows:

    D-pad up            KEY_UP          KEY_VOLUMEUP            's'
    D-pad down          KEY_DOWN        KEY_VOLUMEDOWN          'u'
    D-pad left          KEY_LEFT        KEY_BRIGHTNESSDOWN      'e'
    D-pad right         KEY_RIGHT       KEY_BRIGHTNESSUP        'i'
    A button            KEY_LEFTCTRL
    B button            KEY_LEFTATL
    X button            KEY_SPACE
    Y button            KEY_LEFTSHIFT
    Left shoulder       KEY_TAB		KEY_EXIT
    Right shoulder      KEY_BACKSPACE
    START button        KEY_ENTER
    SELECT button       KEY_ESC         KEY_MENU		'b'

The second column is the generated keycode when the button is pressed normally.
The third column is the generated keycode when the button is pressed while the
power slider is pressed too.
The fourth column is the generated system request when the button is pressed
while both the power slider and the START button are pressed:

's'	Emergency sync of all discs.
'u'	Remount all discs read-only.
'e'	Send SIGTERM to all processes except init.
'i'	Send SIGKILL to all processes except init.
'b'	Reboot immediately.

For example, to reboot the console syncing all disces and mounting read-only,
press and hold POWER, press and hold START, and press secuentially UP, DOWN
and SELECT. Note that SELECT is also used in dual-boot to select linux boot,
so if you hold SELECT pressed at the end of the previous sequence, you should
reboot back into linux.

Note that the POWER + key combinations are selected to enable an user space
daemon handle the volume, LCD bightness, and perhaps an on-screen keyboard.

If you hold the power slider pressed alone this is what will happen:
- After two seconds a KEY_POWER key press and release will be generated.
- After five seconds, an inmediate reboot will happen.

This is subject to change when hardware powerdown or idle support works.

I did my best to come up with a clever and useful keyboard map, but if you
have any suggestions, please do not hesitate to contact me.

-----------
** Sound **
-----------

Sound driver is still OSS. It's quite buggy, but stick to S16 sample
format and everything should be ok.

---------------------------------
** IPU (Image Processing Unit) **
---------------------------------

IPU (Image Processing Unit) memory reservation at startup is disabled
(saves 4MB). If you intend to test video playing, you might want to
enable it:

    General setup
    |---Configure standard kernel features (for small sytems)
        |---Reserve memory for IPU on Ingenic JZ4740 SOC

---------------------------
** CPU frequency scaling **
---------------------------

CPU frequency scaling is now default enabled. Have a look at the stuff
in /sys/devices/system/cpu/cpu0/cpufreq/. Default governor is "userspace".
It is untested, and anyway at the moment you can only REDUCE the CPU
frequency below the 336MHz set by the boot hardware initialization code
(in hwinit if you're booting vía USB boot).

-------------
** Battery **
-------------

You can read the battery status by reading from /proc/jz/battery. You will
read a single line with a decimal value which is the battery voltage in
millivolts.

We want a platform independent way of reading the battery status, and thus
we need something like a percentage of full battery charge. When this and
other info reading is implemented, it will be available in the second and
further lines read from /proc/jz/battery.

-------------------
** LCD backlight **
-------------------

You can change the LCD backlight level by using the FBIOSETBACKLIGHT ioctl
command on the /dev/fb0 interface or by writing to /proc/jz/lcd_backlight.
I recommend the later method since the first requires kernel headers,
which Ingenic didn't event bother to place in the right place (the ioctl
defintions are in drivers/video/jz4740_slcd.h).

Write a value between 0 and 100.

Note: the relation between the value and the luminosity is not linear.
This is likely to be fixed some day.

-------------------
** Miscellaneous **
-------------------

Lots of JZ4740 hardware support is disabled. Not because it doesn't
work but because it is untested. Enable it at your own risk.