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Power Off and Wake Up using GPIO Key Button

This functionality is available with following version.

Ubuntu : The release version should be 3.14.79-107 (Feb 26, 2017) or higher.
Android : Android Marshmallow (v2.4) and higher version include this functionality.

The basic working flow is as following.

[Set-up Flow]

Connect a tab button to the pin port you want to use. (Please refer to the available key table in the end part of this wiki page.)
Setting GPIO number using boot.ini
Run reboot

[Basic Working Scenario]

After booting, based on the GPIO number that is described in boot.ini, gpio_keypad driver will generate KEY_POWER event when you push tab button, and it will make the system power off.
After power off is done, bl301 will check the GPIO status periodically based on the GPIO number that is reported from kernel, and when you push the button, board will wake up.
For the key wake up, the key chattering time is 300ms.

---->>> Power Key Event 

root@odroid64:~# 
[   84.515844] reboot: Power down
.....
ERprocess cCEC cfg:0x2f
WAKEUP GPIO cfg:0x000000d6
set vddee to 0x0352mv
06f1932000000000
(Holding here...)

--->>> Power Key Event

exit_reason:0x09
set vddee to 0x042emv
BL1:08GXBB:BL1:08dafd:0a8993;FEAT:EDFC318C;POC:3;RCY:0;EMMC:800;NAND:81;SD:0;READ:0;CHK:0;
TE: 321463

BL2 Built : 11:44:26, Nov 25 2015. 
.....
.....
secure task start!
high task start!
low task start!
.....
U-Boot 2015.01-00187-g3eb97d4-dirty (Feb 22 2017 - 14:25:18)

Hardware Example

For example, we will use Pin#29 of 40pin expansion connector.
The pin is assigned to GPIOX.BIT0 and its GPIO number is #228.

Its default pin pulled status is UP (High) and switch active will be Low,
so you should connect another port of tab switch to Ground (GND), Pin#39.

Setting boot.ini

You can assign GPIO number with env gpiopower in boot.ini.

# gpio power key : J2 (2x20) Pin#29 , GPIOX.BIT0
setenv gpiopower "228"
...
...
setenv bootargs ${bootargs} gpiopower=${gpiopower}

Setting Power Button Action for Power Off

Ubuntu

When you turn the board off using power button, you need to change power key action pattern.

- Open Power Management Preferences : [System] → [Preferences] → [Hardware] → [Power Management]
- and then Select [General] tab

Android

In case of Android, one short power key event is used for sleep and with long key event, you can handle options of power off/reboot.
With Android Marshmallow v2.4 or higher version, it's available to enter power off sequence using long-pressing (5 sec).

Available Key Numbers

1. J2 - 2×20 pins

Pin Number	Net Name	GPIO Number	Active Level	Pin Number	Net Name	GPIO Number	Active Level
1	3.3V Power			2	5.0V Power
3	I2CA_SDA	N/A		4	5.0V Power
5	I2CA_SCL	N/A		6	Ground
7	GPIOX.BIT21	GPIO#249	High → Low	8	TXD1	N/A
9	Ground			10	RXD1	N/A
11	GPIOX.BIT19	GPIO#247	High → Low	12	GPIOX.BIT10	GPIO#238	High → Low
13	GPIOX.BIT11	GPIO#239	High → Low	14	Ground
15	GPIOX.BIT9	GPIO#237	High → Low	16	GPIOX.BIT8	GPIO#236	High → Low
17	3.3V Power			18	GPIOX.BIT5	GPIO#233	High → Low
19	GPIOX.BIT7	GPIO#235	High → Low	20	Ground
21	GPIOX.BIT4	GPIO#232	High → Low	22	GPIOX.BIT3	GPIO#231	High → Low
23	GPIOX.BIT2	GPIO#230	High → Low	24	GPIOX.BIT1	GPIO#229	High → Low
25	Ground			26	GPIOY.BIT14	GPIO#225	Low → High
27	I2CB_SDA	N/A		28	I2CB_SCL	N/A
29	GPIOX.BIT0	GPIO#228	High → Low	30	Ground
31	GPIOY.BIT8	GPIO#219	High → Low	32	GPIOY.BIT13	GPIO#224	High → Low
33	GPIOX.BIT6	GPIO#234	Low → High	34	Ground
35	GPIOY.BIT3	GPIO#214	High → Low	36	GPIOY.BIT7	GPIO#218	High → Low
37	ADC.AIN1	N/A		38	1.8V Power	N/A
39	Ground			40	ADC.AIN0	N/A

2. J7 - 1×7 pins

Pin Number	Net Name	GPIO Number	Active Level
1	Ground
2	GPIOAO.BIT6	GPIO#128	High → Low
3	P5V0	5.0V Power
4	GPIOAO.BIT8	GPIO#130	High → Low
5	GPIOAO.BIT10	GPIO#132	High → Low
6	GPIOAO.BIT9	GPIO#131	High → Low
7	GPIOAO.BIT11	GPIO#133	High → Low

3. SW1

Pin Number	Net Name	GPIO Number	Active Level
1	NC	N/A
2	GPIOY.BIT5	GPIO#216	High → Low
3	GND	Ground

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