Implement charging mode

I've started with the packaging of the charging-sdl which can be tested in the branch: https://github.com/postmarketOS/pmbootstrap/tree/feature/charging-sdl

Building the package

pmbootstrap checksum charging-sdl pmbootstrap build charging-sdl --arch armhf

Installation on the device

pmbootstrap install --add charging-sdl or copy it into the device: scp $work/packages/armhf/charging-sdl-0.1-r0.apk user@172.16.42.1:/home/user/ ssh user@172.16.42.1 apk add ./charging-sdl-0.1-r0.apk

Testing

export DFBARGS="system=fbdev,no-cursor,disable-module=linux_input" charging-sdl -pcf /usr/share/fonts/ttf-dejavu/DejaVuSans.ttf

Todo

• Package charging-sdl with proper version tag
• Include charging-sdl into the initramfs-extra
• Identify a common way to detect the charging mode on each device
• qualcomm lk adds androidboot.mode=charger to the kernel cmdline when it's supposed to go to charger mode (see lk code) (thanks to @z3ntu)
• some Samsung devices have lpm_boot=1 in the kernel cmdline for charge mode

device	normal	charge mode
samsung-i9070	lpm_boot=0	lpm_boot=1
samsung-klte	androidboot.baseband=msm	androidboot.baseband=lpm androidboot.mode=charger
samsung-maguro	-	androidboot.mode=charger
huawei-y530	-	androidboot.huawei_type=oem_rtc
sony-seagull	startup=0x00000001 warmboot=0x00000000	startup=0x00010004 warmboot=0x77665501

• Update postmarketos-mkinitfs/init.sh.in to handle the charging mode
• Tweak the system to reduce performance and improve charging speed
• example for LG G Watch (dory) here