I recently added an RTC (DS3231) which involves adding RTC support and driver to the O2+ kernel.

Currently I hacked a couple of scripts which I can run after resetting the config files with git. These set the necessary options manually in both the kernel and package config files, but is there a better (proper?) way to do this?

Probably the different options should be set manually after running make menuconfig? But I don't know if the resulting .config file (after make menuconfig and saving .config) will build the same kernel as the one built with the .config from the Onion source repo. I'm doubtful that it will.

fwiw, here are the scripts I wrote in case anyone else finds them useful. I did some light testing, so use at own risk:

set-kerneloptions-RTCds1307.sh
#! /bin/sh

setoption() {
 local loption=$1
 local lstate=$2
 local lconfigfile=$3

 grep "${loption}\(=\| \)" ${lconfigfile} > /dev/null
 if [ $? -eq 0 ]; then
  # set it to the required value
  echo -n Set: ${loption}
  sed -i -r "s/^(${loption}=.*|# ${loption} is not set)/${loption}=${lstate}/" ${lconfigfile}
 else
  # Add the option
  echo -n Add: ${loption}
  echo "${loption}=${lstate}" >> ${lconfigfile}
 fi
 echo " Now: `grep "${loption}\(=\| \)" ${lconfigfile}`"
}

unsetoption() {
 local loption=$1
 local lconfigfile=$2

 grep "${loption}\(=\| \)" ${lconfigfile} > /dev/null
 if [ $? -eq 0 ]; then
  # set it to the required value
  echo -n Unset: ${loption}
  sed -i -r "s/^(${loption}=.*)/# ${loption} is not set/" ${lconfigfile}
 else
  # Add the option
  echo -n Add: ${loption}
  echo "# ${loption} is not set" >> ${lconfigfile}
 fi
 echo " Now: `grep "${loption}\(=\| \)" ${lconfigfile}`"
}

CONFIGFILE="target/linux/ramips/mt7688/config-4.4"

for configoption in CONFIG_RTC_CLASS \
                        CONFIG_RTC_DRV_DS1307 \
                        CONFIG_RTC_SUPPORT
do
 setoption "${configoption}" "y" "${CONFIGFILE}"
done

unsetoption "CONFIG_RTC_HCTOSYS" "${CONFIGFILE}"

Execution is as follows:

root@122126d368fa:~/source# git checkout target/linux/ramips/mt7688/config-4.4
root@122126d368fa:~/source# ./set-kerneloptions-RTCds1307.sh
Add: CONFIG_RTC_CLASS Now: CONFIG_RTC_CLASS=y
Add: CONFIG_RTC_DRV_DS1307 Now: CONFIG_RTC_DRV_DS1307=y
Add: CONFIG_RTC_SUPPORT Now: CONFIG_RTC_SUPPORT=y
Add: CONFIG_RTC_HCTOSYS Now: # CONFIG_RTC_HCTOSYS is not set
root@122126d368fa:~/source#

set-packages-RTCds1307.sh
#! /bin/sh

setoption() {
 local loption=$1
 local lstate=$2
 local lconfigfile=$3

 grep "${loption}\(=\| \)" ${lconfigfile} > /dev/null
 if [ $? -eq 0 ]; then
  # set it to the required value
  echo -n Set: ${loption}
  sed -i -r "s/^(${loption}=.*|# ${loption} is not set)/${loption}=${lstate}/" ${lconfigfile}
 else
  # Add the option
  echo -n Add: ${loption}
  echo "${loption}=${lstate}" >> ${lconfigfile}
 fi
 echo " Now: `grep "${loption}\(=\| \)" ${lconfigfile}`"
}

unsetoption() {
 local loption=$1
 local lconfigfile=$2

 grep "${loption}\(=\| \)" ${lconfigfile} > /dev/null
 if [ $? -eq 0 ]; then
  # set it to the required value
  echo -n Unset: ${loption}
  sed -i -r "s/^(${loption}=.*)/# ${loption} is not set/" ${lconfigfile}
 else
  # Add the option
  echo -n Add: ${loption}
  echo "# ${loption} is not set" >> ${lconfigfile}
 fi
 echo " Now: `grep "${loption}\(=\| \)" ${lconfigfile}`"
}

CONFIGFILE=".config"

for configoption in CONFIG_PACKAGE_kmod-i2c-core \
                        CONFIG_PACKAGE_kmod-i2c-algo-bit \
                        CONFIG_PACKAGE_kmod-i2c-gpio \
                        CONFIG_PACKAGE_kmod-i2c-gpio-custom \
                        CONFIG_PACKAGE_hwclock \
                        CONFIG_PACKAGE_i2c-tools \
                        CONFIG_PACKAGE_kmod-rtc-ds1307
do
 setoption "${configoption}" "y" "${CONFIGFILE}"
done

Execution is as follows:

root@122126d368fa:~/source# git checkout .config
root@122126d368fa:~/source# ./set-packages-RTCds1307.sh
Set: CONFIG_PACKAGE_kmod-i2c-core Now: CONFIG_PACKAGE_kmod-i2c-core=y
Set: CONFIG_PACKAGE_kmod-i2c-algo-bit Now: CONFIG_PACKAGE_kmod-i2c-algo-bit=y
Set: CONFIG_PACKAGE_kmod-i2c-gpio Now: CONFIG_PACKAGE_kmod-i2c-gpio=y
Set: CONFIG_PACKAGE_kmod-i2c-gpio-custom Now: CONFIG_PACKAGE_kmod-i2c-gpio-custom=y
Set: CONFIG_PACKAGE_hwclock Now: CONFIG_PACKAGE_hwclock=y
Set: CONFIG_PACKAGE_i2c-tools Now: CONFIG_PACKAGE_i2c-tools=y
Add: CONFIG_PACKAGE_kmod-rtc-ds1307 Now: CONFIG_PACKAGE_kmod-rtc-ds1307=y
root@122126d368fa:~/source#

The patch to the .config is almost trivially simple:

diff --git a/target/linux/ramips/mt7688/config-4.4 b/target/linux/ramips/mt7688/config-4.4
index c4a844da38..6fc9a91e6d 100644
--- a/target/linux/ramips/mt7688/config-4.4
+++ b/target/linux/ramips/mt7688/config-4.4
@@ -225,8 +225,11 @@ CONFIG_SOC_MT7620=y
 # CONFIG_SOC_RT3883 is not set
 CONFIG_SOUND=m
 CONFIG_SPI=y
+CONFIG_SPI_BITBANG=y
+CONFIG_SPI_DEBUG=y
+CONFIG_SPI_GPIO=y
 CONFIG_SPI_MASTER=y
-CONFIG_SPI_MT7621=y
+# CONFIG_SPI_MT7621 is not set
 # CONFIG_SPI_RT2880 is not set
 CONFIG_SRCU=y
 CONFIG_SWCONFIG=y

Building a new image works fine, but the resulting image -somehow- is not booting. I did not touch anything other that the patch above. Here is the kernel boot output deemed important:

[    0.000000] Kernel command line: console=ttyS0,115200 rootfstype=squashfs,jffs2

**snip**

[    0.435122] VFS: Cannot open root device "(null)" or unknown-block(0,0): error -6
[    0.442720] Please append a correct "root=" boot option; here are the available partitions:
[    0.451254] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(0,0)
[    0.460532] Rebooting in 1 seconds..

Seemingly the kernel is not correctly pointed towards the rootfs. Isn't it u-boot's job to inform the kernel of the whereabouts of the rootfs and the layout of the MTD main storage device?

Me not (yet :)) being an OpwnWRT/Buildroot expert, it's probably something trivial I'm overlooking here. Any handles anyone?

make menuconfig
and selected the required options

I also configured the kernel to load the staging drivers

make kernel_menuconfig

Device drivers -> Graphics support -> Frame buffer Devices -> Support for frame buffer devices
Device drivers -> Staging drivers -> Support for small TFT LCD display modules

<M> FB driver for the ST7735R LCD Controller
<M> Generic FB driver for TFT LCD displays
<M> Module to for adding FBTFT devices

make -j5 V=s

I flashed the Omega with the bin generated.

sysupgrade -n lede-ramips-mt7688-omega2p-squashfs-sysupgrade.bin

But when is time to use the module, it doesn't work, I've tried all of this:

insmod fb_defio
insmod fb
insmod fbtft

modeprobe fbtft

fbtft_device

and nothing works, I don't think the module is correctly configured
Am I missing something?

• satisfy_dependencies_for: Cannot satisfy the following dependencies for shadowsocks-libev:
• kernel (= 4.4.59-1-20e24470450440309f80ab6bf0a84eb9) * kernel (= 4.4.59-1-20e24470450440309f80ab6bf0a84eb9) * kernel (= 4.4.59-1-20e24470450440309f80ab6bf0a84eb9) *
• opkg_install_cmd: Cannot install package shadowsocks-libev.