GPIO

It's time to figure out how the GPIO works. A good start point is here.

http://orion.dherring.com/beagleTouchWiki/DebianRootfs

It seems the methods mentioned in the previous page doesn't work. If OMAP_MUX is set, kernel will have "kernel Panic - not syncing: VFS: unable to mount root fs on unknow-block(179.2).

maybe I have to read more.

Error message:
[ 317.434753] fbcvt: 1024x768@60: CVT Name - .786M3-R
[ 317.470184] Console: switching to colour frame buffer device 128x48
[ 317.490936] clock: clksel_round_rate_div: dpll4_m4_ck target_rate 48000000
[ 317.497863] clock: new_div = 9, new_rate = 48000000
[ 317.511779] Waiting for root device /dev/mmcblk0p2...
[ 318.064971] mmc0: new high speed SDHC card at address 1234
[ 318.071166] mmcblk0: mmc0:1234 SA08G 7.40 GiB (ro)
[ 318.076293] mmcblk0: p1 p2
[ 318.166931] VFS: Cannot open root device "mmcblk0p2" or unknown-block(179,2)
[ 318.174041] Please append a correct "root=" boot option; here are the available partitions:
[ 318.182525] 1f00 512 mtdblock0 (driver?)
[ 318.187530] 1f01 1920 mtdblock1 (driver?)
[ 318.192565] 1f02 128 mtdblock2 (driver?)
[ 318.197570] 1f03 4096 mtdblock3 (driver?)
[ 318.202606] 1f04 255488 mtdblock4 (driver?)
[ 318.207641] b300 7763968 mmcblk0 driver: mmcblk
[ 318.212890] b301 329301 mmcblk0p1
[ 318.217224] b302 7430062 mmcblk0p2
[ 318.221588] Kernel panic - not syncing: VFS: Unable to mount root fs on unknown-block(179,2)