Looks like there is no 'charging' under /sys/devices/platform/fsl-usb2-usd/, instead it appears under '/sys/devices/platform/aplite_charger.0/'. Does it make any sense?
Code:
[root@kindle root]# cd /sys/devices/platform
[root@kindle platform]# ls -l
drwxr-xr-x 3 root root 0 Oct 6 22:09 aplite_charger.0
drwxr-xr-x 3 root root 0 Oct 6 22:05 busfreq.0
drwxr-xr-x 4 root root 0 Oct 6 22:05 cyttsp.0
drwxr-xr-x 4 root root 0 Oct 6 22:09 fsl-usb2-udc
drwxr-xr-x 4 root root 0 Oct 6 22:05 mxc-pxp
drwxr-xr-x 3 root root 0 Oct 6 22:05 mxc_dvfs_core.0
drwxr-xr-x 4 root root 0 Oct 6 22:05 mxc_epdc_fb
drwxr-xr-x 3 root root 0 Oct 6 22:05 mxc_i2c.0
drwxr-xr-x 3 root root 0 Oct 6 22:05 mxc_i2c.1
drwxr-xr-x 3 root root 0 Oct 6 22:05 mxc_i2c.2
drwxr-xr-x 3 root root 0 Oct 6 22:05 mxc_pwm.0
drwxr-xr-x 4 root root 0 Oct 6 22:05 mxc_rtc.0
drwxr-xr-x 3 root root 0 Oct 6 22:05 mxc_sdma
drwxr-xr-x 4 root root 0 Oct 6 22:05 mxc_spi.0
drwxr-xr-x 5 root root 0 Oct 6 22:05 mxc_spi.1
drwxr-xr-x 5 root root 0 Oct 6 22:05 mxc_spi.2
drwxr-xr-x 3 root root 0 Oct 6 22:05 mxc_w1.0
drwxr-xr-x 3 root root 0 Oct 6 22:05 mxc_wdt.0
drwxr-xr-x 3 root root 0 Oct 6 22:05 mxc_zq_calib
drwxr-xr-x 4 root root 0 Oct 6 22:05 mxcintuart.0
drwxr-xr-x 4 root root 0 Oct 6 22:05 mxcintuart.1
drwxr-xr-x 4 root root 0 Oct 6 22:05 mxcintuart.2
drwxr-xr-x 4 root root 0 Oct 6 22:05 mxcintuart.3
drwxr-xr-x 4 root root 0 Oct 6 22:05 mxsdhci.1
drwxr-xr-x 4 root root 0 Oct 6 22:05 mxsdhci.2
drwxr-xr-x 3 root root 0 Oct 6 22:05 pmic_adc.1
drwxr-xr-x 3 root root 0 Oct 6 22:05 pmic_battery.1
drwxr-xr-x 4 root root 0 Oct 6 22:05 pmic_leds.103
drwxr-xr-x 4 root root 0 Oct 6 22:05 pmic_leds.114
drwxr-xr-x 4 root root 0 Oct 6 22:05 pmic_leds.98
drwxr-xr-x 3 root root 0 Oct 6 22:05 pmic_light.1
drwxr-xr-x 3 root root 0 Oct 6 22:05 pmic_power.1
drwxr-xr-x 4 root root 0 Oct 6 22:05 pmic_rtc.1
drwxr-xr-x 2 root root 0 Oct 6 22:17 power
drwxr-xr-x 3 root root 0 Oct 6 22:05 pxp-device
-rw-r--r-- 1 root root 4096 Oct 6 22:05 uevent
drwxr-xr-x 3 root root 0 Oct 6 22:05 usb_wakeup.0
drwxr-xr-x 3 root root 0 Oct 6 22:05 yoshime_fl
drwxr-xr-x 3 root root 0 Oct 6 22:05 yoshime_hall
[root@kindle platform]# cd fsl-usb2-udc
[root@kindle fsl-usb2-udc]# ls -l
lrwxrwxrwx 1 root root 0 Oct 6 22:11 driver -> ../../../bus/ platform/drivers/fsl-usb2-udc
drwxr-xr-x 4 root root 0 Oct 6 22:09 gadget
-r--r--r-- 1 root root 4096 Oct 6 22:11 modalias
-r--r--r-- 1 root root 4096 Oct 6 22:11 pools
drwxr-xr-x 2 root root 0 Oct 6 22:11 power
lrwxrwxrwx 1 root root 0 Oct 6 22:09 subsystem -> ../../../b us/platform
-rw-r--r-- 1 root root 4096 Oct 6 23:14 uevent
[root@kindle fsl-usb2-udc]# find / -name charging
/sys/devices/platform/aplite_charger.0/charging
[root@kindle fsl-usb2-udc]#