Im working on a mobile device based on imx233, using 2.6.31 Linux Kernel available with LTIB.
I'm developing the main application based on qt, which is the only interface with the user, no other applications, minimal kernel configuration.
For low power consumption the screen is blanked after 30 sec with no button pressure.
I also need usb host to connect an usb pen to the device but only when the user need to save data, usb can be down in normal uses.
This is the problem: I see that low freq profiles are allowed only when lcdif clock and usb clock usage are zero.
Browsing the code it seems to me that blanking the screen with echo 4 > /class /graphics/fb0/blank should bring lcdif clock usage count to 0.
I need help understand how to do this with usb, how to enable and then disable it in such a way that the clock usage count is zero, to be finally allowed to use low freq profiles.
Any help is appreciated I've still to learn about usb.