davinci: DA850/OMAP-L138: add frequency scaling support
authorSekhar Nori <nsekhar@ti.com>
Tue, 22 Sep 2009 15:44:01 +0000 (21:14 +0530)
committerKevin Hilman <khilman@deeprootsystems.com>
Wed, 25 Nov 2009 18:21:29 +0000 (10:21 -0800)
commit683b1e1f0e6f7b2690c0ce76751ba8f26f0235c6
tree2b8c1c9cc6067ee1dfca8d9bd9af188f6dd22193
parent6601b8030de3e9c29930684eeac15302a59f991a
davinci: DA850/OMAP-L138: add frequency scaling support

Adds basic frequency scaling support for DA850/OMAP-L138.

Currently, frequency scaling only on PLL0 is supported. No scaling of PLL1
as yet.

Peripherals like MMC/SD which have a clock input synchronous with
ARM clock will not work well since the clock will change behind their backs.
Support for notification to such devices to adjust themselves to the
new frequency will be added in later patches. Current defconfigs keep
CPUFreq disabled so it will not affect normal operation.

The OPP defintions assume clock input of 24MHz to the SoC. This is inline
with hardcoding of input frequency in the <soc>.c files. At some point
this will need to move into board dependent code as new boards appear with
a different reference clock.

Tested on OMAP-L138 EVM with ondemand governer and a shell script to
vary processor load.

Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
arch/arm/mach-davinci/da850.c
arch/arm/mach-davinci/include/mach/da8xx.h