On OMAP-L138 SoC, some of the sysclks need not be at a fixed ratio
to CPU clock and can be kept at a relatively constant rate by
adjusting the PLLDIVn ratio even as cpufreq goes ahead and changes
the CPU clock.
This feature can be used to keep the EMIFA (PLL0 SYSCLK3) clock at a
constant rate so that the EMIF timings need not be re-programmed
whenever the CPU frequency changes.
This patch adds the required suppport to cpufreq driver.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Current cpufreq code does not consider errors that can occur while
changing voltage. Code to increase CPU frequency goes ahead even in
the case the regulator has failed to increase the voltage. This leads
to hard error since lower voltages cannot support increased frequency.
Prevent this by not increasing frequency in case increasing voltage
is not successful.
Also, do not lower the voltage if changing the cpu frequency has failed
for some reason.
Note that we do not return error on failure to decrease voltage as
that is not a hard error.
Build fix for non-cpufreq kernels by Caglar Akyuz.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Cc: Caglar Akyuz <caglar@bilkon-kontrol.com.tr>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Using a device_initcall() for initializing the voltage regulator
on DA850 is not such a good idea because it gets called for all
platforms - even those who do not have a regulator implemented.
This leads to a big fat warning message during boot-up when
regulator cannot be found.
Instead, tie initialization of voltage regulator to cpufreq init.
Define a platform specific init call which in case of DA850 gets
used for initializing the regulator. On other future platforms it
can be used for other purposes.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Adds a basic CPUFreq driver for DaVinci devices registering with the
kernel CPUFreq infrastructure.
Support is added for both frequency and voltage regulation.
Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>
Sekhar Nori