On Mon, Dec 19, 2011 at 10:19:29PM +0800, Richard Zhao wrote:
On Mon, Dec 19, 2011 at 10:05:12AM +0000, Jamie Iles wrote:
Hi Richard,
On Mon, Dec 19, 2011 at 11:21:40AM +0800, Richard Zhao wrote:
It support single core and multi-core ARM SoCs. But currently it assume all cores share the same frequency and voltage.
Signed-off-by: Richard Zhao richard.zhao@linaro.org
.../devicetree/bindings/cpufreq/generic-cpufreq | 7 + drivers/cpufreq/Kconfig | 8 + drivers/cpufreq/Makefile | 2 + drivers/cpufreq/generic-cpufreq.c | 251 ++++++++++++++++++++ 4 files changed, 268 insertions(+), 0 deletions(-) create mode 100644 Documentation/devicetree/bindings/cpufreq/generic-cpufreq create mode 100644 drivers/cpufreq/generic-cpufreq.c
diff --git a/Documentation/devicetree/bindings/cpufreq/generic-cpufreq b/Documentation/devicetree/bindings/cpufreq/generic-cpufreq new file mode 100644 index 0000000..15dd780 --- /dev/null +++ b/Documentation/devicetree/bindings/cpufreq/generic-cpufreq @@ -0,0 +1,7 @@ +Generic cpufreq driver
+Required properties in /cpus/cpu@0: +- compatible : "generic-cpufreq"
I'm not convinced this is the best way to do this. By requiring a generic-cpufreq compatible string we're encoding Linux driver information into the hardware description. The only way I can see to avoid this is to provide a generic_clk_cpufreq_init() function that platforms can call in their machine init code to use the driver.
It'll prevent the driver from being a kernel module.
Hmm, that's not very nice either! I guess you _could_ add an of_machine_is_compatible() check against a list of compatible machines in the driver but that feels a little gross. Hopefully Rob or Grant have a good alternative!
Hi Grant & Rob,
Could you comment?
+- cpu-freqs : cpu frequency points it support +- cpu-volts : cpu voltages required by the frequency point at the same index +- trans-latency : transition_latency diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig index e24a2a1..216eecd 100644 --- a/drivers/cpufreq/Kconfig +++ b/drivers/cpufreq/Kconfig @@ -179,6 +179,14 @@ config CPU_FREQ_GOV_CONSERVATIVE If in doubt, say N. +config GENERIC_CPUFREQ_DRIVER
- bool "Generic cpufreq driver using clock/regulator/devicetree"
- help
This adds generic CPUFreq driver. It assumes allcores of the CPU share the same clock and voltage.If in doubt, say N.I think this needs dependencies on HAVE_CLK, OF and REGULATOR.
right, Thanks. I can not check clk before generic clock framework come in. Added: depends on OF && REGULATOR select CPU_FREQ_TABLE
You can still use HAVE_CLK. That symbol has been around for ages and any platform implementing the clk API should select it so it's fine to depend on it even before there is a generic struct clk.
Jamie