On 14-07-20, 08:26, Jon Hunter wrote: > OK, I can add a get callback. However, there are a few other drivers > that set the current frequency in the init() and don't implement a get() > callback ... > > drivers/cpufreq/pasemi-cpufreq.c > drivers/cpufreq/ppc_cbe_cpufreq.c These are quite old and I am not sure why they didn't do it. > drivers/cpufreq/intel_pstate.c With intel-pstate driver, the firmware sets the frequency of the CPUs and it can be different from what cpufreq core has asked it to. And so the kernel normally has no idea of what the frequency a CPU is running at. -- viresh