powerpc/powermac/cpufreq_32: Set non-infinite transition time for 7447A driver
authorAndreas Schwab <schwab@linux-m68k.org>
Sun, 28 Oct 2012 23:15:14 +0000 (23:15 +0000)
committerBenjamin Herrenschmidt <benh@kernel.crashing.org>
Thu, 15 Nov 2012 02:00:33 +0000 (13:00 +1100)
The transition time for the 7447A is around 8ms which makes it possible
to use the ondemand governor.  This has been tested on the iBook G4
(PowerBook6,7).

Signed-off-by: Andreas Schwab <schwab@linux-m68k.org>
Tested-by: Michel Dänzer <michel@daenzer.net>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
arch/powerpc/platforms/powermac/cpufreq_32.c

index 64171198535ce7b181e6c67cdfb5d195514d588c..311b804353b14820c90e829902518a0ea350c6f2 100644 (file)
@@ -55,6 +55,7 @@ static unsigned int low_freq;
 static unsigned int hi_freq;
 static unsigned int cur_freq;
 static unsigned int sleep_freq;
+static unsigned long transition_latency;
 
 /*
  * Different models uses different mechanisms to switch the frequency
@@ -403,7 +404,7 @@ static int pmac_cpufreq_cpu_init(struct cpufreq_policy *policy)
        if (policy->cpu != 0)
                return -ENODEV;
 
-       policy->cpuinfo.transition_latency      = CPUFREQ_ETERNAL;
+       policy->cpuinfo.transition_latency      = transition_latency;
        policy->cur = cur_freq;
 
        cpufreq_frequency_table_get_attr(pmac_cpu_freqs, policy->cpu);
@@ -658,12 +659,14 @@ static int __init pmac_cpufreq_setup(void)
        if (!value)
                goto out;
        cur_freq = (*value) / 1000;
+       transition_latency = CPUFREQ_ETERNAL;
 
        /*  Check for 7447A based MacRISC3 */
        if (of_machine_is_compatible("MacRISC3") &&
            of_get_property(cpunode, "dynamic-power-step", NULL) &&
            PVR_VER(mfspr(SPRN_PVR)) == 0x8003) {
                pmac_cpufreq_init_7447A(cpunode);
+               transition_latency = 8000000;
        /* Check for other MacRISC3 machines */
        } else if (of_machine_is_compatible("PowerBook3,4") ||
                   of_machine_is_compatible("PowerBook3,5") ||