Subject: [PATCH] powermac/cpufreq_32: set non-infinite transition time for 7447A driver

From: Andreas Schwab <[email-masked]>
Date: Mon, 29 Oct 2012 10:15:14 +0100

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 <[email-masked]>
---
 arch/powerpc/platforms/powermac/cpufreq_32.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/platforms/powermac/cpufreq_32.c b/arch/powerpc/platforms/powermac/cpufreq_32.c
index 6417119..311b804 100644
--- a/arch/powerpc/platforms/powermac/cpufreq_32.c
+++ b/arch/powerpc/platforms/powermac/cpufreq_32.c
@@ -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") ||
-- 
1.8.0

-- 
Andreas Schwab, [email-masked]
GPG Key fingerprint = 58CA 54C7 6D53 942B 1756  01D3 44D5 214B 8276 4ED5
"And now for something completely different."