1 files changed, 13 insertions, 7 deletions

diff --git a/arch/arm/plat-s3c64xx/cpufreq.c b/arch/arm/plat-s3c64xx/cpufreq.c
index bdc3c96971f5..61276bf73927 100644
--- a/arch/arm/plat-s3c64xx/cpufreq.c
+++ b/arch/arm/plat-s3c64xx/cpufreq.c
@@ -19,6 +19,7 @@
 
 static struct clk *armclk;
 static struct regulator *vddarm;
+static unsigned long regulator_latency;
 
 #ifdef CONFIG_CPU_S3C6410
 struct s3c64xx_dvfs {
@@ -141,7 +142,7 @@ err:
 }
 
 #ifdef CONFIG_REGULATOR
-static void __init s3c64xx_cpufreq_constrain_voltages(void)
+static void __init s3c64xx_cpufreq_config_regulator(void)
 {
 	int count, v, i, found;
 	struct cpufreq_frequency_table *freq;
@@ -150,11 +151,10 @@ static void __init s3c64xx_cpufreq_constrain_voltages(void)
 	count = regulator_count_voltages(vddarm);
 	if (count < 0) {
 		pr_err("cpufreq: Unable to check supported voltages\n");
-		return;
 	}
 
 	freq = s3c64xx_freq_table;
-	while (freq->frequency != CPUFREQ_TABLE_END) {
+	while (count > 0 && freq->frequency != CPUFREQ_TABLE_END) {
 		if (freq->frequency == CPUFREQ_ENTRY_INVALID)
 			continue;
 
@@ -175,6 +175,10 @@ static void __init s3c64xx_cpufreq_constrain_voltages(void)
 
 		freq++;
 	}
+
+	/* Guess based on having to do an I2C/SPI write; in future we
+	 * will be able to query the regulator performance here. */
+	regulator_latency = 1 * 1000 * 1000;
 }
 #endif
 
@@ -206,7 +210,7 @@ static int __init s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy)
 		pr_err("cpufreq: Only frequency scaling available\n");
 		vddarm = NULL;
 	} else {
-		s3c64xx_cpufreq_constrain_voltages();
+		s3c64xx_cpufreq_config_regulator();
 	}
 #endif
 
@@ -233,9 +237,11 @@ static int __init s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy)
 
 	policy->cur = clk_get_rate(armclk) / 1000;
 
-	/* Pick a conservative guess in ns: we'll need ~1 I2C/SPI
-	 * write plus clock reprogramming. */
-	policy->cpuinfo.transition_latency = 2 * 1000 * 1000;
+	/* Datasheet says PLL stabalisation time (if we were to use
+	 * the PLLs, which we don't currently) is ~300us worst case,
+	 * but add some fudge.
+	 */
+	policy->cpuinfo.transition_latency = (500 * 1000) + regulator_latency;
 
 	ret = cpufreq_frequency_table_cpuinfo(policy, s3c64xx_freq_table);
 	if (ret != 0) {