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Diffstat (limited to 'arch/arm/plat-s3c64xx/cpufreq.c')
-rw-r--r--arch/arm/plat-s3c64xx/cpufreq.c40
1 files changed, 24 insertions, 16 deletions
diff --git a/arch/arm/plat-s3c64xx/cpufreq.c b/arch/arm/plat-s3c64xx/cpufreq.c
index e6e0843215df..74c0e8347de5 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 {
@@ -27,11 +28,10 @@ struct s3c64xx_dvfs {
};
static struct s3c64xx_dvfs s3c64xx_dvfs_table[] = {
- [0] = { 1000000, 1000000 },
- [1] = { 1000000, 1050000 },
- [2] = { 1050000, 1100000 },
- [3] = { 1050000, 1150000 },
- [4] = { 1250000, 1350000 },
+ [0] = { 1000000, 1150000 },
+ [1] = { 1050000, 1150000 },
+ [2] = { 1100000, 1150000 },
+ [3] = { 1200000, 1350000 },
};
static struct cpufreq_frequency_table s3c64xx_freq_table[] = {
@@ -41,9 +41,9 @@ static struct cpufreq_frequency_table s3c64xx_freq_table[] = {
{ 1, 266000 },
{ 2, 333000 },
{ 2, 400000 },
- { 3, 532000 },
- { 3, 533000 },
- { 4, 667000 },
+ { 2, 532000 },
+ { 2, 533000 },
+ { 3, 667000 },
{ 0, CPUFREQ_TABLE_END },
};
#endif
@@ -141,7 +141,7 @@ 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 +150,10 @@ 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 +174,10 @@ 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 +209,7 @@ 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
@@ -217,8 +220,11 @@ static int __init s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy)
/* Check for frequencies we can generate */
r = clk_round_rate(armclk, freq->frequency * 1000);
r /= 1000;
- if (r != freq->frequency)
+ if (r != freq->frequency) {
+ pr_debug("cpufreq: %dkHz unsupported by clock\n",
+ freq->frequency);
freq->frequency = CPUFREQ_ENTRY_INVALID;
+ }
/* If we have no regulator then assume startup
* frequency is the maximum we can support. */
@@ -230,9 +236,11 @@ 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) {