Hi Kevin,
On Fri, Feb 17, 2012 at 00:50:43, Hilman, Kevin wrote:
> + /* scaling up? scale voltage before frequency */
> + if (mpu_reg && (freqs.new > freqs.old))
> + regulator_set_voltage(mpu_reg, volt, volt);
Probably voltage ranges has to be specified, otherwise
if I understand correctly, if exact voltage 'volt'
is a value that cannot be set by voltage regulator,
it may not work properly.
> ret = clk_set_rate(mpu_clk, freqs.new * 1000);
> - freqs.new = omap_getspeed(policy->cpu);
>
> + /* scaling down? scale voltage after frequency */
> + if (mpu_reg && (freqs.new < freqs.old))
> + regulator_set_voltage(mpu_reg, volt, volt);
> +
> + freqs.new = omap_getspeed(policy->cpu);
It would be better to handle error cases too,
we have a patch for doing DVFS for AM335X as follows
Regards
Afzal
8<------------------------------------------------------
---
drivers/cpufreq/omap-cpufreq.c | 97 +++++++++++++++++++++++++++++++++++++---
1 files changed, 91 insertions(+), 6 deletions(-)
diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
index 5d04c57..a897a9e 100644
--- a/drivers/cpufreq/omap-cpufreq.c
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -25,6 +25,7 @@
#include <linux/opp.h>
#include <linux/cpu.h>
#include <linux/module.h>
+#include <linux/regulator/consumer.h>
#include <asm/system.h>
#include <asm/smp_plat.h>
@@ -37,6 +38,8 @@
#include <mach/hardware.h>
+#define DEFAULT_RESOLUTION 12500
+
#ifdef CONFIG_SMP
struct lpj_info {
unsigned long ref;
@@ -52,6 +55,7 @@ static atomic_t freq_table_users = ATOMIC_INIT(0);
static struct clk *mpu_clk;
static char *mpu_clk_name;
static struct device *mpu_dev;
+static struct regulator *mpu_reg;
static int omap_verify_speed(struct cpufreq_policy *policy)
{
@@ -78,6 +82,8 @@ static int omap_target(struct cpufreq_policy *policy,
unsigned int i;
int ret = 0;
struct cpufreq_freqs freqs;
+ struct opp *opp;
+ int volt_old = 0, volt_new = 0;
if (!freq_table) {
dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
@@ -105,16 +111,45 @@ static int omap_target(struct cpufreq_policy *policy,
if (freqs.old == freqs.new && policy->cur == freqs.new)
return ret;
+ opp = opp_find_freq_exact(mpu_dev, freqs.new * 1000, true);
+ if (IS_ERR(opp)) {
+ dev_err(mpu_dev, "%s: cpu%d: no opp match for freq %d\n",
+ __func__, policy->cpu, target_freq);
+ return -EINVAL;
+ }
+
+ volt_new = opp_get_voltage(opp);
+ if (!volt_new) {
+ dev_err(mpu_dev, "%s: cpu%d: no opp voltage for freq %d\n",
+ __func__, policy->cpu, target_freq);
+ return -EINVAL;
+ }
+
+ volt_old = regulator_get_voltage(mpu_reg);
+
+#ifdef CONFIG_CPU_FREQ_DEBUG
+ pr_info("cpufreq-omap: frequency transition: %u --> %u\n",
+ freqs.old, freqs.new);
+ pr_info("cpufreq-omap: voltage transition: %d --> %d\n",
+ volt_old, volt_new);
+#endif
+
+ if (freqs.new > freqs.old) {
+ ret = regulator_set_voltage(mpu_reg, volt_new,
+ volt_new + DEFAULT_RESOLUTION - 1);
+ if (ret) {
+ dev_err(mpu_dev, "%s: unable to set voltage to %d uV
(for %u MHz)\n",
+ __func__, volt_new, freqs.new/1000);
+ return ret;
+ }
+ }
+
/* notifiers */
for_each_cpu(i, policy->cpus) {
freqs.cpu = i;
cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
}
-#ifdef CONFIG_CPU_FREQ_DEBUG
- pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
-#endif
-
ret = clk_set_rate(mpu_clk, freqs.new * 1000);
freqs.new = omap_getspeed(policy->cpu);
@@ -150,6 +185,38 @@ static int omap_target(struct cpufreq_policy *policy,
cpufreq_notify_transition(&freqs, CPUFREQ_POSTCHANGE);
}
+ if (freqs.new < freqs.old) {
+ ret = regulator_set_voltage(mpu_reg, volt_new,
+ volt_new + DEFAULT_RESOLUTION - 1);
+ if (ret) {
+ unsigned int temp;
+
+ dev_err(mpu_dev, "%s: unable to set voltage to %d uV
(for %u MHz)\n",
+ __func__, volt_new, freqs.new/1000);
+
+ if (clk_set_rate(mpu_clk, freqs.old * 1000)) {
+ dev_err(mpu_dev,
+ "%s: failed restoring clock rate to %u
MHz, clock rate is %u MHz",
+ __func__,
+ freqs.old/1000, freqs.new/1000);
+ return ret;
+ }
+
+ temp = freqs.new;
+ freqs.new = freqs.old;
+ freqs.old = temp;
+
+ for_each_cpu(i, policy->cpus) {
+ freqs.cpu = i;
+ cpufreq_notify_transition(&freqs,
+ CPUFREQ_PRECHANGE);
+ cpufreq_notify_transition(&freqs,
+ CPUFREQ_POSTCHANGE);
+ }
+ return ret;
+ }
+ }
+
return ret;
}
@@ -167,11 +234,27 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy
*policy)
if (IS_ERR(mpu_clk))
return PTR_ERR(mpu_clk);
- if (policy->cpu >= NR_CPUS) {
+ mpu_reg = regulator_get(NULL, "vdd_mpu");
+ if (IS_ERR(mpu_reg)) {
result = -EINVAL;
goto fail_ck;
}
+ /* success of regulator_get doesn't gurantee presence of driver for
+ physical regulator and presence of physical regulator (this
+ situation arises if dummy regulator is enabled),so check voltage
+ to verify that physical regulator and it's driver is present
+ */
+ if (regulator_get_voltage(mpu_reg) < 0) {
+ result = -EINVAL;
+ goto fail_reg;
+ }
+
+ if (policy->cpu >= NR_CPUS) {
+ result = -EINVAL;
+ goto fail_reg;
+ }
+
policy->cur = policy->min = policy->max = omap_getspeed(policy->cpu);
if (atomic_inc_return(&freq_table_users) == 1)
@@ -180,7 +263,7 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy
*policy)
if (result) {
dev_err(mpu_dev, "%s: cpu%d: failed creating freq table[%d]\n",
__func__, policy->cpu, result);
- goto fail_ck;
+ goto fail_reg;
}
result = cpufreq_frequency_table_cpuinfo(policy, freq_table);
@@ -212,6 +295,8 @@ static int __cpuinit omap_cpu_init(struct cpufreq_policy
*policy)
fail_table:
freq_table_free();
+fail_reg:
+ regulator_put(mpu_reg);
fail_ck:
clk_put(mpu_clk);
return result;
--
1.7.1
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