cpufreq: OMAP: scale voltage along with frequency
Kevin Hilman [Fri, 15 Jul 2011 22:05:04 +0000 (15:05 -0700)]
Use the regulator framework to get the voltage regulator associated
with the MPU voltage domain and use it to scale voltage along with
frequency.

While here, CONFIG_CPU_FREQ_DEBUG doesn't exist anymore, so move
debug prints to use dev_dbg().

Special thanks to Afzal Mohammed for suggestions on more robust error
checking.

Cc: Afzal Mohammed <afzal@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

drivers/cpufreq/omap-cpufreq.c

index 5d04c57..9f5d636 100644 (file)
@@ -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>
@@ -52,6 +53,7 @@ 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)
 {
@@ -76,8 +78,10 @@ static int omap_target(struct cpufreq_policy *policy,
                       unsigned int relation)
 {
        unsigned int i;
-       int ret = 0;
+       int r, ret = 0;
        struct cpufreq_freqs freqs;
+       struct opp *opp;
+       unsigned long freq, volt = 0, volt_old = 0;
 
        if (!freq_table) {
                dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
@@ -111,13 +115,49 @@ static int omap_target(struct cpufreq_policy *policy,
                cpufreq_notify_transition(&freqs, CPUFREQ_PRECHANGE);
        }
 
-#ifdef CONFIG_CPU_FREQ_DEBUG
-       pr_info("cpufreq-omap: transition: %u --> %u\n", freqs.old, freqs.new);
-#endif
+       freq = freqs.new * 1000;
+
+       if (mpu_reg) {
+               opp = opp_find_freq_ceil(mpu_dev, &freq);
+               if (IS_ERR(opp)) {
+                       dev_err(mpu_dev, "%s: unable to find MPU OPP for %d\n",
+                               __func__, freqs.new);
+                       return -EINVAL;
+               }
+               volt = opp_get_voltage(opp);
+               volt_old = regulator_get_voltage(mpu_reg);
+       }
+
+       dev_dbg(mpu_dev, "cpufreq-omap: %u MHz, %ld mV --> %u MHz, %ld mV\n", 
+               freqs.old / 1000, volt_old ? volt_old / 1000 : -1,
+               freqs.new / 1000, volt ? volt / 1000 : -1);
+
+       /* scaling up?  scale voltage before frequency */
+       if (mpu_reg && (freqs.new > freqs.old)) {
+               r = regulator_set_voltage(mpu_reg, volt, volt);
+               if (r < 0) {
+                       dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
+                                __func__);
+                       freqs.new = freqs.old;
+                       goto done;
+               }
+       }
 
        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)) {
+               r = regulator_set_voltage(mpu_reg, volt, volt);
+               if (r < 0) {
+                       dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
+                                __func__);
+                       ret = clk_set_rate(mpu_clk, freqs.old * 1000);
+                       freqs.new = freqs.old;
+                       goto done;
+               }
+       }
+
+       freqs.new = omap_getspeed(policy->cpu);
 #ifdef CONFIG_SMP
        /*
         * Note that loops_per_jiffy is not updated on SMP systems in
@@ -144,6 +184,7 @@ static int omap_target(struct cpufreq_policy *policy,
                                        freqs.new);
 #endif
 
+done:
        /* notifiers */
        for_each_cpu(i, policy->cpus) {
                freqs.cpu = i;
@@ -260,6 +301,23 @@ static int __init omap_cpufreq_init(void)
                return -EINVAL;
        }
 
+       mpu_reg = regulator_get(mpu_dev, "vcc");
+       if (IS_ERR(mpu_reg)) {
+               pr_warning("%s: unable to get MPU regulator\n", __func__);
+               mpu_reg = NULL;
+       } else {
+               /* 
+                * Ensure physical regulator is present.
+                * (e.g. could be dummy regulator.)
+                */
+               if (regulator_get_voltage(mpu_reg) < 0) {
+                       pr_warn("%s: physical regulator not present for MPU\n",
+                               __func__);
+                       regulator_put(mpu_reg);
+                       mpu_reg = NULL;
+               }
+       }
+
        return cpufreq_register_driver(&omap_driver);
 }