cpufreq: OMAP: specify range for voltage scaling
Specify voltage in ranges for regulator. Range
used is tolerance specified for OPP.
This helps to achieve DVFS with a wider range of
regulators.
Cc: Kevin Hilman <khilman@ti.com>
Cc: Sekhar Nori <nsekhar@ti.com>
Signed-off-by: Afzal Mohammed <afzal@ti.com>
diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
index 9f5d636..67bbb06 100644
--- a/drivers/cpufreq/omap-cpufreq.c
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -38,6 +38,9 @@
#include <mach/hardware.h>
+/* OPP tolerance in percentage */
+#define OPP_TOLERANCE 4
+
#ifdef CONFIG_SMP
struct lpj_info {
unsigned long ref;
@@ -81,7 +84,7 @@
int r, ret = 0;
struct cpufreq_freqs freqs;
struct opp *opp;
- unsigned long freq, volt = 0, volt_old = 0;
+ unsigned long freq, volt = 0, volt_old = 0, tol = 0;
if (!freq_table) {
dev_err(mpu_dev, "%s: cpu%d: no freq table!\n", __func__,
@@ -125,6 +128,7 @@
return -EINVAL;
}
volt = opp_get_voltage(opp);
+ tol = volt * OPP_TOLERANCE / 100;
volt_old = regulator_get_voltage(mpu_reg);
}
@@ -134,7 +138,7 @@
/* scaling up? scale voltage before frequency */
if (mpu_reg && (freqs.new > freqs.old)) {
- r = regulator_set_voltage(mpu_reg, volt, volt);
+ r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
if (r < 0) {
dev_warn(mpu_dev, "%s: unable to scale voltage up.\n",
__func__);
@@ -147,7 +151,7 @@
/* scaling down? scale voltage after frequency */
if (mpu_reg && (freqs.new < freqs.old)) {
- r = regulator_set_voltage(mpu_reg, volt, volt);
+ r = regulator_set_voltage(mpu_reg, volt - tol, volt + tol);
if (r < 0) {
dev_warn(mpu_dev, "%s: unable to scale voltage down.\n",
__func__);