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authorAfzal Mohammed <afzal@ti.com>2012-02-23 17:49:24 +0400
committerKevin Hilman <khilman@ti.com>2012-03-03 01:55:57 +0400
commit42daffd2d6c665716d442d518022ecaad17ddf64 (patch)
tree7caa90a291f0c9eea522cafe2f6a7b419fb71438 /drivers/cpufreq
parent53dfe8a884e6f85d73379f84cffa72225cd52ad6 (diff)
downloadlinux-42daffd2d6c665716d442d518022ecaad17ddf64.tar.xz
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>
Diffstat (limited to 'drivers/cpufreq')
-rw-r--r--drivers/cpufreq/omap-cpufreq.c10
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
index 9f5d6368766e..67bbb06d0460 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 @@ static int omap_target(struct cpufreq_policy *policy,
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 @@ static int omap_target(struct cpufreq_policy *policy,
return -EINVAL;
}
volt = opp_get_voltage(opp);
+ tol = volt * OPP_TOLERANCE / 100;
volt_old = regulator_get_voltage(mpu_reg);
}
@@ -134,7 +138,7 @@ static int omap_target(struct cpufreq_policy *policy,
/* 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 @@ static int omap_target(struct cpufreq_policy *policy,
/* 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__);