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Subject[PATCH 1/1] cpufreq: cpufreq-cpu0: use the max voltage instead of voltage-tolerance
Date
From: Rongjun Ying <rongjun.ying@csr.com>

Sometime the regulator can't supply appropriate voltages for requestion of cpu.
All voltage tolerance value can't figure out a good voltage.

Signed-off-by: Rongjun Ying <rongjun.ying@csr.com>
---
drivers/cpufreq/cpufreq-cpu0.c | 17 ++++++++++-------
1 files changed, 10 insertions(+), 7 deletions(-)

diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
index c522a95..0c9e6b9 100644
--- a/drivers/cpufreq/cpufreq-cpu0.c
+++ b/drivers/cpufreq/cpufreq-cpu0.c
@@ -23,7 +23,7 @@
#include <linux/slab.h>

static unsigned int transition_latency;
-static unsigned int voltage_tolerance; /* in percentage */
+static unsigned int voltage_max;

static struct device *cpu_dev;
static struct clk *cpu_clk;
@@ -45,7 +45,7 @@ static int cpu0_set_target(struct cpufreq_policy *policy,
{
struct cpufreq_freqs freqs;
struct opp *opp;
- unsigned long volt = 0, volt_old = 0, tol = 0;
+ unsigned long volt = 0, volt_old = 0;
long freq_Hz, freq_exact;
unsigned int index;
int ret;
@@ -82,7 +82,6 @@ static int cpu0_set_target(struct cpufreq_policy *policy,
}
volt = opp_get_voltage(opp);
rcu_read_unlock();
- tol = volt * voltage_tolerance / 100;
volt_old = regulator_get_voltage(cpu_reg);
}

@@ -92,7 +91,7 @@ static int cpu0_set_target(struct cpufreq_policy *policy,

/* scaling up? scale voltage before frequency */
if (!IS_ERR(cpu_reg) && freqs.new > freqs.old) {
- ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
+ ret = regulator_set_voltage(cpu_reg, volt, voltage_max);
if (ret) {
pr_err("failed to scale voltage up: %d\n", ret);
freqs.new = freqs.old;
@@ -104,14 +103,14 @@ static int cpu0_set_target(struct cpufreq_policy *policy,
if (ret) {
pr_err("failed to set clock rate: %d\n", ret);
if (!IS_ERR(cpu_reg))
- regulator_set_voltage_tol(cpu_reg, volt_old, tol);
+ regulator_set_voltage(cpu_reg, volt_old, voltage_max);
freqs.new = freqs.old;
goto post_notify;
}

/* scaling down? scale voltage after frequency */
if (!IS_ERR(cpu_reg) && freqs.new < freqs.old) {
- ret = regulator_set_voltage_tol(cpu_reg, volt, tol);
+ ret = regulator_set_voltage(cpu_reg, volt, voltage_max);
if (ret) {
pr_err("failed to scale voltage down: %d\n", ret);
clk_set_rate(cpu_clk, freqs.old * 1000);
@@ -224,7 +223,11 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev)
goto out_put_node;
}

- of_property_read_u32(np, "voltage-tolerance", &voltage_tolerance);
+ ret = of_property_read_u32(np, "voltage-max", &voltage_max);
+ if (ret) {
+ pr_err("failed to get max voltage: %d\n", ret);
+ goto out_put_node;
+ }

if (of_property_read_u32(np, "clock-latency", &transition_latency))
transition_latency = CPUFREQ_ETERNAL;
--
1.7.5.4


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