[PATCH 3/4] cpufreq: mt8173: check return value of regulator_get_voltage() call

Pi-Cheng Chen
2015-11-29T08:31:51Z

Sometimes regulator_get_voltage() call returns negative values for
reasons(e.g. underlying I2C bus timeout). Add check for the return
values and fail out early.

Signed-off-by: Pi-Cheng Chen <pi-cheng.chen@linaro.org>
---
drivers/cpufreq/mt8173-cpufreq.c | 28 ++++++++++++++++++++++++++++
1 file changed, 28 insertions(+)

diff --git a/drivers/cpufreq/mt8173-cpufreq.c b/drivers/cpufreq/mt8173-cpufreq.c
index 750cda7..9d0fe37 100644
--- a/drivers/cpufreq/mt8173-cpufreq.c
+++ b/drivers/cpufreq/mt8173-cpufreq.c
@@ -59,6 +59,10 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
int old_vproc, old_vsram, new_vsram, vsram, vproc, ret;

old_vproc = regulator_get_voltage(proc_reg);
+ if (old_vproc < 0) {
+ pr_err("%s: invalid Vproc value: %d\n", __func__, old_vproc);
+ return old_vproc;
+ }
/* Vsram should not exceed the maximum allowed voltage of SoC. */
new_vsram = min(new_vproc + MIN_VOLT_SHIFT, MAX_VOLT_LIMIT);

@@ -71,7 +75,17 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
*/
do {
old_vsram = regulator_get_voltage(sram_reg);
+ if (old_vsram < 0) {
+ pr_err("%s: invalid Vsram value: %d\n",
+ __func__, old_vsram);
+ return old_vsram;
+ }
old_vproc = regulator_get_voltage(proc_reg);
+ if (old_vproc < 0) {
+ pr_err("%s: invalid Vproc value: %d\n",
+ __func__, old_vproc);
+ return old_vproc;
+ }

vsram = min(new_vsram, old_vproc + MAX_VOLT_SHIFT);

@@ -116,7 +130,17 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
*/
do {
old_vproc = regulator_get_voltage(proc_reg);
+ if (old_vproc < 0) {
+ pr_err("%s: invalid Vproc value: %d\n",
+ __func__, old_vproc);
+ return old_vproc;
+ }
old_vsram = regulator_get_voltage(sram_reg);
+ if (old_vsram < 0) {
+ pr_err("%s: invalid Vsram value: %d\n",
+ __func__, old_vsram);
+ return old_vsram;
+ }

vproc = max(new_vproc, old_vsram - MAX_VOLT_SHIFT);
ret = regulator_set_voltage(proc_reg, vproc,
@@ -184,6 +208,10 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,

old_freq_hz = clk_get_rate(cpu_clk);
old_vproc = regulator_get_voltage(info->proc_reg);
+ if (old_vproc < 0) {
+ pr_err("%s: invalid Vproc value: %d\n", __func__, old_vproc);
+ return old_vproc;
+ }

freq_hz = freq_table[index].frequency * 1000;

--
1.9.1