cpufreq: mt8173: check return value of regulator_get_voltage() call

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>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpufreq/mt8173-cpufreq.c b/drivers/cpufreq/mt8173-cpufreq.c
index 750cda7876ac5ee946d5a96b21d6010e996a888b..9d0fe37b4c3e46d30d2f3ab8f4a88322494a2d4d 100644 (file)
--- 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;