# \[PATCH V8 5/8\] cpufreq: mediatek: Add record of previous desired vproc value

- From: Andrew-sh.Cheng \<hidden\>
- Date: 2021-03-23 11:37:14 
- List: linux-mediatek
- Page: https://ratatoskr.run/linux-mediatek/2021/03/8805355
- Thread: https://ratatoskr.run/linux-arm-kernel/2021/03/8805351/t.md

```text
From: "Andrew-sh.Cheng" <redacted>

For case of share buck with other module,
the result buck voltage may not exactly the same with what we set.
Need to record the previous desired value instead of read from regulator.

Signed-off-by: Andrew-sh.Cheng <redacted>
---
 drivers/cpufreq/mediatek-cpufreq.c | 16 ++++++++++++----
 1 file changed, 12 insertions(+), 4 deletions(-)

diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
index 432368707ea6..2a82c36aec21 100644
--- a/drivers/cpufreq/mediatek-cpufreq.c
+++ b/drivers/cpufreq/mediatek-cpufreq.c
@@ -42,6 +42,7 @@ struct mtk_cpu_dvfs_info {
 	struct list_head list_head;
 	int intermediate_voltage;
 	bool need_voltage_tracking;
+	int old_vproc;
 };
 
 static LIST_HEAD(dvfs_info_list);
@@ -192,11 +193,16 @@ static int mtk_cpufreq_voltage_tracking(struct mtk_cpu_dvfs_info *info,
 
 static int mtk_cpufreq_set_voltage(struct mtk_cpu_dvfs_info *info, int vproc)
 {
+	int ret;
+
 	if (info->need_voltage_tracking)
-		return mtk_cpufreq_voltage_tracking(info, vproc);
+		ret = mtk_cpufreq_voltage_tracking(info, vproc);
 	else
-		return regulator_set_voltage(info->proc_reg, vproc,
-					     vproc + VOLT_TOL);
+		ret = regulator_set_voltage(info->proc_reg, vproc,
+					    MAX_VOLT_LIMIT);
+	if (!ret)
+		info->old_vproc = vproc;
+	return ret;
 }
 
 static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
@@ -214,7 +220,9 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
 	inter_vproc = info->intermediate_voltage;
 
 	old_freq_hz = clk_get_rate(cpu_clk);
-	old_vproc = regulator_get_voltage(info->proc_reg);
+	old_vproc = info->old_vproc;
+	if (old_vproc == 0)
+		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;
-- 
2.12.5
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```