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-rw-r--r--drivers/regulator/core.c41
-rw-r--r--drivers/regulator/of_regulator.c4
-rw-r--r--include/linux/regulator/machine.h3
3 files changed, 48 insertions, 0 deletions
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 089e8ad8ef57..ba03bdf3716f 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -3191,6 +3191,36 @@ out:
return ret;
}
+static int regulator_limit_voltage_step(struct regulator_dev *rdev,
+ int *current_uV, int *min_uV)
+{
+ struct regulation_constraints *constraints = rdev->constraints;
+
+ /* Limit voltage change only if necessary */
+ if (!constraints->max_uV_step || !_regulator_is_enabled(rdev))
+ return 1;
+
+ if (*current_uV < 0) {
+ *current_uV = _regulator_get_voltage(rdev);
+
+ if (*current_uV < 0)
+ return *current_uV;
+ }
+
+ if (abs(*current_uV - *min_uV) <= constraints->max_uV_step)
+ return 1;
+
+ /* Clamp target voltage within the given step */
+ if (*current_uV < *min_uV)
+ *min_uV = min(*current_uV + constraints->max_uV_step,
+ *min_uV);
+ else
+ *min_uV = max(*current_uV - constraints->max_uV_step,
+ *min_uV);
+
+ return 0;
+}
+
static int regulator_get_optimal_voltage(struct regulator_dev *rdev,
int *current_uV,
int *min_uV, int *max_uV,
@@ -3302,6 +3332,17 @@ static int regulator_get_optimal_voltage(struct regulator_dev *rdev,
desired_min_uV = possible_uV;
finish:
+ /* Apply max_uV_step constraint if necessary */
+ if (state == PM_SUSPEND_ON) {
+ ret = regulator_limit_voltage_step(rdev, current_uV,
+ &desired_min_uV);
+ if (ret < 0)
+ return ret;
+
+ if (ret == 0)
+ done = false;
+ }
+
/* Set current_uV if wasn't done earlier in the code and if necessary */
if (n_coupled > 1 && *current_uV == -1) {
diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index c4223b3e0dff..a732f09d207b 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -170,6 +170,10 @@ static void of_get_regulation_constraints(struct device_node *np,
&pval))
constraints->max_spread = pval;
+ if (!of_property_read_u32(np, "regulator-max-step-microvolt",
+ &pval))
+ constraints->max_uV_step = pval;
+
constraints->over_current_protection = of_property_read_bool(np,
"regulator-over-current-protection");
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index a459a5e973a7..1d34a70ffda2 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -158,6 +158,9 @@ struct regulation_constraints {
/* used for coupled regulators */
int max_spread;
+ /* used for changing voltage in steps */
+ int max_uV_step;
+
/* valid regulator operating modes for this machine */
unsigned int valid_modes_mask;