When voltage constraints are given in the device tree then we should
set the regulator to a valid voltage before enabling it. Without it
we can end up with invalid voltages.
Signed-off-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
---
drivers/regulator/core.c | 60 ++++++++++++++++++++++++++++++++++++++++
1 file changed, 60 insertions(+)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index d08df1dc68..00a2aefce7 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -187,6 +187,62 @@ static int regulator_resolve_supply(struct regulator_dev *rdev)
return 0;
}
+static int regulator_init_voltage(struct regulator_dev *rdev)
+{
+ int target_min, target_max, current_uV, ret;
+
+ if (!rdev->min_uv || !rdev->max_uv)
+ return 0;
+
+ current_uV = regulator_get_voltage_internal(rdev);
+ if (current_uV < 0) {
+ /* This regulator can't be read and must be initialized */
+ rdev_info(rdev, "Setting %d-%duV\n", rdev->min_uv, rdev->max_uv);
+ regulator_set_voltage_internal(rdev, rdev->min_uv, rdev->max_uv);
+ current_uV = regulator_get_voltage_internal(rdev);
+ }
+
+ if (current_uV < 0) {
+ if (current_uV != -EPROBE_DEFER)
+ rdev_err(rdev,
+ "failed to get the current voltage: %pe\n",
+ ERR_PTR(current_uV));
+ return current_uV;
+ }
+
+ /*
+ * If we're below the minimum voltage move up to the
+ * minimum voltage, if we're above the maximum voltage
+ * then move down to the maximum.
+ */
+ target_min = current_uV;
+ target_max = current_uV;
+
+ if (current_uV < rdev->min_uv) {
+ target_min = rdev->min_uv;
+ target_max = rdev->min_uv;
+ }
+
+ if (current_uV > rdev->max_uv) {
+ target_min = rdev->max_uv;
+ target_max = rdev->max_uv;
+ }
+
+ if (target_min != current_uV || target_max != current_uV) {
+ rdev_info(rdev, "Bringing %duV into %d-%duV\n",
+ current_uV, target_min, target_max);
+ ret = regulator_set_voltage_internal(rdev, target_min, target_max);
+ if (ret < 0) {
+ rdev_err(rdev,
+ "failed to apply %d-%duV constraint: %pe\n",
+ target_min, target_max, ERR_PTR(ret));
+ return ret;
+ }
+ }
+
+ return 0;
+}
+
static int __regulator_register(struct regulator_dev *rdev, const char *name)
{
int ret;
@@ -198,6 +254,10 @@ static int __regulator_register(struct regulator_dev *rdev, const char *name)
if (name)
rdev->name = xstrdup(name);
+ ret = regulator_init_voltage(rdev);
+ if (ret)
+ goto err;
+
if (rdev->boot_on || rdev->always_on) {
ret = regulator_resolve_supply(rdev);
if (ret < 0)
--
2.39.2
