Changing voltage and enabling regulator might require delays so the
regulator stabilizes at expected level.
Add support for "regulator-ramp-delay" binding which can introduce
required time to both enabling the regulator and to changing the
voltage.
Signed-off-by: Krzysztof Kozlowski <k...@kernel.org>
---
drivers/power/regulator/regulator-uclass.c | 45 +++++++++++++++++++++-
include/power/regulator.h | 2 +
2 files changed, 45 insertions(+), 2 deletions(-)
diff --git a/drivers/power/regulator/regulator-uclass.c
b/drivers/power/regulator/regulator-uclass.c
index 39e46279d533..4119f244c74b 100644
--- a/drivers/power/regulator/regulator-uclass.c
+++ b/drivers/power/regulator/regulator-uclass.c
@@ -35,10 +35,22 @@ int regulator_get_value(struct udevice *dev)
return ops->get_value(dev);
}
+static void regulator_set_value_delay(struct udevice *dev, int old_uV,
+ int new_uV, unsigned int ramp_delay)
+{
+ int delay = DIV_ROUND_UP(abs(new_uV - old_uV), ramp_delay);
+
+ debug("regulator %s: delay %u us (%d uV -> %d uV)\n", dev->name,
+ delay, old_uV, new_uV);
+
+ udelay(delay);
+}
+
int regulator_set_value(struct udevice *dev, int uV)
{
const struct dm_regulator_ops *ops = dev_get_driver_ops(dev);
struct dm_regulator_uclass_platdata *uc_pdata;
+ int ret, old_uV = uV;
uc_pdata = dev_get_uclass_platdata(dev);
if (uc_pdata->min_uV != -ENODATA && uV < uc_pdata->min_uV)
@@ -49,7 +61,18 @@ int regulator_set_value(struct udevice *dev, int uV)
if (!ops || !ops->set_value)
return -ENOSYS;
- return ops->set_value(dev, uV);
+ if (uc_pdata->ramp_delay)
+ old_uV = regulator_get_value(dev);
+
+ ret = ops->set_value(dev, uV);
+
+ if (!ret) {
+ if (uc_pdata->ramp_delay && old_uV > 0)
+ regulator_set_value_delay(dev, old_uV, uV,
+ uc_pdata->ramp_delay);
+ }
+
+ return ret;
}
/*
@@ -107,6 +130,7 @@ int regulator_set_enable(struct udevice *dev, bool enable)
{
const struct dm_regulator_ops *ops = dev_get_driver_ops(dev);
struct dm_regulator_uclass_platdata *uc_pdata;
+ int ret, old_enable = 0;
if (!ops || !ops->set_enable)
return -ENOSYS;
@@ -115,7 +139,22 @@ int regulator_set_enable(struct udevice *dev, bool enable)
if (!enable && uc_pdata->always_on)
return 0;
- return ops->set_enable(dev, enable);
+ if (uc_pdata->ramp_delay)
+ old_enable = regulator_get_enable(dev);
+
+ ret = ops->set_enable(dev, enable);
+ if (!ret) {
+ if (uc_pdata->ramp_delay && !old_enable) {
+ int uV = regulator_get_value(dev);
+
+ if (uV > 0) {
+ regulator_set_value_delay(dev, 0, uV,
+ uc_pdata->ramp_delay);
+ }
+ }
+ }
+
+ return ret;
}
int regulator_get_mode(struct udevice *dev)
@@ -324,6 +363,8 @@ static int regulator_pre_probe(struct udevice *dev)
-ENODATA);
uc_pdata->always_on = dev_read_bool(dev, "regulator-always-on");
uc_pdata->boot_on = dev_read_bool(dev, "regulator-boot-on");
+ uc_pdata->ramp_delay = dev_read_u32_default(dev, "regulator-ramp-delay",
+ 0);
/* Those values are optional (-ENODATA if unset) */
if ((uc_pdata->min_uV != -ENODATA) &&
diff --git a/include/power/regulator.h b/include/power/regulator.h
index 5318ab3acece..c13fa1f336e5 100644
--- a/include/power/regulator.h
+++ b/include/power/regulator.h
@@ -149,6 +149,7 @@ enum regulator_flag {
* @max_uA* - maximum amperage (micro Amps)
* @always_on* - bool type, true or false
* @boot_on* - bool type, true or false
+ * @ramp_delay - Time to settle down after voltage change (unit: uV/us)
* TODO(s...@chromium.org): Consider putting the above two into @flags
* @flags: - flags value (see REGULATOR_FLAG_...)
* @name** - fdt regulator name - should be taken from the device tree
@@ -169,6 +170,7 @@ struct dm_regulator_uclass_platdata {
int max_uV;
int min_uA;
int max_uA;
+ unsigned int ramp_delay;
bool always_on;
bool boot_on;
const char *name;
--
2.17.1
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
https://lists.denx.de/listinfo/u-boot
