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regulator: Add support for ramp delay

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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 <krzk@kernel.org>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Signed-off-by: Minkyu Kang <mk7.kang@samsung.com>
This commit is contained in:
Krzysztof Kozlowski
2019-03-06 19:37:54 +01:00
committed by Minkyu Kang
parent fce8610060
commit e66d1cb3c2
3 changed files with 49 additions and 2 deletions
Download Patch File Download Diff File Expand all files Collapse all files

47
drivers/power/regulator/regulator-uclass.c
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@@ -35,10 +35,22 @@ int regulator_get_value(struct udevice *dev)
return ops->get_value(dev);
}
static void regulator_set_value_ramp_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, is_enabled = 0;
uc_pdata = dev_get_uclass_platdata(dev);
if (uc_pdata->min_uV != -ENODATA && uV < uc_pdata->min_uV)
@@ -49,7 +61,20 @@ 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) {
is_enabled = regulator_get_enable(dev);
old_uV = regulator_get_value(dev);
}
ret = ops->set_value(dev, uV);
if (!ret) {
if (uc_pdata->ramp_delay && old_uV > 0 && is_enabled)
regulator_set_value_ramp_delay(dev, old_uV, uV,
uc_pdata->ramp_delay);
}
return ret;
}
/*
@@ -107,6 +132,7 @@ 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 +141,22 @@ int regulator_set_enable(struct udevice *dev, bool enable)
if (!enable && uc_pdata->always_on)
return -EACCES;
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 && enable) {
int uV = regulator_get_value(dev);
if (uV > 0) {
regulator_set_value_ramp_delay(dev, 0, uV,
uc_pdata->ramp_delay);
}
}
}
return ret;
}
int regulator_set_enable_if_allowed(struct udevice *dev, bool enable)
@@ -335,6 +376,8 @@ 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) &&