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 --- 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(sjg@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;