On Sun, 10 Feb 2019 at 10:49, Simon Glass <s...@chromium.org> wrote: > > Hi Krzysztof, > > On Sat, 9 Feb 2019 at 16:54, Krzysztof Kozlowski <k...@kernel.org> wrote: > > > > 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. > > Is this binding used in Linux? Can you please add binding > documentation for this?
Yes, these are bindings from the kernel. I will add them. > > > > > 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); > > So the ramp delay is microseconds per (microvolt delta)? The ramp delay is microvolt per microseconds. int delay = uv / (uV/uS) = uS > > > + > > + 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); > > + } > > How come there is a delay when enabling it as well as when setting the > voltage? Enabling a regulator also requires the time, which might be sum of: 1. Initial enable delay (not included here), 2. Rising of voltage delay (ramp delay) from 0 to expected. In Linux kernel this is separate property regulator-enable-ramp-delay. Here I reused the ramp delay to make it simpler. However indeed there is no point to wait with ramp delay if the regulator is disabled. > > > + } > > + } > > + > > + 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) > > us/uV isn't it? No, opposite. > > > * TODO(s...@chromium.org): Consider putting the above two into @flags > > This comment needs updating or moving up. Yes, thanks! Best regards, Krzysztof _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de https://lists.denx.de/listinfo/u-boot