Some regulators (some PWM regulators) have the voltage transition
non-linear i.e. exponentially. On such cases, the settling time
for voltage transition can not be presented in the voltage-ramp-delay.
Add new property for non-linear voltage transition and handle this
in getting the voltage settling time.
Signed-off-by: Laxman Dewangan <ldewangan@xxxxxxxxxx>
---
This patch is continuation of discussion on patch
regulator: pwm: Fix regulator ramp delay for continuous mode
https://patchwork.kernel.org/patch/9216857/
where is it discussed to have separate property for PWM which has
exponential voltage transition.
Changes from V1:
- Use new DT property to finding that voltage ramp is exponential or
not and use flag for having fixed delay for all voltage change.
Changes from V2:
- Based on review comment from V1, make the settling time property
independent of the regulator-ramp-delay and move this to core
framework instead of handling in PWM regulator.
Changes from V3:
- The change was sent long back and resuming this patch.
- Rebase on linux-next tag 20170330 for resend.
---
drivers/regulator/core.c | 2 ++
drivers/regulator/of_regulator.c | 4 ++++
include/linux/regulator/machine.h | 3 +++
3 files changed, 9 insertions(+)
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 0753635..7303454 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2773,6 +2773,8 @@ static int _regulator_set_voltage_time(struct regulator_dev *rdev,
ramp_delay = rdev->constraints->ramp_delay;
else if (rdev->desc->ramp_delay)
ramp_delay = rdev->desc->ramp_delay;
+ else if (rdev->constraints->settling_time)
+ return rdev->constraints->settling_time;
if (ramp_delay == 0) {
rdev_dbg(rdev, "ramp_delay not set\n");
diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 4f613ec..09d677d 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -86,6 +86,10 @@ static void of_get_regulation_constraints(struct device_node *np,
constraints->ramp_disable = true;
}
+ ret = of_property_read_u32(np, "regulator-settling-time-us", &pval);
+ if (!ret)
+ constraints->settling_time = pval;
+
ret = of_property_read_u32(np, "regulator-enable-ramp-delay", &pval);
if (!ret)
constraints->enable_time = pval;
diff --git a/include/linux/regulator/machine.h b/include/linux/regulator/machine.h
index c9f795e..117699d 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -108,6 +108,8 @@ struct regulator_state {
* @initial_state: Suspend state to set by default.
* @initial_mode: Mode to set at startup.
* @ramp_delay: Time to settle down after voltage change (unit: uV/us)
+ * @settling_time: Time to settle down after voltage change when voltage
+ * change is non-linear (unit: microseconds).
* @active_discharge: Enable/disable active discharge. The enum
* regulator_active_discharge values are used for
* initialisation.
@@ -149,6 +151,7 @@ struct regulation_constraints {
unsigned int initial_mode;
unsigned int ramp_delay;
+ unsigned int settling_time;
unsigned int enable_time;
unsigned int active_discharge;
--
2.1.4
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