The turn-on time of the regulator depends on the regulator device's
electrical characteristics. Sometimes regulator turn-on time also
depends on the capacitive load on the given platform and it can be
more than the datasheet value.
The driver provides the enable-time as per datasheet.
Add support for configure the enable ramp time through regulator
constraints so that regulator core can take this value for enable
time for that regulator.
Signed-off-by: Laxman Dewangan <ldewangan@xxxxxxxxxx>
---
Changes from V1:
- Change property name to regulator-enable-ramp-delay and add more details
in DT doc.
- add the valid pointer check for constraints before accessing it.
Changes from V2:
- Rephrase the descripton of property regulator-enable-ramp-delay.
Changes from V3:
- Use the description provided by Stephen to describe
regulator-enable-ramp-delay.
.../devicetree/bindings/regulator/regulator.txt | 5 +++++
drivers/regulator/core.c | 2 ++
drivers/regulator/of_regulator.c | 6 ++++++
include/linux/regulator/machine.h | 2 ++
4 files changed, 15 insertions(+), 0 deletions(-)
diff --git a/Documentation/devicetree/bindings/regulator/regulator.txt b/Documentation/devicetree/bindings/regulator/regulator.txt
index 2bd8f09..e2c7f1e 100644
--- a/Documentation/devicetree/bindings/regulator/regulator.txt
+++ b/Documentation/devicetree/bindings/regulator/regulator.txt
@@ -14,6 +14,11 @@ Optional properties:
- regulator-ramp-delay: ramp delay for regulator(in uV/uS)
For hardwares which support disabling ramp rate, it should be explicitly
intialised to zero (regulator-ramp-delay = <0>) for disabling ramp delay.
+- regulator-enable-ramp-delay: The time taken, in microseconds, for the supply
+ rail to reach the target voltage, plus/minus whatever tolerance the board
+ design requires. This property describes the total system ramp time
+ required due to the combination of internal ramping of the regulator itself,
+ and board design issues such as trace capacitance and load on the supply.
Deprecated properties:
- regulator-compatible: If a regulator chip contains multiple
diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index b698e2b..4eefcc3 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -1167,6 +1167,8 @@ overflow_err:
static int _regulator_get_enable_time(struct regulator_dev *rdev)
{
+ if (rdev->constraints && rdev->constraints->enable_time)
+ return rdev->constraints->enable_time;
if (!rdev->desc->ops->enable_time)
return rdev->desc->enable_time;
return rdev->desc->ops->enable_time(rdev);
diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
index 7827384..ea4f36f 100644
--- a/drivers/regulator/of_regulator.c
+++ b/drivers/regulator/of_regulator.c
@@ -23,6 +23,8 @@ static void of_get_regulation_constraints(struct device_node *np,
const __be32 *min_uA, *max_uA, *ramp_delay;
struct property *prop;
struct regulation_constraints *constraints = &(*init_data)->constraints;
+ int ret;
+ u32 pval;
constraints->name = of_get_property(np, "regulator-name", NULL);
@@ -73,6 +75,10 @@ static void of_get_regulation_constraints(struct device_node *np,
else
constraints->ramp_disable = true;
}
+
+ 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 a9f7c55..730e638 100644
--- a/include/linux/regulator/machine.h
+++ b/include/linux/regulator/machine.h
@@ -95,6 +95,7 @@ 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)
+ * @enable_time: Turn-on time of the rails (unit: microseconds)
*/
struct regulation_constraints {
@@ -129,6 +130,7 @@ struct regulation_constraints {
unsigned int initial_mode;
unsigned int ramp_delay;
+ unsigned int enable_time;
/* constraint flags */
unsigned always_on:1; /* regulator never off when system is on */
--
1.7.1.1
--
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