Commit 00c877c6 authored by Laxman Dewangan's avatar Laxman Dewangan Committed by Mark Brown
Browse files

regulator: core: add support for configuring turn-on time through constraints 



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: default avatarLaxman Dewangan <ldewangan@nvidia.com>
Acked-by: default avatarStephen Warren <swarren@nvidia.com>
Signed-off-by: default avatarMark Brown <broonie@linaro.org>
parent 272b98c6

Documentation/devicetree/bindings/regulator/regulator.txt

+5 −0
Original line number Diff line number Diff line
@@ -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

drivers/regulator/core.c

+2 −0
Original line number Diff line number Diff line
@@ -1186,6 +1186,8 @@ 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);

drivers/regulator/of_regulator.c

+6 −0
Original line number Diff line number Diff line
@@ -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;

}



/**

include/linux/regulator/machine.h

+2 −0
Original line number Diff line number Diff line
@@ -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 */

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