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Unverified Commit 2da8d947 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski Committed by Mark Brown
Browse files

regulator: implement selector stepping 



Some regulators require that the requested voltage be reached gradually
by setting all or some of the intermediate values. Implement a new field
in the regulator description struct that allows users to specify the
number of selectors by which the regulator API should step when ramping
the voltage up/down.

Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20190703161035.31808-2-brgl@bgdev.pl


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent ba2bf340

drivers/regulator/core.c

+63 −0
Original line number Diff line number Diff line
@@ -3106,6 +3106,66 @@ static int _regulator_call_set_voltage_sel(struct regulator_dev *rdev, 
	return ret;

}



static int _regulator_set_voltage_sel_step(struct regulator_dev *rdev,

					   int uV, int new_selector)

{

	const struct regulator_ops *ops = rdev->desc->ops;

	int diff, old_sel, curr_sel, ret;



	/* Stepping is only needed if the regulator is enabled. */

	if (!_regulator_is_enabled(rdev))

		goto final_set;



	if (!ops->get_voltage_sel)

		return -EINVAL;



	old_sel = ops->get_voltage_sel(rdev);

	if (old_sel < 0)

		return old_sel;



	diff = new_selector - old_sel;

	if (diff == 0)

		return 0; /* No change needed. */



	if (diff > 0) {

		/* Stepping up. */

		for (curr_sel = old_sel + rdev->desc->vsel_step;

		     curr_sel < new_selector;

		     curr_sel += rdev->desc->vsel_step) {

			/*

			 * Call the callback directly instead of using

			 * _regulator_call_set_voltage_sel() as we don't

			 * want to notify anyone yet. Same in the branch

			 * below.

			 */

			ret = ops->set_voltage_sel(rdev, curr_sel);

			if (ret)

				goto try_revert;

		}

	} else {

		/* Stepping down. */

		for (curr_sel = old_sel - rdev->desc->vsel_step;

		     curr_sel > new_selector;

		     curr_sel -= rdev->desc->vsel_step) {

			ret = ops->set_voltage_sel(rdev, curr_sel);

			if (ret)

				goto try_revert;

		}

	}



final_set:

	/* The final selector will trigger the notifiers. */

	return _regulator_call_set_voltage_sel(rdev, uV, new_selector);



try_revert:

	/*

	 * At least try to return to the previous voltage if setting a new

	 * one failed.

	 */

	(void)ops->set_voltage_sel(rdev, old_sel);

	return ret;

}



static int _regulator_set_voltage_time(struct regulator_dev *rdev,

				       int old_uV, int new_uV)

{
@@ -3179,6 +3239,9 @@ static int _regulator_do_set_voltage(struct regulator_dev *rdev, 
				selector = ret;

				if (old_selector == selector)

					ret = 0;

				else if (rdev->desc->vsel_step)

					ret = _regulator_set_voltage_sel_step(

						rdev, best_val, selector);

				else

					ret = _regulator_call_set_voltage_sel(

						rdev, best_val, selector);

include/linux/regulator/driver.h

+6 −0
Original line number Diff line number Diff line
@@ -286,6 +286,11 @@ enum regulator_type { 
 * @vsel_range_mask: Mask for register bitfield used for range selector

 * @vsel_reg: Register for selector when using regulator_regmap_X_voltage_

 * @vsel_mask: Mask for register bitfield used for selector

 * @vsel_step: Specify the resolution of selector stepping when setting

 *	       voltage. If 0, then no stepping is done (requested selector is

 *	       set directly), if >0 then the regulator API will ramp the

 *	       voltage up/down gradually each time increasing/decreasing the

 *	       selector by the specified step value.

 * @csel_reg: Register for current limit selector using regmap set_current_limit

 * @csel_mask: Mask for register bitfield used for current limit selector

 * @apply_reg: Register for initiate voltage change on the output when
@@ -360,6 +365,7 @@ struct regulator_desc { 
	unsigned int vsel_range_mask;

	unsigned int vsel_reg;

	unsigned int vsel_mask;

	unsigned int vsel_step;

	unsigned int csel_reg;

	unsigned int csel_mask;

	unsigned int apply_reg;