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regulator: implement selector stepping

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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: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20190703161035.31808-2-brgl@bgdev.pl
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Bartosz Golaszewski 2019-07-03 18:10:34 +02:00 committed by Mark Brown
parent ba2bf340ad
commit 2da8d9473e
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GPG Key ID: 24D68B725D5487D0
2 changed files with 69 additions and 0 deletions
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63
drivers/regulator/core.c
View File

@ -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);

6
include/linux/regulator/driver.h
View File

@ -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;