Unverified Commit b250c20b authored by David Lechner's avatar David Lechner Committed by Mark Brown
Browse files

regulator: devres: add API for reference voltage supplies 



A common use case for regulators is to supply a reference voltage to an
analog input or output device. This adds a new devres API to get,
enable, and get the voltage in a single call. This allows eliminating
boilerplate code in drivers that use reference supplies in this way.

Signed-off-by: default avatarDavid Lechner <dlechner@baylibre.com>
Link: https://lore.kernel.org/r/20240429-regulator-get-enable-get-votlage-v2-1-b1f11ab766c1@baylibre.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent fec50db7

Documentation/driver-api/driver-model/devres.rst

+1 −0
Original line number Diff line number Diff line
@@ -433,6 +433,7 @@ REGULATOR 
  devm_regulator_bulk_put()

  devm_regulator_get()

  devm_regulator_get_enable()

  devm_regulator_get_enable_read_voltage()

  devm_regulator_get_enable_optional()

  devm_regulator_get_exclusive()

  devm_regulator_get_optional()

drivers/regulator/devres.c

+59 −0
Original line number Diff line number Diff line
@@ -145,6 +145,65 @@ struct regulator *devm_regulator_get_optional(struct device *dev, 
}

EXPORT_SYMBOL_GPL(devm_regulator_get_optional);



/**

 * devm_regulator_get_enable_read_voltage - Resource managed regulator get and

 *                                          enable that returns the voltage

 * @dev: device to supply

 * @id:  supply name or regulator ID.

 *

 * Get and enable regulator for duration of the device life-time.

 * regulator_disable() and regulator_put() are automatically called on driver

 * detach. See regulator_get_optional(), regulator_enable(), and

 * regulator_get_voltage() for more information.

 *

 * This is a convenience function for supplies that provide a reference voltage

 * where the consumer driver just needs to know the voltage and keep the

 * regulator enabled.

 *

 * In cases where the supply is not strictly required, callers can check for

 * -ENODEV error and handle it accordingly.

 *

 * Returns: voltage in microvolts on success, or an error code on failure.

 */

int devm_regulator_get_enable_read_voltage(struct device *dev, const char *id)

{

	struct regulator *r;

	int ret;



	/*

	 * Since we need a real voltage, we use devm_regulator_get_optional()

	 * rather than getting a dummy regulator with devm_regulator_get() and

	 * then letting regulator_get_voltage() fail with -EINVAL. This way, the

	 * caller can handle the -ENODEV error code if needed instead of the

	 * ambiguous -EINVAL.

	 */

	r = devm_regulator_get_optional(dev, id);

	if (IS_ERR(r))

		return PTR_ERR(r);



	ret = regulator_enable(r);

	if (ret)

		goto err_regulator_put;



	ret = devm_add_action_or_reset(dev, regulator_action_disable, r);

	if (ret)

		goto err_regulator_put;



	ret = regulator_get_voltage(r);

	if (ret < 0)

		goto err_release_action;



	return 0;



err_release_action:

	devm_release_action(dev, regulator_action_disable, r);

err_regulator_put:

	devm_regulator_put(r);



	return ret;

}

EXPORT_SYMBOL_GPL(devm_regulator_get_enable_read_voltage);



static int devm_regulator_match(struct device *dev, void *res, void *data)

{

	struct regulator **r = res;

include/linux/regulator/consumer.h

+7 −0
Original line number Diff line number Diff line
@@ -164,6 +164,7 @@ struct regulator *__must_check devm_regulator_get_optional(struct device *dev, 
							   const char *id);

int devm_regulator_get_enable(struct device *dev, const char *id);

int devm_regulator_get_enable_optional(struct device *dev, const char *id);

int devm_regulator_get_enable_read_voltage(struct device *dev, const char *id);

void regulator_put(struct regulator *regulator);

void devm_regulator_put(struct regulator *regulator);
@@ -329,6 +330,12 @@ static inline int devm_regulator_get_enable_optional(struct device *dev, 
	return -ENODEV;

}



static inline int devm_regulator_get_enable_read_voltage(struct device *dev,

							 const char *id)

{

	return -ENODEV;

}



static inline struct regulator *__must_check

regulator_get_optional(struct device *dev, const char *id)

{