| Message ID | 20240429-regulator-get-enable-get-votlage-v2-1-b1f11ab766c1@baylibre.com (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | regulator: new API for voltage reference supplies | expand |
On Mon, Apr 29, 2024 at 6:40 PM David Lechner <dlechner@baylibre.com> wrote: > > 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: David Lechner <dlechner@baylibre.com> > --- > > v2 changes: > * removed dev_err_probe() on error return > * dropped optional version of the function since there is no more > difference after dev_err_probe() is removed > * renamed function to devm_regulator_get_enable_read_voltage() > * added unwinding on error paths > --- > Documentation/driver-api/driver-model/devres.rst | 1 + > drivers/regulator/devres.c | 59 ++++++++++++++++++++++++ > include/linux/regulator/consumer.h | 7 +++ > 3 files changed, 67 insertions(+) > > diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst > index 7be8b8dd5f00..18caebad7376 100644 > --- a/Documentation/driver-api/driver-model/devres.rst > +++ b/Documentation/driver-api/driver-model/devres.rst > @@ -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() > diff --git a/drivers/regulator/devres.c b/drivers/regulator/devres.c > index 90bb0d178885..4f290b9b559b 100644 > --- a/drivers/regulator/devres.c > +++ b/drivers/regulator/devres.c > @@ -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; Oof. Apparently I didn't test this as well as I should have after adding the unwinding. This obviously should return ret, not 0. I did more extensive testing today, including faking error returns to test unwinding to make sure I didn't miss anything else. > + > +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); > +
diff --git a/Documentation/driver-api/driver-model/devres.rst b/Documentation/driver-api/driver-model/devres.rst index 7be8b8dd5f00..18caebad7376 100644 --- a/Documentation/driver-api/driver-model/devres.rst +++ b/Documentation/driver-api/driver-model/devres.rst @@ -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() diff --git a/drivers/regulator/devres.c b/drivers/regulator/devres.c index 90bb0d178885..4f290b9b559b 100644 --- a/drivers/regulator/devres.c +++ b/drivers/regulator/devres.c @@ -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; diff --git a/include/linux/regulator/consumer.h b/include/linux/regulator/consumer.h index ed180ca419da..59d0b9a79e6e 100644 --- a/include/linux/regulator/consumer.h +++ b/include/linux/regulator/consumer.h @@ -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 0; } +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) {
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: David Lechner <dlechner@baylibre.com> --- v2 changes: * removed dev_err_probe() on error return * dropped optional version of the function since there is no more difference after dev_err_probe() is removed * renamed function to devm_regulator_get_enable_read_voltage() * added unwinding on error paths --- Documentation/driver-api/driver-model/devres.rst | 1 + drivers/regulator/devres.c | 59 ++++++++++++++++++++++++ include/linux/regulator/consumer.h | 7 +++ 3 files changed, 67 insertions(+)