[PATCH v2 0/7] Devm helpers for regulator get and enable

[Matti Vaittinen]

Devm helpers for regulator get and enable

First patch in the series is actually just a simple documentation fix
which could be taken in as it is now.

A few* drivers seem to use pattern demonstrated by pseudocode:

- devm_regulator_get()
- regulator_enable()
- devm_add_action_or_reset(regulator_disable())

Introducing devm helpers for this pattern would remove bunch of code from
drivers. Typically following:

- replace 3 calls (devm_regulator_get[_optional](), regulator_enable(),
  devm_add_action_or_reset()) with just one
  (devm_regulator_get_enable[_optional]()).
- drop disable callback.
- remove stored pointer to struct regulator - which can lead to problem
  when an devm action for regulator_disable is used.

I believe this simplifies things by removing some dublicated code.

The suggested managed 'get_enable' APIs do not return the pointer to
regulators for user because any call to regulator_disable()
(or regulator_enable()) may easily lead to regulator enable count imbalance
upon device detach. (Eg, if someone calls regulator_disable() and the
device is then detached before user has re-enabled the regulator). Not
returning the pointer to obtained regulator to caller is a good hint that
the enable/disable should not be manually handled when these APIs are used.

OTOH, not returning the pointer reduces the use-cases by not allowing
the consumers to perform other regulator actions. For example request the
voltages. A few drivers which used the "get, enable,
devm_action_to_disable" did also query the voltages. The API does not suit
needs of such users.

This series reowrks only a few drivers as I am short of time. So, there is
still plenty of fish in the sea for people who like to improve the code
(or count the beans ;]).

Finally - most of the converted drivers have not been tested (other than
compile-tested) due to lack of HW. All reviews and testing is _highly_
appreciated (as always!).

Revision history:

RFCv1 => v2:
	- Add devm_regulator_bulk_get_enable() and
	  devm_regulator_bulk_put()
	- Convert a couple of drivers to use the new
	  devm_regulator_bulk_get_enable().
	- Squash all IIO patches into one.

Patch 1:
	Fix docmentation (devres API list) for regulator APIs
Patch 2:
	The new devm helpers.
Patch 3:
	Add new devm-helper APIs to docs.
Patch 4:
	simplified CLK driver(s)
Patch 5:
	simplified GPU driver(s)
Patch 6:
	simplified hwmon driver(s)
Patch 7:
	simplified IIO driver(s)

---

Matti Vaittinen (7):
  docs: devres: regulator: Add missing devm_* functions to devres.rst
  regulator: Add devm helpers for get and enable
  docs: devres: regulator: Add new get_enable functions to devres.rst
  clk: cdce925: simplify using devm_regulator_get_enable()
  gpu: drm: simplify drivers using devm_regulator_*get_enable*()
  hwmon: lm90: simplify using devm_regulator_get_enable()
  iio: Simplify drivers using devm_regulator_*get_enable()

 .../driver-api/driver-model/devres.rst        |  11 ++
 drivers/clk/clk-cdce925.c                     |  21 +--
 drivers/gpu/drm/bridge/sii902x.c              |  22 +--
 drivers/gpu/drm/meson/meson_dw_hdmi.c         |  23 +--
 drivers/hwmon/lm90.c                          |  21 +--
 drivers/iio/adc/ad7192.c                      |  15 +-
 drivers/iio/dac/ltc2688.c                     |  23 +--
 drivers/iio/gyro/bmg160_core.c                |  24 +--
 drivers/iio/imu/st_lsm6dsx/st_lsm6dsx.h       |   2 -
 drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_core.c  |  30 +---
 drivers/regulator/devres.c                    | 164 ++++++++++++++++++
 include/linux/regulator/consumer.h            |  27 +++
 12 files changed, 227 insertions(+), 156 deletions(-)

-- 
2.37.1


-- 
Matti Vaittinen, Linux device drivers
ROHM Semiconductors, Finland SWDC
Kiviharjunlenkki 1E
90220 OULU
FINLAND

~~~ "I don't think so," said Rene Descartes. Just then he vanished ~~~
Simon says - in Latin please.
~~~ "non cogito me" dixit Rene Descarte, deinde evanescavit ~~~
Thanks to Simon Glass for the translation =]

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