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 (even though the rest of the series is a RFC). A few* drivers seem to pattern demonstrated by pseudocode: - devm_regulator_get() - regulator_enable() - devm_add_action_or_reset(regulator_disable()) (*) A rough idea what 'a few' means in this context can be get by issuing: "git grep -In -A10 devm_regulator_get |grep -B5 -A5 add_action |less" and then further checking some of the reported drivers. This is what I did when I realized I needed to enable a regulator for accelerometer and thought I'd go with devm-action... Introducing devm helpers for this pattern would remove bunch of code from drivers. Typically at least 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. I believe this simplifies things by removing some dublicated code. The other RFC aspect besides the question if this actually is useful, is whether the devm_regulator_get_enable[_optional]() should return a pointer to the obtained regulator or not. This RFC version does not return the pointer for user because any call to regulator_disable() may 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 this API is 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 suggested form of the API does not suit needs of such users. The new API in its current form really allows to only cover the very dummy cases where regulator is only enabled for a lifetime of the driver. I am unsure if this is really beneficial (well, there seems to be bunch of drivers doing just this) - or if we should go with a version returning the struct regulator * Some drivers did also manually disable the regulator (even though they had registered the devm-action for disable) for PM functionality. I am unsure if such use for suspend is actually safe(?) I didn't check if we can guarantee that the driver is not detached after the PM suspend has disabled the regulator(?) This RFC converts only few a drivers to demonstrate benefits. This makes it easier to rework the series if people thinks returning the pointer to struct regulator should be done. I can't promise I'll convert all drivers 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!). I have the driver changes in individual patches to make reviewing easier. I will squash the driver changes into one patch / subsystem when I'll drop the "RFC" from the series. Patch 1: Fix docmentation (devres API list) for regulator APIs Patch 2: The devm helpers. Patch 3: Add new devm-helper APIs to docs. Patches 4 ... 7: Example drivers. --- 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: meson: simplify using devm_regulator_get_enable_optional() hwmon: lm90: simplify using devm_regulator_get_enable() adc: ad7192: simplify using devm_regulator_get_enable() .../driver-api/driver-model/devres.rst | 9 +++ drivers/clk/clk-cdce925.c | 21 ++----- drivers/gpu/drm/meson/meson_dw_hdmi.c | 23 +------- drivers/hwmon/lm90.c | 21 +------ drivers/iio/adc/ad7192.c | 15 +---- drivers/regulator/devres.c | 59 +++++++++++++++++++ include/linux/regulator/consumer.h | 13 ++++ 7 files changed, 92 insertions(+), 69 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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