Currently regulator drivers which support DT all repeat very similar code
to supply a list of known regulator identifiers to be matched with DT,
convert that to platform data which is then matched up with the regulators
as they are registered. This is both fiddly to get right and for devices
which can use the standard helpers to provide their operations is the main
source of code in the driver.

Since this code is essentially identical for most drivers we can factor it
out into the core, moving the identifiers in the match table into the
regulator descriptors and also allowing drivers to pass in the name of the
subnode to search. When a driver provides an of_match string for the
regulator the core will attempt to use that to obtain init_data, allowing
the driver to remove all explicit code for DT parsing and simply provide
data instead.

The current code leaks the phandles for the child nodes, this will be
addressed incrementally and makes no practical difference for FDT anyway
as the DT data structures are never freed.

Signed-off-by: Mark Brown <broonie@linaro.org>

In some cases we need to know when a regulator is about to be changed.
Add a way for clients to be notified.  Note that for set_voltage() we
don't necessarily know what voltage we'll end up with, so we tell the
client what the range will be so they can prepare.

Signed-off-by: Heiko Stübner <heiko@sntech.de>
Signed-off-by: Doug Anderson <dianders@chromium.org>
Signed-off-by: Mark Brown <broonie+linaro@kernel.org>

Commit 272e2315fac3 ("regulator: core: add const qualifier to ops in
struct regulator_desc") introduced const qualifier to ops in regulator_desc.

This patch adds 'const' to regulator_ops vars in newly added core APIs
for v3.17-rc1:
 - regulator_get_hardware_vsel_register()
 - regulator_list_hardware_vsel()

This patch also fix a build error in mc13892-regulator.c due to const
regulator_desc.ops. Modification of regulator_desc.ops' member fields is not
allowed.

Signed-off-by: Guodong Xu <guodong.xu@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

Some regulator require a minimum delay between its disable and next enable.
This is to avoid damages when out-of-range frequent disable/enable of a
single regulator can bring to the regulator chip.

Add @off_on_delay to struct regulator_desc. Device drivers' can use this field
to set this guard time.

Add @last_off_jiffy to struct regulator_dev. When @off_on_delay is set by
driver, regulator core can store its last off (disable) time into this field.

Signed-off-by: Guodong Xu <guodong.xu@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

A common delay function can be helpful when implementing new features. Factor
it out to maximize code reusability.

Signed-off-by: Guodong Xu <guodong.xu@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>

struct regulator_ops *ops is a member in struct regulator_desc, which gets
its value from individual regulator driver upon regulator_register() and
is used by regulator core APIs. It's not allowed for regulator core to
modify any of these callbacks in *ops. Add 'const' qualifier to enforce that.

Signed-off-by: Guodong Xu <guodong.xu@linaro.org>
Signed-off-by: Mark Brown <broonie@linaro.org>