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2009-09-22REGULATOR Handle positive returncode from enableLinus Walleij1-1/+2
This makes _regulator_enable() properly handle the case where a regulator is already on when you try to enable it. Currently it will erroneously handle positive return values as an error. Signed-off-by: Linus Walleij <linus.walleij@stericsson.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-09-22regulator: regulator_enable() permission checkingMark Brown1-20/+36
The regulator_enable() code wasn't actually checking that the machine constraints had given permission to enable the regulator. Add code to do that, but only if the regulator is not already on due to something like always_on or being left on at startup since in those cases there's no physical change being introduced and the constraint wouldn't make any sense. Also add matching code for disable(). We need to do less there since either regulator_enable() should have succeeded first or the board setup makes no sense. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-09-22regulator: Push locking for regulator_is_enabled() outMark Brown1-14/+16
Allows use by more of the internal regulator API code. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-09-22regulator: Check for constraints in regulator_init_complete()Mark Brown1-2/+2
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-09-22regulator: Check for constraints before using them for nameMark Brown1-1/+1
Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-09-22regulator: Fix support for deviceless supply mappingsMark Brown1-5/+13
The patch to add support for looking up consumers by device name had the side effect of causing us to require a device which is at best premature since at least cpufreq still operates outside the device model. Remove that requirement. Reported-by: Haojian Zhuang <haojian.zhuang@gmail.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-09-22regulator: Warn when unregistering an in-use regulatorMark Brown1-0/+1
We're probably going to start oopsing fairly soon after this happens. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-09-22regulator: Add regulator voltage range check APIMark Brown1-0/+29
Simplify checking of support for voltage ranges by providing an API which wraps the existing count and list operations. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-09-22regulator: Add regulator_get_exclusive() APIMark Brown1-14/+74
Some consumers require complete control of the regulator and can't tolerate sharing it with other consumers, most commonly because they need to have the regulator actually disabled so can't have other consumers forcing it on. This new regulator_get_exclusive() API call allows these consumers to explicitly request this, documenting the assumptions that they are making. In order to simplify coding of such consumers the use count for regulators they request is forced to match the enabled state of the regulator when it is requested. This is not possible for consumers which can share regulators due to the need to keep track of the ownership of use counts. A new API call is used rather than an additional argument to the existing regulator_get() in order to avoid merge headaches with driver code in other trees. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-09-22regulator: Allow consumer supplies to be set up with dev_name()Mark Brown1-14/+48
Follow the approach suggested by Russell King and implemented by him in the clkdev API and allow consumer device supply mapings to be set up using the dev_name() for the consumer instead of the struct device. In order to avoid making existing machines instabuggy and creating merge issues the use of struct device is still supported for the time being. This resolves problems working with buses such as I2C which make the struct device available late providing that the final device name is known, which is the case for most embedded systems with fixed setups. Consumers must still use the struct device when calling regulator_get(). Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-09-17regulator: Provide mode to status conversion functionMark Brown1-0/+24
This is useful for implementing get_status() in terms of get_mode(). Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
2009-04-28regulator: Fix default constraints for fixed voltage regulatorsMark Brown1-2/+5
Default voltage constraints were being provided for fixed voltage regulator where board constraints were not provided but these constraints used INT_MIN as the default minimum voltage which is not a valid value since it is less than zero. Use 1uV instead. Also set the default values we set in the constraints themselves since otherwise the max_uV constraint we determine will not be stored in the actual constraint strucutre and will therefore not be used. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-04-28regulator core: fix double-free in regulator_register() error pathPaul Walmsley1-0/+4
During regulator registration, any error after device_register() will cause a double-free on the struct regulator_dev 'rdev'. The bug is in drivers/regulator/core.c:regulator_register(): ... scrub: device_unregister(&rdev->dev); clean: kfree(rdev); <--- rdev = ERR_PTR(ret); goto out; ... device_unregister() calls regulator_dev_release() which frees rdev. The subsequent kfree corrupts memory and causes some OMAP3 systems to oops on boot in regulator_get(). Applies against 2.6.30-rc3. Signed-off-by: Paul Walmsley <paul@pwsan.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-04-28drivers/regulator: fix when type is different from REGULATOR_VOLTAGE or REGULATOR_CURRENTDiego Liziero1-2/+2
When regulator_desc->type is something different from REGULATOR_VOLTAGE or REGULATOR_CURRENT the if should probably return ERR_PTR(-EINVAL) The semantic patch that makes this change is as follows: (http://www.emn.fr/x-info/coccinelle/) @@ expression E; constant C; @@ ( - !E == C + E != C ) Signed-off-by: Diego Liziero <diegoliz@gmail.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-04-28unreachable code in drms_uA_update()Dan Carpenter1-2/+2
I removed the extra semi-colon and indented the return statement. The unreachable code was found by smatch (http://repo.or.cz/w/smatch.git). The patch was compile tested. regards, dan carpenter Signed-off-by: Dan Carpenter <error27@gmail.com> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: Support disabling of unused regulators by machinesMark Brown1-0/+92
At present it is not possible for machine constraints to disable regulators which have been left on when the system starts, for example as a result of fixed default configurations in hardware. This means that power may be wasted by these regulators if they are not in use. Provide intial support for this with a late_initcall which will disable any unused regulators if the machine has enabled this feature by calling regulator_has_full_constraints(). If this has not been called then print a warning to encourage users to fully specify their constraints so that we can change this to be the default behaviour in future. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: Don't increment use_count for boot_on regulatorsMark Brown1-1/+0
Don't set use_count for regulators that are enabled at boot since this stops the supply being disabled by well-behaved consumers which do balanced enables and disabled. Any consumers which don't do disables which are not matched by enables are unable to share regulators - shared regulators are the common case so the API should facilitate them. Consumers that want to disable regulators that are enabled when they start have two options: - Do a regulator_enable() prior to the disable to bring the use count in sync with the hardware state; this will ensure that if the regulator was enabled by another driver then this consumer will play nicely with it. - Use regulator_force_disable(); this explicitly bypasses any checks done by the core and documents the inability of the driver to share the supply. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: refcount fixesDavid Brownell1-22/+8
Fix some refcounting issues in the regulator framework, supporting regulator_disable() for regulators that were enabled at boot time via machine constraints: - Update those regulators' usecounts after enabling, so they can cleanly be disabled at that level. - Remove the problematic per-consumer usecount, so there's only one level of enable/disable. Buggy consumers could notice different bug symptoms. The main example would be refcounting bugs; also, any (out-of-tree) users of the experimental regulator_set_optimum_mode() stuff which don't call it when they're done using a regulator. This is a net minor codeshrink. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: Don't warn if we failed to get a regulatorMark Brown1-2/+0
The consumer can print a message if required, some consumers may have optional regulators and wish to downgrade the logging for them or ignore their absence. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: Allow boot_on regulators to be disabled by clientsMark Brown1-9/+4
Rather than incrementing the reference count for boot_on regulators (which prevents them being disabled later on) simply force the regulator to be enabled when applying the constraints. Previously boot_on was essentially equivalent to always_on. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: Don't warn on omitted voltage constraintsMark Brown1-1/+5
Specifying voltage constraints is optional (and only needed if the consumer is allowed to change the voltage) so don't complain unless a voltage has been specified. Also avoid surprises with a dangling else while we're here. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: enumerate voltages (v2)David Brownell1-0/+113
Add a basic mechanism for regulators to report the discrete voltages they support: list_voltage() enumerates them using selectors numbered from 0 to an upper bound. Use those methods to force machine-level constraints into bounds. (Example: regulator supports 1.8V, 2.4V, 2.6V, 3.3V, and board constraints for that rail are 2.0V to 3.6V ... so the range of voltages is then 2.4V to 3.3V on this board.) Export those voltages to the regulator consumer interface, so for example regulator hooked up to an MMC/SD/SDIO slot can report the actual voltage options available to cards connected there. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: Allow regulators to set the initial operating modeMark Brown1-0/+17
This is useful when wishing to run in a fixed operating mode that isn't the default. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: Suggest use of datasheet supply or pin names for consumersMark Brown1-3/+6
Update the documentation to suggest the use of datasheet names for the supplies requested by regulator consumers. Doing this makes it easier to tie the design for a given platform up with the requirements of the driver for a consumer. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: add unset_regulator_supplies to fix regulator_unregisterMike Rapoport1-0/+14
Currently regulator_unregister does not clear regulator <--> consumer mapping. This patch introduces unset_regulator_supplies that clear the map. Signed-off-by: Mike Rapoport <mike@compulab.co.il> Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: Hoist struct regulator_dev out of core to fix notifiersMark Brown1-27/+0
Commit 872ed3fe176833f7d43748eb88010da4bbd2f983 caused regulator drivers to take the struct regulator_dev lock themselves which requires that the struct be visible to them. Band aid this by making the struct visible. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: Pass regulator init data as explict argument when registeringMark Brown1-2/+3
Rather than having the regulator init data read from the platform_data member of the struct device that is registered for the regulator make the init data an explict argument passed in when registering. This allows drivers to use the platform data for their own purposes if they wish. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31Regulator: Push lock out of _notifier_call_chain + add voltage change event.Jonathan Cameron1-5/+10
Regulator: Push lock out of _notifier_call_chain and into caller functions (side effect of fixing deadlock in regulator_force_disable) + Add a voltage changed event. Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-03-31regulator: add get_status()David Brownell1-0/+46
Based on previous LKML discussions: * Update docs for regulator sysfs class attributes to highlight the fact that all current attributes are intended to be control inputs, including notably "state" and "opmode" which previously implied otherwise. * Define a new regulator driver get_status() method, which is the first method reporting regulator outputs instead of inputs. It can report on/off and error status; or instead of simply "on", report the actual operating mode. For the moment, this is a sysfs-only interface, not accessible to regulator clients. Such clients can use the current notification interfaces to detect errors, if the regulator reports them. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: catch some registration errorsDavid Brownell1-0/+14
Prevent registration of duplicate "struct regulator" names. They'd be unavailable, and clearly indicate something wrong. [Edited to remove check for NULL consumer device until we have a solution for things like cpufreq -- broonie] Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: Fix some kerneldoc rendering issuesMark Brown1-7/+11
There are some minor textual changes in here as well, mostly to enable() and disable() but the primary goal of these changes is to fix misrenderings of the kerneldoc documentation for the regulator API. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: Add missing kerneldocMark Brown1-0/+1
This is only the documentation that the kerneldoc system warns about. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: Clean up kerneldoc warningsMark Brown1-22/+22
Remove kerneldoc warnings that don't relate to missing documentation, mostly by renaming parameters in the documentation to match their actual names. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: Remove extraneous kerneldoc annotationsMark Brown1-2/+2
Some of the internal structures have no kerneldoc but the ** at the start of the comment marking them for documentation. Remove the annotation until some is added. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: move set_machine_constraints after regulator device initializationMike Rapoport1-5/+5
Calling set_machine_constraints before regulator device initialization causes crash when constraints have apply_uV set. Signed-off-by: Mike Rapoport <mike@compulab.co.il> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: sysfs attribute reduction (v2)David Brownell1-48/+148
Clean up the sysfs interface to regulators by only exposing the attributes that can be properly displayed. For example: when a particular regulator method is needed to display the value, only create that attribute when that method exists. This cleaned-up interface is much more comprehensible. Most regulators only support a subset of the possible methods, so often more than half the attributes would be meaningless. Many "not defined" values are no longer necessary. (But handling of out-of-range values still looks a bit iffy.) Documentation is updated to reflect that few of the attributes are *always* present, and to briefly explain why a regulator may not have a given attribute. This adds object code, about a dozen bytes more than was removed by the preceding patch, but saves a bunch of per-regulator data associated with the now-removed attributes. So there's a net reduction in memory footprint. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: code shrink (v2)David Brownell1-67/+44
Shrink regulator core by removing duplication in attribute printing and probe() cleanup paths. Saves about 340 bytes (object) on ARM. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: improved mode error checksDavid Brownell1-2/+13
Minor bugfixes in handling of regulator modes: - have the routine verifying regulator modes check against the set of legal modes (!); - have regulator_set_optimum_mode() verify the return value of regulator_ops.get_optimum_mode(), like drms_uA_update(); - one call to regulator_ops.set_mode() treated zero as a failure code; make this consistent with other callers. Both regulator_set_mode() and regulator_set_optimum_mode() now require valid_ops_mask to include REGULATOR_CHANGE_MODE; that seems like a bugfix too. Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: enable/disable refcountingDavid Brownell1-35/+36
Make the <linux/regulator.h> framework treat enable/disable call pairs like the <linux/clk.h> and <linux/interrupt.h> frameworks do: they're refcounted, so that different parts of a driver don't need to put work into coordination that frameworks normally handle. It's a minor object code shrink. It also makes the regulator_is_disabled() kerneldoc say what it's actually returning: return value is not a refcount, and may report an error (e.g. I/O error from I2C). It also fixes some minor regulator_put() goofage: removing unlocked access to the enable state. (But still not making regulator put/get match the refcounting pattern they invoke.) Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2009-01-08regulator: struct device - replace bus_id with dev_name(), dev_set_name()Kay Sievers1-2/+2
This patch is part of a larger patch series which will remove the "char bus_id[20]" name string from struct device. The device name is managed in the kobject anyway, and without any size limitation, and just needlessly copied into "struct device". To set and read the device name dev_name(dev) and dev_set_name(dev) must be used. If your code uses static kobjects, which it shouldn't do, "const char *init_name" can be used to statically provide the name the registered device should have. At registration time, the init_name field is cleared, to enforce the use of dev_name(dev) to access the device name at a later time. We need to get rid of all occurrences of bus_id in the entire tree to be able to enable the new interface. Please apply this patch, and possibly convert any remaining remaining occurrences of bus_id. We want to submit a patch to -next, which will remove bus_id from "struct device", to find the remaining pieces to convert, and finally switch over to the new api, which will remove the 20 bytes array and does no longer have a size limitation. Thanks, Kay From: Kay Sievers <kay.sievers@vrfy.org> Subject: regulator: struct device - replace bus_id with dev_name(), dev_set_name() Cc: Liam Girdwood <lrg@slimlogic.co.uk> Acked-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-Off-By: Kay Sievers <kay.sievers@vrfy.org> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2008-10-13regulator: Export regulator name via sysfsMark Brown1-0/+18
Provide a new file 'name' in the regulator sysfs class with a human readable name for the regulator for use in applications. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2008-10-13regulator: Enable regulators marked as always_onMark Brown1-2/+17
If the machine constraints mark a regulator as always_on but this was not done by the bootloader then enable the regulator when applying constraints. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2008-10-13regulator: Additional diagnostics for machine constraintsMark Brown1-4/+19
Try to find a human readable name for the regulator we're failing on and print a specific diagnostic when we fail to set the suspend state. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2008-10-13regulator: check for init_data on registrationMark Brown1-0/+3
Since it is now mandatory to supply constraints via init_data on device registration check for that when registering, saving us from oopsing later on. Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2008-10-13regulator: core - Rework machine API to remove string based functions.Liam Girdwood1-231/+226
This improves the machine level API in order to configure regulator constraints and consumers as platform data and removes the old string based API that required several calls to set up each regulator. The intention is to create a struct regulator_init_data, populate it's fields with constraints, consumers devices, etc and then register the regulator device from board.c in the standard Linux way. e.g. regulator LDO2 (supplying codec and sim) platform data. /* regulator LDO2 consumer devices */ static struct regulator_consumer_supply ldo2_consumers[] = { { .dev = &platform_audio_device.dev, .supply = "codec_avdd", }, { .dev = &platform_sim_device.dev, .supply = "sim_vcc", } }; /* regulator LDO2 constraints */ static struct regulator_init_data ldo2_data = { .constraints = { .min_uV = 3300000, .max_uV = 3300000, .valid_modes_mask = REGULATOR_MODE_NORMAL, .apply_uV = 1, }, .num_consumer_supplies = ARRAY_SIZE(ldo2_consumers), .consumer_supplies = ldo2_consumers, }; /* machine regulator devices with thier consumers and constraints */ static struct platform_device wm8350_regulator_devices[] = { { .name = "wm8350-regulator", .id = WM8350_LDO_2, .dev = { .platform_data = &ldo2_data, }, }, }; Changes in detail:- o Removed all const char* regulator config functions in machine API. o Created new struct regulator_init_data to contain regulator machine configuration constraints and consmuers. o Changed set_supply(), set_machine_constraints(), set_consumer_device_supply() to remove their string identifier parameters. Also made them static and moved functions nearer top of core.c. o Removed no longer used inline func to_rdev() o Added regulator_get_init_drvdata() to retrieve init data. o Added struct device* as parameter to regulator_register(). o Changed my email address. Signed-off-by: Eric Miao <eric.miao@marvell.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com> Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2008-07-30regulator: regulator framework coreLiam Girdwood1-0/+1903
This adds the regulator framework core. This framework is designed to provide a generic interface to voltage and current regulators within the Linux kernel. It's intended to provide voltage and current control to client or consumer drivers and also provide status information to user space applications through a sysfs interface. The intention is to allow systems to dynamically control regulator output in order to save power and prolong battery life. This applies to both voltage regulators (where voltage output is controllable) and current sinks (where current output is controllable). This framework safely compiles out if not selected so that client drivers can still be used in systems with no software controllable regulators. Signed-off-by: Liam Girdwood <lg@opensource.wolfsonmicro.com> Signed-off-by: Greg Kroah-Hartman <greg@kroah.com> Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>