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Commit 34abbd68 authored by Mark Brown's avatar Mark Brown Committed by Liam Girdwood
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regulator: Provide optional dummy regulator for consumers 



In order to ease transitions with drivers are boards start using regulators
provide an option to cause all regulator_get() calls to succeed, with a
dummy always on regulator being supplied where one has not been configured.
A warning is printed whenever the dummy regulator is used to aid system
development.

This regulator does not implement any regulator operations but will allow
simple consumers which only do enable() and disable() calls to run. It
is kept separate from the fixed voltage regulator to avoid Kconfig
confusion on the part of users when it is extended to allow boards to
explicitly use the dummy regulator to simplify cases where the majority
of supplies are from fixed regulators without software control.

This option is currently only effective for systems which do not specify
full constriants. If required an override could also be provided to allow
these systems to use the dummy regulator, though it is likely that
unconfigured supplies on such systems will lead to error due to
regulators being powered down more aggressively when not in use.

Signed-off-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: default avatarLiam Girdwood <lrg@slimlogic.co.uk>
parent 9a7f6a4c

drivers/regulator/Kconfig

+11 −0
Original line number Diff line number Diff line
@@ -27,6 +27,17 @@ config REGULATOR_DEBUG 
	help

	  Say yes here to enable debugging support.



config REGULATOR_DUMMY

	bool "Provide a dummy regulator if regulator lookups fail"

	help

	  If this option is enabled then when a regulator lookup fails

	  and the board has not specified that it has provided full

	  constraints then the regulator core will provide an always

	  enabled dummy regulator will be provided, allowing consumer

	  drivers to continue.



	  A warning will be generated when this substitution is done.



config REGULATOR_FIXED_VOLTAGE

	tristate "Fixed voltage regulator support"

	help

drivers/regulator/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ obj-$(CONFIG_REGULATOR_VIRTUAL_CONSUMER) += virtual.o 
obj-$(CONFIG_REGULATOR_USERSPACE_CONSUMER) += userspace-consumer.o



obj-$(CONFIG_REGULATOR_BQ24022) += bq24022.o

obj-$(CONFIG_REGULATOR_DUMMY) += dummy.o

obj-$(CONFIG_REGULATOR_LP3971) += lp3971.o

obj-$(CONFIG_REGULATOR_MAX1586) += max1586.o

obj-$(CONFIG_REGULATOR_TWL4030) += twl-regulator.o

drivers/regulator/core.c

+26 −1
Original line number Diff line number Diff line
@@ -24,6 +24,8 @@ 
#include <linux/regulator/driver.h>

#include <linux/regulator/machine.h>



#include "dummy.h"



#define REGULATOR_VERSION "0.5"



static DEFINE_MUTEX(regulator_list_mutex);
@@ -1123,6 +1125,22 @@ static struct regulator *_regulator_get(struct device *dev, const char *id, 
			goto found;

		}

	}



#ifdef CONFIG_REGULATOR_DUMMY

	if (!devname)

		devname = "deviceless";



	/* If the board didn't flag that it was fully constrained then

	 * substitute in a dummy regulator so consumers can continue.

	 */

	if (!has_full_constraints) {

		pr_warning("%s supply %s not found, using dummy regulator\n",

			   devname, id);

		rdev = dummy_regulator_rdev;

		goto found;

	}

#endif



	mutex_unlock(&regulator_list_mutex);

	return regulator;
@@ -2483,8 +2501,15 @@ EXPORT_SYMBOL_GPL(regulator_get_init_drvdata); 


static int __init regulator_init(void)

{

	int ret;



	printk(KERN_INFO "regulator: core version %s\n", REGULATOR_VERSION);

	return class_register(&regulator_class);



	ret = class_register(&regulator_class);



	regulator_dummy_init();



	return ret;

}



/* init early to allow our consumers to complete system booting */

drivers/regulator/dummy.c

0 → 100644
+66 −0
Original line number Diff line number Diff line 
/*

 * dummy.c

 *

 * Copyright 2010 Wolfson Microelectronics PLC.

 *

 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License as

 * published by the Free Software Foundation; either version 2 of the

 * License, or (at your option) any later version.

 *

 * This is useful for systems with mixed controllable and

 * non-controllable regulators, as well as for allowing testing on

 * systems with no controllable regulators.

 */



#include <linux/err.h>

#include <linux/platform_device.h>

#include <linux/regulator/driver.h>

#include <linux/regulator/machine.h>



#include "dummy.h"



struct regulator_dev *dummy_regulator_rdev;



static struct regulator_init_data dummy_initdata;



static struct regulator_ops dummy_ops;



static struct regulator_desc dummy_desc = {

	.name = "dummy",

	.id = -1,

	.type = REGULATOR_VOLTAGE,

	.owner = THIS_MODULE,

	.ops = &dummy_ops,

};



static struct platform_device *dummy_pdev;



void __init regulator_dummy_init(void)

{

	int ret;



	dummy_pdev = platform_device_alloc("reg-dummy", -1);

	if (!dummy_pdev) {

		pr_err("Failed to allocate dummy regulator device\n");

		return;

	}



	ret = platform_device_add(dummy_pdev);

	if (ret != 0) {

		pr_err("Failed to register dummy regulator device: %d\n", ret);

		platform_device_put(dummy_pdev);

		return;

	}



	dummy_regulator_rdev = regulator_register(&dummy_desc, NULL,

						  &dummy_initdata, NULL);

	if (IS_ERR(dummy_regulator_rdev)) {

		ret = PTR_ERR(dummy_regulator_rdev);

		pr_err("Failed to register regulator: %d\n", ret);

		platform_device_unregister(dummy_pdev);

		return;

	}

}

drivers/regulator/dummy.h

0 → 100644
+31 −0
Original line number Diff line number Diff line 
/*

 * dummy.h

 *

 * Copyright 2010 Wolfson Microelectronics PLC.

 *

 * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>

 *

 * This program is free software; you can redistribute it and/or

 * modify it under the terms of the GNU General Public License as

 * published by the Free Software Foundation; either version 2 of the

 * License, or (at your option) any later version.

 *

 * This is useful for systems with mixed controllable and

 * non-controllable regulators, as well as for allowing testing on

 * systems with no controllable regulators.

 */



#ifndef _DUMMY_H

#define _DUMMY_H



struct regulator_dev;



extern struct regulator_dev *dummy_regulator_rdev;



#ifdef CONFIG_REGULATOR_DUMMY

void __init regulator_dummy_init(void);

#else

static inline void regulator_dummy_init(void) { }

#endif



#endif