regulator: sysfs attribute reduction (v2)
David Brownell [Wed, 12 Nov 2008 01:39:02 +0000 (17:39 -0800)]
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>

Documentation/ABI/testing/sysfs-class-regulator
drivers/regulator/core.c

index 3731f6f..873ef1f 100644 (file)
@@ -3,8 +3,9 @@ Date:           April 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
-               state. This holds the regulator output state.
+               Some regulator directories will contain a field called
+               state. This reports the regulator enable status, for
+               regulators which can report that value.
 
                This will be one of the following strings:
 
@@ -18,7 +19,8 @@ Description:
                'disabled' means the regulator output is OFF and is not
                supplying power to the system..
 
-               'unknown' means software cannot determine the state.
+               'unknown' means software cannot determine the state, or
+               the reported state is invalid.
 
                NOTE: this field can be used in conjunction with microvolts
                and microamps to determine regulator output levels.
@@ -53,9 +55,10 @@ Date:                April 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                microvolts. This holds the regulator output voltage setting
-               measured in microvolts (i.e. E-6 Volts).
+               measured in microvolts (i.e. E-6 Volts), for regulators
+               which can report that voltage.
 
                NOTE: This value should not be used to determine the regulator
                output voltage level as this value is the same regardless of
@@ -67,9 +70,10 @@ Date:                April 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                microamps. This holds the regulator output current limit
-               setting measured in microamps (i.e. E-6 Amps).
+               setting measured in microamps (i.e. E-6 Amps), for regulators
+               which can report that current.
 
                NOTE: This value should not be used to determine the regulator
                output current level as this value is the same regardless of
@@ -81,8 +85,9 @@ Date:         April 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
-               opmode. This holds the regulator operating mode setting.
+               Some regulator directories will contain a field called
+               opmode. This holds the current regulator operating mode,
+               for regulators which can report it.
 
                The opmode value can be one of the following strings:
 
@@ -92,7 +97,7 @@ Description:
                'standby'
                'unknown'
 
-               The modes are described in include/linux/regulator/regulator.h
+               The modes are described in include/linux/regulator/consumer.h
 
                NOTE: This value should not be used to determine the regulator
                output operating mode as this value is the same regardless of
@@ -104,9 +109,10 @@ Date:              April 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                min_microvolts. This holds the minimum safe working regulator
-               output voltage setting for this domain measured in microvolts.
+               output voltage setting for this domain measured in microvolts,
+               for regulators which support voltage constraints.
 
                NOTE: this will return the string 'constraint not defined' if
                the power domain has no min microvolts constraint defined by
@@ -118,9 +124,10 @@ Date:              April 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                max_microvolts. This holds the maximum safe working regulator
-               output voltage setting for this domain measured in microvolts.
+               output voltage setting for this domain measured in microvolts,
+               for regulators which support voltage constraints.
 
                NOTE: this will return the string 'constraint not defined' if
                the power domain has no max microvolts constraint defined by
@@ -132,10 +139,10 @@ Date:             April 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                min_microamps. This holds the minimum safe working regulator
                output current limit setting for this domain measured in
-               microamps.
+               microamps, for regulators which support current constraints.
 
                NOTE: this will return the string 'constraint not defined' if
                the power domain has no min microamps constraint defined by
@@ -147,10 +154,10 @@ Date:             April 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                max_microamps. This holds the maximum safe working regulator
                output current limit setting for this domain measured in
-               microamps.
+               microamps, for regulators which support current constraints.
 
                NOTE: this will return the string 'constraint not defined' if
                the power domain has no max microamps constraint defined by
@@ -185,7 +192,7 @@ Date:               April 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                requested_microamps. This holds the total requested load
                current in microamps for this regulator from all its consumer
                devices.
@@ -204,125 +211,102 @@ Date:           May 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                suspend_mem_microvolts. This holds the regulator output
                voltage setting for this domain measured in microvolts when
-               the system is suspended to memory.
-
-               NOTE: this will return the string 'not defined' if
-               the power domain has no suspend to memory voltage defined by
-               platform code.
+               the system is suspended to memory, for voltage regulators
+               implementing suspend voltage configuration constraints.
 
 What:          /sys/class/regulator/.../suspend_disk_microvolts
 Date:          May 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                suspend_disk_microvolts. This holds the regulator output
                voltage setting for this domain measured in microvolts when
-               the system is suspended to disk.
-
-               NOTE: this will return the string 'not defined' if
-               the power domain has no suspend to disk voltage defined by
-               platform code.
+               the system is suspended to disk, for voltage regulators
+               implementing suspend voltage configuration constraints.
 
 What:          /sys/class/regulator/.../suspend_standby_microvolts
 Date:          May 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                suspend_standby_microvolts. This holds the regulator output
                voltage setting for this domain measured in microvolts when
-               the system is suspended to standby.
-
-               NOTE: this will return the string 'not defined' if
-               the power domain has no suspend to standby voltage defined by
-               platform code.
+               the system is suspended to standby, for voltage regulators
+               implementing suspend voltage configuration constraints.
 
 What:          /sys/class/regulator/.../suspend_mem_mode
 Date:          May 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                suspend_mem_mode. This holds the regulator operating mode
                setting for this domain when the system is suspended to
-               memory.
-
-               NOTE: this will return the string 'not defined' if
-               the power domain has no suspend to memory mode defined by
-               platform code.
+               memory, for regulators implementing suspend mode
+               configuration constraints.
 
 What:          /sys/class/regulator/.../suspend_disk_mode
 Date:          May 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                suspend_disk_mode. This holds the regulator operating mode
-               setting for this domain when the system is suspended to disk.
-
-               NOTE: this will return the string 'not defined' if
-               the power domain has no suspend to disk mode defined by
-               platform code.
+               setting for this domain when the system is suspended to disk,
+               for regulators implementing suspend mode configuration
+               constraints.
 
 What:          /sys/class/regulator/.../suspend_standby_mode
 Date:          May 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                suspend_standby_mode. This holds the regulator operating mode
                setting for this domain when the system is suspended to
-               standby.
-
-               NOTE: this will return the string 'not defined' if
-               the power domain has no suspend to standby mode defined by
-               platform code.
+               standby, for regulators implementing suspend mode
+               configuration constraints.
 
 What:          /sys/class/regulator/.../suspend_mem_state
 Date:          May 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                suspend_mem_state. This holds the regulator operating state
-               when suspended to memory.
-
-               This will be one of the following strings:
+               when suspended to memory, for regulators implementing suspend
+               configuration constraints.
 
-               'enabled'
-               'disabled'
-               'not defined'
+               This will be one of the same strings reported by
+               the "state" attribute.
 
 What:          /sys/class/regulator/.../suspend_disk_state
 Date:          May 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                suspend_disk_state. This holds the regulator operating state
-               when suspended to disk.
-
-               This will be one of the following strings:
+               when suspended to disk, for regulators implementing
+               suspend configuration constraints.
 
-               'enabled'
-               'disabled'
-               'not defined'
+               This will be one of the same strings reported by
+               the "state" attribute.
 
 What:          /sys/class/regulator/.../suspend_standby_state
 Date:          May 2008
 KernelVersion: 2.6.26
 Contact:       Liam Girdwood <lrg@slimlogic.co.uk>
 Description:
-               Each regulator directory will contain a field called
+               Some regulator directories will contain a field called
                suspend_standby_state. This holds the regulator operating
-               state when suspended to standby.
-
-               This will be one of the following strings:
+               state when suspended to standby, for regulators implementing
+               suspend configuration constraints.
 
-               'enabled'
-               'disabled'
-               'not defined'
+               This will be one of the same strings reported by
+               the "state" attribute.
index 5109f7d..9a5ff97 100644 (file)
@@ -242,6 +242,7 @@ static ssize_t regulator_uV_show(struct device *dev,
 
        return ret;
 }
+static DEVICE_ATTR(microvolts, 0444, regulator_uV_show, NULL);
 
 static ssize_t regulator_uA_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
@@ -250,6 +251,7 @@ static ssize_t regulator_uA_show(struct device *dev,
 
        return sprintf(buf, "%d\n", _regulator_get_current_limit(rdev));
 }
+static DEVICE_ATTR(microamps, 0444, regulator_uA_show, NULL);
 
 static ssize_t regulator_name_show(struct device *dev,
                             struct device_attribute *attr, char *buf)
@@ -289,6 +291,7 @@ static ssize_t regulator_opmode_show(struct device *dev,
 
        return regulator_print_opmode(buf, _regulator_get_mode(rdev));
 }
+static DEVICE_ATTR(opmode, 0444, regulator_opmode_show, NULL);
 
 static ssize_t regulator_print_state(char *buf, int state)
 {
@@ -307,6 +310,7 @@ static ssize_t regulator_state_show(struct device *dev,
 
        return regulator_print_state(buf, _regulator_is_enabled(rdev));
 }
+static DEVICE_ATTR(state, 0444, regulator_state_show, NULL);
 
 static ssize_t regulator_min_uA_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
@@ -318,6 +322,7 @@ static ssize_t regulator_min_uA_show(struct device *dev,
 
        return sprintf(buf, "%d\n", rdev->constraints->min_uA);
 }
+static DEVICE_ATTR(min_microamps, 0444, regulator_min_uA_show, NULL);
 
 static ssize_t regulator_max_uA_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
@@ -329,6 +334,7 @@ static ssize_t regulator_max_uA_show(struct device *dev,
 
        return sprintf(buf, "%d\n", rdev->constraints->max_uA);
 }
+static DEVICE_ATTR(max_microamps, 0444, regulator_max_uA_show, NULL);
 
 static ssize_t regulator_min_uV_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
@@ -340,6 +346,7 @@ static ssize_t regulator_min_uV_show(struct device *dev,
 
        return sprintf(buf, "%d\n", rdev->constraints->min_uV);
 }
+static DEVICE_ATTR(min_microvolts, 0444, regulator_min_uV_show, NULL);
 
 static ssize_t regulator_max_uV_show(struct device *dev,
                                    struct device_attribute *attr, char *buf)
@@ -351,6 +358,7 @@ static ssize_t regulator_max_uV_show(struct device *dev,
 
        return sprintf(buf, "%d\n", rdev->constraints->max_uV);
 }
+static DEVICE_ATTR(max_microvolts, 0444, regulator_max_uV_show, NULL);
 
 static ssize_t regulator_total_uA_show(struct device *dev,
                                      struct device_attribute *attr, char *buf)
@@ -365,6 +373,7 @@ static ssize_t regulator_total_uA_show(struct device *dev,
        mutex_unlock(&rdev->mutex);
        return sprintf(buf, "%d\n", uA);
 }
+static DEVICE_ATTR(requested_microamps, 0444, regulator_total_uA_show, NULL);
 
 static ssize_t regulator_num_users_show(struct device *dev,
                                      struct device_attribute *attr, char *buf)
@@ -392,131 +401,106 @@ static ssize_t regulator_suspend_mem_uV_show(struct device *dev,
 {
        struct regulator_dev *rdev = dev_get_drvdata(dev);
 
-       if (!rdev->constraints)
-               return sprintf(buf, "not defined\n");
        return sprintf(buf, "%d\n", rdev->constraints->state_mem.uV);
 }
+static DEVICE_ATTR(suspend_mem_microvolts, 0444,
+               regulator_suspend_mem_uV_show, NULL);
 
 static ssize_t regulator_suspend_disk_uV_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
 {
        struct regulator_dev *rdev = dev_get_drvdata(dev);
 
-       if (!rdev->constraints)
-               return sprintf(buf, "not defined\n");
        return sprintf(buf, "%d\n", rdev->constraints->state_disk.uV);
 }
+static DEVICE_ATTR(suspend_disk_microvolts, 0444,
+               regulator_suspend_disk_uV_show, NULL);
 
 static ssize_t regulator_suspend_standby_uV_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
 {
        struct regulator_dev *rdev = dev_get_drvdata(dev);
 
-       if (!rdev->constraints)
-               return sprintf(buf, "not defined\n");
        return sprintf(buf, "%d\n", rdev->constraints->state_standby.uV);
 }
+static DEVICE_ATTR(suspend_standby_microvolts, 0444,
+               regulator_suspend_standby_uV_show, NULL);
 
 static ssize_t regulator_suspend_mem_mode_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
 {
        struct regulator_dev *rdev = dev_get_drvdata(dev);
 
-       if (!rdev->constraints)
-               return sprintf(buf, "not defined\n");
        return regulator_print_opmode(buf,
                rdev->constraints->state_mem.mode);
 }
+static DEVICE_ATTR(suspend_mem_mode, 0444,
+               regulator_suspend_mem_mode_show, NULL);
 
 static ssize_t regulator_suspend_disk_mode_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
 {
        struct regulator_dev *rdev = dev_get_drvdata(dev);
 
-       if (!rdev->constraints)
-               return sprintf(buf, "not defined\n");
        return regulator_print_opmode(buf,
                rdev->constraints->state_disk.mode);
 }
+static DEVICE_ATTR(suspend_disk_mode, 0444,
+               regulator_suspend_disk_mode_show, NULL);
 
 static ssize_t regulator_suspend_standby_mode_show(struct device *dev,
                                struct device_attribute *attr, char *buf)
 {
        struct regulator_dev *rdev = dev_get_drvdata(dev);
 
-       if (!rdev->constraints)
-               return sprintf(buf, "not defined\n");
        return regulator_print_opmode(buf,
                rdev->constraints->state_standby.mode);
 }
+static DEVICE_ATTR(suspend_standby_mode, 0444,
+               regulator_suspend_standby_mode_show, NULL);
 
 static ssize_t regulator_suspend_mem_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
 {
        struct regulator_dev *rdev = dev_get_drvdata(dev);
 
-       if (!rdev->constraints)
-               return sprintf(buf, "not defined\n");
-
        return regulator_print_state(buf,
                        rdev->constraints->state_mem.enabled);
 }
+static DEVICE_ATTR(suspend_mem_state, 0444,
+               regulator_suspend_mem_state_show, NULL);
 
 static ssize_t regulator_suspend_disk_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
 {
        struct regulator_dev *rdev = dev_get_drvdata(dev);
 
-       if (!rdev->constraints)
-               return sprintf(buf, "not defined\n");
-
        return regulator_print_state(buf,
                        rdev->constraints->state_disk.enabled);
 }
+static DEVICE_ATTR(suspend_disk_state, 0444,
+               regulator_suspend_disk_state_show, NULL);
 
 static ssize_t regulator_suspend_standby_state_show(struct device *dev,
                                   struct device_attribute *attr, char *buf)
 {
        struct regulator_dev *rdev = dev_get_drvdata(dev);
 
-       if (!rdev->constraints)
-               return sprintf(buf, "not defined\n");
-
        return regulator_print_state(buf,
                        rdev->constraints->state_standby.enabled);
 }
+static DEVICE_ATTR(suspend_standby_state, 0444,
+               regulator_suspend_standby_state_show, NULL);
+
 
+/*
+ * These are the only attributes are present for all regulators.
+ * Other attributes are a function of regulator functionality.
+ */
 static struct device_attribute regulator_dev_attrs[] = {
        __ATTR(name, 0444, regulator_name_show, NULL),
-       __ATTR(microvolts, 0444, regulator_uV_show, NULL),
-       __ATTR(microamps, 0444, regulator_uA_show, NULL),
-       __ATTR(opmode, 0444, regulator_opmode_show, NULL),
-       __ATTR(state, 0444, regulator_state_show, NULL),
-       __ATTR(min_microvolts, 0444, regulator_min_uV_show, NULL),
-       __ATTR(min_microamps, 0444, regulator_min_uA_show, NULL),
-       __ATTR(max_microvolts, 0444, regulator_max_uV_show, NULL),
-       __ATTR(max_microamps, 0444, regulator_max_uA_show, NULL),
-       __ATTR(requested_microamps, 0444, regulator_total_uA_show, NULL),
        __ATTR(num_users, 0444, regulator_num_users_show, NULL),
        __ATTR(type, 0444, regulator_type_show, NULL),
-       __ATTR(suspend_mem_microvolts, 0444,
-               regulator_suspend_mem_uV_show, NULL),
-       __ATTR(suspend_disk_microvolts, 0444,
-               regulator_suspend_disk_uV_show, NULL),
-       __ATTR(suspend_standby_microvolts, 0444,
-               regulator_suspend_standby_uV_show, NULL),
-       __ATTR(suspend_mem_mode, 0444,
-               regulator_suspend_mem_mode_show, NULL),
-       __ATTR(suspend_disk_mode, 0444,
-               regulator_suspend_disk_mode_show, NULL),
-       __ATTR(suspend_standby_mode, 0444,
-               regulator_suspend_standby_mode_show, NULL),
-       __ATTR(suspend_mem_state, 0444,
-               regulator_suspend_mem_state_show, NULL),
-       __ATTR(suspend_disk_state, 0444,
-               regulator_suspend_disk_state_show, NULL),
-       __ATTR(suspend_standby_state, 0444,
-               regulator_suspend_standby_state_show, NULL),
        __ATTR_NULL,
 };
 
@@ -1711,6 +1695,117 @@ int regulator_notifier_call_chain(struct regulator_dev *rdev,
 }
 EXPORT_SYMBOL_GPL(regulator_notifier_call_chain);
 
+/*
+ * To avoid cluttering sysfs (and memory) with useless state, only
+ * create attributes that can be meaningfully displayed.
+ */
+static int add_regulator_attributes(struct regulator_dev *rdev)
+{
+       struct device           *dev = &rdev->dev;
+       struct regulator_ops    *ops = rdev->desc->ops;
+       int                     status = 0;
+
+       /* some attributes need specific methods to be displayed */
+       if (ops->get_voltage) {
+               status = device_create_file(dev, &dev_attr_microvolts);
+               if (status < 0)
+                       return status;
+       }
+       if (ops->get_current_limit) {
+               status = device_create_file(dev, &dev_attr_microamps);
+               if (status < 0)
+                       return status;
+       }
+       if (ops->get_mode) {
+               status = device_create_file(dev, &dev_attr_opmode);
+               if (status < 0)
+                       return status;
+       }
+       if (ops->is_enabled) {
+               status = device_create_file(dev, &dev_attr_state);
+               if (status < 0)
+                       return status;
+       }
+
+       /* some attributes are type-specific */
+       if (rdev->desc->type == REGULATOR_CURRENT) {
+               status = device_create_file(dev, &dev_attr_requested_microamps);
+               if (status < 0)
+                       return status;
+       }
+
+       /* all the other attributes exist to support constraints;
+        * don't show them if there are no constraints, or if the
+        * relevant supporting methods are missing.
+        */
+       if (!rdev->constraints)
+               return status;
+
+       /* constraints need specific supporting methods */
+       if (ops->set_voltage) {
+               status = device_create_file(dev, &dev_attr_min_microvolts);
+               if (status < 0)
+                       return status;
+               status = device_create_file(dev, &dev_attr_max_microvolts);
+               if (status < 0)
+                       return status;
+       }
+       if (ops->set_current_limit) {
+               status = device_create_file(dev, &dev_attr_min_microamps);
+               if (status < 0)
+                       return status;
+               status = device_create_file(dev, &dev_attr_max_microamps);
+               if (status < 0)
+                       return status;
+       }
+
+       /* suspend mode constraints need multiple supporting methods */
+       if (!(ops->set_suspend_enable && ops->set_suspend_disable))
+               return status;
+
+       status = device_create_file(dev, &dev_attr_suspend_standby_state);
+       if (status < 0)
+               return status;
+       status = device_create_file(dev, &dev_attr_suspend_mem_state);
+       if (status < 0)
+               return status;
+       status = device_create_file(dev, &dev_attr_suspend_disk_state);
+       if (status < 0)
+               return status;
+
+       if (ops->set_suspend_voltage) {
+               status = device_create_file(dev,
+                               &dev_attr_suspend_standby_microvolts);
+               if (status < 0)
+                       return status;
+               status = device_create_file(dev,
+                               &dev_attr_suspend_mem_microvolts);
+               if (status < 0)
+                       return status;
+               status = device_create_file(dev,
+                               &dev_attr_suspend_disk_microvolts);
+               if (status < 0)
+                       return status;
+       }
+
+       if (ops->set_suspend_mode) {
+               status = device_create_file(dev,
+                               &dev_attr_suspend_standby_mode);
+               if (status < 0)
+                       return status;
+               status = device_create_file(dev,
+                               &dev_attr_suspend_mem_mode);
+               if (status < 0)
+                       return status;
+               status = device_create_file(dev,
+                               &dev_attr_suspend_disk_mode);
+               if (status < 0)
+                       return status;
+       }
+
+       return status;
+}
+
 /**
  * regulator_register - register regulator
  * @regulator: regulator source
@@ -1779,6 +1874,11 @@ struct regulator_dev *regulator_register(struct regulator_desc *regulator_desc,
 
        dev_set_drvdata(&rdev->dev, rdev);
 
+       /* add attributes supported by this regulator */
+       ret = add_regulator_attributes(rdev);
+       if (ret < 0)
+               goto scrub;
+
        /* set supply regulator if it exists */
        if (init_data->supply_regulator_dev) {
                ret = set_supply(rdev,