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Subject[patch 2.6.29-rc] regulator: add get_status()
Date
From: David Brownell <dbrownell@users.sourceforge.net>

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>
---

Documentation/ABI/testing/sysfs-class-regulator | 57 ++++++++++++++++++----
drivers/regulator/core.c | 46 +++++++++++++++++
include/linux/regulator/driver.h | 17 ++++++
3 files changed, 111 insertions(+), 9 deletions(-)

--- a/Documentation/ABI/testing/sysfs-class-regulator
+++ b/Documentation/ABI/testing/sysfs-class-regulator
@@ -4,8 +4,8 @@ KernelVersion: 2.6.26
Contact: Liam Girdwood <lrg@slimlogic.co.uk>
Description:
Some regulator directories will contain a field called
- state. This reports the regulator enable status, for
- regulators which can report that value.
+ state. This reports the regulator enable control, for
+ regulators which can report that input value.

This will be one of the following strings:

@@ -14,16 +14,54 @@ Description:
'unknown'

'enabled' means the regulator output is ON and is supplying
- power to the system.
+ power to the system (assuming no error prevents it).

'disabled' means the regulator output is OFF and is not
- supplying power to the system..
+ supplying power to the system (unless some non-Linux
+ control has enabled it).

'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.
+ or microamps to determine configured regulator output levels.
+
+
+What: /sys/class/regulator/.../status
+Description:
+ Some regulator directories will contain a field called
+ "status". This reports the current regulator status, for
+ regulators which can report that output value.
+
+ This will be one of the following strings:
+
+ off
+ on
+ error
+ fast
+ normal
+ idle
+ standby
+
+ "off" means the regulator is not supplying power to the
+ system.
+
+ "on" means the regulator is supplying power to the system,
+ and the regulator can't report a detailed operation mode.
+
+ "error" indicates an out-of-regulation status such as being
+ disabled due to thermal shutdown, or voltage being unstable
+ because of problems with the input power supply.
+
+ "fast", "normal", "idle", and "standby" are all detailed
+ regulator operation modes (described elsewhere). They
+ imply "on", but provide more detail.
+
+ Note that regulator status is a function of many inputs,
+ not limited to control inputs from Linux. For example,
+ the actual load presented may trigger "error" status; or
+ a regulator may be enabled by another user, even though
+ Linux did not enable it.


What: /sys/class/regulator/.../type
@@ -58,7 +96,7 @@ Description:
Some regulator directories will contain a field called
microvolts. This holds the regulator output voltage setting
measured in microvolts (i.e. E-6 Volts), for regulators
- which can report that voltage.
+ which can report the control input for voltage.

NOTE: This value should not be used to determine the regulator
output voltage level as this value is the same regardless of
@@ -73,7 +111,7 @@ Description:
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), for regulators
- which can report that current.
+ which can report the control input for a current limit.

NOTE: This value should not be used to determine the regulator
output current level as this value is the same regardless of
@@ -87,7 +125,7 @@ Contact: Liam Girdwood <lrg@slimlogic.co
Description:
Some regulator directories will contain a field called
opmode. This holds the current regulator operating mode,
- for regulators which can report it.
+ for regulators which can report that control input value.

The opmode value can be one of the following strings:

@@ -101,7 +139,8 @@ Description:

NOTE: This value should not be used to determine the regulator
output operating mode as this value is the same regardless of
- whether the regulator is enabled or disabled.
+ whether the regulator is enabled or disabled. A "status"
+ attribute may be available to determine the actual mode.


What: /sys/class/regulator/.../min_microvolts
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -312,6 +312,47 @@ static ssize_t regulator_state_show(stru
}
static DEVICE_ATTR(state, 0444, regulator_state_show, NULL);

+static ssize_t regulator_status_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct regulator_dev *rdev = dev_get_drvdata(dev);
+ int status;
+ char *label;
+
+ status = rdev->desc->ops->get_status(rdev);
+ if (status < 0)
+ return status;
+
+ switch (status) {
+ case REGULATOR_STATUS_OFF:
+ label = "off";
+ break;
+ case REGULATOR_STATUS_ON:
+ label = "on";
+ break;
+ case REGULATOR_STATUS_ERROR:
+ label = "error";
+ break;
+ case REGULATOR_STATUS_FAST:
+ label = "fast";
+ break;
+ case REGULATOR_STATUS_NORMAL:
+ label = "normal";
+ break;
+ case REGULATOR_STATUS_IDLE:
+ label = "idle";
+ break;
+ case REGULATOR_STATUS_STANDBY:
+ label = "standby";
+ break;
+ default:
+ return -ERANGE;
+ }
+
+ return sprintf(buf, "%s\n", label);
+}
+static DEVICE_ATTR(status, 0444, regulator_status_show, NULL);
+
static ssize_t regulator_min_uA_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -1744,6 +1785,11 @@ static int add_regulator_attributes(stru
if (status < 0)
return status;
}
+ if (ops->get_status) {
+ status = device_create_file(dev, &dev_attr_status);
+ if (status < 0)
+ return status;
+ }

/* some attributes are type-specific */
if (rdev->desc->type == REGULATOR_CURRENT) {
--- a/include/linux/regulator/driver.h
+++ b/include/linux/regulator/driver.h
@@ -21,6 +21,17 @@
struct regulator_dev;
struct regulator_init_data;

+enum regulator_status {
+ REGULATOR_STATUS_OFF,
+ REGULATOR_STATUS_ON,
+ REGULATOR_STATUS_ERROR,
+ /* fast/normal/idle/standby are flavors of "on" */
+ REGULATOR_STATUS_FAST,
+ REGULATOR_STATUS_NORMAL,
+ REGULATOR_STATUS_IDLE,
+ REGULATOR_STATUS_STANDBY,
+};
+
/**
* struct regulator_ops - regulator operations.
*
@@ -46,6 +57,12 @@ struct regulator_ops {
int (*set_mode) (struct regulator_dev *, unsigned int mode);
unsigned int (*get_mode) (struct regulator_dev *);

+ /* report regulator status ... most other accessors report
+ * control inputs, this reports results of combining inputs
+ * from Linux (and other sources) with the actual load.
+ */
+ int (*get_status)(struct regulator_dev *);
+
/* get most efficient regulator operating mode for load */
unsigned int (*get_optimum_mode) (struct regulator_dev *, int input_uV,
int output_uV, int load_uA);

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