2023-10-05 14:26:52

by Naresh Solanki

[permalink] [raw]
Subject: [PATCH] drivers/regulator: Notify sysfs about status changes

From: Patrick Rudolph <[email protected]>

Notify sysfs for state, status & microvolts.

Signed-off-by: Patrick Rudolph <[email protected]>
Signed-off-by: Naresh Solanki <[email protected]>
---
drivers/regulator/core.c | 23 ++++++++++++++++++++++-
1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index 3137e40fcd3e..ef5fa70ae2f1 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -98,6 +98,10 @@ static struct regulator *create_regulator(struct regulator_dev *rdev,
static void destroy_regulator(struct regulator *regulator);
static void _regulator_put(struct regulator *regulator);

+static struct device_attribute dev_attr_status;
+static struct device_attribute dev_attr_microvolts;
+static struct device_attribute dev_attr_state;
+
const char *rdev_get_name(struct regulator_dev *rdev)
{
if (rdev->constraints && rdev->constraints->name)
@@ -2798,6 +2802,8 @@ static int _regulator_do_enable(struct regulator_dev *rdev)
_regulator_delay_helper(delay);
}

+ sysfs_notify(&rdev->dev.kobj, NULL, dev_attr_state.attr.name);
+
trace_regulator_enable_complete(rdev_get_name(rdev));

return 0;
@@ -2980,6 +2986,8 @@ static int _regulator_do_disable(struct regulator_dev *rdev)
if (rdev->desc->off_on_delay)
rdev->last_off = ktime_get_boottime();

+ sysfs_notify(&rdev->dev.kobj, NULL, dev_attr_state.attr.name);
+
trace_regulator_disable_complete(rdev_get_name(rdev));

return 0;
@@ -4848,8 +4856,21 @@ EXPORT_SYMBOL_GPL(regulator_unregister_notifier);
static int _notifier_call_chain(struct regulator_dev *rdev,
unsigned long event, void *data)
{
+ const char *name;
+ int ret;
+
/* call rdev chain first */
- return blocking_notifier_call_chain(&rdev->notifier, event, data);
+ ret = blocking_notifier_call_chain(&rdev->notifier, event, data);
+
+ if (event & REGULATOR_EVENT_VOLTAGE_CHANGE) {
+ name = dev_attr_microvolts.attr.name;
+ sysfs_notify(&rdev->dev.kobj, NULL, name);
+ } else {
+ name = dev_attr_status.attr.name;
+ sysfs_notify(&rdev->dev.kobj, NULL, name);
+ }
+
+ return ret;
}

int _regulator_bulk_get(struct device *dev, int num_consumers,

base-commit: f9a1d31874c383f58bb4f89bfe79b764682cd026
--
2.41.0


2023-10-05 17:12:56

by Mark Brown

[permalink] [raw]
Subject: Re: [PATCH] drivers/regulator: Notify sysfs about status changes

On Thu, Oct 05, 2023 at 03:30:58PM +0200, Naresh Solanki wrote:

> static int _notifier_call_chain(struct regulator_dev *rdev,
> unsigned long event, void *data)
> {
> + const char *name;
> + int ret;
> +
> /* call rdev chain first */
> - return blocking_notifier_call_chain(&rdev->notifier, event, data);
> + ret = blocking_notifier_call_chain(&rdev->notifier, event, data);
> +
> + if (event & REGULATOR_EVENT_VOLTAGE_CHANGE) {
> + name = dev_attr_microvolts.attr.name;
> + sysfs_notify(&rdev->dev.kobj, NULL, name);
> + } else {
> + name = dev_attr_status.attr.name;
> + sysfs_notify(&rdev->dev.kobj, NULL, name);
> + }

We probably should filter the events more, there's events for pre and
post voltage change for example which aren't status changes so would be
spurious. It ought not to break anything but we should still avoid
unneeded work.


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2023-11-02 12:07:47

by Naresh Solanki

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Subject: Re: [PATCH] drivers/regulator: Notify sysfs about status changes

Hi Mark,

On Thu, 5 Oct 2023 at 22:30, Mark Brown <[email protected]> wrote:
>
> On Thu, Oct 05, 2023 at 03:30:58PM +0200, Naresh Solanki wrote:
>
> > static int _notifier_call_chain(struct regulator_dev *rdev,
> > unsigned long event, void *data)
> > {
> > + const char *name;
> > + int ret;
> > +
> > /* call rdev chain first */
> > - return blocking_notifier_call_chain(&rdev->notifier, event, data);
> > + ret = blocking_notifier_call_chain(&rdev->notifier, event, data);
> > +
> > + if (event & REGULATOR_EVENT_VOLTAGE_CHANGE) {
> > + name = dev_attr_microvolts.attr.name;
> > + sysfs_notify(&rdev->dev.kobj, NULL, name);
> > + } else {
> > + name = dev_attr_status.attr.name;
> > + sysfs_notify(&rdev->dev.kobj, NULL, name);
> > + }
>
> We probably should filter the events more, there's events for pre and
> post voltage change for example which aren't status changes so would be
> spurious. It ought not to break anything but we should still avoid
> unneeded work.
Can you please provide me inputs on the additional filtering needed for this.
Like some list of events for notify on status?

2023-11-02 13:07:16

by Mark Brown

[permalink] [raw]
Subject: Re: [PATCH] drivers/regulator: Notify sysfs about status changes

On Thu, Nov 02, 2023 at 05:35:42PM +0530, Naresh Solanki wrote:
> On Thu, 5 Oct 2023 at 22:30, Mark Brown <[email protected]> wrote:
> > On Thu, Oct 05, 2023 at 03:30:58PM +0200, Naresh Solanki wrote:

> > We probably should filter the events more, there's events for pre and
> > post voltage change for example which aren't status changes so would be
> > spurious. It ought not to break anything but we should still avoid
> > unneeded work.

> Can you please provide me inputs on the additional filtering needed for this.
> Like some list of events for notify on status?

I think I'd start off with just reporting things that are obviously
errors and not things that should ever go off during normal operation.


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2023-11-02 14:48:15

by Naresh Solanki

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Subject: Re: [PATCH] drivers/regulator: Notify sysfs about status changes

Hi Mark,

On Thu, 2 Nov 2023 at 18:36, Mark Brown <[email protected]> wrote:
>
> On Thu, Nov 02, 2023 at 05:35:42PM +0530, Naresh Solanki wrote:
> > On Thu, 5 Oct 2023 at 22:30, Mark Brown <[email protected]> wrote:
> > > On Thu, Oct 05, 2023 at 03:30:58PM +0200, Naresh Solanki wrote:
>
> > > We probably should filter the events more, there's events for pre and
> > > post voltage change for example which aren't status changes so would be
> > > spurious. It ought not to break anything but we should still avoid
> > > unneeded work.
>
> > Can you please provide me inputs on the additional filtering needed for this.
> > Like some list of events for notify on status?
>
> I think I'd start off with just reporting things that are obviously
> errors and not things that should ever go off during normal operation.
This is what I could come up with:
if (event & REGULATOR_EVENT_VOLTAGE_CHANGE) {
name = dev_attr_microvolts.attr.name;
sysfs_notify(&rdev->dev.kobj, NULL, name);
} else if (event & (REGULATOR_EVENT_DISABLE | REGULATOR_EVENT_ENABLE)){
name = dev_attr_status.attr.name;
sysfs_notify(&rdev->dev.kobj, NULL, name);
}

Regards,
Naresh

2023-11-02 15:02:25

by Mark Brown

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Subject: Re: [PATCH] drivers/regulator: Notify sysfs about status changes

On Thu, Nov 02, 2023 at 08:17:35PM +0530, Naresh Solanki wrote:
> On Thu, 2 Nov 2023 at 18:36, Mark Brown <[email protected]> wrote:
> > On Thu, Nov 02, 2023 at 05:35:42PM +0530, Naresh Solanki wrote:

> > > > We probably should filter the events more, there's events for pre and
> > > > post voltage change for example which aren't status changes so would be
> > > > spurious. It ought not to break anything but we should still avoid
> > > > unneeded work.

> > > Can you please provide me inputs on the additional filtering needed for this.
> > > Like some list of events for notify on status?

> > I think I'd start off with just reporting things that are obviously
> > errors and not things that should ever go off during normal operation.

> This is what I could come up with:
> if (event & REGULATOR_EVENT_VOLTAGE_CHANGE) {
> name = dev_attr_microvolts.attr.name;
> sysfs_notify(&rdev->dev.kobj, NULL, name);
> } else if (event & (REGULATOR_EVENT_DISABLE | REGULATOR_EVENT_ENABLE)){
> name = dev_attr_status.attr.name;
> sysfs_notify(&rdev->dev.kobj, NULL, name);
> }

That's the opposite sense to what I was thinking of - we're reporting
voltage changes and enables to userspace rather than just errors. My
concern here is that this could generate an awful lot of notificaitons
for normal operation on systems that don't use the uevents, I was
expecting this to be used for errors. Could you remind me what the use
case is here, I think I might've got myself confused sorry?


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2023-11-02 15:35:58

by Naresh Solanki

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Subject: Re: [PATCH] drivers/regulator: Notify sysfs about status changes

Hi Mark,

On Thu, 2 Nov 2023 at 20:31, Mark Brown <[email protected]> wrote:
>
> On Thu, Nov 02, 2023 at 08:17:35PM +0530, Naresh Solanki wrote:
> > On Thu, 2 Nov 2023 at 18:36, Mark Brown <[email protected]> wrote:
> > > On Thu, Nov 02, 2023 at 05:35:42PM +0530, Naresh Solanki wrote:
>
> > > > > We probably should filter the events more, there's events for pre and
> > > > > post voltage change for example which aren't status changes so would be
> > > > > spurious. It ought not to break anything but we should still avoid
> > > > > unneeded work.
>
> > > > Can you please provide me inputs on the additional filtering needed for this.
> > > > Like some list of events for notify on status?
>
> > > I think I'd start off with just reporting things that are obviously
> > > errors and not things that should ever go off during normal operation.
>
> > This is what I could come up with:
> > if (event & REGULATOR_EVENT_VOLTAGE_CHANGE) {
> > name = dev_attr_microvolts.attr.name;
> > sysfs_notify(&rdev->dev.kobj, NULL, name);
> > } else if (event & (REGULATOR_EVENT_DISABLE | REGULATOR_EVENT_ENABLE)){
> > name = dev_attr_status.attr.name;
> > sysfs_notify(&rdev->dev.kobj, NULL, name);
> > }
>
> That's the opposite sense to what I was thinking of - we're reporting
> voltage changes and enables to userspace rather than just errors. My
> concern here is that this could generate an awful lot of notificaitons
> for normal operation on systems that don't use the uevents, I was
> expecting this to be used for errors. Could you remind me what the use
> case is here, I think I might've got myself confused sorry?
Sorry for confusion caused because I should first described my application
requirements.
Currently my application is interested in know regulator status i.e.,
ENABLE, DISABLE or ERROR.
Also events are needed specifically to get them logged like
UNDER_VOLTAGE, OVER_CURRENT, REGULATION_OUT,
OVER_TEMP.


Regards,
Naresh

2023-11-02 16:51:03

by Mark Brown

[permalink] [raw]
Subject: Re: [PATCH] drivers/regulator: Notify sysfs about status changes

On Thu, Nov 02, 2023 at 09:03:40PM +0530, Naresh Solanki wrote:
> On Thu, 2 Nov 2023 at 20:31, Mark Brown <[email protected]> wrote:

> > That's the opposite sense to what I was thinking of - we're reporting
> > voltage changes and enables to userspace rather than just errors. My
> > concern here is that this could generate an awful lot of notificaitons
> > for normal operation on systems that don't use the uevents, I was
> > expecting this to be used for errors. Could you remind me what the use
> > case is here, I think I might've got myself confused sorry?

> Sorry for confusion caused because I should first described my application
> requirements.
> Currently my application is interested in know regulator status i.e.,
> ENABLE, DISABLE or ERROR.
> Also events are needed specifically to get them logged like
> UNDER_VOLTAGE, OVER_CURRENT, REGULATION_OUT,
> OVER_TEMP.

Ah, right. Everything except for the enable and disable there looks
like it should be OK since they should normally just not happen but the
enables and disables might get a bit frequent with runtime PM - not
*super* frequent like voltage scaling but enough that people could have
an issue with it.

Netlink feels like it might be a better fit? Not really looked at the
kernel side of implementing that and how sensible that ends up looking.


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