[PATCH v1] regulator: core: Convert warning to debug print

[PATCH v1] regulator: core: Convert warning to debug print

[Ninad Palsule]

There are some boards without the vcc regulators for eeprom or other
devices. In such cases, we should not see the following warning and
this confuses the user. We want to see this only when it is compiled
with CONFIG_REGULATOR_DEBUG option.

[0.747347] at24 6-0055: supply vcc not found, using dummy regulator
[0.752877] pca953x 6-0074: supply vcc not found, using dummy regulator

Signed-off-by: Ninad Palsule <ninad@linux.ibm.com>
---
 drivers/regulator/core.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
index d8e1caaf207e..7d2e2495234e 100644
--- a/drivers/regulator/core.c
+++ b/drivers/regulator/core.c
@@ -2204,7 +2204,7 @@ struct regulator *_regulator_get(struct device *dev, const char *id,
 			 * enabled, even if it isn't hooked up, and just
 			 * provide a dummy.
 			 */
-			dev_warn(dev, "supply %s not found, using dummy regulator\n", id);
+			dev_dbg(dev, "supply %s not found, using dummy regulator\n", id);
 			rdev = dummy_regulator_rdev;
 			get_device(&rdev->dev);
 			break;
-- 
2.39.2

Re: [PATCH v1] regulator: core: Convert warning to debug print

[Mark Brown]

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On Thu, Oct 12, 2023 at 12:42:35PM -0500, Ninad Palsule wrote:
> There are some boards without the vcc regulators for eeprom or other
> devices. In such cases, we should not see the following warning and
> this confuses the user. We want to see this only when it is compiled
> with CONFIG_REGULATOR_DEBUG option.

> [0.747347] at24 6-0055: supply vcc not found, using dummy regulator
> [0.752877] pca953x 6-0074: supply vcc not found, using dummy regulator

This is a warning saying that the firmware description for the system is
incomplete in case things go wrong later - it is vanishingly unlikely
that these devices actually do not require supplies, we'd probably have
heard about it if they did.  If a supply is not described properly we
may for example decide to power off what we think is an unused supply
with bad results.

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Re: [PATCH v1] regulator: core: Convert warning to debug print

[Ninad Palsule]

Hello Mark,

Thanks for the review.

On 10/12/23 12:47, Mark Brown wrote:
> On Thu, Oct 12, 2023 at 12:42:35PM -0500, Ninad Palsule wrote:
>> There are some boards without the vcc regulators for eeprom or other
>> devices. In such cases, we should not see the following warning and
>> this confuses the user. We want to see this only when it is compiled
>> with CONFIG_REGULATOR_DEBUG option.
>> [0.747347] at24 6-0055: supply vcc not found, using dummy regulator
>> [0.752877] pca953x 6-0074: supply vcc not found, using dummy regulator
> This is a warning saying that the firmware description for the system is
> incomplete in case things go wrong later - it is vanishingly unlikely
> that these devices actually do not require supplies, we'd probably have
> heard about it if they did.  If a supply is not described properly we
> may for example decide to power off what we think is an unused supply
> with bad results.

You are right there are regulators for these supplies but they are 
managed by the
hardware hence not added in the device tree. I checked dts/aspeed 
directory and
non of the machine has “vcc-supply” defined and lot of them use eeprom.
Also, I thought that this message is only useful in the lab to indicate 
developer
whether they missed the device tree definition or not but its not useful 
in the
field.  Hence proposed to put it under DEBUG.

Please let me know if I missed something.

Thanks!

~ Ninad

Re: [PATCH v1] regulator: core: Convert warning to debug print

[Mark Brown]

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On Thu, Oct 12, 2023 at 04:45:48PM -0500, Ninad Palsule wrote:

> You are right there are regulators for these supplies but they are managed
> by the
> hardware hence not added in the device tree. I checked dts/aspeed directory
> and
> non of the machine has “vcc-supply” defined and lot of them use eeprom.

Fixed voltage regulators can be used for this.

> Also, I thought that this message is only useful in the lab to indicate
> developer
> whether they missed the device tree definition or not but its not useful in
> the
> field.  Hence proposed to put it under DEBUG.

The theory is that it shouldn't come up in the field since people see it
during development and fix things then, are people actually looking at
these logs?  I think my understanding was that they're mostly BMCs
people interacted with via a UI of some kind.

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Re: [PATCH v1] regulator: core: Convert warning to debug print

[Ninad Palsule]

Hello Mark,

On 10/13/23 10:38, Mark Brown wrote:
> On Thu, Oct 12, 2023 at 04:45:48PM -0500, Ninad Palsule wrote:
>
>> You are right there are regulators for these supplies but they are managed
>> by the
>> hardware hence not added in the device tree. I checked dts/aspeed directory
>> and
>> non of the machine has “vcc-supply” defined and lot of them use eeprom.
> Fixed voltage regulators can be used for this.
ok, So far we don't need it.
>
>> Also, I thought that this message is only useful in the lab to indicate
>> developer
>> whether they missed the device tree definition or not but its not useful in
>> the
>> field.  Hence proposed to put it under DEBUG.
> The theory is that it shouldn't come up in the field since people see it
> during development and fix things then, are people actually looking at
> these logs?  I think my understanding was that they're mostly BMCs
> people interacted with via a UI of some kind.

During testing people look at this logs. We will ignore this warning for 
now.

Thanks!

~Ninad