From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>

S32G2/S32G3 based boards which integrate the ina231 sensor do not have a
dedicated voltage regulator.

Co-developed-by: Florin Buica <florin.buica@nxp.com>
Signed-off-by: Florin Buica <florin.buica@nxp.com>
Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
---
 drivers/hwmon/ina2xx.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
index 345fe7db9de9..ab4972f94a8c 100644
--- a/drivers/hwmon/ina2xx.c
+++ b/drivers/hwmon/ina2xx.c
@@ -959,8 +959,8 @@ static int ina2xx_probe(struct i2c_client *client)
 		return PTR_ERR(data->regmap);
 	}
 
-	ret = devm_regulator_get_enable(dev, "vs");
-	if (ret)
+	ret = devm_regulator_get_enable_optional(dev, "vs");
+	if (ret < 0 && ret != -ENODEV)
 		return dev_err_probe(dev, ret, "failed to enable vs regulator\n");
 
 	ret = ina2xx_init(dev, data);
-- 
2.45.2

On 4/3/25 03:15, Ciprian Costea wrote:
> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
> 
> S32G2/S32G3 based boards which integrate the ina231 sensor do not have a
> dedicated voltage regulator.
> 
> Co-developed-by: Florin Buica <florin.buica@nxp.com>
> Signed-off-by: Florin Buica <florin.buica@nxp.com>
> Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
> ---
>   drivers/hwmon/ina2xx.c | 4 ++--
>   1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
> index 345fe7db9de9..ab4972f94a8c 100644
> --- a/drivers/hwmon/ina2xx.c
> +++ b/drivers/hwmon/ina2xx.c
> @@ -959,8 +959,8 @@ static int ina2xx_probe(struct i2c_client *client)
>   		return PTR_ERR(data->regmap);
>   	}
>   
> -	ret = (dev, "vs");
> -	if (ret)
> +	ret = devm_regulator_get_enable_optional(dev, "vs");

devm_regulator_get_enable() should provide a dummy regulator if there is
no explicit regulator. Why does this not work ?

> +	if (ret < 0 && ret != -ENODEV)

Why this added check ?

I know it used to be necessary if regulator support is disabled,
but that is no longer the case.

Guenter

>   		return dev_err_probe(dev, ret, "failed to enable vs regulator\n");
>   
>   	ret = ina2xx_init(dev, data);

On 4/3/2025 3:15 PM, Guenter Roeck wrote:
> On 4/3/25 03:15, Ciprian Costea wrote:
>> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
>>
>> S32G2/S32G3 based boards which integrate the ina231 sensor do not have a
>> dedicated voltage regulator.
>>
>> Co-developed-by: Florin Buica <florin.buica@nxp.com>
>> Signed-off-by: Florin Buica <florin.buica@nxp.com>
>> Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
>> ---
>>   drivers/hwmon/ina2xx.c | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
>> index 345fe7db9de9..ab4972f94a8c 100644
>> --- a/drivers/hwmon/ina2xx.c
>> +++ b/drivers/hwmon/ina2xx.c
>> @@ -959,8 +959,8 @@ static int ina2xx_probe(struct i2c_client *client)
>>           return PTR_ERR(data->regmap);
>>       }
>> -    ret = (dev, "vs");
>> -    if (ret)
>> +    ret = devm_regulator_get_enable_optional(dev, "vs");
> 
> devm_regulator_get_enable() should provide a dummy regulator if there is
> no explicit regulator. Why does this not work ?
> 
>> +    if (ret < 0 && ret != -ENODEV)
> 
> Why this added check ?
> 
> I know it used to be necessary if regulator support is disabled,
> but that is no longer the case.
> 
> Guenter
> 

Hello Guenter,

I've just tested and devm_regulator_get_enable() does work as you've 
described, providing a dummy regulator.

But, according to the 'ti,ina2xx' binding [1] I see that the `vs-supply` 
property is not required. Hence wouldn't it be correct for `vs-supply` 
to be optional ? Using 'devm_regulator_get_enable_optional()'


[1] 
https://elixir.bootlin.com/linux/v6.13.7/source/Documentation/devicetree/bindings/hwmon/ti,ina2xx.yaml#L78-L80

Regards,
Ciprian

>>           return dev_err_probe(dev, ret, "failed to enable vs 
>> regulator\n");
>>       ret = ina2xx_init(dev, data);
> 

On Thu, Apr 03, 2025 at 05:29:26PM +0300, Ciprian Marian Costea wrote:
> On 4/3/2025 3:15 PM, Guenter Roeck wrote:
> > On 4/3/25 03:15, Ciprian Costea wrote:
> > > From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
> > > 
> > > S32G2/S32G3 based boards which integrate the ina231 sensor do not have a
> > > dedicated voltage regulator.
> > > 
> > > Co-developed-by: Florin Buica <florin.buica@nxp.com>
> > > Signed-off-by: Florin Buica <florin.buica@nxp.com>
> > > Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
> > > ---
> > >   drivers/hwmon/ina2xx.c | 4 ++--
> > >   1 file changed, 2 insertions(+), 2 deletions(-)
> > > 
> > > diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
> > > index 345fe7db9de9..ab4972f94a8c 100644
> > > --- a/drivers/hwmon/ina2xx.c
> > > +++ b/drivers/hwmon/ina2xx.c
> > > @@ -959,8 +959,8 @@ static int ina2xx_probe(struct i2c_client *client)
> > >           return PTR_ERR(data->regmap);
> > >       }
> > > -    ret = (dev, "vs");
> > > -    if (ret)
> > > +    ret = devm_regulator_get_enable_optional(dev, "vs");
> > 
> > devm_regulator_get_enable() should provide a dummy regulator if there is
> > no explicit regulator. Why does this not work ?
> > 
> > > +    if (ret < 0 && ret != -ENODEV)
> > 
> > Why this added check ?
> > 
> > I know it used to be necessary if regulator support is disabled,
> > but that is no longer the case.
> > 
> > Guenter
> > 
> 
> Hello Guenter,
> 
> I've just tested and devm_regulator_get_enable() does work as you've
> described, providing a dummy regulator.
> 
> But, according to the 'ti,ina2xx' binding [1] I see that the `vs-supply`
> property is not required. Hence wouldn't it be correct for `vs-supply` to be
> optional ? Using 'devm_regulator_get_enable_optional()'
> 
Yes, but the reasoning you provided is different and suggested that the
current code would not work. Since that is not the case, the change would
be purely cosmetic. Also, I still don't see why the -ENODEV check would be
necessary.

Guenter

On 4/3/2025 7:06 PM, Guenter Roeck wrote:
> On Thu, Apr 03, 2025 at 05:29:26PM +0300, Ciprian Marian Costea wrote:
>> On 4/3/2025 3:15 PM, Guenter Roeck wrote:
>>> On 4/3/25 03:15, Ciprian Costea wrote:
>>>> From: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
>>>>
>>>> S32G2/S32G3 based boards which integrate the ina231 sensor do not have a
>>>> dedicated voltage regulator.
>>>>
>>>> Co-developed-by: Florin Buica <florin.buica@nxp.com>
>>>> Signed-off-by: Florin Buica <florin.buica@nxp.com>
>>>> Signed-off-by: Ciprian Marian Costea <ciprianmarian.costea@oss.nxp.com>
>>>> ---
>>>>    drivers/hwmon/ina2xx.c | 4 ++--
>>>>    1 file changed, 2 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
>>>> index 345fe7db9de9..ab4972f94a8c 100644
>>>> --- a/drivers/hwmon/ina2xx.c
>>>> +++ b/drivers/hwmon/ina2xx.c
>>>> @@ -959,8 +959,8 @@ static int ina2xx_probe(struct i2c_client *client)
>>>>            return PTR_ERR(data->regmap);
>>>>        }
>>>> -    ret = (dev, "vs");
>>>> -    if (ret)
>>>> +    ret = devm_regulator_get_enable_optional(dev, "vs");
>>>
>>> devm_regulator_get_enable() should provide a dummy regulator if there is
>>> no explicit regulator. Why does this not work ?
>>>
>>>> +    if (ret < 0 && ret != -ENODEV)
>>>
>>> Why this added check ?
>>>
>>> I know it used to be necessary if regulator support is disabled,
>>> but that is no longer the case.
>>>
>>> Guenter
>>>
>>
>> Hello Guenter,
>>
>> I've just tested and devm_regulator_get_enable() does work as you've
>> described, providing a dummy regulator.
>>
>> But, according to the 'ti,ina2xx' binding [1] I see that the `vs-supply`
>> property is not required. Hence wouldn't it be correct for `vs-supply` to be
>> optional ? Using 'devm_regulator_get_enable_optional()'
>>
> Yes, but the reasoning you provided is different and suggested that the
> current code would not work. Since that is not the case, the change would
> be purely cosmetic. Also, I still don't see why the -ENODEV check would be
> necessary.
> 
> Guenter

For boards such as S32G274A-EVB, S32G274A-RDB2 and S32G399A-RDB3 which 
do not have a voltage regulator, 'devm_regulator_get_enable_optional()' 
would return error value -19 (-ENODEV). Also, other usages from the 
Linux Kernel seem to perform the same error check when using 
'devm_regulator_get_enable_optional()' [1], [2] and [3].

This patch would help in S32G2 and S32G3 to not print an unnecessary 
kernel log warning hinting usage of a dummy regulator when such a 
regulator is not required according to the binding.

Would you like me to send a V2 with the commit title updated as follows ?

"
hwmon: (ina2xx) make regulator 'vs' support optional

According to the 'ti,ina2xx' binding, the 'vs-supply' property is 
optional. Furthermore, S32G2/S32G3 based boards which integrate the 
ina231 sensor do not have a dedicated voltage regulator. Thus, making 
regulator support optional would help in avoiding any unnecessary kernel 
log warnings during boot.
"

[1] 
https://elixir.bootlin.com/linux/v6.13.7/source/drivers/iio/adc/ad7625.c#L524-L525
[2] 
https://elixir.bootlin.com/linux/v6.13.7/source/drivers/pci/controller/pcie-rcar-host.c#L982-L983
[3] 
https://elixir.bootlin.com/linux/v6.13.7/source/drivers/iio/adc/ad7944.c#L514-L515

Regards,
Ciprian