Re: [PATCH 2/2] regulator: userspace-consumer: Multiple regulators

[Naresh Solanki]

Hi Zev,

On 20-04-2023 04:27 pm, Zev Weiss wrote:
> On Thu, Apr 20, 2023 at 01:46:14AM PDT, Naresh Solanki wrote:
> > Hi Zev,
> >
> > On 20-04-2023 05:32 am, Zev Weiss wrote:
> > > On Tue, Apr 18, 2023 at 07:50:51AM PDT, Naresh Solanki wrote:
> > > > Use property regulator-supplies to determine all regulator
> > > > supplies.
> > > > This is useful in case of a connector having 2 or more supplies.
> > > > Example: PCIe connector on mainboard can be powered by 12V & 3.3V
> > > > suplies.
> > > >
> > > > Signed-off-by: Naresh Solanki <Naresh.Solanki@xxxxxxxxxxxxx>
> > > > ---
> > > > drivers/regulator/userspace-consumer.c | 19 +++++++++++++++----
> > > > 1 file changed, 15 insertions(+), 4 deletions(-)
> > > >
> > > > diff --git a/drivers/regulator/userspace-consumer.c 
> > > > b/drivers/regulator/userspace-consumer.c
> > > > index 97f075ed68c9..0bb49547b926 100644
> > > > --- a/drivers/regulator/userspace-consumer.c
> > > > +++ b/drivers/regulator/userspace-consumer.c
> > > > @@ -120,7 +120,10 @@ static int 
> > > > regulator_userspace_consumer_probe(struct platform_device *pdev)
> > > >     struct regulator_userspace_consumer_data tmpdata;
> > > >     struct regulator_userspace_consumer_data *pdata;
> > > >     struct userspace_consumer_data *drvdata;
> > > > -    int ret;
> > > > +    struct device_node *np = pdev->dev.of_node;
> > > > +    struct property *prop;
> > > > +    const char *supply;
> > > > +    int ret, count = 0;
> > > >
> > > >     pdata = dev_get_platdata(&pdev->dev);
> > > >     if (!pdata) {
> > > > @@ -131,11 +134,19 @@ static int 
> > > > regulator_userspace_consumer_probe(struct platform_device *pdev)
> > > >         memset(pdata, 0, sizeof(*pdata));
> > > >
> > > >         pdata->no_autoswitch = true;
> > > > -        pdata->num_supplies = 1;
> > > > -        pdata->supplies = devm_kzalloc(&pdev->dev, 
> > > > sizeof(*pdata->supplies), GFP_KERNEL);
> > > > +        pdata->num_supplies = of_property_count_strings(np, 
> > > > "regulator-supplies");
> > > > +        if (pdata->num_supplies < 0) {
> > > > +            dev_err(&pdev->dev, "could not parse property 
> > > > regulator-supplies");
> > > > +            return -EINVAL;
> > > > +        }
> > > > +        pdata->supplies = devm_kzalloc(&pdev->dev,
> > > > +                           sizeof(*pdata->supplies) * 
> > > > pdata->num_supplies,
> > > > +                           GFP_KERNEL);
> > >
> > > AFAICT this doesn't appear to implement the "vout" default specified 
> > > in the dt-binding patch?
> > The "regulator-supplies" property will hold the default value of 
> > "vout" unless specified otherwise. As a result, the string enumeration 
> > retrieves the value of "vout" by default, and the "vout-supply" 
> > property is utilized for the regulator.
>
> With the disclaimer that I'm not a DT expert, that's not my 
> understanding of how DT works.  I don't think the 'default' value 
> specified in the binding forces the fdt to always include that value if 
> it's not present in the dts (since I'm pretty sure dtc doesn't even look 
> at the binding to know that a default exists when compiling the dts); 
> rather, it's information meant to be used by the software implementing 
> support for that device (e.g. a driver for it) about what value to 
> assume if the property isn't present in the fdt.
I apologize for the oversight on my part. Upon further testing, I have 
discovered that the default did not reflect in the debug prints. I will 
address this issue and include the proper fix in the next patchset. 
Thank you for bringing this to my attention
> > > Also, since the core of the userspace-consumer driver itself already 
> > > supports multiple regulators, it might be nice for the subject line 
> > > to mention DT supplies or something a bit more specifically.
> > Sure. How about 'Support multiple supplies' ?
>
> I meant that it should explicitly mention "DT" (or perhaps "OF").  The 
> driver's structure has supported multiple supplies since it was first 
> introduced in 2009, so "Support multiple supplies" sounds like this 
> commit is adding functionality that was already there.  What this patch 
> is doing is connecting that existing support to the OF support logic so 
> that it can be used in a device-tree context.
Sure. Will make it something like "Support multiple supplies in DT".
> > > >         if (!pdata->supplies)
> > > >             return -ENOMEM;
> > > > -        pdata->supplies[0].supply = "vout";
> > > > +
> > > > +        of_property_for_each_string(np, "regulator-supplies", prop, 
> > > > supply)
> > > > +            pdata->supplies[count++].supply = supply;
> > > >     }
> > > >
> > > >     if (pdata->num_supplies < 1) {
> > > > --
> > > > 2.39.1
> > Regards,
> > Naresh
Regards,
Naresh