2022-09-05 07:19:00

by Dmitry Torokhov

[permalink] [raw]
Subject: [PATCH v1 04/11] usb: phy: tegra: switch to using devm_gpiod_get()

I would like to stop exporting OF-specific devm_gpiod_get_from_of_node()
so that gpiolib can be cleaned a bit, so let's switch to the generic
device property API.

I believe that the only reason the driver, instead of the standard
devm_gpiod_get(), used devm_gpiod_get_from_of_node() is because it
wanted to set up a pretty consumer name for the GPIO, and we now have
a special API for that.

Signed-off-by: Dmitry Torokhov <[email protected]>

diff --git a/drivers/usb/phy/phy-tegra-usb.c b/drivers/usb/phy/phy-tegra-usb.c
index 68cd4b68e3a2..f0240107edb1 100644
--- a/drivers/usb/phy/phy-tegra-usb.c
+++ b/drivers/usb/phy/phy-tegra-usb.c
@@ -1440,16 +1440,22 @@ static int tegra_usb_phy_probe(struct platform_device *pdev)
return err;
}

- gpiod = devm_gpiod_get_from_of_node(&pdev->dev, np,
- "nvidia,phy-reset-gpio",
- 0, GPIOD_OUT_HIGH,
- "ulpi_phy_reset_b");
+ gpiod = devm_gpiod_get(&pdev->dev, "nvidia,phy-reset",
+ GPIOD_OUT_HIGH);
err = PTR_ERR_OR_ZERO(gpiod);
if (err) {
dev_err(&pdev->dev,
"Request failed for reset GPIO: %d\n", err);
return err;
}
+
+ err = gpiod_set_consumer_name(gpiod, "ulpi_phy_reset_b");
+ if (err) {
+ dev_err(&pdev->dev,
+ "Failed to set up reset GPIO name: %d\n", err);
+ return err;
+ }
+
tegra_phy->reset_gpio = gpiod;

phy = devm_otg_ulpi_create(&pdev->dev,

--
b4 0.10.0-dev-fc921


2022-09-05 11:31:23

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH v1 04/11] usb: phy: tegra: switch to using devm_gpiod_get()

On Mon, Sep 5, 2022 at 9:32 AM Dmitry Torokhov
<[email protected]> wrote:
>
> I would like to stop exporting OF-specific devm_gpiod_get_from_of_node()
> so that gpiolib can be cleaned a bit, so let's switch to the generic
> device property API.
>
> I believe that the only reason the driver, instead of the standard
> devm_gpiod_get(), used devm_gpiod_get_from_of_node() is because it
> wanted to set up a pretty consumer name for the GPIO, and we now have
> a special API for that.

...

> - gpiod = devm_gpiod_get_from_of_node(&pdev->dev, np,
> - "nvidia,phy-reset-gpio",
> - 0, GPIOD_OUT_HIGH,
> - "ulpi_phy_reset_b");
> + gpiod = devm_gpiod_get(&pdev->dev, "nvidia,phy-reset",
> + GPIOD_OUT_HIGH);
> err = PTR_ERR_OR_ZERO(gpiod);

What does _OR_ZERO mean now?

> if (err) {
> dev_err(&pdev->dev,
> "Request failed for reset GPIO: %d\n", err);
> return err;
> }



--
With Best Regards,
Andy Shevchenko

2022-09-05 20:02:44

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH v1 04/11] usb: phy: tegra: switch to using devm_gpiod_get()

On Mon, Sep 5, 2022 at 10:40 PM Dmitry Torokhov
<[email protected]> wrote:
> On Mon, Sep 05, 2022 at 01:59:44PM +0300, Andy Shevchenko wrote:
> > On Mon, Sep 5, 2022 at 9:32 AM Dmitry Torokhov
> > <[email protected]> wrote:

...

> > > - gpiod = devm_gpiod_get_from_of_node(&pdev->dev, np,
> > > - "nvidia,phy-reset-gpio",
> > > - 0, GPIOD_OUT_HIGH,
> > > - "ulpi_phy_reset_b");
> > > + gpiod = devm_gpiod_get(&pdev->dev, "nvidia,phy-reset",
> > > + GPIOD_OUT_HIGH);
> > > err = PTR_ERR_OR_ZERO(gpiod);
> >
> > What does _OR_ZERO mean now?
>
> This converts a pointer to an error code if a pointer represents
> ERR_PTR() encoded error, or 0 to indicate success.

Yes, I know that. My point is, how is it useful now (or even before)?
I mean that devm_gpio_get() never returns NULL, right?

--
With Best Regards,
Andy Shevchenko

2022-09-05 20:03:00

by Dmitry Torokhov

[permalink] [raw]
Subject: Re: [PATCH v1 04/11] usb: phy: tegra: switch to using devm_gpiod_get()

On Mon, Sep 05, 2022 at 10:41:40PM +0300, Andy Shevchenko wrote:
> On Mon, Sep 5, 2022 at 10:40 PM Dmitry Torokhov
> <[email protected]> wrote:
> > On Mon, Sep 05, 2022 at 01:59:44PM +0300, Andy Shevchenko wrote:
> > > On Mon, Sep 5, 2022 at 9:32 AM Dmitry Torokhov
> > > <[email protected]> wrote:
>
> ...
>
> > > > - gpiod = devm_gpiod_get_from_of_node(&pdev->dev, np,
> > > > - "nvidia,phy-reset-gpio",
> > > > - 0, GPIOD_OUT_HIGH,
> > > > - "ulpi_phy_reset_b");
> > > > + gpiod = devm_gpiod_get(&pdev->dev, "nvidia,phy-reset",
> > > > + GPIOD_OUT_HIGH);
> > > > err = PTR_ERR_OR_ZERO(gpiod);
> > >
> > > What does _OR_ZERO mean now?
> >
> > This converts a pointer to an error code if a pointer represents
> > ERR_PTR() encoded error, or 0 to indicate success.
>
> Yes, I know that. My point is, how is it useful now (or even before)?
> I mean that devm_gpio_get() never returns NULL, right?

What does returning NULL have to do with anything. It converts a pointer
to a "classic" return code, with negative errors and 0 on success.

It allows to not use multiple IS_ERR/PTR_ERR in the code (I'd need 1
IS_ERR and 2 PTR_ERR, one in dev_err() and another to return).

Thanks.

--
Dmitry

2022-09-05 20:03:06

by Dmitry Torokhov

[permalink] [raw]
Subject: Re: [PATCH v1 04/11] usb: phy: tegra: switch to using devm_gpiod_get()

On Mon, Sep 05, 2022 at 01:59:44PM +0300, Andy Shevchenko wrote:
> On Mon, Sep 5, 2022 at 9:32 AM Dmitry Torokhov
> <[email protected]> wrote:
> >
> > I would like to stop exporting OF-specific devm_gpiod_get_from_of_node()
> > so that gpiolib can be cleaned a bit, so let's switch to the generic
> > device property API.
> >
> > I believe that the only reason the driver, instead of the standard
> > devm_gpiod_get(), used devm_gpiod_get_from_of_node() is because it
> > wanted to set up a pretty consumer name for the GPIO, and we now have
> > a special API for that.
>
> ...
>
> > - gpiod = devm_gpiod_get_from_of_node(&pdev->dev, np,
> > - "nvidia,phy-reset-gpio",
> > - 0, GPIOD_OUT_HIGH,
> > - "ulpi_phy_reset_b");
> > + gpiod = devm_gpiod_get(&pdev->dev, "nvidia,phy-reset",
> > + GPIOD_OUT_HIGH);
> > err = PTR_ERR_OR_ZERO(gpiod);
>
> What does _OR_ZERO mean now?

This converts a pointer to an error code if a pointer represents
ERR_PTR() encoded error, or 0 to indicate success.

static inline int __must_check PTR_ERR_OR_ZERO(__force const void *ptr)
{
if (IS_ERR(ptr))
return PTR_ERR(ptr);
else
return 0;
}

Thanks.

--
Dmitry

2022-09-05 20:22:09

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH v1 04/11] usb: phy: tegra: switch to using devm_gpiod_get()

On Mon, Sep 5, 2022 at 10:51 PM Dmitry Torokhov
<[email protected]> wrote:
> On Mon, Sep 05, 2022 at 10:41:40PM +0300, Andy Shevchenko wrote:
> > On Mon, Sep 5, 2022 at 10:40 PM Dmitry Torokhov
> > <[email protected]> wrote:
> > > On Mon, Sep 05, 2022 at 01:59:44PM +0300, Andy Shevchenko wrote:
> > > > On Mon, Sep 5, 2022 at 9:32 AM Dmitry Torokhov
> > > > <[email protected]> wrote:

...

> > > > > - gpiod = devm_gpiod_get_from_of_node(&pdev->dev, np,
> > > > > - "nvidia,phy-reset-gpio",
> > > > > - 0, GPIOD_OUT_HIGH,
> > > > > - "ulpi_phy_reset_b");
> > > > > + gpiod = devm_gpiod_get(&pdev->dev, "nvidia,phy-reset",
> > > > > + GPIOD_OUT_HIGH);
> > > > > err = PTR_ERR_OR_ZERO(gpiod);
> > > >
> > > > What does _OR_ZERO mean now?
> > >
> > > This converts a pointer to an error code if a pointer represents
> > > ERR_PTR() encoded error, or 0 to indicate success.
> >
> > Yes, I know that. My point is, how is it useful now (or even before)?
> > I mean that devm_gpio_get() never returns NULL, right?
>
> What does returning NULL have to do with anything.

It has to do with a dead code. If defm_gpiod_get() does not return
NULL, then why do we even bother to check?

> It converts a pointer
> to a "classic" return code, with negative errors and 0 on success.
>
> It allows to not use multiple IS_ERR/PTR_ERR in the code (I'd need 1
> IS_ERR and 2 PTR_ERR, one in dev_err() and another to return).

I don't see how this is relevant.

--
With Best Regards,
Andy Shevchenko

2022-09-05 22:10:37

by Guenter Roeck

[permalink] [raw]
Subject: Re: [PATCH v1 04/11] usb: phy: tegra: switch to using devm_gpiod_get()

On 9/5/22 12:55, Andy Shevchenko wrote:
> On Mon, Sep 5, 2022 at 10:51 PM Dmitry Torokhov
> <[email protected]> wrote:
>> On Mon, Sep 05, 2022 at 10:41:40PM +0300, Andy Shevchenko wrote:
>>> On Mon, Sep 5, 2022 at 10:40 PM Dmitry Torokhov
>>> <[email protected]> wrote:
>>>> On Mon, Sep 05, 2022 at 01:59:44PM +0300, Andy Shevchenko wrote:
>>>>> On Mon, Sep 5, 2022 at 9:32 AM Dmitry Torokhov
>>>>> <[email protected]> wrote:
>
> ...
>
>>>>>> - gpiod = devm_gpiod_get_from_of_node(&pdev->dev, np,
>>>>>> - "nvidia,phy-reset-gpio",
>>>>>> - 0, GPIOD_OUT_HIGH,
>>>>>> - "ulpi_phy_reset_b");
>>>>>> + gpiod = devm_gpiod_get(&pdev->dev, "nvidia,phy-reset",
>>>>>> + GPIOD_OUT_HIGH);
>>>>>> err = PTR_ERR_OR_ZERO(gpiod);
>>>>>
>>>>> What does _OR_ZERO mean now?
>>>>
>>>> This converts a pointer to an error code if a pointer represents
>>>> ERR_PTR() encoded error, or 0 to indicate success.
>>>
>>> Yes, I know that. My point is, how is it useful now (or even before)?
>>> I mean that devm_gpio_get() never returns NULL, right?
>>
>> What does returning NULL have to do with anything.
>
> It has to do with a dead code. If defm_gpiod_get() does not return
> NULL, then why do we even bother to check?
>

PTR_ERR_OR_ZERO() converts into an error code (if the pointer is an
ERR_PTR) or 0 if it is a real pointer. Its purpose is not to convert
NULL into 0, its purpose is to convert a pointer either into an error
code or 0. That is what is done here, and it is done all over the place
in the kernel. I don't see your problem with it. Care to explain ?

>> It converts a pointer
>> to a "classic" return code, with negative errors and 0 on success.
>>
>> It allows to not use multiple IS_ERR/PTR_ERR in the code (I'd need 1
>> IS_ERR and 2 PTR_ERR, one in dev_err() and another to return).
>
> I don't see how this is relevant.
>

You lost me. Really, please explain your problem with PTR_ERR_OR_ZERO().

Thanks,
Guenter

2022-09-06 13:23:19

by Andy Shevchenko

[permalink] [raw]
Subject: Re: [PATCH v1 04/11] usb: phy: tegra: switch to using devm_gpiod_get()

On Mon, Sep 05, 2022 at 03:07:48PM -0700, Guenter Roeck wrote:
> On 9/5/22 12:55, Andy Shevchenko wrote:
> > On Mon, Sep 5, 2022 at 10:51 PM Dmitry Torokhov
> > <[email protected]> wrote:
> > > On Mon, Sep 05, 2022 at 10:41:40PM +0300, Andy Shevchenko wrote:
> > > > On Mon, Sep 5, 2022 at 10:40 PM Dmitry Torokhov
> > > > <[email protected]> wrote:
> > > > > On Mon, Sep 05, 2022 at 01:59:44PM +0300, Andy Shevchenko wrote:
> > > > > > On Mon, Sep 5, 2022 at 9:32 AM Dmitry Torokhov
> > > > > > <[email protected]> wrote:

...

> > > > > > > + gpiod = devm_gpiod_get(&pdev->dev, "nvidia,phy-reset",
> > > > > > > + GPIOD_OUT_HIGH);
> > > > > > > err = PTR_ERR_OR_ZERO(gpiod);
> > > > > >
> > > > > > What does _OR_ZERO mean now?
> > > > >
> > > > > This converts a pointer to an error code if a pointer represents
> > > > > ERR_PTR() encoded error, or 0 to indicate success.
> > > >
> > > > Yes, I know that. My point is, how is it useful now (or even before)?
> > > > I mean that devm_gpio_get() never returns NULL, right?
> > >
> > > What does returning NULL have to do with anything.
> >
> > It has to do with a dead code. If defm_gpiod_get() does not return
> > NULL, then why do we even bother to check?
>
> PTR_ERR_OR_ZERO() converts into an error code (if the pointer is an
> ERR_PTR) or 0 if it is a real pointer. Its purpose is not to convert
> NULL into 0, its purpose is to convert a pointer either into an error
> code or 0. That is what is done here, and it is done all over the place
> in the kernel. I don't see your problem with it. Care to explain ?
>
> > > It converts a pointer
> > > to a "classic" return code, with negative errors and 0 on success.
> > >
> > > It allows to not use multiple IS_ERR/PTR_ERR in the code (I'd need 1
> > > IS_ERR and 2 PTR_ERR, one in dev_err() and another to return).
> >
> > I don't see how this is relevant.
>
> You lost me. Really, please explain your problem with PTR_ERR_OR_ZERO().

I don't know what I was thinking about... You, guys, are right, sorry for
my noise.

--
With Best Regards,
Andy Shevchenko