diff mbox series

[v1,06/11] PCI: aardvark: switch to using devm_gpiod_get_optional()

Message ID 20220903-gpiod_get_from_of_node-remove-v1-6-b29adfb27a6c@gmail.com (mailing list archive)
State Handled Elsewhere
Delegated to: Lorenzo Pieralisi
Headers show
Series Get rid of [devm_]gpiod_get_from_of_node() public APIs | expand

Commit Message

Dmitry Torokhov Sept. 5, 2022, 6:30 a.m. UTC
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_optional(), 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 <dmitry.torokhov@gmail.com>

Comments

Pali Rohár Sept. 5, 2022, 7 a.m. UTC | #1
On Sunday 04 September 2022 23:30:58 Dmitry Torokhov 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_optional(), used devm_gpiod_get_from_of_node() is
> because it wanted to set up a pretty consumer name for the GPIO,

IIRC consumer name is not used at all.

The reason was to specify full name of DTS property, for easier
identification of the code. DTS property is "reset-gpios" but API
specify only "reset".

> and we now have a special API for that.
> 
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> 
> diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> index 4834198cc86b..4a8a4a8522cb 100644
> --- a/drivers/pci/controller/pci-aardvark.c
> +++ b/drivers/pci/controller/pci-aardvark.c
> @@ -1856,20 +1856,19 @@ static int advk_pcie_probe(struct platform_device *pdev)
>  		return ret;
>  	}
>  
> -	pcie->reset_gpio = devm_gpiod_get_from_of_node(dev, dev->of_node,
> -						       "reset-gpios", 0,
> -						       GPIOD_OUT_LOW,
> -						       "pcie1-reset");
> +	pcie->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
>  	ret = PTR_ERR_OR_ZERO(pcie->reset_gpio);
>  	if (ret) {
> -		if (ret == -ENOENT) {
> -			pcie->reset_gpio = NULL;
> -		} else {
> -			if (ret != -EPROBE_DEFER)
> -				dev_err(dev, "Failed to get reset-gpio: %i\n",
> -					ret);
> -			return ret;
> -		}
> +		if (ret != -EPROBE_DEFER)
> +			dev_err(dev, "Failed to get reset-gpio: %i\n",
> +				ret);
> +		return ret;
> +	}
> +
> +	ret = gpiod_set_consumer_name(pcie->reset_gpio, "pcie1-reset");
> +	if (ret) {
> +		dev_err(dev, "Failed to set reset gpio name: %d\n", ret);
> +		return ret;
>  	}
>  
>  	ret = of_pci_get_max_link_speed(dev->of_node);
> 
> -- 
> b4 0.10.0-dev-fc921
Andy Shevchenko Sept. 5, 2022, 10:47 a.m. UTC | #2
On Mon, Sep 5, 2022 at 10:02 AM Pali Rohár <pali@kernel.org> wrote:
> On Sunday 04 September 2022 23:30:58 Dmitry Torokhov 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_optional(), used devm_gpiod_get_from_of_node() is
> > because it wanted to set up a pretty consumer name for the GPIO,
>
> IIRC consumer name is not used at all.

It's. The user space tools use it as a label. So, GPIO line can have
"name" (this is provider specific) and "label" (which is consumer
specific, i.o.w. how we use this line).

...

> > +             if (ret != -EPROBE_DEFER)
> > +                     dev_err(dev, "Failed to get reset-gpio: %i\n",
> > +                             ret);
> > +             return ret;

I understand that in the input subsystem maintainer's hat you don't
like dev_err_probe(), but it's a good case to have it here.

...

> > +     ret = gpiod_set_consumer_name(pcie->reset_gpio, "pcie1-reset");
> > +     if (ret) {
> > +             dev_err(dev, "Failed to set reset gpio name: %d\n", ret);
> > +             return ret;
> >       }

Ditto.
Dmitry Torokhov Sept. 5, 2022, 7:54 p.m. UTC | #3
On Mon, Sep 05, 2022 at 01:47:41PM +0300, Andy Shevchenko wrote:
> On Mon, Sep 5, 2022 at 10:02 AM Pali Rohár <pali@kernel.org> wrote:
> > On Sunday 04 September 2022 23:30:58 Dmitry Torokhov 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_optional(), used devm_gpiod_get_from_of_node() is
> > > because it wanted to set up a pretty consumer name for the GPIO,
> >
> > IIRC consumer name is not used at all.
> 
> It's. The user space tools use it as a label. So, GPIO line can have
> "name" (this is provider specific) and "label" (which is consumer
> specific, i.o.w. how we use this line).
> 
> ...
> 
> > > +             if (ret != -EPROBE_DEFER)
> > > +                     dev_err(dev, "Failed to get reset-gpio: %i\n",
> > > +                             ret);
> > > +             return ret;
> 
> I understand that in the input subsystem maintainer's hat you don't
> like dev_err_probe(), but it's a good case to have it here.

The driver currently does not use this API, so I elected not to
introduce it in this series.

Thanks,
Dmitry Torokhov Sept. 5, 2022, 10:54 p.m. UTC | #4
On Mon, Sep 05, 2022 at 09:00:46AM +0200, Pali Rohár wrote:
> On Sunday 04 September 2022 23:30:58 Dmitry Torokhov 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_optional(), used devm_gpiod_get_from_of_node() is
> > because it wanted to set up a pretty consumer name for the GPIO,
> 
> IIRC consumer name is not used at all.
> 
> The reason was to specify full name of DTS property, for easier
> identification of the code. DTS property is "reset-gpios" but API
> specify only "reset".

I see. Do you want me to reset the patch with updated desctiption as to
the reason devm_gpiod_get_from_of_node() was used?

> 
> > and we now have a special API for that.
> > 
> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > 
> > diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> > index 4834198cc86b..4a8a4a8522cb 100644
> > --- a/drivers/pci/controller/pci-aardvark.c
> > +++ b/drivers/pci/controller/pci-aardvark.c
> > @@ -1856,20 +1856,19 @@ static int advk_pcie_probe(struct platform_device *pdev)
> >  		return ret;
> >  	}
> >  
> > -	pcie->reset_gpio = devm_gpiod_get_from_of_node(dev, dev->of_node,
> > -						       "reset-gpios", 0,
> > -						       GPIOD_OUT_LOW,
> > -						       "pcie1-reset");
> > +	pcie->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
> >  	ret = PTR_ERR_OR_ZERO(pcie->reset_gpio);
> >  	if (ret) {
> > -		if (ret == -ENOENT) {
> > -			pcie->reset_gpio = NULL;
> > -		} else {
> > -			if (ret != -EPROBE_DEFER)
> > -				dev_err(dev, "Failed to get reset-gpio: %i\n",
> > -					ret);
> > -			return ret;
> > -		}
> > +		if (ret != -EPROBE_DEFER)
> > +			dev_err(dev, "Failed to get reset-gpio: %i\n",
> > +				ret);
> > +		return ret;
> > +	}
> > +
> > +	ret = gpiod_set_consumer_name(pcie->reset_gpio, "pcie1-reset");
> > +	if (ret) {
> > +		dev_err(dev, "Failed to set reset gpio name: %d\n", ret);
> > +		return ret;
> >  	}
> >  
> >  	ret = of_pci_get_max_link_speed(dev->of_node);
> > 
> > -- 
> > b4 0.10.0-dev-fc921

Thanks.
Pali Rohár Sept. 5, 2022, 11:10 p.m. UTC | #5
On Monday 05 September 2022 15:54:53 Dmitry Torokhov wrote:
> On Mon, Sep 05, 2022 at 09:00:46AM +0200, Pali Rohár wrote:
> > On Sunday 04 September 2022 23:30:58 Dmitry Torokhov 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_optional(), used devm_gpiod_get_from_of_node() is
> > > because it wanted to set up a pretty consumer name for the GPIO,
> > 
> > IIRC consumer name is not used at all.
> > 
> > The reason was to specify full name of DTS property, for easier
> > identification of the code. DTS property is "reset-gpios" but API
> > specify only "reset".
> 
> I see. Do you want me to reset the patch with updated desctiption as to
> the reason devm_gpiod_get_from_of_node() was used?

I think it is fine. So add my:

Acked-by: Pali Rohár <pali@kernel.org>

Anyway as another improvement for future I would suggest some API
function with _optional_ logic, so it could be used for more PCIe
controller drivers (e.g. also tegra) without need to reimplement
-ENOENT handling. It is really strange if for acquiring same PERST#
line via GPIO ("reset-gpios" DT property) are used more API functions
in different PCIe drivers.

> > 
> > > and we now have a special API for that.
> > > 
> > > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > > 
> > > diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
> > > index 4834198cc86b..4a8a4a8522cb 100644
> > > --- a/drivers/pci/controller/pci-aardvark.c
> > > +++ b/drivers/pci/controller/pci-aardvark.c
> > > @@ -1856,20 +1856,19 @@ static int advk_pcie_probe(struct platform_device *pdev)
> > >  		return ret;
> > >  	}
> > >  
> > > -	pcie->reset_gpio = devm_gpiod_get_from_of_node(dev, dev->of_node,
> > > -						       "reset-gpios", 0,
> > > -						       GPIOD_OUT_LOW,
> > > -						       "pcie1-reset");
> > > +	pcie->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
> > >  	ret = PTR_ERR_OR_ZERO(pcie->reset_gpio);
> > >  	if (ret) {
> > > -		if (ret == -ENOENT) {
> > > -			pcie->reset_gpio = NULL;
> > > -		} else {
> > > -			if (ret != -EPROBE_DEFER)
> > > -				dev_err(dev, "Failed to get reset-gpio: %i\n",
> > > -					ret);
> > > -			return ret;
> > > -		}
> > > +		if (ret != -EPROBE_DEFER)
> > > +			dev_err(dev, "Failed to get reset-gpio: %i\n",
> > > +				ret);
> > > +		return ret;
> > > +	}
> > > +
> > > +	ret = gpiod_set_consumer_name(pcie->reset_gpio, "pcie1-reset");
> > > +	if (ret) {
> > > +		dev_err(dev, "Failed to set reset gpio name: %d\n", ret);
> > > +		return ret;
> > >  	}
> > >  
> > >  	ret = of_pci_get_max_link_speed(dev->of_node);
> > > 
> > > -- 
> > > b4 0.10.0-dev-fc921
> 
> Thanks.
> 
> -- 
> Dmitry
Dmitry Torokhov Sept. 5, 2022, 11:18 p.m. UTC | #6
On Tue, Sep 06, 2022 at 01:10:10AM +0200, Pali Rohár wrote:
> On Monday 05 September 2022 15:54:53 Dmitry Torokhov wrote:
> > On Mon, Sep 05, 2022 at 09:00:46AM +0200, Pali Rohár wrote:
> > > On Sunday 04 September 2022 23:30:58 Dmitry Torokhov 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_optional(), used devm_gpiod_get_from_of_node() is
> > > > because it wanted to set up a pretty consumer name for the GPIO,
> > > 
> > > IIRC consumer name is not used at all.
> > > 
> > > The reason was to specify full name of DTS property, for easier
> > > identification of the code. DTS property is "reset-gpios" but API
> > > specify only "reset".
> > 
> > I see. Do you want me to reset the patch with updated desctiption as to
> > the reason devm_gpiod_get_from_of_node() was used?
> 
> I think it is fine. So add my:
> 
> Acked-by: Pali Rohár <pali@kernel.org>
> 
> Anyway as another improvement for future I would suggest some API
> function with _optional_ logic, so it could be used for more PCIe

I think we need to see how many are attaching reset lines to subnodes.
If there are multiple then I agree we could add _optional. So far I see:

dtor@dtor-ws:~/kernel/linux-next (gpiod_get_from_of_node-remove)$ git grep '"reset"' -- drivers/pci/controller/
drivers/pci/controller/cadence/pci-j721e.c:             gpiod = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
drivers/pci/controller/dwc/pci-keystone.c:      gpiod = devm_gpiod_get_optional(dev, "reset",
drivers/pci/controller/dwc/pci-meson.c: mp->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
drivers/pci/controller/dwc/pcie-dw-rockchip.c:  rockchip->rst_gpio = devm_gpiod_get_optional(&pdev->dev, "reset",
drivers/pci/controller/dwc/pcie-fu740.c:        afp->reset = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
drivers/pci/controller/dwc/pcie-intel-gw.c:     pcie->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
drivers/pci/controller/dwc/pcie-keembay.c:      pcie->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
drivers/pci/controller/dwc/pcie-qcom-ep.c:      pcie_ep->reset = devm_gpiod_get(dev, "reset", GPIOD_IN);
drivers/pci/controller/dwc/pcie-tegra194.c:     pcie->pex_rst_gpiod = devm_gpiod_get(pcie->dev, "reset", GPIOD_IN);
drivers/pci/controller/pci-aardvark.c:  pcie->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
drivers/pci/controller/pci-tegra.c:                                                    "reset",
drivers/pci/controller/pcie-apple.c:                                   "reset", 0, GPIOD_OUT_LOW, "PERST#");
drivers/pci/controller/pcie-mt7621.c:   port->gpio_rst = devm_gpiod_get_index_optional(dev, "reset", slot,

So majority have reset lines attached to the "main" node and thus can use
devm_gpiod_get_optional().

Thanks.
Linus Walleij Sept. 8, 2022, 8:32 a.m. UTC | #7
On Mon, Sep 5, 2022 at 8:31 AM Dmitry Torokhov
<dmitry.torokhov@gmail.com> 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_optional(), 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 <dmitry.torokhov@gmail.com>

Reviewed-by: Linus Walleij <linus.walleij@linaro.org>

Yours,
Linus Walleij
diff mbox series

Patch

diff --git a/drivers/pci/controller/pci-aardvark.c b/drivers/pci/controller/pci-aardvark.c
index 4834198cc86b..4a8a4a8522cb 100644
--- a/drivers/pci/controller/pci-aardvark.c
+++ b/drivers/pci/controller/pci-aardvark.c
@@ -1856,20 +1856,19 @@  static int advk_pcie_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	pcie->reset_gpio = devm_gpiod_get_from_of_node(dev, dev->of_node,
-						       "reset-gpios", 0,
-						       GPIOD_OUT_LOW,
-						       "pcie1-reset");
+	pcie->reset_gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_LOW);
 	ret = PTR_ERR_OR_ZERO(pcie->reset_gpio);
 	if (ret) {
-		if (ret == -ENOENT) {
-			pcie->reset_gpio = NULL;
-		} else {
-			if (ret != -EPROBE_DEFER)
-				dev_err(dev, "Failed to get reset-gpio: %i\n",
-					ret);
-			return ret;
-		}
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Failed to get reset-gpio: %i\n",
+				ret);
+		return ret;
+	}
+
+	ret = gpiod_set_consumer_name(pcie->reset_gpio, "pcie1-reset");
+	if (ret) {
+		dev_err(dev, "Failed to set reset gpio name: %d\n", ret);
+		return ret;
 	}
 
 	ret = of_pci_get_max_link_speed(dev->of_node);