[PATCH v3 1/6] gpio: mmio: Add compatible for opencores GPIO

[PATCH v3 1/6] gpio: mmio: Add compatible for opencores GPIO

[Stafford Horne]

On FPGA Development boards with GPIOs the OpenRISC architecture uses the
opencores gpio verilog rtl.  This is compatible with the gpio-mmio.  Add
the compatible string to allow probing this driver from the devicetree.

Link: https://opencores.org/projects/gpio
Signed-off-by: Stafford Horne <shorne@gmail.com>
---
Since v2:
 - New patch

 drivers/gpio/gpio-mmio.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/gpio/gpio-mmio.c b/drivers/gpio/gpio-mmio.c
index 5daf962b0323..edbcaad57d00 100644
--- a/drivers/gpio/gpio-mmio.c
+++ b/drivers/gpio/gpio-mmio.c
@@ -724,6 +724,7 @@ static const struct of_device_id gpio_mmio_of_match[] = {
 	{ .compatible = "wd,mbl-gpio" },
 	{ .compatible = "ni,169445-nand-gpio" },
 	{ .compatible = "intel,ixp4xx-expansion-bus-mmio-gpio" },
+	{ .compatible = "opencores,gpio" },
 	{ }
 };
 MODULE_DEVICE_TABLE(of, gpio_mmio_of_match);
-- 
2.51.0

[PATCH v3 2/6] dt-bindings: gpio-mmio: Add opencores GPIO

[Stafford Horne]

Add a device tree binding for the opencores GPIO controller.

On FPGA Development boards with GPIOs the OpenRISC architecture uses the
opencores gpio verilog rtl which is compatible with the MMIO GPIO driver.

Link: https://opencores.org/projects/gpio
Signed-off-by: Stafford Horne <shorne@gmail.com>
---
Since v2:
 - Fixup patch to simply add opencores,gpio and add an example.
Since v1:
 - Fix schema to actually match the example.

 Documentation/devicetree/bindings/gpio/gpio-mmio.yaml | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml b/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml
index ee5d5d25ae82..d44edc181e0a 100644
--- a/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml
+++ b/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml
@@ -23,6 +23,7 @@ properties:
       - ni,169445-nand-gpio
       - wd,mbl-gpio # Western Digital MyBook Live memory-mapped GPIO controller
       - intel,ixp4xx-expansion-bus-mmio-gpio
+      - opencores,gpio
 
   big-endian: true
 
@@ -160,3 +161,11 @@ examples:
             intel,ixp4xx-eb-write-enable = <1>;
         };
     };
+
+    gpio@91000000 {
+        compatible = "opencores,gpio";
+        reg = <0x91000000 0x1>, <0x91000001 0x1>;
+        reg-names = "dat", "dirout";
+        gpio-controller;
+        #gpio-cells = <2>;
+    };
-- 
2.51.0

Re: [PATCH v3 1/6] gpio: mmio: Add compatible for opencores GPIO

[Linus Walleij]

On Fri, Jan 9, 2026 at 2:44 PM Stafford Horne <shorne@gmail.com> wrote:

> On FPGA Development boards with GPIOs the OpenRISC architecture uses the
> opencores gpio verilog rtl.  This is compatible with the gpio-mmio.  Add
> the compatible string to allow probing this driver from the devicetree.
>
> Link: https://opencores.org/projects/gpio
> Signed-off-by: Stafford Horne <shorne@gmail.com>

Reviewed-by: Linus Walleij <linusw@kernel.org>

Yours,
Linus Walleij

Re: [PATCH v3 2/6] dt-bindings: gpio-mmio: Add opencores GPIO

[Linus Walleij]

On Fri, Jan 9, 2026 at 2:44 PM Stafford Horne <shorne@gmail.com> wrote:

> Add a device tree binding for the opencores GPIO controller.
>
> On FPGA Development boards with GPIOs the OpenRISC architecture uses the
> opencores gpio verilog rtl which is compatible with the MMIO GPIO driver.
>
> Link: https://opencores.org/projects/gpio
> Signed-off-by: Stafford Horne <shorne@gmail.com>

Reviewed-by: Linus Walleij <linusw@kernel.org>

Yours,
Linus Walleij

Re: [PATCH v3 2/6] dt-bindings: gpio-mmio: Add opencores GPIO

[Geert Uytterhoeven]

On Fri, 9 Jan 2026 at 14:48, Stafford Horne <shorne@gmail.com> wrote:
> Add a device tree binding for the opencores GPIO controller.
>
> On FPGA Development boards with GPIOs the OpenRISC architecture uses the
> opencores gpio verilog rtl which is compatible with the MMIO GPIO driver.
>
> Link: https://opencores.org/projects/gpio
> Signed-off-by: Stafford Horne <shorne@gmail.com>
> ---
> Since v2:
>  - Fixup patch to simply add opencores,gpio and add an example.
> Since v1:
>  - Fix schema to actually match the example.

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v3 1/6] gpio: mmio: Add compatible for opencores GPIO

[Geert Uytterhoeven]

On Fri, 9 Jan 2026 at 14:48, Stafford Horne <shorne@gmail.com> wrote:
> On FPGA Development boards with GPIOs the OpenRISC architecture uses the
> opencores gpio verilog rtl.  This is compatible with the gpio-mmio.  Add
> the compatible string to allow probing this driver from the devicetree.
>
> Link: https://opencores.org/projects/gpio
> Signed-off-by: Stafford Horne <shorne@gmail.com>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds

Re: [PATCH v3 2/6] dt-bindings: gpio-mmio: Add opencores GPIO

[Krzysztof Kozlowski]

On Fri, Jan 09, 2026 at 01:43:53PM +0000, Stafford Horne wrote:
> Add a device tree binding for the opencores GPIO controller.
> 
> On FPGA Development boards with GPIOs the OpenRISC architecture uses the
> opencores gpio verilog rtl which is compatible with the MMIO GPIO driver.
> 
> Link: https://opencores.org/projects/gpio
> Signed-off-by: Stafford Horne <shorne@gmail.com>
> ---
> Since v2:
>  - Fixup patch to simply add opencores,gpio and add an example.

Simplify? You completely changed the meaning of binding here - now
device is not compatible.

I don't know which one is correct, but your changelog must explain why
now devices are not compatible but they were before.

> Since v1:
>  - Fix schema to actually match the example.
> 
>  Documentation/devicetree/bindings/gpio/gpio-mmio.yaml | 9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml b/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml
> index ee5d5d25ae82..d44edc181e0a 100644
> --- a/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml
> +++ b/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml
> @@ -23,6 +23,7 @@ properties:
>        - ni,169445-nand-gpio
>        - wd,mbl-gpio # Western Digital MyBook Live memory-mapped GPIO controller
>        - intel,ixp4xx-expansion-bus-mmio-gpio
> +      - opencores,gpio
>  
>    big-endian: true
>  
> @@ -160,3 +161,11 @@ examples:
>              intel,ixp4xx-eb-write-enable = <1>;
>          };
>      };
> +
> +    gpio@91000000 {

Please do not grow the examples if they are exactly the same as other.

> +        compatible = "opencores,gpio";
> +        reg = <0x91000000 0x1>, <0x91000001 0x1>;
> +        reg-names = "dat", "dirout";
> +        gpio-controller;
> +        #gpio-cells = <2>;
> +    };
> -- 
> 2.51.0
> 

Re: [PATCH v3 2/6] dt-bindings: gpio-mmio: Add opencores GPIO

[Krzysztof Kozlowski]

On Fri, Jan 09, 2026 at 01:43:53PM +0000, Stafford Horne wrote:
> Add a device tree binding for the opencores GPIO controller.
> 
> On FPGA Development boards with GPIOs the OpenRISC architecture uses the
> opencores gpio verilog rtl which is compatible with the MMIO GPIO driver.
> 
> Link: https://opencores.org/projects/gpio
> Signed-off-by: Stafford Horne <shorne@gmail.com>
> ---
> Since v2:
>  - Fixup patch to simply add opencores,gpio and add an example.
> Since v1:
>  - Fix schema to actually match the example.
> 
>  Documentation/devicetree/bindings/gpio/gpio-mmio.yaml | 9 +++++++++
>  1 file changed, 9 insertions(+)

This does not even apply now. Your previous version was applied almost
one month before and you WERE notified about it.

Why did you ignore Bartosz's reply?

Best regards,
Krzysztof

Re: [PATCH v3 2/6] dt-bindings: gpio-mmio: Add opencores GPIO

[Stafford Horne]

On Sun, Jan 11, 2026 at 11:20:38AM +0100, Krzysztof Kozlowski wrote:
> On Fri, Jan 09, 2026 at 01:43:53PM +0000, Stafford Horne wrote:
> > Add a device tree binding for the opencores GPIO controller.
> > 
> > On FPGA Development boards with GPIOs the OpenRISC architecture uses the
> > opencores gpio verilog rtl which is compatible with the MMIO GPIO driver.
> > 
> > Link: https://opencores.org/projects/gpio
> > Signed-off-by: Stafford Horne <shorne@gmail.com>
> > ---
> > Since v2:
> >  - Fixup patch to simply add opencores,gpio and add an example.
> > Since v1:
> >  - Fix schema to actually match the example.
> > 
> >  Documentation/devicetree/bindings/gpio/gpio-mmio.yaml | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> 
> This does not even apply now. Your previous version was applied almost
> one month before and you WERE notified about it.
> 
> Why did you ignore Bartosz's reply?

Hi Krzysztof,

Sorry for the confusion, we discussed [1] this patch in the last Series with Geert
and Linus W. We decided to Fixup (replace) the original patch with this and a
patch to the GPIO MMIO driver instead.  I pointed it out in the cover letter but
it may have not been clear.

I will reply to Bartosz's original mail too so he can understand the intent.

[1] https://lore.kernel.org/lkml/CAD++jLm1u9ChqsftwvbOptiG3Qo2KWxPjqN2snOVuZDYuVST5Q@mail.gmail.com/

-Stafford

Re: [PATCH v3 2/6] dt-bindings: gpio-mmio: Add opencores GPIO

[Stafford Horne]

On Sun, Jan 11, 2026 at 11:18:42AM +0100, Krzysztof Kozlowski wrote:
> On Fri, Jan 09, 2026 at 01:43:53PM +0000, Stafford Horne wrote:
> > Add a device tree binding for the opencores GPIO controller.
> > 
> > On FPGA Development boards with GPIOs the OpenRISC architecture uses the
> > opencores gpio verilog rtl which is compatible with the MMIO GPIO driver.
> > 
> > Link: https://opencores.org/projects/gpio
> > Signed-off-by: Stafford Horne <shorne@gmail.com>
> > ---
> > Since v2:
> >  - Fixup patch to simply add opencores,gpio and add an example.
> 
> Simplify? You completely changed the meaning of binding here - now
> device is not compatible.
>
> I don't know which one is correct, but your changelog must explain why
> now devices are not compatible but they were before.

Hello,

Did you miss the 1/6 patch in this series?  We add the compatible string to the
driver there before we add it here.

Sorry, I thought the series and the over letter would be enough to understand
what I meant by the "Fixup" description here.

> > Since v1:
> >  - Fix schema to actually match the example.
> > 
> >  Documentation/devicetree/bindings/gpio/gpio-mmio.yaml | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml b/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml
> > index ee5d5d25ae82..d44edc181e0a 100644
> > --- a/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml
> > +++ b/Documentation/devicetree/bindings/gpio/gpio-mmio.yaml
> > @@ -23,6 +23,7 @@ properties:
> >        - ni,169445-nand-gpio
> >        - wd,mbl-gpio # Western Digital MyBook Live memory-mapped GPIO controller
> >        - intel,ixp4xx-expansion-bus-mmio-gpio
> > +      - opencores,gpio
> >  
> >    big-endian: true
> >  
> > @@ -160,3 +161,11 @@ examples:
> >              intel,ixp4xx-eb-write-enable = <1>;
> >          };
> >      };
> > +
> > +    gpio@91000000 {
> 
> Please do not grow the examples if they are exactly the same as other.

I figured this is a new compatible string with a different set of 8 bit
registers so having this example would be beneficial.

> > +        compatible = "opencores,gpio";
> > +        reg = <0x91000000 0x1>, <0x91000001 0x1>;
> > +        reg-names = "dat", "dirout";
> > +        gpio-controller;
> > +        #gpio-cells = <2>;
> > +    };
> > -- 
> > 2.51.0
> > 

Re: [PATCH v3 2/6] dt-bindings: gpio-mmio: Add opencores GPIO

[Krzysztof Kozlowski]

On 11/01/2026 17:46, Stafford Horne wrote:
> On Sun, Jan 11, 2026 at 11:18:42AM +0100, Krzysztof Kozlowski wrote:
>> On Fri, Jan 09, 2026 at 01:43:53PM +0000, Stafford Horne wrote:
>>> Add a device tree binding for the opencores GPIO controller.
>>>
>>> On FPGA Development boards with GPIOs the OpenRISC architecture uses the
>>> opencores gpio verilog rtl which is compatible with the MMIO GPIO driver.
>>>
>>> Link: https://opencores.org/projects/gpio
>>> Signed-off-by: Stafford Horne <shorne@gmail.com>
>>> ---
>>> Since v2:
>>>  - Fixup patch to simply add opencores,gpio and add an example.
>>
>> Simplify? You completely changed the meaning of binding here - now
>> device is not compatible.
>>
>> I don't know which one is correct, but your changelog must explain why
>> now devices are not compatible but they were before.
> 
> Hello,
> 
> Did you miss the 1/6 patch in this series?  We add the compatible string to the

There is no 1/6!

> driver there before we add it here.

How does it matter? How can you add something to the driver before you
document the ABI? Did you read the submitting patches doc?


> 
> Sorry, I thought the series and the over letter would be enough to understand
> what I meant by the "Fixup" description here.

You still did not answer to my comments.



Best regards,
Krzysztof

Re: [PATCH v3 2/6] dt-bindings: gpio-mmio: Add opencores GPIO

[Krzysztof Kozlowski]

On 11/01/2026 17:34, Stafford Horne wrote:
> On Sun, Jan 11, 2026 at 11:20:38AM +0100, Krzysztof Kozlowski wrote:
>> On Fri, Jan 09, 2026 at 01:43:53PM +0000, Stafford Horne wrote:
>>> Add a device tree binding for the opencores GPIO controller.
>>>
>>> On FPGA Development boards with GPIOs the OpenRISC architecture uses the
>>> opencores gpio verilog rtl which is compatible with the MMIO GPIO driver.
>>>
>>> Link: https://opencores.org/projects/gpio
>>> Signed-off-by: Stafford Horne <shorne@gmail.com>
>>> ---
>>> Since v2:
>>>  - Fixup patch to simply add opencores,gpio and add an example.
>>> Since v1:
>>>  - Fix schema to actually match the example.
>>>
>>>  Documentation/devicetree/bindings/gpio/gpio-mmio.yaml | 9 +++++++++
>>>  1 file changed, 9 insertions(+)
>>
>> This does not even apply now. Your previous version was applied almost
>> one month before and you WERE notified about it.
>>
>> Why did you ignore Bartosz's reply?
> 
> Hi Krzysztof,
> 
> Sorry for the confusion, we discussed [1] this patch in the last Series with Geert
> and Linus W. We decided to Fixup (replace) the original patch with this and a
> patch to the GPIO MMIO driver instead.  I pointed it out in the cover letter but
> it may have not been clear.
> 
> I will reply to Bartosz's original mail too so he can understand the intent.

But you did not send any fixup, anything which would change what was
applied almost one month ago!

Best regards,
Krzysztof

Re: [PATCH v3 2/6] dt-bindings: gpio-mmio: Add opencores GPIO

[Stafford Horne]

On Mon, Jan 12, 2026 at 08:31:03AM +0100, Krzysztof Kozlowski wrote:
> On 11/01/2026 17:46, Stafford Horne wrote:
> > On Sun, Jan 11, 2026 at 11:18:42AM +0100, Krzysztof Kozlowski wrote:
> >> On Fri, Jan 09, 2026 at 01:43:53PM +0000, Stafford Horne wrote:
> >>> Add a device tree binding for the opencores GPIO controller.
> >>>
> >>> On FPGA Development boards with GPIOs the OpenRISC architecture uses the
> >>> opencores gpio verilog rtl which is compatible with the MMIO GPIO driver.
> >>>
> >>> Link: https://opencores.org/projects/gpio
> >>> Signed-off-by: Stafford Horne <shorne@gmail.com>
> >>> ---
> >>> Since v2:
> >>>  - Fixup patch to simply add opencores,gpio and add an example.
> >>
> >> Simplify? You completely changed the meaning of binding here - now
> >> device is not compatible.
> >>
> >> I don't know which one is correct, but your changelog must explain why
> >> now devices are not compatible but they were before.

Trying to answer this better this time:

As per our discussion with Geert and Linus W.  It was pointed out that the
original patch, which added openrisc,gpio to be allowed along with the broadcom
chip e.g. ( compatible = "opencores,gpio", "brcm,bcm6345-gpio"; ), was wrong.

The opencores,gpio is compatible with the gpio-mmio driver, but it is not a
hardware clone with the broadcomm chip.  It has 8-bit registers vs 32-bit
registers and the register map is different.  Instead of allowing opencores,gpio
to be specified along with the broadcom chip, opencores,gpio should be specified
on its own.

So we agreed to resend the patch with to parts:

 1. A commit to add the opencores,gpio to the driver compatibility list. (new
    1/6)
 2. A commit to add opencores,gpio to the binding (replacement of the
    original patch 2/6)

(now I understand this order is bad, I can resend)

This is a "simplification" as we are now just adding the opencores,gpio string
to the list rather than changing the schema with oneOf and items.

I wanted top get it out quickly so it can be fixed up before the merge window
opens.

> > Hello,
> > 
> > Did you miss the 1/6 patch in this series?  We add the compatible string to the
> 
> There is no 1/6!

It seems you are not on it, but it is on lore here, if you missed it.

 https://lore.kernel.org/lkml/20260109134409.2153333-2-shorne@gmail.com/

Reading the bindings submitting patches doc's it seems I need to send the whole
series to the bindings list.  Which may explain.

> > driver there before we add it here.
> 
> How does it matter? How can you add something to the driver before you
> document the ABI? Did you read the submitting patches doc?

Sorry, I didn't read, or realize there was a device tree bindings specific patch
document.  I see it now, and I see point 5 makes it clear that we should
document the binding before the code change.  I got the order swapped.

 https://docs.kernel.org/devicetree/bindings/submitting-patches.html

If necessary I can resend the 2 patches in the right order as a series to the
devicetree list.  devicetree@vger.kernel.org

> > 
> > Sorry, I thought the series and the over letter would be enough to understand
> > what I meant by the "Fixup" description here.
> 
> You still did not answer to my comments.

OK, I tried again above.

-stafford