2022-08-01 10:19:26

by Chen-Yu Tsai

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: mediatek: watchdog: Fix compatible fallbacks and example

On Thu, Jul 21, 2022 at 10:50 AM Allen-KH Cheng
<[email protected]> wrote:
>
> The watchdog timer of mt8186. mt8195 and mt7986 have their DT data.
> We should not use 'mediatek,mt6589-wdt' as fallback.
>
> For mediatek,wdt example of mt8183, We remove mediatek,mt6589-wdt fallback.

I think this needs some more information.

Right now on the kernel side, mt6589-wdt provides just watchdog support.
The SoC-specific compatibles that are touched by this patch provide reset
controls in addition to the standard watchdog, which remains the same.

If that is the case, then the fallback compatibles are correct. A fallback
says that the new hardware is compatible with some older hardware, and
can be run with the driver supporting that older hardware, likely with
reduced functionality.

As an example, if mt8195-wdt is backward compatible with mt6589-wdt,
then it should run as mt6589-wdt, and would just be missing new
functionality, in this case the reset controls.

So either mt6589-wdt also contains a reset control that is not the same
as the other newer chips, or has some other functionality that the other
chips contain, and justifies the removal of the fallback, or this patch
is incorrect. Note that mt2701-wdt and mt762*-wdt are still listed as
compatible with mt6589-wdt. So I think a better explanation is required.


Regards
ChenYu


> Fixes:a45b408a020b("dt-bindings: watchdog: Add compatible for MediaTek MT8186")
> Fixes:b326f2c85f3d("dt-bindings: watchdog: Add compatible for Mediatek MT8195")
> Fixes:41e73feb1024("dt-bindings: watchdog: Add compatible for Mediatek MT7986")
> Fixes:f43f97a0fc0e("dt-bindings: mediatek: mt8183: Add #reset-cells")
> Signed-off-by: Allen-KH Cheng <[email protected]>
> Reviewed-by: AngeloGioacchino Del Regno <[email protected]>
> ---
> Documentation/devicetree/bindings/watchdog/mtk-wdt.txt | 9 ++++-----
> 1 file changed, 4 insertions(+), 5 deletions(-)
>
> diff --git a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> index 762c62e428ef..67ef991ec4cf 100644
> --- a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> +++ b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> @@ -14,12 +14,12 @@ Required properties:
> "mediatek,mt7622-wdt", "mediatek,mt6589-wdt": for MT7622
> "mediatek,mt7623-wdt", "mediatek,mt6589-wdt": for MT7623
> "mediatek,mt7629-wdt", "mediatek,mt6589-wdt": for MT7629
> - "mediatek,mt7986-wdt", "mediatek,mt6589-wdt": for MT7986
> + "mediatek,mt7986-wdt": for MT7986
> "mediatek,mt8183-wdt": for MT8183
> - "mediatek,mt8186-wdt", "mediatek,mt6589-wdt": for MT8186
> + "mediatek,mt8186-wdt": for MT8186
> "mediatek,mt8516-wdt", "mediatek,mt6589-wdt": for MT8516
> "mediatek,mt8192-wdt": for MT8192
> - "mediatek,mt8195-wdt", "mediatek,mt6589-wdt": for MT8195
> + "mediatek,mt8195-wdt": for MT8195
>
> - reg : Specifies base physical address and size of the registers.
>
> @@ -32,8 +32,7 @@ Optional properties:
> Example:
>
> watchdog: watchdog@10007000 {
> - compatible = "mediatek,mt8183-wdt",
> - "mediatek,mt6589-wdt";
> + compatible = "mediatek,mt8183-wdt";
> mediatek,disable-extrst;
> reg = <0 0x10007000 0 0x100>;
> interrupts = <GIC_SPI 139 IRQ_TYPE_NONE>;
> --
> 2.18.0
>
>


2022-08-02 11:55:26

by Matthias Brugger

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: mediatek: watchdog: Fix compatible fallbacks and example



On 01/08/2022 11:29, Chen-Yu Tsai wrote:
> On Thu, Jul 21, 2022 at 10:50 AM Allen-KH Cheng
> <[email protected]> wrote:
>>
>> The watchdog timer of mt8186. mt8195 and mt7986 have their DT data.
>> We should not use 'mediatek,mt6589-wdt' as fallback.
>>
>> For mediatek,wdt example of mt8183, We remove mediatek,mt6589-wdt fallback.
>
> I think this needs some more information.
>
> Right now on the kernel side, mt6589-wdt provides just watchdog support.
> The SoC-specific compatibles that are touched by this patch provide reset
> controls in addition to the standard watchdog, which remains the same.
>
> If that is the case, then the fallback compatibles are correct. A fallback
> says that the new hardware is compatible with some older hardware, and
> can be run with the driver supporting that older hardware, likely with
> reduced functionality.
>

My understanding is, that we add a fallback because although at the time we
entered the compatible, the functionality of the device is the same as the
fallback. Nonetheless we add a compatible specific for the device in case in the
future we realize that the device has some functionality that is not and can not
be covered by the fallback.

This is the case here. Actually adding the fallback in the first place was
wrong, because the driver since ever supports the extra function for the device,
the reset.

So this is a mere cleanup of the binding to reflect what was always present in
the driver.

Regards,
Matthias

> As an example, if mt8195-wdt is backward compatible with mt6589-wdt,
> then it should run as mt6589-wdt, and would just be missing new
> functionality, in this case the reset controls.
>
> So either mt6589-wdt also contains a reset control that is not the same
> as the other newer chips, or has some other functionality that the other
> chips contain, and justifies the removal of the fallback, or this patch
> is incorrect. Note that mt2701-wdt and mt762*-wdt are still listed as
> compatible with mt6589-wdt. So I think a better explanation is required.
>
>
> Regards
> ChenYu
>
>
>> Fixes:a45b408a020b("dt-bindings: watchdog: Add compatible for MediaTek MT8186")
>> Fixes:b326f2c85f3d("dt-bindings: watchdog: Add compatible for Mediatek MT8195")
>> Fixes:41e73feb1024("dt-bindings: watchdog: Add compatible for Mediatek MT7986")
>> Fixes:f43f97a0fc0e("dt-bindings: mediatek: mt8183: Add #reset-cells")
>> Signed-off-by: Allen-KH Cheng <[email protected]>
>> Reviewed-by: AngeloGioacchino Del Regno <[email protected]>
>> ---
>> Documentation/devicetree/bindings/watchdog/mtk-wdt.txt | 9 ++++-----
>> 1 file changed, 4 insertions(+), 5 deletions(-)
>>
>> diff --git a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
>> index 762c62e428ef..67ef991ec4cf 100644
>> --- a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
>> +++ b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
>> @@ -14,12 +14,12 @@ Required properties:
>> "mediatek,mt7622-wdt", "mediatek,mt6589-wdt": for MT7622
>> "mediatek,mt7623-wdt", "mediatek,mt6589-wdt": for MT7623
>> "mediatek,mt7629-wdt", "mediatek,mt6589-wdt": for MT7629
>> - "mediatek,mt7986-wdt", "mediatek,mt6589-wdt": for MT7986
>> + "mediatek,mt7986-wdt": for MT7986
>> "mediatek,mt8183-wdt": for MT8183
>> - "mediatek,mt8186-wdt", "mediatek,mt6589-wdt": for MT8186
>> + "mediatek,mt8186-wdt": for MT8186
>> "mediatek,mt8516-wdt", "mediatek,mt6589-wdt": for MT8516
>> "mediatek,mt8192-wdt": for MT8192
>> - "mediatek,mt8195-wdt", "mediatek,mt6589-wdt": for MT8195
>> + "mediatek,mt8195-wdt": for MT8195
>>
>> - reg : Specifies base physical address and size of the registers.
>>
>> @@ -32,8 +32,7 @@ Optional properties:
>> Example:
>>
>> watchdog: watchdog@10007000 {
>> - compatible = "mediatek,mt8183-wdt",
>> - "mediatek,mt6589-wdt";
>> + compatible = "mediatek,mt8183-wdt";
>> mediatek,disable-extrst;
>> reg = <0 0x10007000 0 0x100>;
>> interrupts = <GIC_SPI 139 IRQ_TYPE_NONE>;
>> --
>> 2.18.0
>>
>>

2022-08-03 10:07:46

by Allen-KH Cheng

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: mediatek: watchdog: Fix compatible fallbacks and example

Hi Chen-Yu and Mathias,

Sincere apologies for the delayed response.

On Tue, 2022-08-02 at 13:04 +0200, Matthias Brugger wrote:
>
> On 01/08/2022 11:29, Chen-Yu Tsai wrote:
> > On Thu, Jul 21, 2022 at 10:50 AM Allen-KH Cheng
> > <[email protected]> wrote:
> > >
> > > The watchdog timer of mt8186. mt8195 and mt7986 have their DT
> > > data.
> > > We should not use 'mediatek,mt6589-wdt' as fallback.
> > >
> > > For mediatek,wdt example of mt8183, We remove mediatek,mt6589-wdt
> > > fallback.
> >
> > I think this needs some more information.
> >
> > Right now on the kernel side, mt6589-wdt provides just watchdog
> > support.
> > The SoC-specific compatibles that are touched by this patch provide
> > reset
> > controls in addition to the standard watchdog, which remains the
> > same.
> >
> > If that is the case, then the fallback compatibles are correct. A
> > fallback
> > says that the new hardware is compatible with some older hardware,
> > and
> > can be run with the driver supporting that older hardware, likely
> > with
> > reduced functionality.
> >
>
> My understanding is, that we add a fallback because although at the
> time we
> entered the compatible, the functionality of the device is the same
> as the
> fallback. Nonetheless we add a compatible specific for the device in
> case in the
> future we realize that the device has some functionality that is not
> and can not
> be covered by the fallback.
>
> This is the case here. Actually adding the fallback in the first
> place was
> wrong, because the driver since ever supports the extra function for
> the device,
> the reset.
>
> So this is a mere cleanup of the binding to reflect what was always
> present in
> the driver.
>
> Regards,
> Matthias
>

mt6589-wdt dosen't contains a reset control for other modules, like
chen-yu mention "mt6589-wdt provides just watchdog support."

For instance, there is a reset control in mt8195-wdt and we have a DT
data to define its reset number of TOPRGU. I thought it's better not
use mt6589-wdt as fallback.

Please let me know if this works and if you have any suggestions or
comments.

Thanks,
Allen

> > As an example, if mt8195-wdt is backward compatible with mt6589-
> > wdt,
> > then it should run as mt6589-wdt, and would just be missing new
> > functionality, in this case the reset controls.
> >
> > So either mt6589-wdt also contains a reset control that is not the
> > same
> > as the other newer chips, or has some other functionality that the
> > other
> > chips contain, and justifies the removal of the fallback, or this
> > patch
> > is incorrect. Note that mt2701-wdt and mt762*-wdt are still listed
> > as
> > compatible with mt6589-wdt. So I think a better explanation is
> > required.
> >
> >
> > Regards
> > ChenYu
> >
> >
> > > Fixes:a45b408a020b("dt-bindings: watchdog: Add compatible for
> > > MediaTek MT8186")
> > > Fixes:b326f2c85f3d("dt-bindings: watchdog: Add compatible for
> > > Mediatek MT8195")
> > > Fixes:41e73feb1024("dt-bindings: watchdog: Add compatible for
> > > Mediatek MT7986")
> > > Fixes:f43f97a0fc0e("dt-bindings: mediatek: mt8183: Add #reset-
> > > cells")
> > > Signed-off-by: Allen-KH Cheng <[email protected]>
> > > Reviewed-by: AngeloGioacchino Del Regno <
> > > [email protected]>
> > > ---
> > > Documentation/devicetree/bindings/watchdog/mtk-wdt.txt | 9
> > > ++++-----
> > > 1 file changed, 4 insertions(+), 5 deletions(-)
> > >
> > > diff --git a/Documentation/devicetree/bindings/watchdog/mtk-
> > > wdt.txt b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> > > index 762c62e428ef..67ef991ec4cf 100644
> > > --- a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> > > +++ b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> > > @@ -14,12 +14,12 @@ Required properties:
> > > "mediatek,mt7622-wdt", "mediatek,mt6589-wdt": for MT7622
> > > "mediatek,mt7623-wdt", "mediatek,mt6589-wdt": for MT7623
> > > "mediatek,mt7629-wdt", "mediatek,mt6589-wdt": for MT7629
> > > - "mediatek,mt7986-wdt", "mediatek,mt6589-wdt": for MT7986
> > > + "mediatek,mt7986-wdt": for MT7986
> > > "mediatek,mt8183-wdt": for MT8183
> > > - "mediatek,mt8186-wdt", "mediatek,mt6589-wdt": for MT8186
> > > + "mediatek,mt8186-wdt": for MT8186
> > > "mediatek,mt8516-wdt", "mediatek,mt6589-wdt": for MT8516
> > > "mediatek,mt8192-wdt": for MT8192
> > > - "mediatek,mt8195-wdt", "mediatek,mt6589-wdt": for MT8195
> > > + "mediatek,mt8195-wdt": for MT8195
> > >
> > > - reg : Specifies base physical address and size of the
> > > registers.
> > >
> > > @@ -32,8 +32,7 @@ Optional properties:
> > > Example:
> > >
> > > watchdog: watchdog@10007000 {
> > > - compatible = "mediatek,mt8183-wdt",
> > > - "mediatek,mt6589-wdt";
> > > + compatible = "mediatek,mt8183-wdt";
> > > mediatek,disable-extrst;
> > > reg = <0 0x10007000 0 0x100>;
> > > interrupts = <GIC_SPI 139 IRQ_TYPE_NONE>;
> > > --
> > > 2.18.0
> > >
> > >


2022-08-08 17:25:36

by Nícolas F. R. A. Prado

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: mediatek: watchdog: Fix compatible fallbacks and example

Hi,

On Wed, Aug 03, 2022 at 05:23:57PM +0800, Allen-KH Cheng wrote:
> Hi Chen-Yu and Mathias,
>
> Sincere apologies for the delayed response.
>
> On Tue, 2022-08-02 at 13:04 +0200, Matthias Brugger wrote:
> >
> > On 01/08/2022 11:29, Chen-Yu Tsai wrote:
> > > On Thu, Jul 21, 2022 at 10:50 AM Allen-KH Cheng
> > > <[email protected]> wrote:
> > > >
> > > > The watchdog timer of mt8186. mt8195 and mt7986 have their DT
> > > > data.
> > > > We should not use 'mediatek,mt6589-wdt' as fallback.
> > > >
> > > > For mediatek,wdt example of mt8183, We remove mediatek,mt6589-wdt
> > > > fallback.
> > >
> > > I think this needs some more information.
> > >
> > > Right now on the kernel side, mt6589-wdt provides just watchdog
> > > support.
> > > The SoC-specific compatibles that are touched by this patch provide
> > > reset
> > > controls in addition to the standard watchdog, which remains the
> > > same.
> > >
> > > If that is the case, then the fallback compatibles are correct. A
> > > fallback
> > > says that the new hardware is compatible with some older hardware,
> > > and
> > > can be run with the driver supporting that older hardware, likely
> > > with
> > > reduced functionality.
> > >
> >
> > My understanding is, that we add a fallback because although at the
> > time we
> > entered the compatible, the functionality of the device is the same
> > as the
> > fallback. Nonetheless we add a compatible specific for the device in
> > case in the
> > future we realize that the device has some functionality that is not
> > and can not
> > be covered by the fallback.
> >
> > This is the case here. Actually adding the fallback in the first
> > place was
> > wrong, because the driver since ever supports the extra function for
> > the device,
> > the reset.
> >
> > So this is a mere cleanup of the binding to reflect what was always
> > present in
> > the driver.
> >
> > Regards,
> > Matthias
> >
>
> mt6589-wdt dosen't contains a reset control for other modules, like
> chen-yu mention "mt6589-wdt provides just watchdog support."
>
> For instance, there is a reset control in mt8195-wdt and we have a DT
> data to define its reset number of TOPRGU. I thought it's better not
> use mt6589-wdt as fallback.
>
> Please let me know if this works and if you have any suggestions or
> comments.

The only practical usecase that I can think of that relies on keeping the
fallback compatibles is using the current DT with an older kernel that didn't
yet support the specific watchdog compatibles. In this case, dropping the
fallback compatibles would make the watchdog not work at all in such a kernel.

I'm not sure how relevant/common of a usecase that would be, but maybe it's
worth considering given that the advantage of removing the fallback compatible
is purely aesthetic?

Thanks,
N?colas

>
> Thanks,
> Allen
>
> > > As an example, if mt8195-wdt is backward compatible with mt6589-
> > > wdt,
> > > then it should run as mt6589-wdt, and would just be missing new
> > > functionality, in this case the reset controls.
> > >
> > > So either mt6589-wdt also contains a reset control that is not the
> > > same
> > > as the other newer chips, or has some other functionality that the
> > > other
> > > chips contain, and justifies the removal of the fallback, or this
> > > patch
> > > is incorrect. Note that mt2701-wdt and mt762*-wdt are still listed
> > > as
> > > compatible with mt6589-wdt. So I think a better explanation is
> > > required.
> > >
> > >
> > > Regards
> > > ChenYu
> > >
> > >
> > > > Fixes:a45b408a020b("dt-bindings: watchdog: Add compatible for
> > > > MediaTek MT8186")
> > > > Fixes:b326f2c85f3d("dt-bindings: watchdog: Add compatible for
> > > > Mediatek MT8195")
> > > > Fixes:41e73feb1024("dt-bindings: watchdog: Add compatible for
> > > > Mediatek MT7986")
> > > > Fixes:f43f97a0fc0e("dt-bindings: mediatek: mt8183: Add #reset-
> > > > cells")
> > > > Signed-off-by: Allen-KH Cheng <[email protected]>
> > > > Reviewed-by: AngeloGioacchino Del Regno <
> > > > [email protected]>
> > > > ---
> > > > Documentation/devicetree/bindings/watchdog/mtk-wdt.txt | 9
> > > > ++++-----
> > > > 1 file changed, 4 insertions(+), 5 deletions(-)
> > > >
> > > > diff --git a/Documentation/devicetree/bindings/watchdog/mtk-
> > > > wdt.txt b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> > > > index 762c62e428ef..67ef991ec4cf 100644
> > > > --- a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> > > > +++ b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> > > > @@ -14,12 +14,12 @@ Required properties:
> > > > "mediatek,mt7622-wdt", "mediatek,mt6589-wdt": for MT7622
> > > > "mediatek,mt7623-wdt", "mediatek,mt6589-wdt": for MT7623
> > > > "mediatek,mt7629-wdt", "mediatek,mt6589-wdt": for MT7629
> > > > - "mediatek,mt7986-wdt", "mediatek,mt6589-wdt": for MT7986
> > > > + "mediatek,mt7986-wdt": for MT7986
> > > > "mediatek,mt8183-wdt": for MT8183
> > > > - "mediatek,mt8186-wdt", "mediatek,mt6589-wdt": for MT8186
> > > > + "mediatek,mt8186-wdt": for MT8186
> > > > "mediatek,mt8516-wdt", "mediatek,mt6589-wdt": for MT8516
> > > > "mediatek,mt8192-wdt": for MT8192
> > > > - "mediatek,mt8195-wdt", "mediatek,mt6589-wdt": for MT8195
> > > > + "mediatek,mt8195-wdt": for MT8195
> > > >
> > > > - reg : Specifies base physical address and size of the
> > > > registers.
> > > >
> > > > @@ -32,8 +32,7 @@ Optional properties:
> > > > Example:
> > > >
> > > > watchdog: watchdog@10007000 {
> > > > - compatible = "mediatek,mt8183-wdt",
> > > > - "mediatek,mt6589-wdt";
> > > > + compatible = "mediatek,mt8183-wdt";
> > > > mediatek,disable-extrst;
> > > > reg = <0 0x10007000 0 0x100>;
> > > > interrupts = <GIC_SPI 139 IRQ_TYPE_NONE>;
> > > > --
> > > > 2.18.0
> > > >
> > > >
>
>

2022-08-10 13:01:07

by Allen-KH Cheng

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: mediatek: watchdog: Fix compatible fallbacks and example

Hi Nícolas,

On Mon, 2022-08-08 at 13:03 -0400, Nícolas F. R. A. Prado wrote:
> Hi,
>
> On Wed, Aug 03, 2022 at 05:23:57PM +0800, Allen-KH Cheng wrote:
> > Hi Chen-Yu and Mathias,
> >
> > Sincere apologies for the delayed response.
> >
> > On Tue, 2022-08-02 at 13:04 +0200, Matthias Brugger wrote:
> > >
> > > On 01/08/2022 11:29, Chen-Yu Tsai wrote:
> > > > On Thu, Jul 21, 2022 at 10:50 AM Allen-KH Cheng
> > > > <[email protected]> wrote:
> > > > >
> > > > > The watchdog timer of mt8186. mt8195 and mt7986 have their DT
> > > > > data.
> > > > > We should not use 'mediatek,mt6589-wdt' as fallback.
> > > > >
> > > > > For mediatek,wdt example of mt8183, We remove
> > > > > mediatek,mt6589-wdt
> > > > > fallback.
> > > >
> > > > I think this needs some more information.
> > > >
> > > > Right now on the kernel side, mt6589-wdt provides just watchdog
> > > > support.
> > > > The SoC-specific compatibles that are touched by this patch
> > > > provide
> > > > reset
> > > > controls in addition to the standard watchdog, which remains
> > > > the
> > > > same.
> > > >
> > > > If that is the case, then the fallback compatibles are correct.
> > > > A
> > > > fallback
> > > > says that the new hardware is compatible with some older
> > > > hardware,
> > > > and
> > > > can be run with the driver supporting that older hardware,
> > > > likely
> > > > with
> > > > reduced functionality.
> > > >
> > >
> > > My understanding is, that we add a fallback because although at
> > > the
> > > time we
> > > entered the compatible, the functionality of the device is the
> > > same
> > > as the
> > > fallback. Nonetheless we add a compatible specific for the device
> > > in
> > > case in the
> > > future we realize that the device has some functionality that is
> > > not
> > > and can not
> > > be covered by the fallback.
> > >
> > > This is the case here. Actually adding the fallback in the first
> > > place was
> > > wrong, because the driver since ever supports the extra function
> > > for
> > > the device,
> > > the reset.
> > >
> > > So this is a mere cleanup of the binding to reflect what was
> > > always
> > > present in
> > > the driver.
> > >
> > > Regards,
> > > Matthias
> > >
> >
> > mt6589-wdt dosen't contains a reset control for other modules, like
> > chen-yu mention "mt6589-wdt provides just watchdog support."
> >
> > For instance, there is a reset control in mt8195-wdt and we have a
> > DT
> > data to define its reset number of TOPRGU. I thought it's better
> > not
> > use mt6589-wdt as fallback.
> >
> > Please let me know if this works and if you have any suggestions or
> > comments.
>
> The only practical usecase that I can think of that relies on keeping
> the
> fallback compatibles is using the current DT with an older kernel
> that didn't
> yet support the specific watchdog compatibles. In this case, dropping
> the
> fallback compatibles would make the watchdog not work at all in such
> a kernel.
>
> I'm not sure how relevant/common of a usecase that would be, but
> maybe it's
> worth considering given that the advantage of removing the fallback
> compatible
> is purely aesthetic?
>
> Thanks,
> Nícolas
>

Thanks for your comments.

I agree the advantage of patch is aesthetic. Since I also want to send
another "watchdog: Convert binding to YAML" PATCH, it's better let all
wdt compatibles in the binding match the contents of mtk_wdt_dt_ids in
drivers/watchdog/mtk_wdt.c

static const struct of_device_id mtk_wdt_dt_ids[] = {
{ .compatible = "mediatek,mt2712-wdt", .data = &mt2712_data },
{ .compatible = "mediatek,mt6589-wdt" },
{ .compatible = "mediatek,mt7986-wdt", .data = &mt7986_data },
{ .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data },
{ .compatible = "mediatek,mt8186-wdt", .data = &mt8186_data },
{ .compatible = "mediatek,mt8192-wdt", .data = &mt8192_data },
{ .compatible = "mediatek,mt8195-wdt", .data = &mt8195_data },
{ /* sentinel */ }
};

We have "mediatek,mt8186-wdt" "mediatek,mt8195-wdt" and
"mediatek,mt7986-wdt" now and they have their DT data for the reset
control.

It's weird and unuseful to add "mediatek,mt6589-wdt" as fallback.


Please kindly let me know if I missed anything

BRs,
Allen

> >
> > Thanks,
> > Allen
> >
> > > > As an example, if mt8195-wdt is backward compatible with
> > > > mt6589-
> > > > wdt,
> > > > then it should run as mt6589-wdt, and would just be missing new
> > > > functionality, in this case the reset controls.
> > > >
> > > > So either mt6589-wdt also contains a reset control that is not
> > > > the
> > > > same
> > > > as the other newer chips, or has some other functionality that
> > > > the
> > > > other
> > > > chips contain, and justifies the removal of the fallback, or
> > > > this
> > > > patch
> > > > is incorrect. Note that mt2701-wdt and mt762*-wdt are still
> > > > listed
> > > > as
> > > > compatible with mt6589-wdt. So I think a better explanation is
> > > > required.
> > > >
> > > >
> > > > Regards
> > > > ChenYu
> > > >
> > > >
> > > > > Fixes:a45b408a020b("dt-bindings: watchdog: Add compatible for
> > > > > MediaTek MT8186")
> > > > > Fixes:b326f2c85f3d("dt-bindings: watchdog: Add compatible for
> > > > > Mediatek MT8195")
> > > > > Fixes:41e73feb1024("dt-bindings: watchdog: Add compatible for
> > > > > Mediatek MT7986")
> > > > > Fixes:f43f97a0fc0e("dt-bindings: mediatek: mt8183: Add
> > > > > #reset-
> > > > > cells")
> > > > > Signed-off-by: Allen-KH Cheng <[email protected]>
> > > > > Reviewed-by: AngeloGioacchino Del Regno <
> > > > > [email protected]>
> > > > > ---
> > > > > Documentation/devicetree/bindings/watchdog/mtk-wdt.txt | 9
> > > > > ++++-----
> > > > > 1 file changed, 4 insertions(+), 5 deletions(-)
> > > > >
> > > > > diff --git a/Documentation/devicetree/bindings/watchdog/mtk-
> > > > > wdt.txt b/Documentation/devicetree/bindings/watchdog/mtk-
> > > > > wdt.txt
> > > > > index 762c62e428ef..67ef991ec4cf 100644
> > > > > --- a/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> > > > > +++ b/Documentation/devicetree/bindings/watchdog/mtk-wdt.txt
> > > > > @@ -14,12 +14,12 @@ Required properties:
> > > > > "mediatek,mt7622-wdt", "mediatek,mt6589-wdt": for
> > > > > MT7622
> > > > > "mediatek,mt7623-wdt", "mediatek,mt6589-wdt": for
> > > > > MT7623
> > > > > "mediatek,mt7629-wdt", "mediatek,mt6589-wdt": for
> > > > > MT7629
> > > > > - "mediatek,mt7986-wdt", "mediatek,mt6589-wdt": for
> > > > > MT7986
> > > > > + "mediatek,mt7986-wdt": for MT7986
> > > > > "mediatek,mt8183-wdt": for MT8183
> > > > > - "mediatek,mt8186-wdt", "mediatek,mt6589-wdt": for
> > > > > MT8186
> > > > > + "mediatek,mt8186-wdt": for MT8186
> > > > > "mediatek,mt8516-wdt", "mediatek,mt6589-wdt": for
> > > > > MT8516
> > > > > "mediatek,mt8192-wdt": for MT8192
> > > > > - "mediatek,mt8195-wdt", "mediatek,mt6589-wdt": for
> > > > > MT8195
> > > > > + "mediatek,mt8195-wdt": for MT8195
> > > > >
> > > > > - reg : Specifies base physical address and size of the
> > > > > registers.
> > > > >
> > > > > @@ -32,8 +32,7 @@ Optional properties:
> > > > > Example:
> > > > >
> > > > > watchdog: watchdog@10007000 {
> > > > > - compatible = "mediatek,mt8183-wdt",
> > > > > - "mediatek,mt6589-wdt";
> > > > > + compatible = "mediatek,mt8183-wdt";
> > > > > mediatek,disable-extrst;
> > > > > reg = <0 0x10007000 0 0x100>;
> > > > > interrupts = <GIC_SPI 139 IRQ_TYPE_NONE>;
> > > > > --
> > > > > 2.18.0
> > > > >
> > > > >
> >
> >

2022-08-10 16:55:25

by Krzysztof Kozlowski

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: mediatek: watchdog: Fix compatible fallbacks and example

On 10/08/2022 15:58, Allen-KH Cheng wrote:
> I agree the advantage of patch is aesthetic. Since I also want to send
> another "watchdog: Convert binding to YAML" PATCH, it's better let all
> wdt compatibles in the binding match the contents of mtk_wdt_dt_ids in
> drivers/watchdog/mtk_wdt.c
>
> static const struct of_device_id mtk_wdt_dt_ids[] = {
> { .compatible = "mediatek,mt2712-wdt", .data = &mt2712_data },
> { .compatible = "mediatek,mt6589-wdt" },
> { .compatible = "mediatek,mt7986-wdt", .data = &mt7986_data },
> { .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data },
> { .compatible = "mediatek,mt8186-wdt", .data = &mt8186_data },
> { .compatible = "mediatek,mt8192-wdt", .data = &mt8192_data },
> { .compatible = "mediatek,mt8195-wdt", .data = &mt8195_data },
> { /* sentinel */ }
> };
>
> We have "mediatek,mt8186-wdt" "mediatek,mt8195-wdt" and
> "mediatek,mt7986-wdt" now and they have their DT data for the reset
> control.
>
> It's weird and unuseful to add "mediatek,mt6589-wdt" as fallback.
>
>
> Please kindly let me know if I missed anything

How the driver arranges it should not be a reason to use or not to use
specific fallback. Although Rob acked it, but I still think you did not
provide valid reason for the change.

Valid reason is usually the actual hardware (so they are actually not
compatible with mt6589), not exactly how once someone did it in the driver.

Best regards,
Krzysztof

2022-08-11 10:10:30

by Allen-KH Cheng

[permalink] [raw]
Subject: Re: [PATCH v4 1/4] dt-bindings: mediatek: watchdog: Fix compatible fallbacks and example

he SoC-specific compatibles Hi Krzysztof,

On Wed, 2022-08-10 at 19:50 +0300, Krzysztof Kozlowski wrote:
> On 10/08/2022 15:58, Allen-KH Cheng wrote:
> > I agree the advantage of patch is aesthetic. Since I also want to
> > send
> > another "watchdog: Convert binding to YAML" PATCH, it's better let
> > all
> > wdt compatibles in the binding match the contents of mtk_wdt_dt_ids
> > in
> > drivers/watchdog/mtk_wdt.c
> >
> > static const struct of_device_id mtk_wdt_dt_ids[] = {
> > { .compatible = "mediatek,mt2712-wdt", .data = &mt2712_data },
> > { .compatible = "mediatek,mt6589-wdt" },
> > { .compatible = "mediatek,mt7986-wdt", .data = &mt7986_data },
> > { .compatible = "mediatek,mt8183-wdt", .data = &mt8183_data },
> > { .compatible = "mediatek,mt8186-wdt", .data = &mt8186_data },
> > { .compatible = "mediatek,mt8192-wdt", .data = &mt8192_data },
> > { .compatible = "mediatek,mt8195-wdt", .data = &mt8195_data },
> > { /* sentinel */ }
> > };
> >
> > We have "mediatek,mt8186-wdt" "mediatek,mt8195-wdt" and
> > "mediatek,mt7986-wdt" now and they have their DT data for the reset
> > control.
> >
> > It's weird and unuseful to add "mediatek,mt6589-wdt" as fallback.
> >
> >
> > Please kindly let me know if I missed anything
>
> How the driver arranges it should not be a reason to use or not to
> use
> specific fallback. Although Rob acked it, but I still think you did
> not
> provide valid reason for the change.
>
> Valid reason is usually the actual hardware (so they are actually not
> compatible with mt6589), not exactly how once someone did it in the
> driver.
>
> Best regards,
> Krzysztof

Thank you for your detailed and clear explanation.

"mediatek,mt6589-wdt" provides the mtk watchdog support and the SoC-
specific compatibles is for reset controls to standard wdt.

"mediatek,mt6589-wdt" is compatible with mt8186, mt8195 and mt7986 and
just not support the reset controls.

Based on the discussion of email thread, please drop my series.


Thanks to everyone for your comments.

Best regards,
Allen