[PATCH] MFD: mt6397: do not use generic name for keypad sub-devices

[PATCH] MFD: mt6397: do not use generic name for keypad sub-devices

[Dmitry Torokhov]

Do not use "mtk-pmic-keys" when creating sub-device for the keypad to
make sure the keypad driver will only bind to the sub-device if it has
support for the variant/has matching compatible.

Reported-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
Fixes: 6e31bb8d3a63 ("mfd: mt6397: Add initial support for MT6328")
Fixes: de58cee8c6b8 ("mfd: mt6397-core: Add MT6357 PMIC support")
Fixes: 4a901e305011 ("mfd: mt6397-core: Add resources for PMIC keys for MT6359")
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
---

This is not tested so if someone with hardware could try it out that
would be great. I *think* it should work...

 drivers/mfd/mt6397-core.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c
index 5f8ed8988907..3e58d0764c7e 100644
--- a/drivers/mfd/mt6397-core.c
+++ b/drivers/mfd/mt6397-core.c
@@ -136,7 +136,7 @@ static const struct mfd_cell mt6323_devs[] = {
 		.name = "mt6323-led",
 		.of_compatible = "mediatek,mt6323-led"
 	}, {
-		.name = "mtk-pmic-keys",
+		.name = "mt6323-keys",
 		.num_resources = ARRAY_SIZE(mt6323_keys_resources),
 		.resources = mt6323_keys_resources,
 		.of_compatible = "mediatek,mt6323-keys"
@@ -153,7 +153,7 @@ static const struct mfd_cell mt6328_devs[] = {
 		.name = "mt6328-regulator",
 		.of_compatible = "mediatek,mt6328-regulator"
 	}, {
-		.name = "mtk-pmic-keys",
+		.name = "mt6328-keys",
 		.num_resources = ARRAY_SIZE(mt6328_keys_resources),
 		.resources = mt6328_keys_resources,
 		.of_compatible = "mediatek,mt6328-keys"
@@ -175,7 +175,7 @@ static const struct mfd_cell mt6357_devs[] = {
 		.name = "mt6357-sound",
 		.of_compatible = "mediatek,mt6357-sound"
 	}, {
-		.name = "mtk-pmic-keys",
+		.name = "mt6357-keys",
 		.num_resources = ARRAY_SIZE(mt6357_keys_resources),
 		.resources = mt6357_keys_resources,
 		.of_compatible = "mediatek,mt6357-keys"
@@ -196,7 +196,7 @@ static const struct mfd_cell mt6331_mt6332_devs[] = {
 		.name = "mt6332-regulator",
 		.of_compatible = "mediatek,mt6332-regulator"
 	}, {
-		.name = "mtk-pmic-keys",
+		.name = "mt6331-keys",
 		.num_resources = ARRAY_SIZE(mt6331_keys_resources),
 		.resources = mt6331_keys_resources,
 		.of_compatible = "mediatek,mt6331-keys"
@@ -240,7 +240,7 @@ static const struct mfd_cell mt6359_devs[] = {
 	},
 	{ .name = "mt6359-sound", },
 	{
-		.name = "mtk-pmic-keys",
+		.name = "mt6359-keys",
 		.num_resources = ARRAY_SIZE(mt6359_keys_resources),
 		.resources = mt6359_keys_resources,
 		.of_compatible = "mediatek,mt6359-keys"
@@ -272,7 +272,7 @@ static const struct mfd_cell mt6397_devs[] = {
 		.name = "mt6397-pinctrl",
 		.of_compatible = "mediatek,mt6397-pinctrl",
 	}, {
-		.name = "mtk-pmic-keys",
+		.name = "mt6397-keys",
 		.num_resources = ARRAY_SIZE(mt6397_keys_resources),
 		.resources = mt6397_keys_resources,
 		.of_compatible = "mediatek,mt6397-keys"
-- 
2.50.0.727.gbf7dc18ff4-goog


-- 
Dmitry

Re: [PATCH] MFD: mt6397: do not use generic name for keypad sub-devices

[Lee Jones]

On Mon, 30 Jun 2025, Dmitry Torokhov wrote:

> Do not use "mtk-pmic-keys" when creating sub-device for the keypad to
> make sure the keypad driver will only bind to the sub-device if it has
> support for the variant/has matching compatible.
> 
> Reported-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
> Fixes: 6e31bb8d3a63 ("mfd: mt6397: Add initial support for MT6328")
> Fixes: de58cee8c6b8 ("mfd: mt6397-core: Add MT6357 PMIC support")
> Fixes: 4a901e305011 ("mfd: mt6397-core: Add resources for PMIC keys for MT6359")
> Cc: stable@vger.kernel.org
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---
> 
> This is not tested so if someone with hardware could try it out that
> would be great. I *think* it should work...

My suspicion is that this will not work.  Providing compatible strings
here is only for device to node matching.  I do not believe the drivers
will probe using them.

You don't need H/W to test this theory.  You can just feed in a DTB and
see if it probes.  QEMU should be good enough for this.

>  drivers/mfd/mt6397-core.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c
> index 5f8ed8988907..3e58d0764c7e 100644
> --- a/drivers/mfd/mt6397-core.c
> +++ b/drivers/mfd/mt6397-core.c
> @@ -136,7 +136,7 @@ static const struct mfd_cell mt6323_devs[] = {
>  		.name = "mt6323-led",
>  		.of_compatible = "mediatek,mt6323-led"
>  	}, {
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6323-keys",
>  		.num_resources = ARRAY_SIZE(mt6323_keys_resources),
>  		.resources = mt6323_keys_resources,
>  		.of_compatible = "mediatek,mt6323-keys"
> @@ -153,7 +153,7 @@ static const struct mfd_cell mt6328_devs[] = {
>  		.name = "mt6328-regulator",
>  		.of_compatible = "mediatek,mt6328-regulator"
>  	}, {
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6328-keys",
>  		.num_resources = ARRAY_SIZE(mt6328_keys_resources),
>  		.resources = mt6328_keys_resources,
>  		.of_compatible = "mediatek,mt6328-keys"
> @@ -175,7 +175,7 @@ static const struct mfd_cell mt6357_devs[] = {
>  		.name = "mt6357-sound",
>  		.of_compatible = "mediatek,mt6357-sound"
>  	}, {
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6357-keys",
>  		.num_resources = ARRAY_SIZE(mt6357_keys_resources),
>  		.resources = mt6357_keys_resources,
>  		.of_compatible = "mediatek,mt6357-keys"
> @@ -196,7 +196,7 @@ static const struct mfd_cell mt6331_mt6332_devs[] = {
>  		.name = "mt6332-regulator",
>  		.of_compatible = "mediatek,mt6332-regulator"
>  	}, {
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6331-keys",
>  		.num_resources = ARRAY_SIZE(mt6331_keys_resources),
>  		.resources = mt6331_keys_resources,
>  		.of_compatible = "mediatek,mt6331-keys"
> @@ -240,7 +240,7 @@ static const struct mfd_cell mt6359_devs[] = {
>  	},
>  	{ .name = "mt6359-sound", },
>  	{
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6359-keys",
>  		.num_resources = ARRAY_SIZE(mt6359_keys_resources),
>  		.resources = mt6359_keys_resources,
>  		.of_compatible = "mediatek,mt6359-keys"
> @@ -272,7 +272,7 @@ static const struct mfd_cell mt6397_devs[] = {
>  		.name = "mt6397-pinctrl",
>  		.of_compatible = "mediatek,mt6397-pinctrl",
>  	}, {
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6397-keys",
>  		.num_resources = ARRAY_SIZE(mt6397_keys_resources),
>  		.resources = mt6397_keys_resources,
>  		.of_compatible = "mediatek,mt6397-keys"
> -- 
> 2.50.0.727.gbf7dc18ff4-goog
> 
> 
> -- 
> Dmitry

-- 
Lee Jones [李琼斯]

Re: [PATCH] MFD: mt6397: do not use generic name for keypad sub-devices

[Dmitry Torokhov]

On Tue, Jul 01, 2025 at 11:58:11AM +0100, Lee Jones wrote:
> On Mon, 30 Jun 2025, Dmitry Torokhov wrote:
> 
> > Do not use "mtk-pmic-keys" when creating sub-device for the keypad to
> > make sure the keypad driver will only bind to the sub-device if it has
> > support for the variant/has matching compatible.
> > 
> > Reported-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
> > Fixes: 6e31bb8d3a63 ("mfd: mt6397: Add initial support for MT6328")
> > Fixes: de58cee8c6b8 ("mfd: mt6397-core: Add MT6357 PMIC support")
> > Fixes: 4a901e305011 ("mfd: mt6397-core: Add resources for PMIC keys for MT6359")
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> > ---
> > 
> > This is not tested so if someone with hardware could try it out that
> > would be great. I *think* it should work...
> 
> My suspicion is that this will not work.  Providing compatible strings
> here is only for device to node matching.  I do not believe the drivers
> will probe using them.

Actually it should. If we check the drivers for "mt6323-rtc" you will
see that MFD core defines a sub-device with this name and similar
compatible, but the RTC platform driver only lists compatible:

dtor@dtor-ws:~/kernel/work $ git grep mt6323-rtc -- drivers/
drivers/mfd/mt6397-core.c:              .name = "mt6323-rtc",
drivers/mfd/mt6397-core.c:              .of_compatible = "mediatek,mt6323-rtc",
drivers/rtc/rtc-mt6397.c:       { .compatible = "mediatek,mt6323-rtc", .data = &mt6397_rtc_data },

Driver name that is defined in drivers/rtc/rtc-mt6397.c is "mt6397-rtc"
not "mt6323-rtc". 

And if we look into MFD core we can see how it works: mfd_add_device()
scans the main (parent) device tree node children, locates devices with
matching compatibles, and calls mfd_match_of_node_to_dev() for them. The
latter essentially copies/assigns device tree node to the platform
device that is being created, compatibles and all. From that point
normal binding rules will work and they take into account OF
compatibles; we no longer need to have matching platform driver name to
match.

Thanks.

-- 
Dmitry

Re: [PATCH] MFD: mt6397: do not use generic name for keypad sub-devices

[Louis-Alexis Eyraud]

Hi Dmitry,

On Mon, 2025-06-30 at 16:01 -0700, Dmitry Torokhov wrote:
> Do not use "mtk-pmic-keys" when creating sub-device for the keypad to
> make sure the keypad driver will only bind to the sub-device if it
> has
> support for the variant/has matching compatible.
> 
> Reported-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com>
> Fixes: 6e31bb8d3a63 ("mfd: mt6397: Add initial support for MT6328")
> Fixes: de58cee8c6b8 ("mfd: mt6397-core: Add MT6357 PMIC support")
> Fixes: 4a901e305011 ("mfd: mt6397-core: Add resources for PMIC keys
> for MT6359")
> Cc: stable@vger.kernel.org
> Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> ---
> 
> This is not tested so if someone with hardware could try it out that
> would be great. I *think* it should work...
> 
>  drivers/mfd/mt6397-core.c | 12 ++++++------
>  1 file changed, 6 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mfd/mt6397-core.c b/drivers/mfd/mt6397-core.c
> index 5f8ed8988907..3e58d0764c7e 100644
> --- a/drivers/mfd/mt6397-core.c
> +++ b/drivers/mfd/mt6397-core.c
> @@ -136,7 +136,7 @@ static const struct mfd_cell mt6323_devs[] = {
>  		.name = "mt6323-led",
>  		.of_compatible = "mediatek,mt6323-led"
>  	}, {
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6323-keys",
>  		.num_resources = ARRAY_SIZE(mt6323_keys_resources),
>  		.resources = mt6323_keys_resources,
>  		.of_compatible = "mediatek,mt6323-keys"
> @@ -153,7 +153,7 @@ static const struct mfd_cell mt6328_devs[] = {
>  		.name = "mt6328-regulator",
>  		.of_compatible = "mediatek,mt6328-regulator"
>  	}, {
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6328-keys",
>  		.num_resources = ARRAY_SIZE(mt6328_keys_resources),
>  		.resources = mt6328_keys_resources,
>  		.of_compatible = "mediatek,mt6328-keys"
> @@ -175,7 +175,7 @@ static const struct mfd_cell mt6357_devs[] = {
>  		.name = "mt6357-sound",
>  		.of_compatible = "mediatek,mt6357-sound"
>  	}, {
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6357-keys",
>  		.num_resources = ARRAY_SIZE(mt6357_keys_resources),
>  		.resources = mt6357_keys_resources,
>  		.of_compatible = "mediatek,mt6357-keys"
> @@ -196,7 +196,7 @@ static const struct mfd_cell mt6331_mt6332_devs[]
> = {
>  		.name = "mt6332-regulator",
>  		.of_compatible = "mediatek,mt6332-regulator"
>  	}, {
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6331-keys",
>  		.num_resources = ARRAY_SIZE(mt6331_keys_resources),
>  		.resources = mt6331_keys_resources,
>  		.of_compatible = "mediatek,mt6331-keys"
> @@ -240,7 +240,7 @@ static const struct mfd_cell mt6359_devs[] = {
>  	},
>  	{ .name = "mt6359-sound", },
>  	{
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6359-keys",
>  		.num_resources = ARRAY_SIZE(mt6359_keys_resources),
>  		.resources = mt6359_keys_resources,
>  		.of_compatible = "mediatek,mt6359-keys"
> @@ -272,7 +272,7 @@ static const struct mfd_cell mt6397_devs[] = {
>  		.name = "mt6397-pinctrl",
>  		.of_compatible = "mediatek,mt6397-pinctrl",
>  	}, {
> -		.name = "mtk-pmic-keys",
> +		.name = "mt6397-keys",
>  		.num_resources = ARRAY_SIZE(mt6397_keys_resources),
>  		.resources = mt6397_keys_resources,
>  		.of_compatible = "mediatek,mt6397-keys"
> -- 
> 2.50.0.727.gbf7dc18ff4-goog
> 
Thanks for the patch.

I've tested it with a kernel based on next-20250702 on both Mediatek
Genio 350-EVK and Genio 1200-EVK boards with mtk-pmic-keys driver
enabled either as builtin or module.

With the Genio 350-EVK, the mtk-pmic-keys driver probes OK: 
```
[    0.601874] input: mtk-pmic-keys as
/devices/platform/soc/1000d000.pwrap/1000d000.pwrap:pmic/mt6357-
keys/input/input0
```
The keys work too.

For the Genio 1200-EVK, it fails to probe as expected (because
'mediatek,mt6359-keys' compatible is missing) and there is indeed no
kernel panic in the builtin case (the issue I reported with my patch)
```
[    0.459178] mt6359-keys: Failed to locate of_node [id: -1]
```

Tested-by: Louis-Alexis Eyraud <louisalexis.eyraud@collabora.com> # on
Mediatek Genio 350-EVK and Genio 1200-EVK

Regards,
Louis-Alexis