diff mbox series

[v2,1/2] dt-bindings: Add bindings for aspeed pwm-tach and pwm.

Message ID 20210414104939.1093-2-billy_tsai@aspeedtech.com
State Changes Requested
Headers show
Series Support pwm driver for aspeed ast26xx | expand

Commit Message

Billy Tsai April 14, 2021, 10:49 a.m. UTC
This patch adds device bindings for aspeed pwm-tach device which is a
multi-function device include pwn and tach function and pwm device which
should be the sub-node of pwm-tach device.

Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
Change-Id: I18d9dea14c3a04e1b7e38ffecd49d45917b9b545
---
 .../bindings/mfd/aspeed,ast2600-pwm-tach.yaml | 60 +++++++++++++++++++
 .../bindings/pwm/aspeed,ast2600-pwm.yaml      | 44 ++++++++++++++
 2 files changed, 104 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
 create mode 100644 Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml

Comments

Rob Herring April 14, 2021, 2:50 p.m. UTC | #1
On Wed, 14 Apr 2021 18:49:38 +0800, Billy Tsai wrote:
> This patch adds device bindings for aspeed pwm-tach device which is a
> multi-function device include pwn and tach function and pwm device which
> should be the sub-node of pwm-tach device.
> 
> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
> Change-Id: I18d9dea14c3a04e1b7e38ffecd49d45917b9b545
> ---
>  .../bindings/mfd/aspeed,ast2600-pwm-tach.yaml | 60 +++++++++++++++++++
>  .../bindings/pwm/aspeed,ast2600-pwm.yaml      | 44 ++++++++++++++
>  2 files changed, 104 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
>  create mode 100644 Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
> 

My bot found errors running 'make DT_CHECKER_FLAGS=-m dt_binding_check'
on your patch (DT_CHECKER_FLAGS is new in v5.13):

yamllint warnings/errors:

dtschema/dtc warnings/errors:
Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.example.dt.yaml:0:0: /example-0/pwm_tach@1e610000/tach@1: failed to match any schema with compatible: ['aspeed,ast2600-tach']

See https://patchwork.ozlabs.org/patch/1466127

This check can fail if there are any dependencies. The base for a patch
series is generally the most recent rc1.

If you already ran 'make dt_binding_check' and didn't see the above
error(s), then make sure 'yamllint' is installed and dt-schema is up to
date:

pip3 install dtschema --upgrade

Please check and re-submit.
Rob Herring April 14, 2021, 10:15 p.m. UTC | #2
On Wed, Apr 14, 2021 at 06:49:38PM +0800, Billy Tsai wrote:
> This patch adds device bindings for aspeed pwm-tach device which is a
> multi-function device include pwn and tach function and pwm device which
> should be the sub-node of pwm-tach device.
> 
> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
> Change-Id: I18d9dea14c3a04e1b7e38ffecd49d45917b9b545

Drop

> ---
>  .../bindings/mfd/aspeed,ast2600-pwm-tach.yaml | 60 +++++++++++++++++++
>  .../bindings/pwm/aspeed,ast2600-pwm.yaml      | 44 ++++++++++++++
>  2 files changed, 104 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
>  create mode 100644 Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
> 
> diff --git a/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
> new file mode 100644
> index 000000000000..eaf8bdf8d44e
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
> @@ -0,0 +1,60 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +# Copyright (C) 2021 ASPEED, Inc.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/mfd/aspeed,ast2600-pwm-tach.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: PWM Tach controller Device Tree Bindings
> +
> +description: |
> +  The PWM Tach controller is represented as a multi-function device which
> +  includes:
> +    PWM
> +    Tach

But is it really? A PWM and tach sounds like a fan controller. Look at 
other existing PWM+tach bindings we have for fans.

> +
> +maintainers:
> +  - Billy Tsai <billy_tsai@aspeedtech.com>
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - aspeed,ast2600-pwm-tach
> +      - const: syscon
> +      - const: simple-mfd
> +  reg:
> +    maxItems: 1
> +  "#address-cells":
> +    const: 1
> +  "#size-cells":
> +    const: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - "#address-cells"
> +  - "#size-cells"
> +
> +additionalProperties:
> +  type: object

As you know the 2 node names, they should be documented. However, see 
below.

> +
> +examples:
> +  - |
> +    pwm_tach: pwm_tach@1e610000 {
> +      compatible = "aspeed,ast2600-pwm-tach", "syscon", "simple-mfd";
> +      #address-cells = <1>;
> +      #size-cells = <1>;
> +      reg = <0x1e610000 0x100>;
> +
> +      pwm: pwm@0 {
> +        compatible = "aspeed,ast2600-pwm";
> +        #pwm-cells = <3>;
> +        reg = <0x0 0x100>;
> +      };
> +
> +      tach: tach@1 {
> +        compatible = "aspeed,ast2600-tach";
> +        reg = <0x0 0x100>;

You have 2 nodes at the same address. Not valid.

> +      };

There's no real need for 2 child nodes. The parent node can be a PWM 
provider.

> +    };
> diff --git a/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml b/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
> new file mode 100644
> index 000000000000..97923e68ccb9
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
> @@ -0,0 +1,44 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +# Copyright (C) 2021 ASPEED, Inc.
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/pwm/aspeed,ast2600-pwm.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: ASPEED AST2600 PWM controller
> +
> +maintainers:
> +  - Billy Tsai <billy_tsai@aspeedtech.com>
> +
> +description: |
> +  The ASPEED PWM controller can support upto 16 PWM outputs.
> +
> +properties:
> +  compatible:
> +    enum:
> +      - aspeed,ast2600-pwm
> +
> +  "#pwm-cells":
> +    const: 3
> +
> +  reg:
> +    maxItems: 1
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    // The PWM should be a subnode of a "aspeed,ast2600-pwm-tach" compatible
> +    // node.
> +    pwm_tach: pwm_tach@1e610000 {
> +      compatible = "aspeed,ast2600-pwm-tach", "syscon", "simple-mfd";
> +      #address-cells = <1>;
> +      #size-cells = <1>;
> +      reg = <0x1e610000 0x100>;
> +
> +      pwm: pwm@0 {
> +        compatible = "aspeed,ast2600-pwm";
> +        #pwm-cells = <3>;
> +        reg = <0x0 0x100>;
> +      };
> +    };
> -- 
> 2.25.1
>
Billy Tsai April 15, 2021, 3:44 a.m. UTC | #3
Hi Rob,

On 2021/4/15, 6:16 AM,Rob Herringwrote:

    On Wed, Apr 14, 2021 at 06:49:38PM +0800, Billy Tsai wrote:
    >> This patch adds device bindings for aspeed pwm-tach device which is a
    >> multi-function device include pwn and tach function and pwm device which
    >> should be the sub-node of pwm-tach device.
    >> 
    >> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
    >> Change-Id: I18d9dea14c3a04e1b7e38ffecd49d45917b9b545
    >
    >Drop
    >
    >> ---
    >>  .../bindings/mfd/aspeed,ast2600-pwm-tach.yaml | 60 +++++++++++++++++++
    >>  .../bindings/pwm/aspeed,ast2600-pwm.yaml      | 44 ++++++++++++++
    >>  2 files changed, 104 insertions(+)
    >>  create mode 100644 Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
    >>  create mode 100644 Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
    >> 
    >> diff --git a/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
    >> new file mode 100644
    >> index 000000000000..eaf8bdf8d44e
    >> --- /dev/null
    >> +++ b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
    >> @@ -0,0 +1,60 @@
    >> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
    >> +# Copyright (C) 2021 ASPEED, Inc.
    >> +%YAML 1.2
    >> +---
    >> +$id: http://devicetree.org/schemas/mfd/aspeed,ast2600-pwm-tach.yaml#
    >> +$schema: http://devicetree.org/meta-schemas/core.yaml#
    >> +
    >> +title: PWM Tach controller Device Tree Bindings
    >> +
    >> +description: |
    >> +  The PWM Tach controller is represented as a multi-function device which
    >> +  includes:
    >> +    PWM
    >> +    Tach

    > But is it really? A PWM and tach sounds like a fan controller. Look at 

Our PWM is not only for fans but also used for the motor, led, buzzer, and so on. 
So I want to split the function into two devices with a multi-function device. 
One for PWM output and one for tach monitor.

    > other existing PWM+tach bindings we have for fans.

I didn't see the PWM+tach bindings can you give some example for me, thanks.

    >> +
    >> +maintainers:
    >> +  - Billy Tsai <billy_tsai@aspeedtech.com>
    >> +
    >> +properties:
    >> +  compatible:
    >> +    items:
    >> +      - enum:
    >> +          - aspeed,ast2600-pwm-tach
    >> +      - const: syscon
    >> +      - const: simple-mfd
    >> +  reg:
    >> +    maxItems: 1
    >> +  "#address-cells":
    >> +    const: 1
    >> +  "#size-cells":
    >> +    const: 1
    >> +
    >> +required:
    >> +  - compatible
    >> +  - reg
    >> +  - "#address-cells"
    >> +  - "#size-cells"
    >> +
    >> +additionalProperties:
    >> +  type: object

    > As you know the 2 node names, they should be documented. However, see 
    > below.

    >> +
    >> +examples:
    >> +  - |
    >> +    pwm_tach: pwm_tach@1e610000 {
    >> +      compatible = "aspeed,ast2600-pwm-tach", "syscon", "simple-mfd";
    >> +      #address-cells = <1>;
    >> +      #size-cells = <1>;
    >> +      reg = <0x1e610000 0x100>;
    >> +
    >> +      pwm: pwm@0 {
    >> +        compatible = "aspeed,ast2600-pwm";
    >> +        #pwm-cells = <3>;
    >> +        reg = <0x0 0x100>;
    >> +      };
    >> +
    >> +      tach: tach@1 {
    >> +        compatible = "aspeed,ast2600-tach";
    >> +        reg = <0x0 0x100>;

    > You have 2 nodes at the same address. Not valid.

Our pwm and tach is used the same base address and the offset is like below:

PWM0 used 0x0 0x4, Tach0 used 0x8 0xc
PWM1 used 0x10 0x14, Tach1 used 0x18 0x1c
...

I will remove the reg property from pwm and tach node and remove the "#address-cells" and
"#size-cells" from the parent node.

    >> +      };

    > There's no real need for 2 child nodes. The parent node can be a PWM 
    > provider.

However, In our usage, the parent node is a mfd, not a simple PWM device only. I don't want to
combine the different functions with the one device node.


    >> +    };
    >> diff --git a/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml b/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
    >> new file mode 100644
    >> index 000000000000..97923e68ccb9
    >> --- /dev/null
    >> +++ b/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
    >> @@ -0,0 +1,44 @@
    >> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
    >> +# Copyright (C) 2021 ASPEED, Inc.
    >> +%YAML 1.2
    >> +---
    >> +$id: http://devicetree.org/schemas/pwm/aspeed,ast2600-pwm.yaml#
    >> +$schema: http://devicetree.org/meta-schemas/core.yaml#
    >> +
    >> +title: ASPEED AST2600 PWM controller
    >> +
    >> +maintainers:
    >> +  - Billy Tsai <billy_tsai@aspeedtech.com>
    >> +
    >> +description: |
    >> +  The ASPEED PWM controller can support upto 16 PWM outputs.
    >> +
    >> +properties:
    >> +  compatible:
    >> +    enum:
    >> +      - aspeed,ast2600-pwm
    >> +
    >> +  "#pwm-cells":
    >> +    const: 3
    >> +
    >> +  reg:
    >> +    maxItems: 1
    >> +
    >> +additionalProperties: false
    >> +
    >> +examples:
    >> +  - |
    >> +    // The PWM should be a subnode of a "aspeed,ast2600-pwm-tach" compatible
    >> +    // node.
    >> +    pwm_tach: pwm_tach@1e610000 {
    >> +      compatible = "aspeed,ast2600-pwm-tach", "syscon", "simple-mfd";
    >> +      #address-cells = <1>;
    >> +      #size-cells = <1>;
    >> +      reg = <0x1e610000 0x100>;
    >> +
    >> +      pwm: pwm@0 {
    >> +        compatible = "aspeed,ast2600-pwm";
    >> +        #pwm-cells = <3>;
    >> +        reg = <0x0 0x100>;
    >> +      };
    >> +    };
    >> -- 
    >> 2.25.1
    >>
Rob Herring April 15, 2021, 2:43 p.m. UTC | #4
On Wed, Apr 14, 2021 at 10:44 PM Billy Tsai <billy_tsai@aspeedtech.com> wrote:
>
> Hi Rob,
>
> On 2021/4/15, 6:16 AM,Rob Herringwrote:
>
>     On Wed, Apr 14, 2021 at 06:49:38PM +0800, Billy Tsai wrote:
>     >> This patch adds device bindings for aspeed pwm-tach device which is a
>     >> multi-function device include pwn and tach function and pwm device which
>     >> should be the sub-node of pwm-tach device.
>     >>
>     >> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
>     >> Change-Id: I18d9dea14c3a04e1b7e38ffecd49d45917b9b545
>     >
>     >Drop
>     >
>     >> ---
>     >>  .../bindings/mfd/aspeed,ast2600-pwm-tach.yaml | 60 +++++++++++++++++++
>     >>  .../bindings/pwm/aspeed,ast2600-pwm.yaml      | 44 ++++++++++++++
>     >>  2 files changed, 104 insertions(+)
>     >>  create mode 100644 Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
>     >>  create mode 100644 Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
>     >>
>     >> diff --git a/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
>     >> new file mode 100644
>     >> index 000000000000..eaf8bdf8d44e
>     >> --- /dev/null
>     >> +++ b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
>     >> @@ -0,0 +1,60 @@
>     >> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>     >> +# Copyright (C) 2021 ASPEED, Inc.
>     >> +%YAML 1.2
>     >> +---
>     >> +$id: http://devicetree.org/schemas/mfd/aspeed,ast2600-pwm-tach.yaml#
>     >> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>     >> +
>     >> +title: PWM Tach controller Device Tree Bindings
>     >> +
>     >> +description: |
>     >> +  The PWM Tach controller is represented as a multi-function device which
>     >> +  includes:
>     >> +    PWM
>     >> +    Tach
>
>     > But is it really? A PWM and tach sounds like a fan controller. Look at
>
> Our PWM is not only for fans but also used for the motor, led, buzzer, and so on.
> So I want to split the function into two devices with a multi-function device.
> One for PWM output and one for tach monitor.
>
>     > other existing PWM+tach bindings we have for fans.
>
> I didn't see the PWM+tach bindings can you give some example for me, thanks.

Let me grep 'tach' for you:

Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
Documentation/devicetree/bindings/hwmon/npcm750-pwm-fan.txt

Hey, look at that, there's already one for ASpeed. So the question is
how is the newer h/w different?

>
>     >> +
>     >> +maintainers:
>     >> +  - Billy Tsai <billy_tsai@aspeedtech.com>
>     >> +
>     >> +properties:
>     >> +  compatible:
>     >> +    items:
>     >> +      - enum:
>     >> +          - aspeed,ast2600-pwm-tach
>     >> +      - const: syscon
>     >> +      - const: simple-mfd
>     >> +  reg:
>     >> +    maxItems: 1
>     >> +  "#address-cells":
>     >> +    const: 1
>     >> +  "#size-cells":
>     >> +    const: 1
>     >> +
>     >> +required:
>     >> +  - compatible
>     >> +  - reg
>     >> +  - "#address-cells"
>     >> +  - "#size-cells"
>     >> +
>     >> +additionalProperties:
>     >> +  type: object
>
>     > As you know the 2 node names, they should be documented. However, see
>     > below.
>
>     >> +
>     >> +examples:
>     >> +  - |
>     >> +    pwm_tach: pwm_tach@1e610000 {
>     >> +      compatible = "aspeed,ast2600-pwm-tach", "syscon", "simple-mfd";
>     >> +      #address-cells = <1>;
>     >> +      #size-cells = <1>;
>     >> +      reg = <0x1e610000 0x100>;
>     >> +
>     >> +      pwm: pwm@0 {
>     >> +        compatible = "aspeed,ast2600-pwm";
>     >> +        #pwm-cells = <3>;
>     >> +        reg = <0x0 0x100>;
>     >> +      };
>     >> +
>     >> +      tach: tach@1 {
>     >> +        compatible = "aspeed,ast2600-tach";
>     >> +        reg = <0x0 0x100>;
>
>     > You have 2 nodes at the same address. Not valid.
>
> Our pwm and tach is used the same base address and the offset is like below:
>
> PWM0 used 0x0 0x4, Tach0 used 0x8 0xc
> PWM1 used 0x10 0x14, Tach1 used 0x18 0x1c
> ...
>
> I will remove the reg property from pwm and tach node and remove the "#address-cells" and
> "#size-cells" from the parent node.

That's not really the solution...

>
>     >> +      };
>
>     > There's no real need for 2 child nodes. The parent node can be a PWM
>     > provider.
>
> However, In our usage, the parent node is a mfd, not a simple PWM device only. I don't want to
> combine the different functions with the one device node.

Looks like a single h/w block to me. If you want to divide that up
into multiple drivers, then that's an OS problem. A single node can be
multiple providers. For example, on the existing aspeed binding, just
add '#pwm-cells' to the node if you want to also expose it as a PWM
provider.

Rob
Billy Tsai April 16, 2021, 8:44 a.m. UTC | #5
On 2021/4/15, 10:44 PM,Rob Herringwrote:

    >On Wed, Apr 14, 2021 at 10:44 PM Billy Tsai <billy_tsai@aspeedtech.com> wrote:
    >>
    >> Hi Rob,
    >>
    >> On 2021/4/15, 6:16 AM,Rob Herringwrote:
    >>
    >>     On Wed, Apr 14, 2021 at 06:49:38PM +0800, Billy Tsai wrote:
    >>     >> This patch adds device bindings for aspeed pwm-tach device which is a
    >>     >> multi-function device include pwn and tach function and pwm device which
    >>     >> should be the sub-node of pwm-tach device.
    >>     >>
    >>     >> Signed-off-by: Billy Tsai <billy_tsai@aspeedtech.com>
    >>     >> Change-Id: I18d9dea14c3a04e1b7e38ffecd49d45917b9b545
    >>     >
    >>     >Drop
    >>     >
    >>     >> ---
    >>     >>  .../bindings/mfd/aspeed,ast2600-pwm-tach.yaml | 60 +++++++++++++++++++
    >>     >>  .../bindings/pwm/aspeed,ast2600-pwm.yaml      | 44 ++++++++++++++
    >>     >>  2 files changed, 104 insertions(+)
    >>     >>  create mode 100644 Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
    >>     >>  create mode 100644 Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
    >>     >>
    >>     >> diff --git a/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
    >>     >> new file mode 100644
    >>     >> index 000000000000..eaf8bdf8d44e
    >>     >> --- /dev/null
    >>     >> +++ b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
    >>     >> @@ -0,0 +1,60 @@
    >>     >> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
    >>     >> +# Copyright (C) 2021 ASPEED, Inc.
    >>     >> +%YAML 1.2
    >>     >> +---
    >>     >> +$id: http://devicetree.org/schemas/mfd/aspeed,ast2600-pwm-tach.yaml#
    >>     >> +$schema: http://devicetree.org/meta-schemas/core.yaml#
    >>     >> +
    >>     >> +title: PWM Tach controller Device Tree Bindings
    >>     >> +
    >>     >> +description: |
    >>     >> +  The PWM Tach controller is represented as a multi-function device which
    >>     >> +  includes:
    >>     >> +    PWM
    >>     >> +    Tach
    >>
    >>     > But is it really? A PWM and tach sounds like a fan controller. Look at
    >>
    >> Our PWM is not only for fans but also used for the motor, led, buzzer, and so on.
    >> So I want to split the function into two devices with a multi-function device.
    >> One for PWM output and one for tach monitor.
    >>
    >>     > other existing PWM+tach bindings we have for fans.
    >>
    >> I didn't see the PWM+tach bindings can you give some example for me, thanks.
    >
    >Let me grep 'tach' for you:
    >
    >Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
    >Documentation/devicetree/bindings/hwmon/npcm750-pwm-fan.txt
    >
    >Hey, look at that, there's already one for ASpeed. So the question is
    >how is the newer h/w different?
    >>
    >>     >> +
    >>     >> +maintainers:
    >>     >> +  - Billy Tsai <billy_tsai@aspeedtech.com>
    >>     >> +
    >>     >> +properties:
    >>     >> +  compatible:
    >>     >> +    items:
    >>     >> +      - enum:
    >>     >> +          - aspeed,ast2600-pwm-tach
    >>     >> +      - const: syscon
    >>     >> +      - const: simple-mfd
    >>     >> +  reg:
    >>     >> +    maxItems: 1
    >>     >> +  "#address-cells":
    >>     >> +    const: 1
    >>     >> +  "#size-cells":
    >>     >> +    const: 1
    >>     >> +
    >>     >> +required:
    >>     >> +  - compatible
    >>     >> +  - reg
    >>     >> +  - "#address-cells"
    >>     >> +  - "#size-cells"
    >>     >> +
    >>     >> +additionalProperties:
    >>     >> +  type: object
    >>
    >>     > As you know the 2 node names, they should be documented. However, see
    >>     > below.
    >>
    >>     >> +
    >>     >> +examples:
    >>     >> +  - |
    >>     >> +    pwm_tach: pwm_tach@1e610000 {
    >>     >> +      compatible = "aspeed,ast2600-pwm-tach", "syscon", "simple-mfd";
    >>     >> +      #address-cells = <1>;
    >>     >> +      #size-cells = <1>;
    >>     >> +      reg = <0x1e610000 0x100>;
    >>     >> +
    >>     >> +      pwm: pwm@0 {
    >>     >> +        compatible = "aspeed,ast2600-pwm";
    >>     >> +        #pwm-cells = <3>;
    >>     >> +        reg = <0x0 0x100>;
    >>     >> +      };
    >>     >> +
    >>     >> +      tach: tach@1 {
    >>     >> +        compatible = "aspeed,ast2600-tach";
    >>     >> +        reg = <0x0 0x100>;
    >>
    >>     > You have 2 nodes at the same address. Not valid.
    >>
    >> Our pwm and tach is used the same base address and the offset is like below:
    >>
    >> PWM0 used 0x0 0x4, Tach0 used 0x8 0xc
    >> PWM1 used 0x10 0x14, Tach1 used 0x18 0x1c
    >> ...
    >>
    >> I will remove the reg property from pwm and tach node and remove the "#address-cells" and
    >> "#size-cells" from the parent node.
    >
    >That's not really the solution...
    >
    >>
    >>     >> +      };
    >>
    >>     > There's no real need for 2 child nodes. The parent node can be a PWM
    >>     > provider.
    >>
    >> However, In our usage, the parent node is a mfd, not a simple PWM device only. I don't want to
    >> combine the different functions with the one device node.
    >
    >Looks like a single h/w block to me. If you want to divide that up
    >into multiple drivers, then that's an OS problem. A single node can be
    >multiple providers. For example, on the existing aspeed binding, just
    >add '#pwm-cells' to the node if you want to also expose it as a PWM
    >provider.
    >
    >Rob

I don't think the pwm/tach should be a single h/w block. 
See the kontron,sl28cpld.yaml:
hwmon@b {
        compatible = "kontron,sl28cpld-fan";
        reg = <0xb>;
};

pwm@c {
        compatible = "kontron,sl28cpld-pwm";
        reg = <0xc>;
        #pwm-cells = <2>;
};
They can be the different function from the dts.

Documentation/devicetree/bindings/hwmon/aspeed-pwm-tacho.txt
Documentation/devicetree/bindings/hwmon/npcm750-pwm-fan.txt

These two devices are specific to the used for fan like
Documentation/devicetree/bindings/hwmon/pwm-fan.txt, but with our usage,
it doesn't just for the fan. In our scenario, the customer wants to
create a pwm-beeper, so he needs one pwm input and he doesn't need the
tach function. If I used the pwm-fan as the beeper's pwm input, it look
weird.
Therefore, I want to split these two functions into different devices.

If my thinking is wrong, please let me know.

Very appreciate.
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
new file mode 100644
index 000000000000..eaf8bdf8d44e
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/aspeed,ast2600-pwm-tach.yaml
@@ -0,0 +1,60 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2021 ASPEED, Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/mfd/aspeed,ast2600-pwm-tach.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: PWM Tach controller Device Tree Bindings
+
+description: |
+  The PWM Tach controller is represented as a multi-function device which
+  includes:
+    PWM
+    Tach
+
+maintainers:
+  - Billy Tsai <billy_tsai@aspeedtech.com>
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - aspeed,ast2600-pwm-tach
+      - const: syscon
+      - const: simple-mfd
+  reg:
+    maxItems: 1
+  "#address-cells":
+    const: 1
+  "#size-cells":
+    const: 1
+
+required:
+  - compatible
+  - reg
+  - "#address-cells"
+  - "#size-cells"
+
+additionalProperties:
+  type: object
+
+examples:
+  - |
+    pwm_tach: pwm_tach@1e610000 {
+      compatible = "aspeed,ast2600-pwm-tach", "syscon", "simple-mfd";
+      #address-cells = <1>;
+      #size-cells = <1>;
+      reg = <0x1e610000 0x100>;
+
+      pwm: pwm@0 {
+        compatible = "aspeed,ast2600-pwm";
+        #pwm-cells = <3>;
+        reg = <0x0 0x100>;
+      };
+
+      tach: tach@1 {
+        compatible = "aspeed,ast2600-tach";
+        reg = <0x0 0x100>;
+      };
+    };
diff --git a/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml b/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
new file mode 100644
index 000000000000..97923e68ccb9
--- /dev/null
+++ b/Documentation/devicetree/bindings/pwm/aspeed,ast2600-pwm.yaml
@@ -0,0 +1,44 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2021 ASPEED, Inc.
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/pwm/aspeed,ast2600-pwm.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ASPEED AST2600 PWM controller
+
+maintainers:
+  - Billy Tsai <billy_tsai@aspeedtech.com>
+
+description: |
+  The ASPEED PWM controller can support upto 16 PWM outputs.
+
+properties:
+  compatible:
+    enum:
+      - aspeed,ast2600-pwm
+
+  "#pwm-cells":
+    const: 3
+
+  reg:
+    maxItems: 1
+
+additionalProperties: false
+
+examples:
+  - |
+    // The PWM should be a subnode of a "aspeed,ast2600-pwm-tach" compatible
+    // node.
+    pwm_tach: pwm_tach@1e610000 {
+      compatible = "aspeed,ast2600-pwm-tach", "syscon", "simple-mfd";
+      #address-cells = <1>;
+      #size-cells = <1>;
+      reg = <0x1e610000 0x100>;
+
+      pwm: pwm@0 {
+        compatible = "aspeed,ast2600-pwm";
+        #pwm-cells = <3>;
+        reg = <0x0 0x100>;
+      };
+    };