linux-kernel - Re: [PATCH 1/2] dt-bindings: counter: Add new ti,omap-dmtimer-cap compatible

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Message-ID: <9653740a-44fe-46bb-92c8-f7fc26cbe5ee@ti.com>
Date: Fri, 26 Sep 2025 14:36:36 +0530
From: Gokul Praveen <g-praveen@...com>
To: Krzysztof Kozlowski <krzk@...nel.org>, <j-keerthy@...com>,
        <vigneshr@...com>, <wbg@...nel.org>, <linux-kernel@...r.kernel.org>,
        <robh@...nel.org>, <krzk+dt@...nel.org>, <conor+dt@...nel.org>,
        <devicetree@...r.kernel.org>
CC: <u-kumar1@...com>, <n-francis@...com>, Gokul Praveen <g-praveen@...com>
Subject: Re: [PATCH 1/2] dt-bindings: counter: Add new ti,omap-dmtimer-cap
 compatible

Hi Krzysztof,

Really sorry and apologies for the delay.

On 10/09/25 12:38, Krzysztof Kozlowski wrote:
> On 09/09/2025 10:00, Gokul Praveen wrote:
>> This commit adds a YAML binding for OMAP DM timer used in
> 
> Please do not use "This commit/patch/change", but imperative mood. See
> longer explanation here:
> https://elixir.bootlin.com/linux/v6.16/source/Documentation/process/submitting-patches.rst#L94
> 
> Don't use "YAML binding" - there is no such thing.
> 
> Instead just describe the hardware.
> 

Sure Krzysztof.

>> capture operating mode.
>>
>> Signed-off-by: Gokul Praveen <g-praveen@...com>
>> ---
>>   .../bindings/counter/ti,omap-dmtimer-cap.yaml | 34 +++++++++++++++++++
>>   1 file changed, 34 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/counter/ti,omap-dmtimer-cap.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/counter/ti,omap-dmtimer-cap.yaml b/Documentation/devicetree/bindings/counter/ti,omap-dmtimer-cap.yaml
>> new file mode 100644
>> index 000000000000..8de9cf58aee5
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/counter/ti,omap-dmtimer-cap.yaml
>> @@ -0,0 +1,34 @@
>> +# SPDX-License-Identifier: GPL-2.0-only OR BSD-2-Clause
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/counter/ti,omap-dmtimer-cap.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: TI dual mode timer Capture Module
>> +
>> +maintainers:
>> +  - Gokul Praveen <g-praveen@...com>
>> +
>> +description:
>> +  TI dual mode timer instances have an IO pin for Capture capability.
>> +
>> +properties:
>> +  compatible:
>> +    const: ti,omap-dmtimer-cap
> 
> Missing SoC specific part. OMAP is family, no?
> 
>> +
>> +  ti,timers:
>> +    description: Timer instance phandle for the Capture
> 
> So the only resource is phandle? That's completely fake device then. NAK.
> 


The OMAP Timer IP can operate in 3 modes: Timer, PWM mode or capture
(mutually exclusive).
The timer/ti,timer-dm.yaml file describes the timer mode of operation.
It encapsulates base IP block and reg property is also part the same
binding.

This node represents the capture mode with phandle reference to the
timer DT node. This is modeled all the same lines as how PWM
functionality is implemented in pwm/ti,omap-dmtimer-pwm.yaml

Now, if this needs to change, please suggest alternate.

One solution is perhaps to add a new property to ti,timer-dm.yaml itself
to indicate the mode of IP?


>> +    $ref: /schemas/types.yaml#/definitions/phandle
>> +
>> +required:
>> +  - compatible
>> +  - ti,timers
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    main_cap10: dmtimer-main-cap-10 {
> 
> Node names should be generic. See also an explanation and list of
> examples (not exhaustive) in DT specification:
> https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#generic-names-recommendation
> If you cannot find a name matching your device, please check in kernel
> sources for similar cases or you can grow the spec (via pull request to
> DT spec repo).
> 
> 

Sure, I will update that Krzysztof.

Regards
Gokul

> Best regards,
> Krzysztof