Re: Re: [PATCH 1/2] dt-bindings: mux-controller: ti: add binding for event mux router

[rahul sharma <r-sharma3@ti.com>]

Hi Conor,

Thanks for reviewing.
Apologies for the delay in responding.

On 28/08/26 21:57, Conor Dooley wrote:
> On Fri, Aug 28, 2026 at 03:36:14PM +0530, Rahul Sharma wrote:
>> Add binding for the event mux router of TI's K3 based SoC AM62L.
>>
>> The TI K3 mux routers which route the GPIO input events or Time-Sync
>> events b/w peripherals instead of routing to a CPU.
>>
>> Refer Section 10.2 and 10.2.1 of https://www.ti.com/lit/pdf/sprujb4
>>
>> Signed-off-by: Rahul Sharma <r-sharma3@ti.com>
>> ---
>>   .../mux/ti,am62l-event-mux-router.yaml        | 79 +++++++++++++++++++
>>   1 file changed, 79 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/mux/ti,am62l-event-mux-router.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/mux/ti,am62l-event-mux-router.yaml b/Documentation/devicetree/bindings/mux/ti,am62l-event-mux-router.yaml
>> new file mode 100644
>> index 000000000000..a5ba7f78a156
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/mux/ti,am62l-event-mux-router.yaml
>> @@ -0,0 +1,79 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/mux/ti,am62l-event-mux-router.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: TI Event Multiplexer on K3 SoCs
>> +
>> +maintainers:
>> +  - Rahul Sharma <r-sharma3@ti.com>
>> +
>> +description:
>> +  The TI K3 mux routers routes the GPIO input events or Time
>> +  Sync events between peripherals instead of routing to a CPU.
>> +
>> +allOf:
>> +  - $ref: mux-controller.yaml#
>> +
>> +properties:
>> +  compatible:
>> +    const: ti,am62l-event-mux-router
>> +
>> +  reg:
>> +    description: Register base address and size.
>> +    maxItems: 1
>> +
>> +  '#mux-control-cells':
>> +    const: 1
>> +    description:
>> +      Number of cells in a mux control specifier. This should be 1.
>> +      The cell specifies which mux control to use (0-based index).
>> +
>> +  ti,reg-mask-val:
>> +    $ref: /schemas/types.yaml#/definitions/uint32-matrix
>> +    items:
>> +      items:
>> +        - description: Register offset (relative to reg base)
>> +        - description: Bit mask for the mux control bits
>> +        - description: Value to write when mux is active (state 1)
>> +    minItems: 1
>> +    description: |
>> +      Array of triplets specifying register offset, mask, and value for each
>> +      mux control. Each triplet contains:
>> +      - register offset (relative to reg base)
>> +      - bit mask for the mux control bits
>> +      - value to write when mux is active (state 1)
> 
> You have a device-specific compatible, why do you need this? If the
> active setting depends on the device or w/e, why can that not come from
> a mux-control-cell?

This is a boot-time/board-fixed routing decision, not a 
runtime-selectable mux that any driver ever calls mux_control_select() on.

Please refer below link for the IP block diagram:
https://github.com/lucifer-9852/linux/commit/aed1746e411a9f0ad7824f4e4a7121e6f56a4ef2

For detailed view of IP you can refer Section 10.2 and 10.2.1 of TRM
https://www.ti.com/lit/pdf/sprujb4

That's precisely why we added ti,reg-mask-val as a controller-side 
property rather than sourcing the value from a consumer's 
mux-control-cell: there is no runtime consumer selecting between states, 
so the routing has to be fully described on the provider.

BR,
Rahul

> 
>> +
>> +  idle-states:
>> +    $ref: /schemas/types.yaml#/definitions/uint32-array
> 
> This is not needed, you get the type from mux-controller.yaml.
> 
> pw-bot: changes-requested
> 
> Thanks,
> Conor.
> 
>> +    description: |
>> +      Idle state for each mux control. Each entry corresponds to a mux control:
>> +      - 0: clear masked bits when idle, also refers to inactive state
>> +      - 1: set configured value when idle, also refers to active state
>> +      - MUX_IDLE_AS_IS (-1): keep current state when idle
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - '#mux-control-cells'
>> +  - ti,reg-mask-val
>> +  - idle-states
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/mux/mux.h>
>> +
>> +    // Example 1: TI AM62L GPIO Mux Router
>> +    mux-controller@a00000 {
>> +        compatible = "ti,am62l-event-mux-router";
>> +        reg = <0xa00000 0x400>;
>> +        #mux-control-cells = <1>;
>> +
>> +        /* Mux Register addresses: 0xa00004 + (J × 4) */
>> +        /* GPIO0_40 -> BCDMA trigger 15 */
>> +        ti,reg-mask-val = <0x40 0x000ff 0x00028>;
>> +        idle-states = <0>;
>> +    };
>> -- 
>> 2.34.1
>>