Re: [PATCH RESEND v5 1/2] dt-bindings: i2c: spacemit: add support for K1 SoC

[Samuel Holland <samuel.holland@sifive.com>]

Hi Troy,

On 2025-03-03 3:35 AM, Yixun Lan wrote:
> On 13:30 Mon 03 Mar     , Troy Mitchell wrote:
>> The I2C of K1 supports fast-speed-mode and high-speed-mode,
>> and supports FIFO transmission.
>>
>> Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
>> Signed-off-by: Troy Mitchell <troymitchell988@gmail.com>
>> ---
>>  .../devicetree/bindings/i2c/spacemit,k1-i2c.yaml   | 59 ++++++++++++++++++++++
>>  1 file changed, 59 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml b/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml
>> new file mode 100644
>> index 0000000000000000000000000000000000000000..db49f1f473e6f166f534b276c86b3951d86341c3
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/i2c/spacemit,k1-i2c.yaml
>> @@ -0,0 +1,59 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/i2c/spacemit,k1-i2c.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: I2C controller embedded in SpacemiT's K1 SoC
>> +
>> +maintainers:
>> +  - Troy Mitchell <troymitchell988@gmail.com>
>> +
>> +properties:
>> +  compatible:
>> +    const: spacemit,k1-i2c
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    maxItems: 1
>> +
> ..
>> +  clocks:
>> +    minItems: 2
>> +    maxItems: 2
>> +
>> +  clock-names:
>> +    minItems: 2
>> +    maxItems: 2
> I'd suggest to give a brief description and explicit clock name here,
> you can consult marvell,mv64xxx-i2c.yaml for example
> 
>> +
>> +  clock-frequency:
>> +    description: |
>> +      K1 support three different modes which running different frequencies
>> +      standard speed mode: up to 100000 (100Hz)
>> +      fast speed mode    : up to 400000 (400Hz)
>> +      high speed mode    : up to 3300000 (3.3Mhz)
>> +    default: 400000
>> +    maximum: 3300000
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - interrupts
>> +  - clocks
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    i2c@d4010800 {
>> +        compatible = "spacemit,k1-i2c";
>> +        reg = <0xd4010800 0x38>;
>> +        interrupt-parent = <&plic>;
>> +        interrupts = <36>;
>> +        clocks = <&ccu 176>, <&ccu 90>;
>> +        clock-names = "apb", "twsi";
> 9.1.4.61 TWSI0 CLOCK RESET CONTROL REGISTER(APBC_TWSI0_CLK_RST)
> https://developer.spacemit.com/documentation?token=LCrKwWDasiJuROkVNusc2pWTnEb#part594
> from above docs, there are two clocks 
> bit[1] - FNCLK, TWSI0 Functional Clock Enable/Disable
> bit[0] - APBCLK, TWSI0 APB Bus Clock Enable/Disable
> 
> I'd suggest to name it according to the functionality, thus 'func', 'bus'
> clock, not its source.. which would make it more system wide consistent

Also in that same register is:

2	RST	RW	0x1	TWSI0 Reset Generation
This field resets both the APB and functional domain.
- 0: No Reset
- 1: Reset

Which means you need a 'resets' property in the binding as well.

Regards,
Samuel

>> +        clock-frequency = <100000>;
>> +    };
>> +
>> +...
>>
>> -- 
>> 2.34.1
>>
>