回复: [PATCH v2 1/3] dt-bindings: phy: Add CIX Sky1 DP PHY

[Luo Liu (刘罗)]

HI Conor, 

	Thank you very much for your reply and suggestions.

-----邮件原件-----
发件人: Conor Dooley <conor at kernel.org> 
发送时间: 2026年10月13日 2:55
收件人: Luo Liu (刘罗) <Luo.Liu at cixtech.com>
抄送: vkoul at kernel.org; neil.armstrong at linaro.org; mani at kernel.org; robh at kernel.org; krzk+dt at kernel.org; conor+dt at kernel.org; Gary Yang (杨新伟) <gary.yang at cixtech.com>; Fugang Duan (段富刚) <fugang.duan at cixtech.com>; linux-phy at lists.infradead.org; devicetree at vger.kernel.org; linux-arm-kernel at lists.infradead.org; cix-kernel-upstream <cix-kernel-upstream at cixtech.com>; p.zabel at pengutronix.de; linux-kernel at vger.kernel.org; Wuyi Shen (沈武义) <Wuyi.Shen at cixtech.com>; Eastlake Yang (杨东虎) <EastLake.Yang at cixtech.com>
主题: Re: [PATCH v2 1/3] dt-bindings: phy: Add CIX Sky1 DP PHY

On Mon, Oct 12, 2026 at 08:36:16PM +0800, Luo Liu wrote:
> Document the dedicated DisplayPort PHY on CIX Sky1, including the 
> optional cix,external-dp board property for external connector swing.
> Add a MAINTAINERS entry for the binding and driver.
> 
> Signed-off-by: Luo Liu <Luo.Liu at cixtech.com>
> ---
>  .../bindings/phy/cix,sky1-dp-phy.yaml         | 53 +++++++++++++++++++
>  MAINTAINERS                                   |  8 +++
>  2 files changed, 61 insertions(+)
>  create mode 100644 
> Documentation/devicetree/bindings/phy/cix,sky1-dp-phy.yaml
> 
> diff --git 
> a/Documentation/devicetree/bindings/phy/cix,sky1-dp-phy.yaml 
> b/Documentation/devicetree/bindings/phy/cix,sky1-dp-phy.yaml
> new file mode 100644
> index 000000000000..c6914cab74e0
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/phy/cix,sky1-dp-phy.yaml
> @@ -0,0 +1,53 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) %YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/phy/cix,sky1-dp-phy.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: CIX Sky1 DisplayPort PHY
> +
> +maintainers:
> +  - Luo Liu <Luo.Liu at cixtech.com>
> +
> +description:
> +  The CIX Sky1 DP PHY provides the PMA/CDB register interface for the
> +  dedicated DisplayPort instance on CIX Sky1.
> +
> +properties:
> +  compatible:
> +    const: cix,sky1-dp-phy
> +
> +  reg:
> +    maxItems: 1
> +
> +  "#phy-cells":
> +    const: 0
> +
> +  resets:
> +    maxItems: 1
> +    description: PHY hardware reset
> +
> +  cix,external-dp:
> +    type: boolean
> +    description:
> +      Use voltage swing values suitable for an external DisplayPort
> +      connector instead of the default low-voltage values.
> +
> +required:
> +  - compatible
> +  - reg
> +  - "#phy-cells"
> +  - resets

A reset but no clocks? That's a bit hard to believe.

Seems fine otherwise, unless I am missing some sort of common property for the voltage swing stuff.

Thanks,
Conor.


1，Regarding the missing clocks property: 

	The PHY APB clock is physically the same clock as the DPTx controller APB clock. It is described and 

managed only by the DPTx controller driver, so the PHY node does not list a separate clocks property.

The PHY driver only implements the standard PHY callbacks. It does not touch the hardware in probe; 

All PHY programming happens later, when the DPTx driver actively calls phy_init() / phy_power_on() / phy_configure() 

and similar interfaces. 

	By that time the shared APB clock is already under DPTx control.

So from this binding's point of view there are no clocks to describe ― only the reset line owned by the PHY node.


2，On the voltage swing property: there is no suitable common DT property for this.

	The flag only selects which vendor calibration table to use for the same PHY IP ― the DisplayPort swing/EQ table 

versus the eDP table. 

	Runtime swing/pre-emphasis levels still come from phy_configure_opts_dp as usual.

The old name cix,external-dp was misleading. I will rename it to cix,edp (present => eDP table, absent => DP table)

and update the driver and binding accordingly in v3.


Thanks,
Luo.


> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/reset/cix,sky1-s5-system-control.h>
> +
> +    phy at 1414c000 {
> +        compatible = "cix,sky1-dp-phy";
> +        reg = <0x1414c000 0x4000>;
> +        resets = <&s5_syscon SKY1_DP_PHY_RST_N>;
> +        #phy-cells = <0>;
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS index 
> 3a19da74d00c..b46d0f4220a9 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -6360,6 +6360,14 @@ M:	Satish Kharat <satishkh at cisco.com>
>  S:	Supported
>  F:	drivers/infiniband/hw/usnic/
>  
> +CIX SKY1 DISPLAYPORT PHY DRIVER
> +M:	Luo Liu <Luo.Liu at cixtech.com>
> +R:	CIX Linux Kernel Upstream Group <cix-kernel-upstream at cixtech.com>
> +L:	linux-phy at lists.infradead.org
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/phy/cix,sky1-dp-phy.yaml
> +F:	drivers/phy/cix/
> +
>  CLANG CONTEXT ANALYSIS
>  M:	Marco Elver <elver at google.com>
>  R:	Bart Van Assche <bvanassche at acm.org>
> --
> 2.25.1
>