Re: [PATCH v2 1/4] doc: dt-binding: ci-hdrc-usb2: add property for imx picophy

[Rob Herring <robh@kernel.org>]

On Fri, Jul 17, 2020 at 12:22:23PM +0800, Peter Chen wrote:
> Add two parameters which are used to tune USB signal for imx picophy,
> picophy is used at imx7d, imx8mm, and imx8mn.
> 
> Reviewed-by: Jun Li <jun.li@nxp.com>
> Signed-off-by: Peter Chen <peter.chen@nxp.com>
> ---
> No changes for v2.
> 
>  Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
> index 51376cbe5f3d..e9858dafb08f 100644
> --- a/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
> +++ b/Documentation/devicetree/bindings/usb/ci-hdrc-usb2.txt
> @@ -100,6 +100,13 @@ i.mx specific properties
>    It's recommended to specify the over current polarity.
>  - power-active-high: power signal polarity is active high
>  - external-vbus-divider: enables off-chip resistor divider for Vbus
> +- picophy,pre-emp-curr-control: HS Transmitter Pre-Emphasis Current

Form is <vendor>,<prop-name> and picophy is not a vendor.

> +  Control. This signal controls the amount of current sourced to the
> +  USB_OTG*_DP and USB_OTG*_DN pins after a J-to-K or K-to-J transition.
> +  Details can refer to TXPREEMPAMPTUNE0 bits of USBNC_n_PHY_CFG1.

What's the range of values? What's the default if not specified?

> +- picophy,dc-vol-level-adjust: HS DC Voltage Level Adjustment.
> +  Adjust the high-speed transmitter DC level voltage, details can refer
> +  to TXVREFTUNE0 bits of USBNC_n_PHY_CFG1.

Same comments here.

>  
>  Example:
>  
> -- 
> 2.17.1
>