Re: [PATCH 6/6] dt-bindings: usb: ci-hdrc-usb2: Add more phy tuning properties

On Thu, Oct 13, 2022 at 12:14:12PM +0200, Sascha Hauer wrote:

On Wed, Oct 12, 2022 at 11:08:06AM -0500, Rob Herring wrote:

quoted

On Tue, Oct 11, 2022 at 10:29:24AM +0200, Sascha Hauer wrote:

quoted

Following the example of samsung,picophy-dc-vol-level-adjust more
phy tuning properties are added for configuring the remaining bitfields
in the USBNC_n_PHY_CFG1 register.

All these properties really doesn't scale. These properties should go 
in the phy node as they are properties or the phy. There's no rule that 
you can only read properties from the driver's device node.

I understand and agree.

On i.MX8M we currently use the usb-nop-xceiv. I guess it's not an option
to just add these properties there, so we'll need a phy node with a new
compatible like fsl,imx8mm-usbphy. The driver would basically just
register a usb-nop-xceiv and the node would be a container for the new
property. Does this sound sane?

I think it would be fine if you do:

compatible = "fsl,imx8mm-usbphy", "usb-nop-xceiv";

You'll have to rework the usb-nop-xceiv schema 'select' like we have to 
do for any compatible appearing in multiple schema files.

Or don't have the fallback and add "fsl,imx8mm-usbphy" to the 
phy-generic.c driver. But that should be marked for stable for at least 
some compatibility with old kernels.

For existing kernel binaries to work, you have to go with the former 
option.

Rob

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