RE: [PATCH 2/2] usb: typec: ucsi: itepd: Add DisplayPort alternate mode support

[<amber.kao@ite.com.tw>]

On Sun, Sep 13, 2026 at 09:05:40AM +0000, Krzysztof Kozlowski wrote:
> >  static const struct of_device_id itepd_of_match_table[] = {
> >  	{ .compatible = "ite,it8851" },
> > +		{ .compatible = "ite,it5271" },
> 
> So devices are fully compatible?

Yes. The IT527x series shares the same programming interface as
IT8851/IT8853: same register map, same UCSI command path, and the
driver does not branch on the part number -- neither match entry
carries match data.

The integrated MUX/SBU on IT527x is transparent to the host. The mux
and retimer are resolved through the connector's OF graph, so a board
without an external mux simply has no port@2 and the same code path
does the right thing.

I will drop the "ite,it5271" entry in v2 and express the relationship
as a fallback in the binding instead, consistent with ite,it8853. I
will also update MODULE_DESCRIPTION to cover the IT527x series.

Thanks,
Amber

-----Original Message-----
From: Krzysztof Kozlowski <krzk@kernel.org> 
Sent: Sunday, September 13, 2026 5:06 PM
To: ITE_PD <ite_pd@ite.com.tw>
Cc: Amber Kao (高鈺盈) <amber.kao@ite.com.tw>; Jeson Yang (楊志賢) <jeson.yang@ite.com.tw>; Yaode Fang (方耀德) <Yaode.Fang@ite.com.tw>; Greg Kroah-Hartman <gregkh@linuxfoundation.org>; Rob Herring <robh@kernel.org>; Krzysztof Kozlowski <krzk+dt@kernel.org>; Conor Dooley <conor+dt@kernel.org>; Heikki Krogerus <heikki.krogerus@linux.intel.com>; linux-usb@vger.kernel.org; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org
Subject: Re: [PATCH 2/2] usb: typec: ucsi: itepd: Add DisplayPort alternate mode support

On Fri, Sep 11, 2026 at 06:17:58PM +0800, Amber Kao wrote:
> +	ret = itepd_bridges_add(itepd);
> +	if (ret)
> +		goto out_ucsi_unregister;
> +
>  	return 0;
>  
> +out_ucsi_unregister:
> +	ucsi_unregister(itepd->ucsi);
>  out_free_irq:
>  	free_irq(client->irq, itepd);
>  out_ucsi_destroy:
> @@ -330,6 +715,7 @@ static void itepd_remove(struct i2c_client *client)
>  
>  static const struct of_device_id itepd_of_match_table[] = {
>  	{ .compatible = "ite,it8851" },
> +	{ .compatible = "ite,it5271" },

So devices are fully compatible?

Best regards,
Krzysztof