linux-kernel - Re: [PATCHv3 2/2] usb: typec: anx7688: Add driver for ANX7688 USB-C HDMI bridge

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Date: Tue, 9 Apr 2024 18:35:50 +0300
From: Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To: Pavel Machek <pavel@....cz>
Cc: Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 
	phone-devel@...r.kernel.org, kernel list <linux-kernel@...r.kernel.org>, fiona.klute@....de, 
	martijn@...xit.nl, samuel@...lland.org, gregkh@...uxfoundation.org, 
	linux-usb@...r.kernel.org, megi@....cz
Subject: Re: [PATCHv3 2/2] usb: typec: anx7688: Add driver for ANX7688 USB-C
 HDMI bridge

On Tue, Apr 09, 2024 at 01:04:12PM +0200, Pavel Machek wrote:
> Hi!
> 
> > > This is driver for ANX7688 USB-C HDMI, with flashing and debugging
> > > features removed. ANX7688 is rather criticial piece on PinePhone,
> > > there's no display and no battery charging without it.
> > > 
> > > There's likely more work to be done here, but having basic support
> > > in mainline is needed to be able to work on the other stuff
> > > (networking, cameras, power management).
> > > 
> > > Signed-off-by: Ondrej Jirman <megi@....cz>
> > > Co-developed-by: Martijn Braam <martijn@...xit.nl>
> > > Co-developed-by: Samuel Holland <samuel@...lland.org>
> > > Signed-off-by: Pavel Machek <pavel@....cz>
> > 
> > Just couple of quick comments below - I did not have time to go over
> > this very thoroughly, but I think you need to make a new version in
> > any case because of comments in 1/2.
> 

[skipped]

> 
> > > +static int anx7688_connect(struct anx7688 *anx7688)
> > > +{
> > > +	struct typec_partner_desc desc = {};
> > > +	int ret, i;
> > > +	u8 fw[2];
> > > +	const u8 dp_snk_identity[16] = {
> > > +		0x00, 0x00, 0x00, 0xec,	/* id header */
> > > +		0x00, 0x00, 0x00, 0x00,	/* cert stat */
> > > +		0x00, 0x00, 0x00, 0x00,	/* product type */
> > > +		0x39, 0x00, 0x00, 0x51	/* alt mode adapter */
> > > +	};
> > > +	const u8 svid[4] = {
> > > +		0x00, 0x00, 0x01, 0xff,
> > > +	};
> > 
> > Why not get those from DT?
> 
> Are you sure it belongs to the DT (and that DT people will agree)?

>From Documentation/devicetree/bindings/connector/usb-connector.yaml:

            altmodes {
                displayport {
                    svid = /bits/ 16 <0xff01>;
                    vdo = <0x00001c46>;
                };
            };

BTW, I don't see the VDO for the DP altmode in your code. Maybe I missed
it at a quick glance.

> 
> > > +	u32 caps[8];
> > > +


-- 
With best wishes
Dmitry