linux-kernel - Re: [PATCH] platform/chrome: cros_ec_typec: Set Pin Assignment E in DP PORT VDO

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Message-ID: <aA-_tpJp7Nh2pm3J@google.com>
Date: Mon, 28 Apr 2025 17:49:42 +0000
From: Benson Leung <bleung@...gle.com>
To: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
Cc: Benson Leung <bleung@...omium.org>, jthies@...gle.com,
	akuchynski@...omium.org, tzungbi@...nel.org,
	chrome-platform@...ts.linux.dev, linux-kernel@...r.kernel.org,
	sukoo@...gle.com
Subject: Re: [PATCH] platform/chrome: cros_ec_typec: Set Pin Assignment E in
 DP PORT VDO

Hi Abhishek,

On Mon, Apr 28, 2025 at 09:24:08AM -0700, Abhishek Pandit-Subedi wrote:
> On Fri, Apr 25, 2025 at 7:48 PM Benson Leung <bleung@...omium.org> wrote:
> >
> > Pin C and D are used on C-to-C cable applications including docks,
> > and for USB-C adapters that convert from DP over USB-C to other
> > video standards.
> >
> > Pin Assignment E is intended to be used with adapter from USB-C to DP
> > plugs or receptacles.
> >
> > All Chromebook USB-C DFPs support DisplayPort Alternate Mode as the DP
> > Source with support for all 3 pin assignments. Pin Assignment E is required
> > in order to support if the user attaches a Pin E C-to-DP cable.
> >
> > Without this, the displayport.c alt mode driver will error out of
> > dp_altmode_probe with an -ENODEV, as it cannot find a compatible matching
> > pin assignment between the DFP_D and UFP_D.
> >
> > Signed-off-by: Benson Leung <bleung@...omium.org>
> > ---
> >  drivers/platform/chrome/cros_ec_typec.c | 6 ++++--
> >  1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/platform/chrome/cros_ec_typec.c b/drivers/platform/chrome/cros_ec_typec.c
> > index d2228720991f..7678e3d05fd3 100644
> > --- a/drivers/platform/chrome/cros_ec_typec.c
> > +++ b/drivers/platform/chrome/cros_ec_typec.c
> > @@ -22,8 +22,10 @@
> >
> >  #define DRV_NAME "cros-ec-typec"
> >
> > -#define DP_PORT_VDO    (DP_CONF_SET_PIN_ASSIGN(BIT(DP_PIN_ASSIGN_C) | BIT(DP_PIN_ASSIGN_D)) | \
> > -                               DP_CAP_DFP_D | DP_CAP_RECEPTACLE)
> > +#define DP_PORT_VDO    (DP_CAP_DFP_D | DP_CAP_RECEPTACLE | \
> > +                        DP_CONF_SET_PIN_ASSIGN(BIT(DP_PIN_ASSIGN_C) | \
> > +                                               BIT(DP_PIN_ASSIGN_D) | \
> > +                                               BIT(DP_PIN_ASSIGN_E)))
> >
> >  static void cros_typec_role_switch_quirk(struct fwnode_handle *fwnode)
> >  {
> > --
> > 2.49.0.850.g28803427d3-goog
> >
> 
> Please add a Fixes: dbb3fc0ffa95788e00e50ffc6501eb0085d48231

Done, Thanks!

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