linux-kernel - Re: [PATCH v3 3/3] usb: typec: ucsi: Get PD revision for partner

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Date: Tue, 6 Feb 2024 12:18:32 +0200
From: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
Cc: Prashant Malani <pmalani@...omium.org>, linux-usb@...r.kernel.org,
	jthies@...gle.com,
	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
	Bjorn Andersson <andersson@...nel.org>,
	Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
	Fabrice Gasnier <fabrice.gasnier@...s.st.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Hans de Goede <hdegoede@...hat.com>,
	Neil Armstrong <neil.armstrong@...aro.org>,
	Rajaram Regupathy <rajaram.regupathy@...el.com>,
	Saranya Gopal <saranya.gopal@...el.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 3/3] usb: typec: ucsi: Get PD revision for partner

Hi Abhishek,

On Mon, Feb 05, 2024 at 02:05:38PM -0800, Abhishek Pandit-Subedi wrote:
> Hi Heikki,
> 
> Friendly ping to review this patch (I see you added Reviewed-by to the
> other two in this series).

I think Prashant said that he prefers macros with those version checks,
and I kinda agree. But I'll leave this to you to decide. I think
that's also something that can be improved later.

> On Fri, Jan 26, 2024 at 12:25 PM Prashant Malani <pmalani@...omium.org> wrote:
> >
> > Hi Abhishek,
> >
> > On Fri, Jan 26, 2024 at 10:39 AM Abhishek Pandit-Subedi
> > <abhishekpandit@...omium.org> wrote:
> > >
> > > PD major revision for the port partner is described in
> > > GET_CONNECTOR_CAPABILITY and is only valid on UCSI 2.0 and newer. Update
> > > the pd_revision on the partner if the UCSI version is 2.0 or newer.
> > >
> > > Signed-off-by: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>

So this okay by me:

Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

> > > ---
> > > $ cat /sys/class/typec/port2-partner/usb_power_delivery_revision
> > > 3.0
> > >
> > > (no changes since v2)
> > >
> > > Changes in v2:
> > >   - Formatting changes and update macro to use brackets.
> > >   - Fix incorrect guard condition when checking connector capability.
> > >
> > >  drivers/usb/typec/ucsi/ucsi.c | 23 +++++++++++++++++++++++
> > >  drivers/usb/typec/ucsi/ucsi.h |  3 +++
> > >  2 files changed, 26 insertions(+)
> > >
> > > diff --git a/drivers/usb/typec/ucsi/ucsi.c b/drivers/usb/typec/ucsi/ucsi.c
> > > index a35056ee3e96..2b7983d2fdae 100644
> > > --- a/drivers/usb/typec/ucsi/ucsi.c
> > > +++ b/drivers/usb/typec/ucsi/ucsi.c
> > > @@ -782,6 +782,7 @@ static int ucsi_register_partner(struct ucsi_connector *con)
> > >         }
> > >
> > >         desc.usb_pd = pwr_opmode == UCSI_CONSTAT_PWR_OPMODE_PD;
> > > +       desc.pd_revision = UCSI_CONCAP_FLAG_PARTNER_PD_MAJOR_REV_AS_BCD(con->cap.flags);
> > >
> > >         partner = typec_register_partner(con->port, &desc);
> > >         if (IS_ERR(partner)) {
> > > @@ -856,6 +857,27 @@ static void ucsi_partner_change(struct ucsi_connector *con)
> > >                         con->num, u_role);
> > >  }
> > >
> > > +static int ucsi_check_connector_capability(struct ucsi_connector *con)
> > > +{
> > > +       u64 command;
> > > +       int ret;
> > > +
> > > +       if (!con->partner || !IS_MIN_VERSION_2_0(con->ucsi))
> >
> > I'll reiterate my comment from a previous version, since this series
> > has been revv-ed a few
> > times since and it may have gotten lost; no need to respond to it if
> > you don't want to,
> > since I believe we left it to the maintainer(s) to decide [1]:
> >
> > This macro is unnecessary. Since the version is in BCD format and we
> > already have the
> > macros for versions, just a simple comparison is enough:
> >          if (!con-partner || con->ucsi->version < UCSI_VERSION_2_0)
> >                  return 0;
> >
> > I'll add that Patch 1 of this series [2] is also using the same style
> > for comparing version numbers.
> >
> > > +               return 0;
> > > +
> > > +       command = UCSI_GET_CONNECTOR_CAPABILITY | UCSI_CONNECTOR_NUMBER(con->num);
> > > +       ret = ucsi_send_command(con->ucsi, command, &con->cap, sizeof(con->cap));
> > > +       if (ret < 0) {
> > > +               dev_err(con->ucsi->dev, "GET_CONNECTOR_CAPABILITY failed (%d)\n", ret);
> >
> > nit: I know this is being done elsewhere in this file, but we should
> > avoid putting error
> > numbers in parentheses [3]. Perhaps something for a separate cleanup patch.
> > 
> > [1] https://lore.kernel.org/linux-usb/CANFp7mXP=aN8bQi4akKKcoMZE8RaCBuFnwTa5hbp0MZvZe0hYQ@mail.gmail.com/
> > [2] https://lore.kernel.org/linux-usb/20240126103859.v3.1.Iacf5570a66b82b73ef03daa6557e2fc0db10266a@changeid/
> > [3] https://www.kernel.org/doc/html/latest/process/coding-style.html#printing-kernel-messages

thanks,

-- 
heikki