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

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Date: Fri, 26 Jan 2024 12:25:41 -0800
From: Prashant Malani <pmalani@...omium.org>
To: Abhishek Pandit-Subedi <abhishekpandit@...omium.org>
Cc: Heikki Krogerus <heikki.krogerus@...ux.intel.com>, 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 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>
> ---
> $ 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