linux-kernel - Re: [PATCH v12 03/10] drm/display: Add Type-C switch helpers

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Message-ID: <CAEXTbpcOA06Cf-niurjM4_3Rx6xa9Pi+fuJHUQCKmwaJL2ibmA@mail.gmail.com>
Date:   Wed, 22 Feb 2023 16:53:41 +0800
From:   Pin-yen Lin <treapking@...omium.org>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Andrzej Hajda <andrzej.hajda@...el.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Robert Foss <rfoss@...nel.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Jonas Karlman <jonas@...boo.se>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        David Airlie <airlied@...il.com>,
        Daniel Vetter <daniel@...ll.ch>,
        Rob Herring <robh+dt@...nel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Daniel Scally <djrscally@...il.com>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Prashant Malani <pmalani@...omium.org>,
        Benson Leung <bleung@...omium.org>,
        Guenter Roeck <groeck@...omium.org>,
        linux-kernel@...r.kernel.org, Hsin-Yi Wang <hsinyi@...omium.org>,
        Marek Vasut <marex@...x.de>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        dri-devel@...ts.freedesktop.org, Xin Ji <xji@...logixsemi.com>,
        Lyude Paul <lyude@...hat.com>,
        Allen Chen <allen.chen@....com.tw>, devicetree@...r.kernel.org,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Nícolas F . R . A . Prado 
        <nfraprado@...labora.com>, chrome-platform@...ts.linux.dev,
        Javier Martinez Canillas <javierm@...hat.com>,
        linux-acpi@...r.kernel.org, Stephen Boyd <swboyd@...omium.org>,
        Douglas Anderson <dianders@...omium.org>,
        "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Imre Deak <imre.deak@...el.com>,
        Jani Nikula <jani.nikula@...el.com>,
        Kees Cook <keescook@...omium.org>
Subject: Re: [PATCH v12 03/10] drm/display: Add Type-C switch helpers

Hi Andy,

Thanks for the review.

On Tue, Feb 21, 2023 at 7:48 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Tue, Feb 21, 2023 at 05:50:47PM +0800, Pin-yen Lin wrote:
> > Add helpers to register and unregister Type-C "switches" for bridges
> > capable of switching their output between two downstream devices.
> >
> > The helper registers USB Type-C mode switches when the "mode-switch"
> > and the "reg" properties are available in Device Tree.
> >
> > Signed-off-by: Pin-yen Lin <treapking@...omium.org>
>
> ...
>
> > +     fwnode_for_each_typec_mode_switch(port, sw)
> > +             switch_desc->num_typec_switches++;
> > +
> > +     if (!switch_desc->num_typec_switches) {
> > +             dev_dbg(dev, "No Type-C switches node found\n");
> > +             return 0;
> > +     }
>
> What about
>
> static inline unsigned int typec_mode_switch_node_count(... *port)
> {
>         ... *sw;
>         unsigned int count = 0;
>
>         for_each_typec_mode_switch_node(port, sw)
>                 count++;
>
>         return count;
> }
>
>
> And then it seems something like
>
>         unsigned int count;
>
>         count = typec_mode_switch_node_count(port);
>         if (!count) {
>                 ...
>         }
>
>         _switches = count;
>
> ...
>
> > +     switch_desc->typec_ports = devm_kcalloc(
> > +             dev, switch_desc->num_typec_switches,
>
> Strange indentation.
>
> > +             sizeof(struct drm_dp_typec_port_data), GFP_KERNEL);
>
> > +
>
> Redundant blank line.
>
> > +     if (!switch_desc->typec_ports)
> > +             return -ENOMEM;
>
> ...
>
> > +void drm_dp_unregister_typec_switches(struct drm_dp_typec_switch_desc *switch_desc)
> > +{
> > +     int i;
>
> unsigned?
>
> > +     for (i = 0; i < switch_desc->num_typec_switches; i++)
> > +             typec_mux_unregister(switch_desc->typec_ports[i].typec_mux);
> > +}
>
> ...
>
> >  #include <linux/delay.h>
> >  #include <linux/i2c.h>
> > +#include <linux/usb/typec_mux.h>
>
> I don't see users of this.
> But a few forward declarations are missing.

I can put a `struct typec_mux_dev;` here, but there is also a usage of
typec_mux_set_fn_t.

Should I add the typedef into this header file as well?

Regards,
Pin-yen
>
> >  #include <drm/display/drm_dp.h>
> >  #include <drm/drm_connector.h>
>
> ...
>
> > +#define fwnode_for_each_typec_mode_switch(port, sw)  \
> > +     fwnode_for_each_child_node((port), (sw))        \
> > +             for_each_if(fwnode_property_present((sw), "mode-switch"))
>
> Please don't use fwnode namespace (see above), something like
>
> #define for_each_typec_mode_switch_node(port, sw)       \
>         ...
>
> --
> With Best Regards,
> Andy Shevchenko
>
>