linux-kernel - Re: [PATCH v2 5/7] drm/bridge: anx7625: Register number of Type C switches

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Date:   Mon, 13 Jun 2022 13:48:13 -0700
From:   Prashant Malani <pmalani@...omium.org>
To:     Nícolas F. R. A. Prado 
        <nfraprado@...labora.com>
Cc:     linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
        bleung@...omium.org, swboyd@...omium.org,
        heikki.krogerus@...ux.intel.com,
        Andrzej Hajda <andrzej.hajda@...el.com>,
        AngeloGioacchino Del Regno 
        <angelogioacchino.delregno@...labora.com>,
        Daniel Vetter <daniel@...ll.ch>,
        David Airlie <airlied@...ux.ie>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@...r.kernel.org>,
        "open list:DRM DRIVERS" <dri-devel@...ts.freedesktop.org>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Hsin-Yi Wang <hsinyi@...omium.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>,
        Jonas Karlman <jonas@...boo.se>,
        José Expósito <jose.exposito89@...il.com>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@...aro.org>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Maxime Ripard <maxime@...no.tech>,
        Neil Armstrong <narmstrong@...libre.com>,
        Pin-Yen Lin <treapking@...omium.org>,
        Robert Foss <robert.foss@...aro.org>,
        Rob Herring <robh+dt@...nel.org>,
        Sam Ravnborg <sam@...nborg.org>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Tzung-Bi Shih <tzungbi@...gle.com>,
        Xin Ji <xji@...logixsemi.com>
Subject: Re: [PATCH v2 5/7] drm/bridge: anx7625: Register number of Type C switches

Hi Nícolas,

On Mon, Jun 13, 2022 at 1:45 PM Nícolas F. R. A. Prado
<nfraprado@...labora.com> wrote:
>
> Hi Prashant,
>
> On Thu, Jun 09, 2022 at 06:09:44PM +0000, Prashant Malani wrote:
> > Parse the "switches" node, if available, and count and store the number
> > of Type-C switches within it. Since we currently don't do anything with
> > this info, no functional changes are expected from this change.
> >
> > This patch sets a foundation for the actual registering of Type-C
> > switches with the Type-C connector class framework.
> >
> > Signed-off-by: Prashant Malani <pmalani@...omium.org>
> > ---
> >
> > Changes since v1:
> > - No changes.
> >
> >  drivers/gpu/drm/bridge/analogix/anx7625.c | 20 ++++++++++++++++++++
> >  drivers/gpu/drm/bridge/analogix/anx7625.h |  1 +
> >  2 files changed, 21 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.c b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > index 53a5da6c49dd..07ed44c6b839 100644
> > --- a/drivers/gpu/drm/bridge/analogix/anx7625.c
> > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.c
> > @@ -2581,6 +2581,22 @@ static void anx7625_runtime_disable(void *data)
> >       pm_runtime_disable(data);
> >  }
> >
> > +static int anx7625_register_typec_switches(struct device *device, struct anx7625_data *ctx)
> > +{
> > +     struct device_node *of = NULL;
> > +     int ret = 0;
> > +
> > +     of = of_get_child_by_name(device->of_node, "switches");
> > +     if (!of)
> > +             return -ENODEV;
> > +
> > +     ctx->num_typec_switches = of_get_child_count(of);
> > +     if (ctx->num_typec_switches <= 0)
> > +             return -ENODEV;
>
> Since the hardware only allows at most 2 switches (based on the dt-bindings),
> you should have a define for that limit and check that it isn't exceeded here.

This is already enforced by the DT binding (see the
"patternProperties" in patch 4/7, suggested by Krzysztof in the
previous version)

>
> Thanks,
> Nícolas
>
> > +
> > +     return ret;
> > +}
> > +
> >  static int anx7625_i2c_probe(struct i2c_client *client,
> >                            const struct i2c_device_id *id)
> >  {
> > @@ -2686,6 +2702,10 @@ static int anx7625_i2c_probe(struct i2c_client *client,
> >       if (platform->pdata.intp_irq)
> >               queue_work(platform->workqueue, &platform->work);
> >
> > +     ret = anx7625_register_typec_switches(dev, platform);
> > +     if (ret)
> > +             dev_info(dev, "Didn't register Type C switches, err: %d\n", ret);
> > +
> >       platform->bridge.funcs = &anx7625_bridge_funcs;
> >       platform->bridge.of_node = client->dev.of_node;
> >       if (!anx7625_of_panel_on_aux_bus(&client->dev))
> > diff --git a/drivers/gpu/drm/bridge/analogix/anx7625.h b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > index e257a84db962..d5cbca708842 100644
> > --- a/drivers/gpu/drm/bridge/analogix/anx7625.h
> > +++ b/drivers/gpu/drm/bridge/analogix/anx7625.h
> > @@ -473,6 +473,7 @@ struct anx7625_data {
> >       struct drm_connector *connector;
> >       struct mipi_dsi_device *dsi;
> >       struct drm_dp_aux aux;
> > +     int num_typec_switches;
> >  };
> >
> >  #endif  /* __ANX7625_H__ */
> > --
> > 2.36.1.476.g0c4daa206d-goog
> >