Message-ID: <CAEXTbpd1kQWbJazRSvLabH26teiWvo75+rKOTL0A9Jm3eXeACQ@mail.gmail.com>
Date:   Fri, 31 Mar 2023 17:18:16 +0900
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>,
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        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
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        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
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        chrome-platform@...ts.linux.dev, devicetree@...r.kernel.org
Subject: Re: [PATCH v14 07/10] drm/bridge: anx7625: Register Type C mode switches

Hi Andy,

Thanks for the review.

On Wed, Mar 22, 2023 at 8:16 PM Andy Shevchenko
<andriy.shevchenko@...ux.intel.com> wrote:
>
> On Wed, Mar 22, 2023 at 06:46:36PM +0800, Pin-yen Lin wrote:
> > Register USB Type-C mode switches when the "mode-switch" property and
> > relevant ports are available in Device Tree. Configure the crosspoint
> > switch based on the entered alternate mode for a specific Type-C
> > connector.
> >
> > Crosspoint switch can also be used for switching the output signal for
> > different orientations of a single USB Type-C connector, but the
> > orientation switch is not implemented yet. A TODO is added for this.
>
> ...
>
> > +static int anx7625_typec_mux_set(struct typec_mux_dev *mux,
> > +                              struct typec_mux_state *state)
> > +{
> > +     struct drm_dp_typec_port_data *port = typec_mux_get_drvdata(mux);
> > +     struct anx7625_data *ctx = port->data;
> > +     struct device *dev = ctx->dev;
> > +     struct drm_dp_typec_switch_desc switch_desc = ctx->switch_desc;
> > +     bool new_dp_connected, old_dp_connected;
> > +
> > +     if (switch_desc.num_typec_switches == 1)
> > +             return 0;
>
> > +     wait_for_completion(&ctx->mux_register);
>
> How do we guarantee this won't become an infinite waiting?
> Perhaps a comment explaining that?
>
> > +     old_dp_connected = ctx->port_data[0].dp_connected ||
> > +                        ctx->port_data[1].dp_connected;
> > +
> > +     ctx->port_data[port->port_num].dp_connected =
> > +             state->alt &&
> > +             state->alt->svid == USB_TYPEC_DP_SID &&
> > +             state->alt->mode == USB_TYPEC_DP_MODE;
> > +
> > +     dev_dbg(dev, "mux_set dp_connected: c0=%d, c1=%d\n",
> > +             ctx->port_data[0].dp_connected, ctx->port_data[1].dp_connected);
> > +
> > +     new_dp_connected = ctx->port_data[0].dp_connected ||
> > +                        ctx->port_data[1].dp_connected;
> > +
> > +     /* DP on, power on first */
> > +     if (!old_dp_connected && new_dp_connected)
> > +             pm_runtime_get_sync(dev);
> > +
> > +     anx7625_typec_two_ports_update(ctx);
> > +
> > +     /* DP off, power off last */
> > +     if (old_dp_connected && !new_dp_connected)
> > +             pm_runtime_put_sync(dev);
> > +
> > +     return 0;
> > +}
>
> ...
>
> > +     struct device_node *port_node = of_graph_get_port_by_id(dev->of_node, 1);
>
> You use fwnode below, so why not fwnode_graph_...(dev_fwnode(dev), ...) ?

There is no existing helper like `fwnode_graph_get_port_by_id`, so
using of_graph variant is easier here. Should I add a
`fwnode_graph_get_port_by_id` helper for this?
>
> > +     struct drm_dp_typec_switch_desc *switch_desc = &ctx->switch_desc;
> > +     int ret;
> > +     u32 dp_lanes[4];
> > +     unsigned int i, num_lanes;
> > +
> > +     /*
> > +      * Currently, only mode switch is implemented.
> > +      * TODO: Implement Type-C orientation switch for anx7625.
> > +      */
> > +     ret = drm_dp_register_typec_switches(dev, &port_node->fwnode,
> > +                                          &ctx->switch_desc, ctx,
> > +                                          anx7625_typec_mux_set);
> > +     if (ret)
> > +             return ret;
> > +
> > +     ctx->port_data = devm_kcalloc(dev, switch_desc->num_typec_switches,
> > +                                   sizeof(struct anx7625_typec_port_data),
>
>                                       sizeof(*ctx->port_data),
>
> ?
>
> > +                                   GFP_KERNEL);
> > +     if (!ctx->port_data) {
> > +             ret = -ENOMEM;
> > +             goto unregister_mux;
> > +     }
>
> ...
>
> > +struct anx7625_typec_port_data {
> > +     bool dp_connected;
> > +     enum typec_orientation orientation;
>
> Most likely enum will be 32-bit and bool 8-bit. Which means that the data type
> size become 8 bytes for no reason. Can you swap the lines and perhaps check this
> with `pahole` tool?
>
> > +};
>
> --
> With Best Regards,
> Andy Shevchenko
>
>

Best regards,
Pin-yen

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