linux-kernel - Re: [PATCH 3/8] drm/bridge: it66121: Add a helper function to read bus width

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Message-ID: <CAA8EJprhnxx6bS6cn1JAbdzyB_+N1BbajkuO8zs2_OxXPeV84Q@mail.gmail.com>
Date:   Tue, 14 Nov 2023 18:03:47 +0200
From:   Dmitry Baryshkov <dmitry.baryshkov@...aro.org>
To:     Sui Jingfeng <sui.jingfeng@...ux.dev>
Cc:     Phong LE <ple@...libre.com>,
        Neil Armstrong <neil.armstrong@...aro.org>,
        Maxime Ripard <mripard@...nel.org>,
        Sui Jingfeng <suijingfeng@...ngson.cn>,
        linux-kernel@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Thomas Zimmermann <tzimmermann@...e.de>
Subject: Re: [PATCH 3/8] drm/bridge: it66121: Add a helper function to read
 bus width

On Tue, 14 Nov 2023 at 17:09, Sui Jingfeng <sui.jingfeng@...ux.dev> wrote:
>
> From: Sui Jingfeng <suijingfeng@...ngson.cn>
>
> Group those relavent code lines (which with common purpose) into one helper
> function, suppress the dependency on DT to function level. Just trivial
> cleanup, no functional change.
>
> Signed-off-by: Sui Jingfeng <suijingfeng@...ngson.cn>
> ---
>  drivers/gpu/drm/bridge/ite-it66121.c | 32 ++++++++++++++++++++--------
>  1 file changed, 23 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/ite-it66121.c b/drivers/gpu/drm/bridge/ite-it66121.c
> index 83dbdbfc9ed8..0f78737adc83 100644
> --- a/drivers/gpu/drm/bridge/ite-it66121.c
> +++ b/drivers/gpu/drm/bridge/ite-it66121.c
> @@ -320,6 +320,26 @@ static inline struct it66121_ctx *bridge_to_it66121(struct drm_bridge *bridge)
>         return container_of(bridge, struct it66121_ctx, bridge);
>  }
>
> +static int it66121_of_read_bus_width(struct device *dev, u32 *bus_width)

Using a pointer to return int value doesn't look right. Just return a
signed int here and if it is not an error, assign it to ctx->bus_width

> +{
> +       struct device_node *np;
> +       u32 bw;
> +
> +       np = of_graph_get_endpoint_by_regs(dev->of_node, 0, 0);
> +       if (!np)
> +               return -EINVAL;
> +
> +       of_property_read_u32(np, "bus-width", &bw);
> +       of_node_put(np);
> +
> +       if (bw != 12 && bw != 24)
> +               return -EINVAL;
> +
> +       *bus_width = bw;
> +
> +       return 0;
> +}
> +
>  static const struct regmap_range_cfg it66121_regmap_banks[] = {
>         {
>                 .name = "it66121",
> @@ -1525,19 +1545,13 @@ static int it66121_probe(struct i2c_client *client)
>         if (!ctx)
>                 return -ENOMEM;
>
> -       ep = of_graph_get_endpoint_by_regs(dev->of_node, 0, 0);
> -       if (!ep)
> -               return -EINVAL;
> -
>         ctx->dev = dev;
>         ctx->client = client;
>         ctx->info = i2c_get_match_data(client);
>
> -       of_property_read_u32(ep, "bus-width", &ctx->bus_width);
> -       of_node_put(ep);
> -
> -       if (ctx->bus_width != 12 && ctx->bus_width != 24)
> -               return -EINVAL;
> +       ret = it66121_of_read_bus_width(dev, &ctx->bus_width);
> +       if (ret)
> +               return ret;
>
>         ep = of_graph_get_remote_node(dev->of_node, 1, -1);
>         if (!ep) {
> --
> 2.34.1
>


-- 
With best wishes
Dmitry