[PATCHv2 4/4] drm: exynos: hdmi: add support for pixel clock limitation

Rahul Sharma r.sh.open at gmail.com
Tue Apr 15 02:42:24 PDT 2014


Hi Tomasz,

On 15 April 2014 14:57, Tomasz Stanislawski <t.stanislaws at samsung.com> wrote:
> Adds support for limitation of maximal pixel clock of HDMI
> signal. This feature is needed on boards that contains
> lines or bridges with frequency limitations.
>
> Signed-off-by: Tomasz Stanislawski <t.stanislaws at samsung.com>
> ---
>  .../devicetree/bindings/video/exynos_hdmi.txt      |    4 ++++
>  drivers/gpu/drm/exynos/exynos_hdmi.c               |   12 ++++++++++++
>  include/media/s5p_hdmi.h                           |    1 +
>  3 files changed, 17 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/video/exynos_hdmi.txt b/Documentation/devicetree/bindings/video/exynos_hdmi.txt
> index f9187a2..8718f8d 100644
> --- a/Documentation/devicetree/bindings/video/exynos_hdmi.txt
> +++ b/Documentation/devicetree/bindings/video/exynos_hdmi.txt
> @@ -28,6 +28,10 @@ Required properties:
>  - ddc: phandle to the hdmi ddc node
>  - phy: phandle to the hdmi phy node
>
> +Optional properties:
> +- max-pixel-clock: used to limit the maximal pixel clock if a board has lines,
> +       connectors or bridges not capable of carring higher frequencies
> +
>  Example:
>
>         hdmi {
> diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
> index 2a18f4e..404f1b7 100644
> --- a/drivers/gpu/drm/exynos/exynos_hdmi.c
> +++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
> @@ -195,6 +195,7 @@ struct hdmi_context {
>         struct hdmi_resources           res;
>
>         int                             hpd_gpio;
> +       u32                             max_pixel_clock;
>
>         enum hdmi_type                  type;
>  };
> @@ -887,6 +888,9 @@ static int hdmi_mode_valid(struct drm_connector *connector,
>         if (ret)
>                 return MODE_BAD;
>
> +       if (mode->clock * 1000 > hdata->max_pixel_clock)
> +               return MODE_BAD;
> +
>         ret = hdmi_find_phy_conf(hdata, mode->clock * 1000);
>         if (ret < 0)
>                 return MODE_BAD;
> @@ -2031,6 +2035,8 @@ static struct s5p_hdmi_platform_data *drm_hdmi_dt_parse_pdata
>                 return NULL;
>         }
>
> +       of_property_read_u32(np, "max-pixel-clock", &pd->max_pixel_clock);
> +
>         return pd;
>  }
>
> @@ -2067,6 +2073,11 @@ static int hdmi_probe(struct platform_device *pdev)
>         if (!pdata)
>                 return -EINVAL;
>
> +       if (!pdata->max_pixel_clock) {
> +               DRM_INFO("max-pixel-clock is zero, using INF\n");
> +               pdata->max_pixel_clock = U32_MAX;
> +       }
> +
>         hdata = devm_kzalloc(dev, sizeof(struct hdmi_context), GFP_KERNEL);
>         if (!hdata)
>                 return -ENOMEM;
> @@ -2083,6 +2094,7 @@ static int hdmi_probe(struct platform_device *pdev)
>         hdata->type = drv_data->type;
>
>         hdata->hpd_gpio = pdata->hpd_gpio;
> +       hdata->max_pixel_clock = pdata->max_pixel_clock;
>         hdata->dev = dev;
>
>         ret = hdmi_resources_init(hdata);
> diff --git a/include/media/s5p_hdmi.h b/include/media/s5p_hdmi.h
> index 181642b..7272d65 100644
> --- a/include/media/s5p_hdmi.h
> +++ b/include/media/s5p_hdmi.h
> @@ -31,6 +31,7 @@ struct s5p_hdmi_platform_data {
>         int mhl_bus;
>         struct i2c_board_info *mhl_info;
>         int hpd_gpio;
> +       u32 max_pixel_clock;
>  };

We have already removed Non DT support from the drm hdmi
driver. IMO we should not be extending the pdata struct.

Regards,
Rahul Sharma

>
>  #endif /* S5P_HDMI_H */
> --
> 1.7.9.5
>
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