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

[Rahul Sharma]

On 15 April 2014 18:41, Tomasz Stanislawski <t.stanislaws at samsung.com> wrote:
> On 04/15/2014 11:42 AM, Rahul Sharma wrote:
>> 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
>
> Hi Rahul,
>
> This is not a non-DT patch. The s5p_hdmi_platform_data is
> generated from DT itself. This structure is just
> a parsed version of DT attributes.
>
> It may be a good idea to rename s5p_hdmi_platform_data
> to exynos_hdmi_pdata and move it to exynos_hdmi_drm.c file
> or parse DT directly in probe function.
>
> I can prepare a patch for that.

Else we can completely remove the dependency from
s5p_hdmi_platform_data. We can directly assign to hdmi context
variables. Later we can remove that struct itself from include/.
What you say?

Regards,
Rahul Sharma

>
> Regards,
> Tomasz Stanislawski
>
>
>>
>>>
>>>  #endif /* S5P_HDMI_H */
>>> --
>>> 1.7.9.5
>>>
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>>> dri-devel at lists.freedesktop.org
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>