[PATCH v13 04/18] drm: exynos: dsi: Switch to DSI panel or bridge find helper

[Marek Vasut]

On 2/27/23 20:15, Jagan Teki wrote:
> On Tue, Feb 28, 2023 at 12:38 AM Marek Vasut <marex at denx.de> wrote:
>>
>> On 2/27/23 20:01, Jagan Teki wrote:
>>> On Tue, Feb 28, 2023 at 12:25 AM Marek Vasut <marex at denx.de> wrote:
>>>>
>>>> On 2/27/23 12:39, Jagan Teki wrote:
>>>>> drm_of_dsi_find_panel_or_bridge is capable of looking up the
>>>>> downstream DSI bridge and panel and trying to add a panel bridge
>>>>> if the panel is found.
>>>>>
>>>>> Replace explicit finding calls with drm_of_dsi_find_panel_or_bridge
>>>>> followed with drmm_panel_bridge_add.
>>>>>
>>>>> Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
>>>>> ---
>>>>> Changes for v13, v12, v11:
>>>>> - none
>>>>> Changes for v10:
>>>>> - new patch
>>>>>
>>>>>     drivers/gpu/drm/exynos/exynos_drm_dsi.c | 25 +++++++++++++------------
>>>>>     1 file changed, 13 insertions(+), 12 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
>>>>> index df15501b1075..12a6dd987e8f 100644
>>>>> --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
>>>>> +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
>>>>> @@ -25,6 +25,7 @@
>>>>>     #include <drm/drm_atomic_helper.h>
>>>>>     #include <drm/drm_bridge.h>
>>>>>     #include <drm/drm_mipi_dsi.h>
>>>>> +#include <drm/drm_of.h>
>>>>>     #include <drm/drm_panel.h>
>>>>>     #include <drm/drm_print.h>
>>>>>     #include <drm/drm_probe_helper.h>
>>>>> @@ -1470,24 +1471,26 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
>>>>>         struct device *dev = dsi->dev;
>>>>>         struct drm_encoder *encoder = &dsi->encoder;
>>>>>         struct drm_device *drm = encoder->dev;
>>>>> +     struct drm_bridge *bridge;
>>>>>         struct drm_panel *panel;
>>>>>         int ret;
>>>>>
>>>>> -     panel = of_drm_find_panel(device->dev.of_node);
>>>>> -     if (!IS_ERR(panel)) {
>>>>> -             dsi->out_bridge = devm_drm_panel_bridge_add(dev, panel);
>>>>> -     } else {
>>>>> -             dsi->out_bridge = of_drm_find_bridge(device->dev.of_node);
>>>>> -             if (!dsi->out_bridge)
>>>>> -                     dsi->out_bridge = ERR_PTR(-EINVAL);
>>>>> -     }
>>>>
>>>> As far as I understand this from my conversation with Maxime (please put
>>>> him on CC of V15), the change here should instead perform the panel look
>>>> up NOT in exynos_dsi_host_attach() , but in exynos_dsi_bind() , i.e. in
>>>> the component_ops .bind callback . Here is an example of correct
>>>> implementation:
>>>>
>>>> https://cgit.freedesktop.org/drm-misc/tree/drivers/gpu/drm/vc4/vc4_dsi.c#n1805
>>>
>>> But, we don't have component_ops.bind for imx8m case, so where do we
>>> want to place the panel hook?
>>>
>>> Exynos drm drivers are component-based but, imx8mm is not.
>>
>> In 14/18 patch, the same should be added to generic_dsim_register_host()
>> , which is called from the driver .probe() callback, but that is OK.
>>
>> That's ^ is the iMX part.
> 
> Ohh. You mean, we need to find the panel hook separately in two places like
> - bind for exynos
> - probe for imx8mm

Yes

> If so? how can I find the drm_device pointer in the probe?

What for ? The panel lookup uses OF graph . Where do you need the 
drm_device in it ?