Den 11.08.2019 16.16, skrev Sam Ravnborg:
> Hi Noralf.
>
> I really like how this allows us to have a single file for all
> the uses of a driver IC.
> And this patch-set is much easier to grasp than the first RFC.
>
> General things:
>
> - The current design have a tight connection between the display
> controller and the panel. Will this hurt in the long run?
> In other words, should we try to add a panel_bridge in-between?
> For now I think this would just make something simple more
> complicated.
> So this note was to say - no I think we should not use panel_bridge.
>
I did look at panel_bridge but it didn't give me anything I needed, it
would only be a 1:1 passthrough layer.
> - drm_panel has proper support for modes.
> This is today duplicated in mipi_dbi.
> Could we make it so that when a panel is used then the panel
> has the mode info - as we then use the panel more in the way we do
> in other cases?
> As it is now the mode is specified in mipi_dbi_dev_init()
> The drm_connector would then, if a panel is used, ask the panel for
> the mode.
> I did not really think to the end of this, but it seems wrong that
> we introduce drm_panel and then keep modes in mipi_dbi.
>
I considered that, but it would would just generate duplicate code for
the connector. It would make sense to refactor this when/if all mipi dbi
drivers are turned into panel drivers.
> - For backlight support please move this to drm_panel.
> I have patches that makes it simple to use backlight with drm_panel,
> and this will then benefit from it.
> The drm_panel backlight supports requires that a backlight
> phandle is specified in the DT node of the panel.
>
I can fix that when I respin if those patches have landed by then.
> Some more specific comments in the following.
>
> Sam
>
> On Thu, Aug 01, 2019 at 03:52:46PM +0200, Noralf Trønnes wrote:
>> This adds a function that registers a DRM driver for use with MIPI DBI
>> panels in command mode. That is, framebuffer upload over DBI.
>>
>> Signed-off-by: Noralf Trønnes <noralf@xxxxxxxxxxx>
>> ---
>> drivers/gpu/drm/drm_mipi_dbi.c | 92 ++++++++++++++++++++++++++++++++++
>> include/drm/drm_mipi_dbi.h | 34 +++++++++++++
>> 2 files changed, 126 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_mipi_dbi.c b/drivers/gpu/drm/drm_mipi_dbi.c
>> index 1961f713aaab..797a20e3a017 100644
>> --- a/drivers/gpu/drm/drm_mipi_dbi.c
>> +++ b/drivers/gpu/drm/drm_mipi_dbi.c
>> @@ -17,11 +17,13 @@
>> #include <drm/drm_damage_helper.h>
>> #include <drm/drm_drv.h>
>> #include <drm/drm_gem_cma_helper.h>
>> +#include <drm/drm_fb_helper.h>
>> #include <drm/drm_format_helper.h>
>> #include <drm/drm_fourcc.h>
>> #include <drm/drm_gem_framebuffer_helper.h>
>> #include <drm/drm_mipi_dbi.h>
>> #include <drm/drm_modes.h>
>> +#include <drm/drm_panel.h>
>> #include <drm/drm_probe_helper.h>
>> #include <drm/drm_rect.h>
>> #include <drm/drm_vblank.h>
>> @@ -597,6 +599,96 @@ void mipi_dbi_release(struct drm_device *drm)
>> }
>> EXPORT_SYMBOL(mipi_dbi_release);
>>
>> +static void drm_mipi_dbi_panel_pipe_enable(struct drm_simple_display_pipe *pipe,
>> + struct drm_crtc_state *crtc_state,
>> + struct drm_plane_state *plane_state)
>> +{
>> + struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
>> + struct drm_panel *panel = dbidev->panel;
>> + int ret, idx;
>> +
>> + if (!drm_dev_enter(pipe->crtc.dev, &idx))
>> + return;
>> +
>> + DRM_DEBUG_KMS("\n");
> Still usefull?
>
No I think this can go (it was in the code I copied from the driver).
>> +
>> + ret = drm_panel_prepare(panel);
>> + if (ret)
>> + goto out_exit;
>> +
>> + mipi_dbi_enable_flush(dbidev, crtc_state, plane_state);
>> +
>> + drm_panel_enable(panel);
>> +out_exit:
> nit - blank line above label?
>
>> + drm_dev_exit(idx);
>> +}
>> +
>> +static void drm_mipi_dbi_panel_pipe_disable(struct drm_simple_display_pipe *pipe)
>> +{
>> + struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(pipe->crtc.dev);
>> + struct drm_panel *panel = dbidev->panel;
>> +
>> + if (!dbidev->enabled)
>> + return;
>> +
>> + DRM_DEBUG_KMS("\n");
> Still usefull?
>> +
>> + dbidev->enabled = false;
>> + drm_panel_disable(panel);
>> + drm_panel_unprepare(panel);
>> +}
>> +
>> +static const struct drm_simple_display_pipe_funcs drm_mipi_dbi_pipe_funcs = {
>> + .enable = drm_mipi_dbi_panel_pipe_enable,
>> + .disable = drm_mipi_dbi_panel_pipe_disable,
>> + .update = mipi_dbi_pipe_update,
>> + .prepare_fb = drm_gem_fb_simple_display_pipe_prepare_fb,
>> +};
>> +
>> +/**
>> + * drm_mipi_dbi_panel_register - Register a MIPI DBI DRM driver
>> + * @panel: DRM Panel
>> + * @dbidev: MIPI DBI device structure to initialize
>> + * @mode: Display mode
>> + *
>> + * This function registeres a DRM driver with @panel attached.
>> + *
>> + * Returns:
>> + * Zero on success, negative error code on failure.
>> + */
>> +int drm_mipi_dbi_panel_register(struct drm_panel *panel, struct mipi_dbi_dev *dbidev,
>> + struct drm_driver *driver, const struct drm_display_mode *mode,
>> + u32 rotation)
> Can we make this use enum drm_panel_orientation - so we can use
> of_drm_get_panel_orientation() in the callers?
> of_drm_get_panel_orientation() is not merged yet, but we could do so if
> this patch-set needs it.
>
> I know that this would require mipi_dbi_dev_init() and all users to be
> updated. But it is a simpler interface so worth it.
>
That would break rotation on userspace that doesn't know about the panel
orientation property which is a recent addition. These panels are mostly
used in the embedded world not desktop. It also would break fbdev 90/270
rotation (see drm_client_rotation()).
Noralf.
>> +{
>> + struct device *dev = panel->dev;
>> + struct drm_device *drm;
>> + int ret;
>> +
>> + dbidev->panel = panel;
>> +
>> + drm = &dbidev->drm;
>> + ret = devm_drm_dev_init(dev, drm, driver);
>> + if (ret) {
>> + kfree(dbidev);
>> + return ret;
>> + }
>> +
>> + drm_mode_config_init(drm);
>> +
>> + ret = mipi_dbi_dev_init(dbidev, &drm_mipi_dbi_pipe_funcs, mode, rotation);
>> +
>> + drm_mode_config_reset(drm);
>> +
>> + ret = drm_dev_register(drm, 0);
>> + if (ret)
>> + return ret;
>> +
>> + drm_fbdev_generic_setup(drm, 16);
>> +
>> + return 0;
>> +}
>> +EXPORT_SYMBOL(drm_mipi_dbi_panel_register);
>> +
>> /**
>> * mipi_dbi_hw_reset - Hardware reset of controller
>> * @dbi: MIPI DBI structure
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
