Hi Eric,
On Thu, 11 May 2017 11:31:28 -0700
Eric Anholt <eric@xxxxxxxxxx> wrote:
> This cuts 135 lines of boilerplate, at the cost of losing the
> filtering of get_modes() using atmel_hlcdc_dc_mode_valid(). The
> atomic check will still check that we don't set an invalid mode,
> though.
Nice.
>
> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx>
Acked-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxxxxxxxxx>
A few comments below (no need to address them, those are just minor
things that can be fixed later on, or things I'm not comfortable
with but cannot be addressed easily).
> ---
>
> This patch is just a proposal for atmel-hlcdc if you like it -- maybe
> you still want the filtering of get_modes(). I'm not sure from a
> userspace API perspective if we should really have the encoder (your
> CRTC's limits) filtering modes from a connector, but I'm also pretty
> sure it doesn't actually matter.
Actually I added this check because someone suggested it :-). I don't
think it's a real problem, and that should definitely be checked at the
CRTC level, not here.
>
> drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c | 163 ++---------------------
> 1 file changed, 14 insertions(+), 149 deletions(-)
>
> diff --git a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
> index 4b2cfbd0d43f..340ef962aa81 100644
> --- a/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
> +++ b/drivers/gpu/drm/atmel-hlcdc/atmel_hlcdc_output.c
> @@ -23,191 +23,56 @@
>
> #include <drm/drmP.h>
> #include <drm/drm_of.h>
> +#include <drm/drm_bridge.h>
>
> #include "atmel_hlcdc_dc.h"
>
> -/**
> - * Atmel HLCDC RGB connector structure
> - *
> - * This structure stores RGB slave device information.
> - *
> - * @connector: DRM connector
> - * @encoder: DRM encoder
> - * @dc: pointer to the atmel_hlcdc_dc structure
> - * @panel: panel connected on the RGB output
> - */
> -struct atmel_hlcdc_rgb_output {
> - struct drm_connector connector;
> - struct drm_encoder encoder;
> - struct atmel_hlcdc_dc *dc;
> - struct drm_panel *panel;
> -};
> -
> -static inline struct atmel_hlcdc_rgb_output *
> -drm_connector_to_atmel_hlcdc_rgb_output(struct drm_connector *connector)
> -{
> - return container_of(connector, struct atmel_hlcdc_rgb_output,
> - connector);
> -}
> -
> -static inline struct atmel_hlcdc_rgb_output *
> -drm_encoder_to_atmel_hlcdc_rgb_output(struct drm_encoder *encoder)
> -{
> - return container_of(encoder, struct atmel_hlcdc_rgb_output, encoder);
> -}
> -
> -static void atmel_hlcdc_rgb_encoder_enable(struct drm_encoder *encoder)
> -{
> - struct atmel_hlcdc_rgb_output *rgb =
> - drm_encoder_to_atmel_hlcdc_rgb_output(encoder);
> -
> - if (rgb->panel) {
> - drm_panel_prepare(rgb->panel);
> - drm_panel_enable(rgb->panel);
> - }
> -}
> -
> -static void atmel_hlcdc_rgb_encoder_disable(struct drm_encoder *encoder)
> -{
> - struct atmel_hlcdc_rgb_output *rgb =
> - drm_encoder_to_atmel_hlcdc_rgb_output(encoder);
> -
> - if (rgb->panel) {
> - drm_panel_disable(rgb->panel);
> - drm_panel_unprepare(rgb->panel);
> - }
> -}
> -
> -static const struct drm_encoder_helper_funcs atmel_hlcdc_panel_encoder_helper_funcs = {
> - .disable = atmel_hlcdc_rgb_encoder_disable,
> - .enable = atmel_hlcdc_rgb_encoder_enable,
> -};
> -
> static const struct drm_encoder_funcs atmel_hlcdc_panel_encoder_funcs = {
> .destroy = drm_encoder_cleanup,
> };
>
> -static int atmel_hlcdc_panel_get_modes(struct drm_connector *connector)
> -{
> - struct atmel_hlcdc_rgb_output *rgb =
> - drm_connector_to_atmel_hlcdc_rgb_output(connector);
> -
> - if (rgb->panel)
> - return rgb->panel->funcs->get_modes(rgb->panel);
> -
> - return 0;
> -}
> -
> -static int atmel_hlcdc_rgb_mode_valid(struct drm_connector *connector,
> - struct drm_display_mode *mode)
> -{
> - struct atmel_hlcdc_rgb_output *rgb =
> - drm_connector_to_atmel_hlcdc_rgb_output(connector);
> -
> - return atmel_hlcdc_dc_mode_valid(rgb->dc, mode);
> -}
> -
> -static const struct drm_connector_helper_funcs atmel_hlcdc_panel_connector_helper_funcs = {
> - .get_modes = atmel_hlcdc_panel_get_modes,
> - .mode_valid = atmel_hlcdc_rgb_mode_valid,
> -};
> -
> -static enum drm_connector_status
> -atmel_hlcdc_panel_connector_detect(struct drm_connector *connector, bool force)
> -{
> - struct atmel_hlcdc_rgb_output *rgb =
> - drm_connector_to_atmel_hlcdc_rgb_output(connector);
> -
> - if (rgb->panel)
> - return connector_status_connected;
> -
> - return connector_status_disconnected;
> -}
> -
> -static void
> -atmel_hlcdc_panel_connector_destroy(struct drm_connector *connector)
> -{
> - struct atmel_hlcdc_rgb_output *rgb =
> - drm_connector_to_atmel_hlcdc_rgb_output(connector);
> -
> - if (rgb->panel)
> - drm_panel_detach(rgb->panel);
> -
> - drm_connector_cleanup(connector);
> -}
> -
> -static const struct drm_connector_funcs atmel_hlcdc_panel_connector_funcs = {
> - .dpms = drm_atomic_helper_connector_dpms,
> - .detect = atmel_hlcdc_panel_connector_detect,
> - .fill_modes = drm_helper_probe_single_connector_modes,
> - .destroy = atmel_hlcdc_panel_connector_destroy,
> - .reset = drm_atomic_helper_connector_reset,
> - .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
> - .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> -};
> -
> static int atmel_hlcdc_attach_endpoint(struct drm_device *dev,
> const struct device_node *np)
> {
> - struct atmel_hlcdc_dc *dc = dev->dev_private;
> - struct atmel_hlcdc_rgb_output *output;
> + struct drm_encoder *encoder;
> struct drm_panel *panel;
> struct drm_bridge *bridge;
> int ret;
>
> - output = devm_kzalloc(dev->dev, sizeof(*output), GFP_KERNEL);
> - if (!output)
> + encoder = devm_kzalloc(dev->dev, sizeof(*encoder), GFP_KERNEL);
> + if (!encoder)
> return -EINVAL;
>
> - output->dc = dc;
> -
> - drm_encoder_helper_add(&output->encoder,
> - &atmel_hlcdc_panel_encoder_helper_funcs);
> - ret = drm_encoder_init(dev, &output->encoder,
> + ret = drm_encoder_init(dev, encoder,
> &atmel_hlcdc_panel_encoder_funcs,
atmel_hlcdc_panel_encoder_funcs should probably be renamed
atmel_hlcdc_dpi_encoder_funcs, but it's just a detail.
> DRM_MODE_ENCODER_NONE, NULL);
> if (ret)
> return ret;
>
> - output->encoder.possible_crtcs = 0x1;
> + encoder->possible_crtcs = 0x1;
>
> ret = drm_of_find_panel_or_bridge(np, 0, 0, &panel, &bridge);
> if (ret)
> return ret;
>
> if (panel) {
> - output->connector.dpms = DRM_MODE_DPMS_OFF;
> - output->connector.polled = DRM_CONNECTOR_POLL_CONNECT;
> - drm_connector_helper_add(&output->connector,
> - &atmel_hlcdc_panel_connector_helper_funcs);
> - ret = drm_connector_init(dev, &output->connector,
> - &atmel_hlcdc_panel_connector_funcs,
> - DRM_MODE_CONNECTOR_Unknown);
> - if (ret)
> - goto err_encoder_cleanup;
> -
> - drm_mode_connector_attach_encoder(&output->connector,
> - &output->encoder);
> -
> - ret = drm_panel_attach(panel, &output->connector);
> - if (ret) {
> - drm_connector_cleanup(&output->connector);
> - goto err_encoder_cleanup;
> - }
> -
> - output->panel = panel;
> + bridge = drm_panel_bridge_add(panel, DRM_MODE_CONNECTOR_Unknown);
> + if (IS_ERR(bridge))
> + return PTR_ERR(bridge);
It would even be simpler if panels were directly registering
themselves to the bridge infrastructure so that they can be found with
drm_of_find_bridge() and we don't have to explicitly create this
bride->panel wrapper, but I remember that Thierry was not a big fan of
this idea.
Also, I keep thinking that we're abusing objects. A bridge is supposed
to convert a pixel stream in a given format/encoding into a different
format/encoding. Here, there's no conversion taking place in this
panel_bridge, it's just a way to expose the panel as a generic element
that can be easily connected to many display controller drivers.
To be perfectly clear, I really like this idea of providing a generic
wrapper, I'm just unsure exposing this wrapper as a bridge is such a
good idea, unless we clarify the meaning/goal of a 'drm_bridge' object.
The more I look at it, the more I think the drm_bridge is turning into a
generic element that is taking a stream of pixel in a specific format
and either consuming it of transforming it before forwarding it to the
next element in the chain.
Regards,
Boris
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