[PATCH v5 3/7] drm: sun4i: dsi: Convert to bridge driver
Laurent Pinchart
laurent.pinchart at ideasonboard.com
Mon Nov 22 04:45:19 PST 2021
Hi Maxime,
On Mon, Nov 22, 2021 at 11:07:12AM +0100, Maxime Ripard wrote:
> On Mon, Nov 22, 2021 at 12:22:19PM +0530, Jagan Teki wrote:
> > Some display panels would come up with a non-DSI output, those
> > can have an option to connect the DSI host by means of interface
> > bridge converter.
> >
> > This DSI to non-DSI interface bridge converter would requires
> > DSI Host to handle drm bridge functionalities in order to DSI
> > Host to Interface bridge.
>
> In order to do this you would need to use the DRM bridge API...
>
> > This patch convert the existing to a drm bridge driver with a
> > built-in encoder support for compatibility with existing
> > component drivers.
>
> ... but changing the encoder driver to a bridge is completely
> unnecessary to do so. Why did you need to make that change?
>
> > Signed-off-by: Jagan Teki <jagan at amarulasolutions.com>
> >
> > ---
> > Changes for v5:
> > - add atomic APIs
> > - find host and device variant DSI devices.
> > Changes for v4, v3:
> > - none
> >
> > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c | 112 ++++++++++++++++++++-----
> > drivers/gpu/drm/sun4i/sun6i_mipi_dsi.h | 7 ++
> > 2 files changed, 96 insertions(+), 23 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > index 43d9c9e5198d..a6a272b55f77 100644
> > --- a/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > +++ b/drivers/gpu/drm/sun4i/sun6i_mipi_dsi.c
> > @@ -21,6 +21,7 @@
> >
> > #include <drm/drm_atomic_helper.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>
> > @@ -713,10 +714,11 @@ static int sun6i_dsi_start(struct sun6i_dsi *dsi,
> > return 0;
> > }
> >
> > -static void sun6i_dsi_encoder_enable(struct drm_encoder *encoder)
> > +static void sun6i_dsi_bridge_atomic_enable(struct drm_bridge *bridge,
> > + struct drm_bridge_state *old_bridge_state)
> > {
> > - struct drm_display_mode *mode = &encoder->crtc->state->adjusted_mode;
> > - struct sun6i_dsi *dsi = encoder_to_sun6i_dsi(encoder);
> > + struct sun6i_dsi *dsi = bridge_to_sun6i_dsi(bridge);
> > + struct drm_display_mode *mode = &bridge->encoder->crtc->state->adjusted_mode;
> > struct mipi_dsi_device *device = dsi->device;
> > union phy_configure_opts opts = { };
> > struct phy_configure_opts_mipi_dphy *cfg = &opts.mipi_dphy;
> > @@ -772,6 +774,9 @@ static void sun6i_dsi_encoder_enable(struct drm_encoder *encoder)
> > if (dsi->panel)
> > drm_panel_prepare(dsi->panel);
> >
> > + if (dsi->next_bridge)
> > + dsi->next_bridge->funcs->atomic_pre_enable(dsi->next_bridge, old_bridge_state);
> > +
>
> Please use the proper helpers.
I don't know about this series in particular, but overall we try to move
encoders to bridge drivers in order to standardize on a single API. The
drm_encoder can't be removed as it's exposed to userspace, so it then
becomes a dumb encoder, without any operation implemented.
> > /*
> > * FIXME: This should be moved after the switch to HS mode.
> > *
> > @@ -787,6 +792,9 @@ static void sun6i_dsi_encoder_enable(struct drm_encoder *encoder)
> > if (dsi->panel)
> > drm_panel_enable(dsi->panel);
> >
> > + if (dsi->next_bridge)
> > + dsi->next_bridge->funcs->atomic_enable(dsi->next_bridge, old_bridge_state);
> > +
>
> Ditto
>
> > sun6i_dsi_start(dsi, DSI_START_HSC);
> >
> > udelay(1000);
> > @@ -794,15 +802,19 @@ static void sun6i_dsi_encoder_enable(struct drm_encoder *encoder)
> > sun6i_dsi_start(dsi, DSI_START_HSD);
> > }
> >
> > -static void sun6i_dsi_encoder_disable(struct drm_encoder *encoder)
> > +static void sun6i_dsi_bridge_atomic_disable(struct drm_bridge *bridge,
> > + struct drm_bridge_state *old_bridge_state)
> > {
> > - struct sun6i_dsi *dsi = encoder_to_sun6i_dsi(encoder);
> > + struct sun6i_dsi *dsi = bridge_to_sun6i_dsi(bridge);
> >
> > DRM_DEBUG_DRIVER("Disabling DSI output\n");
> >
> > if (dsi->panel) {
> > drm_panel_disable(dsi->panel);
> > drm_panel_unprepare(dsi->panel);
> > + } else if (dsi->next_bridge) {
> > + dsi->next_bridge->funcs->atomic_disable(dsi->next_bridge, old_bridge_state);
> > + dsi->next_bridge->funcs->atomic_post_disable(dsi->next_bridge, old_bridge_state);
>
> Ditto
>
> > }
> >
> > phy_power_off(dsi->dphy);
> > @@ -842,9 +854,25 @@ static const struct drm_connector_funcs sun6i_dsi_connector_funcs = {
> > .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
> > };
> >
> > -static const struct drm_encoder_helper_funcs sun6i_dsi_enc_helper_funcs = {
> > - .disable = sun6i_dsi_encoder_disable,
> > - .enable = sun6i_dsi_encoder_enable,
> > +static int sun6i_dsi_bridge_attach(struct drm_bridge *bridge,
> > + enum drm_bridge_attach_flags flags)
> > +{
> > + struct sun6i_dsi *dsi = bridge_to_sun6i_dsi(bridge);
> > +
> > + if (dsi->next_bridge)
> > + return drm_bridge_attach(bridge->encoder, dsi->next_bridge,
> > + NULL, 0);
> > +
> > + return 0;
> > +}
> > +
> > +static const struct drm_bridge_funcs sun6i_dsi_bridge_funcs = {
> > + .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> > + .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> > + .atomic_reset = drm_atomic_helper_bridge_reset,
> > + .atomic_enable = sun6i_dsi_bridge_atomic_enable,
> > + .atomic_disable = sun6i_dsi_bridge_atomic_disable,
> > + .attach = sun6i_dsi_bridge_attach,
> > };
> >
> > static u32 sun6i_dsi_dcs_build_pkt_hdr(struct sun6i_dsi *dsi,
> > @@ -966,8 +994,6 @@ static int sun6i_dsi_bind(struct device *dev, struct device *master,
> > struct sun6i_dsi *dsi = dev_get_drvdata(dev);
> > int ret;
> >
> > - drm_encoder_helper_add(&dsi->encoder,
> > - &sun6i_dsi_enc_helper_funcs);
> > ret = drm_simple_encoder_init(drm, &dsi->encoder,
> > DRM_MODE_ENCODER_DSI);
> > if (ret) {
> > @@ -976,18 +1002,26 @@ static int sun6i_dsi_bind(struct device *dev, struct device *master,
> > }
> > dsi->encoder.possible_crtcs = BIT(0);
> >
> > - drm_connector_helper_add(&dsi->connector,
> > - &sun6i_dsi_connector_helper_funcs);
> > - ret = drm_connector_init(drm, &dsi->connector,
> > - &sun6i_dsi_connector_funcs,
> > - DRM_MODE_CONNECTOR_DSI);
> > + ret = drm_bridge_attach(&dsi->encoder, &dsi->bridge, NULL, 0);
> > if (ret) {
> > - dev_err(dsi->dev,
> > - "Couldn't initialise the DSI connector\n");
> > + dev_err(dsi->dev, "Couldn't attach drm bridge\n");
> > goto err_cleanup_connector;
> > }
> >
> > - drm_connector_attach_encoder(&dsi->connector, &dsi->encoder);
> > + if (dsi->panel) {
> > + drm_connector_helper_add(&dsi->connector,
> > + &sun6i_dsi_connector_helper_funcs);
> > + ret = drm_connector_init(drm, &dsi->connector,
> > + &sun6i_dsi_connector_funcs,
> > + DRM_MODE_CONNECTOR_DSI);
> > + if (ret) {
> > + dev_err(dsi->dev,
> > + "Couldn't initialise the DSI connector\n");
> > + goto err_cleanup_connector;
> > + }
> > +
> > + drm_connector_attach_encoder(&dsi->connector, &dsi->encoder);
> > + }
> >
> > return 0;
> >
> > @@ -1013,16 +1047,46 @@ static int sun6i_dsi_attach(struct mipi_dsi_host *host,
> > struct mipi_dsi_device *device)
> > {
> > struct sun6i_dsi *dsi = host_to_sun6i_dsi(host);
> > - struct drm_panel *panel = of_drm_find_panel(device->dev.of_node);
> > + struct device_node *remote = device->dev.of_node;
> > int ret;
> >
> > - if (IS_ERR(panel))
> > - return PTR_ERR(panel);
> > + if (!of_device_is_available(remote)) {
> > + /**
> > + * I2C interfaced DSI bridges will register DSI host on the
> > + * bridge drivers instead of conventional device.
> > + *
> > + * Those are probed via host of_node instead of device of_node.
> > + */
>
> I have no idea what you mean here. Can you expand on what issue you've
> tried to solve here?
>
> > + remote = of_graph_get_remote_node(host->dev->of_node, 0, 0);
> > + if (!remote)
> > + return -ENODEV;
> > + }
> > +
> > + dsi->panel = of_drm_find_panel(remote);
> > + if (IS_ERR(dsi->panel)) {
> > + dsi->panel = NULL;
> > +
> > + dsi->next_bridge = of_drm_find_bridge(remote);
> > + if (IS_ERR(dsi->next_bridge)) {
> > + dev_err(dsi->dev, "failed to find bridge\n");
> > + return PTR_ERR(dsi->next_bridge);
> > + }
> > + } else {
> > + dsi->next_bridge = NULL;
> > + }
> > +
> > + of_node_put(remote);
>
> Using devm_drm_of_get_bridge would greatly simplify the driver
>
> Maxime
--
Regards,
Laurent Pinchart
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