[PATCH v5 3/7] drm: sun4i: dsi: Convert to bridge driver
Jagan Teki
jagan at amarulasolutions.com
Tue Nov 23 10:32:47 PST 2021
Hi Maxime,
On Mon, Nov 22, 2021 at 7:49 PM Jagan Teki <jagan at amarulasolutions.com> wrote:
>
> Hi Maxime,
>
> On Mon, Nov 22, 2021 at 7:35 PM Maxime Ripard <maxime at cerno.tech> wrote:
> >
> > On Mon, Nov 22, 2021 at 07:18:13PM +0530, Jagan Teki wrote:
> > > Hi Maxime,
> > >
> > > On Mon, Nov 22, 2021 at 3:37 PM Maxime Ripard <maxime at cerno.tech> 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...
> > >
> > > Sorry, which bridge API do you mean?
> >
> > Any variant of of_drm_find_bridge, and drm_bridge_attach. Just like
> > we're doing in sun4i_rgb.c
>
> Yes, we have drm_bridge_attach in bind and bridge_function.attach
> calls in this patch and of_drm_find_bridge in sun6i_mipi_dsi_attach.
> Not sure which API's I've missed.
>
> >
> > > > > 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?
> > >
> > > Idea of this series is to convert the driver to bridge and use the
> > > latest bridge function from the v1 series.
> >
> > Ok, but it's not at all what you mention in your commit log? You don't
> > need any of that in order to support a bridge downstream.
>
> I've mentioned "Converting to bridge driver" and thought it has
> meaning of converting encoder related function to bridge functions as
> well. Not think about specific description to describe on commit
> message. Will update this.
>
> >
> > > >
> > > > > 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.
> > >
> > > If we use bridge_functions we need to take atomic functions as
> > > precedence as the next bridge functions might convert atomic calls.
> >
> > We've had this discussion over and over again, but this is something
> > that needs to be documented and / or in your commit log.
> >
> > You must not deviate from the standard (and expected) behavior without
> > any kind of justification.
>
> Not exactly sure about what you mean, sorry. All these atomic bridge
> functions are already documented if I'm not wrong and Laurent have
> patches to switch the normal functions to atomic. Not sure what else
> need to document here and need justification for it if the driver is
> converting to bridge.
>
> >
> > > >
> > > > > /*
> > > > > * 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?
> > >
> > > I2C interface DSI bridges will register DSI host on the bridge
> > > drivers.
> >
> > DSI bridges don't register a DSI host.
>
> Please check what I mean here,
> https://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git/tree/drivers/gpu/drm/bridge/ti-sn65dsi83.c#n623
>
> I've tested it anyway, if you have any relevant one please check as well.
>
> >
> > > Those can be found using host->dev->of_node and cannot be find using
> > > device->dev.of_node
> > >
> > > >
> > > > > + 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
> > >
> > > I'm aware of this and this would break the existing sunxi dsi binding,
> > > we are not using ports based pipeline in dsi node. Of-course you have
> > > pointed the same before, please check below
> > > https://patchwork.kernel.org/project/dri-devel/patch/20210322140152.101709-2-jagan@amarulasolutions.com/
> >
> > Then drm_of_find_panel_or_bridge needs to be adjusted to handle the DSI
> > bindings and look for a panel or bridge not only through the OF graph,
> > but also on the child nodes
>
> Okay. I need to check this.
devm_drm_of_get_bridge is not working with legacy binding like the one
used in sun6i dsi
https://patchwork.kernel.org/project/dri-devel/patch/20211122065223.88059-6-jagan@amarulasolutions.com/
dsi->next_bridge = devm_drm_of_get_bridge(dsi->dev, dsi->dev->of_node, 0, 0);
if (IS_ERR(dsi->next_bridge))
return PTR_ERR(dsi->next_bridge);
It is only working if we have ports on the pipeline, something like this
https://patchwork.kernel.org/project/dri-devel/patch/20210214194102.126146-8-jagan@amarulasolutions.com/
Please have a look and let me know if I miss anything?
Jagan.
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