Re: [PATCH v3 2/7] drm: exynos: dsi: Use drm panel_bridge API

On 12.12.2021 19:14, Jagan Teki wrote:

Replace the manual panel handling code by a drm panel_bridge via devm_drm_of_get_bridge().

Adding panel_bridge handling,

• Drops drm_connector and related operations as drm_bridge_attach creates connector during attachment.

• Drops panel pointer and iterate the bridge, so-that it can operate the normal bridge and panel_bridge in constitutive callbacks.

This simplifies the driver and allows all components in the display pipeline to be treated as bridges.

Signed-off-by: Jagan Teki jagan@amarulasolutions.com

Changes for v3:

• fix port number
• add print for attached device

Changes for v2:

• new patch

  drivers/gpu/drm/exynos/exynos_drm_dsi.c | 165 ++++-------------------- 1 file changed, 26 insertions(+), 139 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c index 0bb44e476633..d1039628b6f2 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c +++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c @@ -221,6 +221,11 @@ enum exynos_dsi_transfer_type { EXYNOS_DSI_RX, };

+enum {

• DSI_PORT_IN,
• DSI_PORT_OUT

+};

• struct exynos_dsi_transfer { struct list_head list; struct completion completed;

@@ -254,8 +259,6 @@ struct exynos_dsi_driver_data { struct exynos_dsi { struct drm_encoder encoder; struct mipi_dsi_host dsi_host;

• struct drm_connector connector;
• struct drm_panel *panel; struct list_head bridge_chain; struct drm_bridge *out_bridge; struct device *dev;

@@ -285,7 +288,6 @@ struct exynos_dsi { };

#define host_to_dsi(host) container_of(host, struct exynos_dsi, dsi_host) -#define connector_to_dsi(c) container_of(c, struct exynos_dsi, connector)

static inline struct exynos_dsi *encoder_to_dsi(struct drm_encoder *e) { @@ -1391,42 +1393,21 @@ static void exynos_dsi_enable(struct drm_encoder *encoder)

dsi->state |= DSIM_STATE_ENABLED;

• if (dsi->panel) {

• ret = drm_panel_prepare(dsi->panel);
  

• if (ret < 0)
  

• 	goto err_put_sync;
  

• } else {

• list_for_each_entry_reverse(iter, &dsi->bridge_chain,
  

• 			    chain_node) {
  

• 	if (iter->funcs->pre_enable)
  

• 		iter->funcs->pre_enable(iter);
  

• }
  

• list_for_each_entry_reverse(iter, &dsi->bridge_chain, chain_node) {

• if (iter->funcs->pre_enable)
  

• 	iter->funcs->pre_enable(iter);
  

  }

  exynos_dsi_set_display_mode(dsi); exynos_dsi_set_display_enable(dsi, true);

• if (dsi->panel) {

• ret = drm_panel_enable(dsi->panel);
  

• if (ret < 0)
  

• 	goto err_display_disable;
  

• } else {

• list_for_each_entry(iter, &dsi->bridge_chain, chain_node) {
  

• 	if (iter->funcs->enable)
  

• 		iter->funcs->enable(iter);
  

• }
  

• list_for_each_entry(iter, &dsi->bridge_chain, chain_node) {

• if (iter->funcs->enable)
  

• 	iter->funcs->enable(iter);
  

  }

  dsi->state |= DSIM_STATE_VIDOUT_AVAILABLE; return;

-err_display_disable:

• exynos_dsi_set_display_enable(dsi, false);
• drm_panel_unprepare(dsi->panel);

-err_put_sync:

• dsi->state &= ~DSIM_STATE_ENABLED;

• pm_runtime_put(dsi->dev); }

  static void exynos_dsi_disable(struct drm_encoder *encoder)

@@ -1439,17 +1420,12 @@ static void exynos_dsi_disable(struct drm_encoder *encoder)

dsi->state &= ~DSIM_STATE_VIDOUT_AVAILABLE;

• if (dsi->panel)

• drm_panel_disable(dsi->panel);
  

• list_for_each_entry_reverse(iter, &dsi->bridge_chain, chain_node) { if (iter->funcs->disable) iter->funcs->disable(iter); }

  exynos_dsi_set_display_enable(dsi, false);

• if (dsi->panel)

• drm_panel_unprepare(dsi->panel);
  
  

  list_for_each_entry(iter, &dsi->bridge_chain, chain_node) { if (iter->funcs->post_disable)

@@ -1460,70 +1436,6 @@ static void exynos_dsi_disable(struct drm_encoder *encoder) pm_runtime_put_sync(dsi->dev); }

-static enum drm_connector_status -exynos_dsi_detect(struct drm_connector *connector, bool force) -{

• return connector->status;

-}

-static void exynos_dsi_connector_destroy(struct drm_connector *connector) -{

• drm_connector_unregister(connector);
• drm_connector_cleanup(connector);
• connector->dev = NULL;

-}

-static const struct drm_connector_funcs exynos_dsi_connector_funcs = {

• .detect = exynos_dsi_detect,
• .fill_modes = drm_helper_probe_single_connector_modes,
• .destroy = exynos_dsi_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 exynos_dsi_get_modes(struct drm_connector *connector) -{

• struct exynos_dsi *dsi = connector_to_dsi(connector);
• if (dsi->panel)

• return drm_panel_get_modes(dsi->panel, connector);
  

• return 0;

-}

-static const struct drm_connector_helper_funcs exynos_dsi_connector_helper_funcs = {

• .get_modes = exynos_dsi_get_modes,

-};

-static int exynos_dsi_create_connector(struct drm_encoder *encoder) -{

• struct exynos_dsi *dsi = encoder_to_dsi(encoder);
• struct drm_connector *connector = &dsi->connector;
• struct drm_device *drm = encoder->dev;
• int ret;
• connector->polled = DRM_CONNECTOR_POLL_HPD;
• ret = drm_connector_init(drm, connector, &exynos_dsi_connector_funcs,

• 		 DRM_MODE_CONNECTOR_DSI);
  

• if (ret) {

• DRM_DEV_ERROR(dsi->dev,
  

• 	      "Failed to initialize connector with drm\n");
  

• return ret;
  

• }
• connector->status = connector_status_disconnected;
• drm_connector_helper_add(connector, &exynos_dsi_connector_helper_funcs);
• drm_connector_attach_encoder(connector, encoder);
• if (!drm->registered)

• return 0;
  

• connector->funcs->reset(connector);
• drm_connector_register(connector);
• return 0;

-}

• static const struct drm_encoder_helper_funcs exynos_dsi_encoder_helper_funcs = { .enable = exynos_dsi_enable, .disable = exynos_dsi_disable,

@@ -1537,31 +1449,20 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host, struct exynos_dsi *dsi = host_to_dsi(host); struct drm_encoder *encoder = &dsi->encoder; struct drm_device *drm = encoder->dev;

• struct drm_bridge *out_bridge;
• out_bridge = of_drm_find_bridge(device->dev.of_node);
• if (out_bridge) {

• drm_bridge_attach(encoder, out_bridge, NULL, 0);
  

• dsi->out_bridge = out_bridge;
  

• list_splice_init(&encoder->bridge_chain, &dsi->bridge_chain);
  

• } else {

• int ret = exynos_dsi_create_connector(encoder);
  

• if (ret) {
  

• 	DRM_DEV_ERROR(dsi->dev,
  

• 		      "failed to create connector ret = %d\n",
  

• 		      ret);
  

• 	drm_encoder_cleanup(encoder);
  

• 	return ret;
  

• }
  

• int ret;

• dsi->panel = of_drm_find_panel(device->dev.of_node);
  

• if (IS_ERR(dsi->panel))
  

• 	dsi->panel = NULL;
  

• else
  

• 	dsi->connector.status = connector_status_connected;
  

• dsi->out_bridge = devm_drm_of_get_bridge(dsi->dev, dsi->dev->of_node, DSI_PORT_OUT, 0);

• if (IS_ERR(dsi->out_bridge)) {

• ret = PTR_ERR(dsi->out_bridge);
  

• DRM_DEV_ERROR(dsi->dev, "failed to find the bridge: %d\n", ret);
  

• return ret;
  

  }

• DRM_DEV_INFO(dsi->dev, "Attached %s device\n", device->name);

• drm_bridge_attach(encoder, dsi->out_bridge, NULL, 0);

• list_splice_init(&encoder->bridge_chain, &dsi->bridge_chain);

• /*

  • This is a temporary solution and should be made by more generic way.

@@ -1569,7 +1470,7 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host, * TE interrupt handler. */ if (!(device->mode_flags & MIPI_DSI_MODE_VIDEO)) {

• int ret = exynos_dsi_register_te_irq(dsi, &device->dev);
  

• ret = exynos_dsi_register_te_irq(dsi, &device->dev);
  

  if (ret) return ret; }

@@ -1596,18 +1497,9 @@ static int exynos_dsi_host_detach(struct mipi_dsi_host *host, struct exynos_dsi *dsi = host_to_dsi(host); struct drm_device *drm = dsi->encoder.dev;

• if (dsi->panel) {

• mutex_lock(&drm->mode_config.mutex);
  

• exynos_dsi_disable(&dsi->encoder);
  

• dsi->panel = NULL;
  

• dsi->connector.status = connector_status_disconnected;
  

• mutex_unlock(&drm->mode_config.mutex);
  

• } else {

• if (dsi->out_bridge->funcs->detach)
  

• 	dsi->out_bridge->funcs->detach(dsi->out_bridge);
  

• dsi->out_bridge = NULL;
  

• INIT_LIST_HEAD(&dsi->bridge_chain);
  

• }

• if (dsi->out_bridge->funcs->detach)

• dsi->out_bridge->funcs->detach(dsi->out_bridge);
  

• INIT_LIST_HEAD(&dsi->bridge_chain);

This is fishy. Currently the only bridge used with exynos_dsi (tc358764) on detach callback unregisters/puts the connector it has created.

With this code panel_bridge on detach will call drm_connector_cleanup, which will WARN about unregistered connector - ie it assumes detach should be called at least AFTER unregistration of exynos_drm device (???).

Since panel/bridge unbind in general case is not handled properly maybe it is not an issue :)

Regards

Andrzej

if (drm->mode_config.poll_enabled) drm_kms_helper_hotplug_event(drm); @@ -1663,11 +1555,6 @@ static int exynos_dsi_of_read_u32(const struct device_node *np, return ret; }

-enum {

• DSI_PORT_IN,
• DSI_PORT_OUT

-};

• static int exynos_dsi_parse_dt(struct exynos_dsi *dsi) { struct device *dev = dsi->dev;