Thread (1 message) 1 message, 1 author, 2018-08-14
DORMANTno replies

[PATCH v4 3/8] drm/bridge/synopsys: dsi: add ability to have glue-specific attach and detach

From: Heiko Stuebner <hidden>
Date: 2018-08-14 10:26:49
Also in: dri-devel, linux-rockchip
Subsystem: drm drivers, drm drivers and misc gpu patches, drm drivers for bridge chips, the rest · Maintainers: David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Andrzej Hajda, Neil Armstrong, Robert Foss, Linus Torvalds

Possibly related (same subject, not in this thread)

With the regular means of adding the dsi-component in probe it creates
a race condition with the panel probing, as the panel device only gets
created after the dsi-bus got created.

When the panel-driver is build as a module it currently fails hard as the
panel cannot be probed directly:

dw_mipi_dsi_bind()
  __dw_mipi_dsi_probe()
    creates dsi bus
    creates panel device
    triggers panel module load
    panel not probed (module not loaded or panel probe slow)
  drm_bridge_attach
    fails with -EINVAL due to empty panel_bridge

Additionally the panel probing can run concurrently with dsi bringup
making it possible that the panel can already be found but dsi-attach
hasn't finished running.

To solve that cleanly we may want to only create the component after
the panel has finished probing, by calling component_add from the
host-attach dsi callback.

As that is specific to glue drivers, add a new struct for host_ops
so that glue drivers can tell the bridge to call specific functions
after the common host-attach and before the common host-detach run.

Suggested-by: Andrzej Hajda <redacted>
Signed-off-by: Heiko Stuebner <redacted>
---
 drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 15 +++++++++++++++
 include/drm/bridge/dw_mipi_dsi.h              |  8 ++++++++
 2 files changed, 23 insertions(+)
diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
index bb4aeca5c0f9..3962e5d84e1e 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
@@ -270,6 +270,7 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
 				   struct mipi_dsi_device *device)
 {
 	struct dw_mipi_dsi *dsi = host_to_dsi(host);
+	const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
 	struct drm_bridge *bridge;
 	struct drm_panel *panel;
 	int ret;
@@ -300,6 +301,12 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
 
 	drm_bridge_add(&dsi->bridge);
 
+	if (pdata->host_ops && pdata->host_ops->attach) {
+		ret = pdata->host_ops->attach(pdata->priv_data, device);
+		if (ret < 0)
+			return ret;
+	}
+
 	return 0;
 }
 
@@ -307,6 +314,14 @@ static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
 				   struct mipi_dsi_device *device)
 {
 	struct dw_mipi_dsi *dsi = host_to_dsi(host);
+	const struct dw_mipi_dsi_plat_data *pdata = dsi->plat_data;
+	int ret;
+
+	if (pdata->host_ops && pdata->host_ops->detach) {
+		ret = pdata->host_ops->detach(pdata->priv_data, device);
+		if (ret < 0)
+			return ret;
+	}
 
 	drm_of_panel_bridge_remove(host->dev->of_node, 1, 0);
 
diff --git a/include/drm/bridge/dw_mipi_dsi.h b/include/drm/bridge/dw_mipi_dsi.h
index 6d7f8eb5d9f2..a9c03099cf3e 100644
--- a/include/drm/bridge/dw_mipi_dsi.h
+++ b/include/drm/bridge/dw_mipi_dsi.h
@@ -19,6 +19,13 @@ struct dw_mipi_dsi_phy_ops {
 			     unsigned int *lane_mbps);
 };
 
+struct dw_mipi_dsi_host_ops {
+	int (*attach)(void *priv_data,
+		      struct mipi_dsi_device *dsi);
+	int (*detach)(void *priv_data,
+		      struct mipi_dsi_device *dsi);
+};
+
 struct dw_mipi_dsi_plat_data {
 	void __iomem *base;
 	unsigned int max_data_lanes;
@@ -27,6 +34,7 @@ struct dw_mipi_dsi_plat_data {
 					   const struct drm_display_mode *mode);
 
 	const struct dw_mipi_dsi_phy_ops *phy_ops;
+	const struct dw_mipi_dsi_host_ops *host_ops;
 
 	void *priv_data;
 };
-- 
2.17.0
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