[PATCH v3 3/8] drm/bridge/synopsys: dsi: add ability to check dsi-device attachment
From: Heiko Stuebner <heiko@sntech.de>
Date: 2018-07-09 13:48:29
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
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.
The newly added function provides the ability for glue drivers to
check if a dsi device was actually attached and also protects
the attach part to prevent concurrency issues from panel-assignment
and drm_bridge_create.
Using that check glue drivers are able to for example defer probe/bind
in the case that the panel is not completely set up yet.
Signed-off-by: Heiko Stuebner <heiko@sntech.de>
---
drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 25 +++++++++++++++++++
include/drm/bridge/dw_mipi_dsi.h | 1 +
2 files changed, 26 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..88fed22ff3f6 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c@@ -12,6 +12,7 @@ #include <linux/component.h> #include <linux/iopoll.h> #include <linux/module.h> +#include <linux/mutex.h> #include <linux/of_device.h> #include <linux/pm_runtime.h> #include <linux/reset.h>
@@ -219,6 +220,7 @@ struct dw_mipi_dsi { struct drm_bridge bridge; struct mipi_dsi_host dsi_host; struct drm_bridge *panel_bridge; + struct mutex panel_mutex; struct device *dev; void __iomem *base;
@@ -296,10 +298,14 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host, return PTR_ERR(bridge); } + mutex_lock(&dsi->panel_mutex); + dsi->panel_bridge = bridge; drm_bridge_add(&dsi->bridge); + mutex_unlock(&dsi->panel_mutex); + return 0; }
@@ -308,13 +314,30 @@ static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host, { struct dw_mipi_dsi *dsi = host_to_dsi(host); + mutex_lock(&dsi->panel_mutex); + + dsi->panel_bridge = NULL; drm_of_panel_bridge_remove(host->dev->of_node, 1, 0); drm_bridge_remove(&dsi->bridge); + mutex_unlock(&dsi->panel_mutex); + return 0; } +bool dw_mipi_dsi_device_attached(struct dw_mipi_dsi *dsi) +{ + bool output; + + mutex_lock(&dsi->panel_mutex); + output = !!dsi->panel_bridge; + mutex_unlock(&dsi->panel_mutex); + + return output; +} +EXPORT_SYMBOL_GPL(dw_mipi_dsi_device_attached); + static void dw_mipi_message_config(struct dw_mipi_dsi *dsi, const struct mipi_dsi_msg *msg) {
@@ -867,6 +890,8 @@ __dw_mipi_dsi_probe(struct platform_device *pdev, dsi->dev = dev; dsi->plat_data = plat_data; + mutex_init(&dsi->panel_mutex); + if (!plat_data->phy_ops->init || !plat_data->phy_ops->get_lane_mbps) { DRM_ERROR("Phy not properly configured\n"); return ERR_PTR(-ENODEV);
diff --git a/include/drm/bridge/dw_mipi_dsi.h b/include/drm/bridge/dw_mipi_dsi.h
index 6d7f8eb5d9f2..131ff2569ed4 100644
--- a/include/drm/bridge/dw_mipi_dsi.h
+++ b/include/drm/bridge/dw_mipi_dsi.h@@ -31,6 +31,7 @@ struct dw_mipi_dsi_plat_data { void *priv_data; }; +bool dw_mipi_dsi_device_attached(struct dw_mipi_dsi *dsi); struct dw_mipi_dsi *dw_mipi_dsi_probe(struct platform_device *pdev, const struct dw_mipi_dsi_plat_data *plat_data);
--
2.17.0
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