Re: [PATCH v4 3/8] drm/bridge/synopsys: dsi: add ability to have glue-specific attach and detach
From: Andrzej Hajda <hidden>
Date: 2018-08-20 10:34:37
Also in:
dri-devel, linux-rockchip
On 14.08.2018 12:26, Heiko Stuebner wrote:
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.Sometimes I have an impression that core/glue driver architecture with callbacks to glue drivers is quite complicated, and smells mid-layer mistake :), I wonder if simple bunch of helpers with some base object wouldn't be better, but this is subject for other discussion.
quoted hunk
Suggested-by: Andrzej Hajda <redacted> Signed-off-by: Heiko Stuebner <heiko@sntech.de> --- 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;
It could be replaced by: return pdata->host_ops->attach(pdata->priv_data, device); But no strong feelings. With or without the change: Reviewed-by: Andrzej Hajda <redacted> -- Regards Andrzej
quoted hunk
+ } + 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; };
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