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Message-ID: <3406999.krX5sgqVKE@diego>
Date: Fri, 18 Sep 2020 16:15:16 +0200
From: Heiko Stuebner <heiko.stuebner@...obroma-systems.com>
To: Andrzej Hajda <a.hajda@...sung.com>,
Neil Armstrong <narmstrong@...libre.com>,
Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
Jonas Karlman <jonas@...boo.se>,
Jernej Skrabec <jernej.skrabec@...l.net>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Philippe Cornu <philippe.cornu@...com>,
Antonio Borneo <antonio.borneo@...com>,
Yannick Fertre <yannick.fertre@...com>,
Angelo Ribeiro <Angelo.Ribeiro@...opsys.com>,
Markus Elfring <elfring@...rs.sourceforge.net>,
dri-devel@...ts.freedesktop.org, linux-kernel@...r.kernel.org,
Yannick Fertre <yannick.fertre@...com>
Subject: Re: [PATCH] drm/bridge/synopsys: dsi: fix initialization sequence
Am Freitag, 18. September 2020, 13:46:53 CEST schrieb Yannick Fertre:
> The current driver calls drm_bridge_add(), to add the dsi bridge
> to the global bridge list, in dw_mipi_dsi_host_attach().
> Thus, it relies on the probing of panel or bridge sub-nodes to
> trigger the execution of dsi host attach() that will, in turn,
> call dw_mipi_dsi_host_attach().
> This causes an incomplete driver initialization if the panel or
> the next bridge is not present as sub-node, e.g. because it is an
> i2c device, thus sub-node of the respective i2c controller.
Actually the drm_of_find_panel_or_bridge() works on of-graph nodes,
so having an remote-port pointing to the i2c/spi/whatever driver
should just work - and no need for the driver to be a subnode itself.
And while my memory is fuzzy, I think I remember Andrzej requesting
only registering the bridge once we know something is connected,
aka when it calls dsi_attach.
Heiko
>
> Move the relevant code from host attach() to probe(), and the
> corresponding code from detach() to remove().
>
> Signed-off-by: Antonio Borneo <antonio.borneo@...com>
> Signed-off-by: Yannick Fertre <yannick.fertre@...com>
> ---
> drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c | 73 ++++++++++++-------
> 1 file changed, 48 insertions(+), 25 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> index 6b268f9445b3..aa74abddc79f 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-mipi-dsi.c
> @@ -314,9 +314,7 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
> {
> 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;
> + int ret = -ENODEV;
>
> if (device->lanes > dsi->plat_data->max_data_lanes) {
> dev_err(dsi->dev, "the number of data lanes(%u) is too many\n",
> @@ -329,22 +327,6 @@ static int dw_mipi_dsi_host_attach(struct mipi_dsi_host *host,
> dsi->format = device->format;
> dsi->mode_flags = device->mode_flags;
>
> - ret = drm_of_find_panel_or_bridge(host->dev->of_node, 1, 0,
> - &panel, &bridge);
> - if (ret)
> - return ret;
> -
> - if (panel) {
> - bridge = drm_panel_bridge_add_typed(panel,
> - DRM_MODE_CONNECTOR_DSI);
> - if (IS_ERR(bridge))
> - return PTR_ERR(bridge);
> - }
> -
> - dsi->panel_bridge = bridge;
> -
> - 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)
> @@ -367,10 +349,6 @@ static int dw_mipi_dsi_host_detach(struct mipi_dsi_host *host,
> return ret;
> }
>
> - drm_of_panel_bridge_remove(host->dev->of_node, 1, 0);
> -
> - drm_bridge_remove(&dsi->bridge);
> -
> return 0;
> }
>
> @@ -1105,6 +1083,9 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
> struct device *dev = &pdev->dev;
> struct reset_control *apb_rst;
> struct dw_mipi_dsi *dsi;
> + struct drm_bridge *bridge;
> + struct drm_panel *panel;
> + int i, nb_endpoints;
> int ret;
>
> dsi = devm_kzalloc(dev, sizeof(*dsi), GFP_KERNEL);
> @@ -1172,8 +1153,7 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
> ret = mipi_dsi_host_register(&dsi->dsi_host);
> if (ret) {
> dev_err(dev, "Failed to register MIPI host: %d\n", ret);
> - dw_mipi_dsi_debugfs_remove(dsi);
> - return ERR_PTR(ret);
> + goto err_pmr_enable;
> }
>
> dsi->bridge.driver_private = dsi;
> @@ -1182,11 +1162,54 @@ __dw_mipi_dsi_probe(struct platform_device *pdev,
> dsi->bridge.of_node = pdev->dev.of_node;
> #endif
>
> + /* Get number of endpoints */
> + nb_endpoints = of_graph_get_endpoint_count(pdev->dev.of_node);
> + if (!nb_endpoints) {
> + ret = -ENODEV;
> + goto err_host_reg;
> + }
> +
> + for (i = 1; i < nb_endpoints; i++) {
> + ret = drm_of_find_panel_or_bridge(pdev->dev.of_node, i, 0,
> + &panel, &bridge);
> + if (!ret)
> + break;
> + else if (ret == -EPROBE_DEFER)
> + goto err_host_reg;
> + }
> +
> + /* check if an error is returned >> no panel or bridge detected */
> + if (ret)
> + goto err_host_reg;
> +
> + if (panel) {
> + bridge = drm_panel_bridge_add_typed(panel, DRM_MODE_CONNECTOR_DSI);
> + if (IS_ERR(bridge)) {
> + ret = PTR_ERR(bridge);
> + goto err_host_reg;
> + }
> + }
> +
> + dsi->panel_bridge = bridge;
> +
> + drm_bridge_add(&dsi->bridge);
> +
> return dsi;
> +
> +err_host_reg:
> + mipi_dsi_host_unregister(&dsi->dsi_host);
> +
> +err_pmr_enable:
> + pm_runtime_disable(dev);
> + dw_mipi_dsi_debugfs_remove(dsi);
> +
> + return ERR_PTR(ret);
> }
>
> static void __dw_mipi_dsi_remove(struct dw_mipi_dsi *dsi)
> {
> + drm_bridge_remove(&dsi->bridge);
> + drm_panel_bridge_remove(dsi->panel_bridge);
> mipi_dsi_host_unregister(&dsi->dsi_host);
>
> pm_runtime_disable(dsi->dev);
>
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