linux-kernel - [PATCH v4 24/24] drm/exynos: dsi: Adjust probe order

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Message-Id: <20210910101218.1632297-25-maxime@cerno.tech>
Date:   Fri, 10 Sep 2021 12:12:18 +0200
From:   Maxime Ripard <maxime@...no.tech>
To:     Andrzej Hajda <a.hajda@...sung.com>,
        Sam Ravnborg <sam@...nborg.org>,
        Daniel Vetter <daniel.vetter@...el.com>,
        David Airlie <airlied@...ux.ie>,
        Jonas Karlman <jonas@...boo.se>,
        Laurent Pinchart <Laurent.pinchart@...asonboard.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Maarten Lankhorst <maarten.lankhorst@...ux.intel.com>,
        Thomas Zimmermann <tzimmermann@...e.de>,
        Maxime Ripard <maxime@...no.tech>,
        Neil Armstrong <narmstrong@...libre.com>,
        Robert Foss <robert.foss@...aro.org>,
        Jernej Skrabec <jernej.skrabec@...il.com>
Cc:     Sean Paul <sean@...rly.run>, freedreno@...ts.freedesktop.org,
        Kyungmin Park <kyungmin.park@...sung.com>,
        linux-kernel@...r.kernel.org,
        Xinliang Liu <xinliang.liu@...aro.org>,
        Seung-Woo Kim <sw0312.kim@...sung.com>,
        Tian Tao <tiantao6@...ilicon.com>,
        Inki Dae <inki.dae@...sung.com>,
        linux-samsung-soc@...r.kernel.org, linux-arm-msm@...r.kernel.org,
        Rob Clark <robdclark@...il.com>,
        dri-devel@...ts.freedesktop.org,
        John Stultz <john.stultz@...aro.org>,
        Chen Feng <puck.chen@...ilicon.com>,
        Xinwei Kong <kong.kongxinwei@...ilicon.com>,
        Joonyoung Shim <jy0922.shim@...sung.com>
Subject: [PATCH v4 24/24] drm/exynos: dsi: Adjust probe order

Without proper care and an agreement between how DSI hosts and devices
drivers register their MIPI-DSI entities and potential components, we can
end up in a situation where the drivers can never probe.

Most drivers were taking evasive maneuvers to try to workaround this,
but not all of them were following the same conventions, resulting in
various incompatibilities between DSI hosts and devices.

Now that we have a sequence agreed upon and documented, let's convert
exynos to it.

Signed-off-by: Maxime Ripard <maxime@...no.tech>
---
 drivers/gpu/drm/exynos/exynos_drm_dsi.c | 19 ++++++++++++-------
 1 file changed, 12 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index e39fac889edc..dfda2b259c44 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -1529,6 +1529,7 @@ static const struct drm_encoder_helper_funcs exynos_dsi_encoder_helper_funcs = {
 
 MODULE_DEVICE_TABLE(of, exynos_dsi_of_match);
 
+static const struct component_ops exynos_dsi_component_ops;
 static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
 				  struct mipi_dsi_device *device)
 {
@@ -1536,6 +1537,7 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
 	struct drm_encoder *encoder = &dsi->encoder;
 	struct drm_device *drm = encoder->dev;
 	struct drm_bridge *out_bridge;
+	struct device *dev = host->dev;
 
 	out_bridge  = of_drm_find_bridge(device->dev.of_node);
 	if (out_bridge) {
@@ -1585,7 +1587,7 @@ static int exynos_dsi_host_attach(struct mipi_dsi_host *host,
 	if (drm->mode_config.poll_enabled)
 		drm_kms_helper_hotplug_event(drm);
 
-	return 0;
+	return component_add(dev, &exynos_dsi_component_ops);
 }
 
 static int exynos_dsi_host_detach(struct mipi_dsi_host *host,
@@ -1593,6 +1595,9 @@ 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;
+	struct device *dev = host->dev;
+
+	component_del(dev, &exynos_dsi_component_ops);
 
 	if (dsi->panel) {
 		mutex_lock(&drm->mode_config.mutex);
@@ -1716,7 +1721,7 @@ static int exynos_dsi_bind(struct device *dev, struct device *master,
 		of_node_put(in_bridge_node);
 	}
 
-	return mipi_dsi_host_register(&dsi->dsi_host);
+	return 0;
 }
 
 static void exynos_dsi_unbind(struct device *dev, struct device *master,
@@ -1726,8 +1731,6 @@ static void exynos_dsi_unbind(struct device *dev, struct device *master,
 	struct drm_encoder *encoder = &dsi->encoder;
 
 	exynos_dsi_disable(encoder);
-
-	mipi_dsi_host_unregister(&dsi->dsi_host);
 }
 
 static const struct component_ops exynos_dsi_component_ops = {
@@ -1821,7 +1824,7 @@ static int exynos_dsi_probe(struct platform_device *pdev)
 
 	pm_runtime_enable(dev);
 
-	ret = component_add(dev, &exynos_dsi_component_ops);
+	ret = mipi_dsi_host_register(&dsi->dsi_host);
 	if (ret)
 		goto err_disable_runtime;
 
@@ -1835,10 +1838,12 @@ static int exynos_dsi_probe(struct platform_device *pdev)
 
 static int exynos_dsi_remove(struct platform_device *pdev)
 {
+	struct exynos_dsi *dsi = platform_get_drvdata(pdev);
+
+	mipi_dsi_host_unregister(&dsi->dsi_host);
+
 	pm_runtime_disable(&pdev->dev);
 
-	component_del(&pdev->dev, &exynos_dsi_component_ops);
-
 	return 0;
 }
 
-- 
2.31.1