linux-kernel - [PATCH v4 23/24] drm/kirin: dsi: Adjust probe order

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Date:   Fri, 10 Sep 2021 12:12:17 +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 23/24] drm/kirin: 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
kirin to it.

Signed-off-by: Maxime Ripard <maxime@...no.tech>
---
 drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c | 27 +++++++++++++++-----
 1 file changed, 20 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
index 952cfdb1961d..be20c2ffe798 100644
--- a/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
+++ b/drivers/gpu/drm/hisilicon/kirin/dw_drm_dsi.c
@@ -720,10 +720,13 @@ static int dw_drm_encoder_init(struct device *dev,
 	return 0;
 }
 
+static const struct component_ops dsi_ops;
 static int dsi_host_attach(struct mipi_dsi_host *host,
 			   struct mipi_dsi_device *mdsi)
 {
 	struct dw_dsi *dsi = host_to_dsi(host);
+	struct device *dev = host->dev;
+	int ret;
 
 	if (mdsi->lanes < 1 || mdsi->lanes > 4) {
 		DRM_ERROR("dsi device params invalid\n");
@@ -734,13 +737,20 @@ static int dsi_host_attach(struct mipi_dsi_host *host,
 	dsi->format = mdsi->format;
 	dsi->mode_flags = mdsi->mode_flags;
 
+	ret = component_add(dev, &dsi_ops);
+	if (ret)
+		return ret;
+
 	return 0;
 }
 
 static int dsi_host_detach(struct mipi_dsi_host *host,
 			   struct mipi_dsi_device *mdsi)
 {
-	/* do nothing */
+	struct device *dev = host->dev;
+
+	component_del(dev, &dsi_ops);
+
 	return 0;
 }
 
@@ -785,10 +795,6 @@ static int dsi_bind(struct device *dev, struct device *master, void *data)
 	if (ret)
 		return ret;
 
-	ret = dsi_host_init(dev, dsi);
-	if (ret)
-		return ret;
-
 	ret = dsi_bridge_init(drm_dev, dsi);
 	if (ret)
 		return ret;
@@ -859,12 +865,19 @@ static int dsi_probe(struct platform_device *pdev)
 
 	platform_set_drvdata(pdev, data);
 
-	return component_add(&pdev->dev, &dsi_ops);
+	ret = dsi_host_init(&pdev->dev, dsi);
+	if (ret)
+		return ret;
+
+	return 0;
 }
 
 static int dsi_remove(struct platform_device *pdev)
 {
-	component_del(&pdev->dev, &dsi_ops);
+	struct dsi_data *data = platform_get_drvdata(pdev);
+	struct dw_dsi *dsi = &data->dsi;
+
+	mipi_dsi_host_unregister(&dsi->host);
 
 	return 0;
 }
-- 
2.31.1