linux-kernel - [PATCH v2] drm/exynos: dsi: Remove bridge node reference in error handling path in probe function

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Message-Id: <20200516105736.269669-1-christophe.jaillet@wanadoo.fr>
Date:   Sat, 16 May 2020 12:57:36 +0200
From:   Christophe JAILLET <christophe.jaillet@...adoo.fr>
To:     inki.dae@...sung.com, jy0922.shim@...sung.com,
        sw0312.kim@...sung.com, kyungmin.park@...sung.com,
        airlied@...ux.ie, daniel@...ll.ch, kgene@...nel.org,
        krzk@...nel.org
Cc:     dri-devel@...ts.freedesktop.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel-janitors@...r.kernel.org,
        Christophe JAILLET <christophe.jaillet@...adoo.fr>
Subject: [PATCH v2] drm/exynos: dsi: Remove bridge node reference in error handling path in probe function

'exynos_dsi_parse_dt()' takes a reference to 'dsi->in_bridge_node'.
This must be released in the error handling path.

In order to do that, add an error handling path and move the
'exynos_dsi_parse_dt()' call from the beginning to the end of the probe
function to ease the error handling path.
This function only sets some variables which are used only in the
'transfer' function.

The call chain is:
   .transfer
    --> exynos_dsi_host_transfer
      --> exynos_dsi_init
        --> exynos_dsi_enable_clock  (use burst_clk_rate and esc_clk_rate)
          --> exynos_dsi_set_pll     (use pll_clk_rate)

While at it, also handle cases where 'component_add()' fails.

This patch is similar to commit 70505c2ef94b ("drm/exynos: dsi: Remove bridge node reference in removal")
which fixed the issue in the remove function.

Signed-off-by: Christophe JAILLET <christophe.jaillet@...adoo.fr>
---
A Fixes tag could be required, but I've not been able to figure out which
one to use.

v2: move around 'exynos_dsi_parse_dt' instead of adding many gotos
    handle component_add failures
---
 drivers/gpu/drm/exynos/exynos_drm_dsi.c | 20 +++++++++++++++-----
 1 file changed, 15 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_drm_dsi.c b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
index 902938d2568f..a9d24402fabf 100644
--- a/drivers/gpu/drm/exynos/exynos_drm_dsi.c
+++ b/drivers/gpu/drm/exynos/exynos_drm_dsi.c
@@ -1759,10 +1759,6 @@ static int exynos_dsi_probe(struct platform_device *pdev)
 	dsi->dev = dev;
 	dsi->driver_data = of_device_get_match_data(dev);
 
-	ret = exynos_dsi_parse_dt(dsi);
-	if (ret)
-		return ret;
-
 	dsi->supplies[0].supply = "vddcore";
 	dsi->supplies[1].supply = "vddio";
 	ret = devm_regulator_bulk_get(dev, ARRAY_SIZE(dsi->supplies),
@@ -1823,11 +1819,25 @@ static int exynos_dsi_probe(struct platform_device *pdev)
 		return ret;
 	}
 
+	ret = exynos_dsi_parse_dt(dsi);
+	if (ret)
+		return ret;
+
 	platform_set_drvdata(pdev, &dsi->encoder);
 
 	pm_runtime_enable(dev);
 
-	return component_add(dev, &exynos_dsi_component_ops);
+	ret = component_add(dev, &exynos_dsi_component_ops);
+	if (ret)
+		goto err_disable_runtime;
+
+	return 0;
+
+err_disable_runtime:
+	pm_runtime_disable(dev);
+	of_node_put(dsi->in_bridge_node);
+
+	return ret;
 }
 
 static int exynos_dsi_remove(struct platform_device *pdev)
-- 
2.25.1