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From:   Neil Armstrong <narmstrong@baylibre.com>
To:     khilman@baylibre.com
Cc:     Neil Armstrong <narmstrong@baylibre.com>,
        linux-amlogic@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: [PATCH] soc: amlogic: canvas: Fix meson_canvas_get when probe failed
Date:   Mon,  4 Feb 2019 10:49:37 +0100
Message-Id: <20190204094937.22763-1-narmstrong@baylibre.com>
MIME-Version: 1.0
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Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

When probe fails, a platforn_device is still associated to the node,
but dev_get_drvdata() returns NULL.

Handle this case by returning a consistent error.

Fixes: d4983983d987 ("soc: amlogic: add meson-canvas driver")
Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/soc/amlogic/meson-canvas.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

This fix depends on "soc: amlogic: add missing of_node_put()" at [1]

[1] https://patchwork.kernel.org/patch/10794545/

diff --git a/drivers/soc/amlogic/meson-canvas.c b/drivers/soc/amlogic/meson-canvas.c
index 87a6c6e23591..151aa84bc593 100644
--- a/drivers/soc/amlogic/meson-canvas.c
+++ b/drivers/soc/amlogic/meson-canvas.c
@@ -51,6 +51,7 @@ struct meson_canvas *meson_canvas_get(struct device *dev)
 {
 	struct device_node *canvas_node;
 	struct platform_device *canvas_pdev;
+	struct meson_canvas *canvas;
 
 	canvas_node = of_parse_phandle(dev->of_node, "amlogic,canvas", 0);
 	if (!canvas_node)
@@ -63,7 +64,17 @@ struct meson_canvas *meson_canvas_get(struct device *dev)
 	}
 
 	of_node_put(canvas_node);
-	return dev_get_drvdata(&canvas_pdev->dev);
+
+	/*
+	 * If priv is NULL, it's probably because the canvas hasn't
+	 * properly initialized. Bait out with -EINVAL because, in the
+	 * current state, this driver probe cannot return -EPROBE_DEFER
+	 */
+	canvas = dev_get_drvdata(&canvas_pdev->dev);
+	if (!canvas)
+		return ERR_PTR(-EINVAL);
+
+	return canvas;
 }
 EXPORT_SYMBOL_GPL(meson_canvas_get);
 
-- 
2.20.1