[PATCH 3/4] simplefb: disable dt node upon remove

[Luc Verhaegen <libv@skynet.be>]

The next commit will handle clocks correctly, so that these do not get
automatically disabled on certain SoC simplefb implementations. As a
result, the removal of this simplefb driver, and the release of the
clocks, is rather final, and only a full display driver can work after
this. So, it makes sense to also flag the dt node as disabled, even
though it has no real value today.

Signed-off-by: Luc Verhaegen <libv@skynet.be>
---
 drivers/video/fbdev/simplefb.c |   43 ++++++++++++++++++++++++++++++++++++---
 1 files changed, 39 insertions(+), 4 deletions(-)

diff --git a/drivers/video/fbdev/simplefb.c b/drivers/video/fbdev/simplefb.c
index 72a4f20..74c4b2a 100644
--- a/drivers/video/fbdev/simplefb.c
+++ b/drivers/video/fbdev/simplefb.c
@@ -138,6 +138,32 @@ static int simplefb_parse_dt(struct platform_device *pdev,
 	return 0;
 }
 
+/*
+ * Make sure that nothing tries to inadvertedly re-use this node...
+ */
+static int
+simplefb_dt_disable(struct platform_device *pdev)
+{
+	struct device_node *np = pdev->dev.of_node;
+	struct property *property;
+	int ret;
+
+	property = kzalloc(sizeof(struct property), GFP_KERNEL);
+	if (!property)
+		return -ENOMEM;
+
+	property->name = "status";
+	property->value = "disabled";
+	property->length = strlen(property->value) + 1;
+
+	ret = of_update_property(np, property);
+	if (ret)
+		dev_err(&pdev->dev, "%s: failed to update property: %d\n",
+			__func__, ret);
+
+	return ret;
+}
+
 static int simplefb_parse_pd(struct platform_device *pdev,
 			     struct simplefb_params *params)
 {
@@ -187,17 +213,20 @@ static int simplefb_probe(struct platform_device *pdev)
 		ret = simplefb_parse_dt(pdev, &params);
 
 	if (ret)
-		return ret;
+		goto error_dt_disable;
 
 	mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (!mem) {
 		dev_err(&pdev->dev, "No memory resource\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto error_dt_disable;
 	}
 
 	info = framebuffer_alloc(sizeof(struct simplefb_par), &pdev->dev);
-	if (!info)
-		return -ENOMEM;
+	if (!info) {
+		ret = -ENOMEM;
+		goto error_dt_disable;
+	}
 	platform_set_drvdata(pdev, info);
 
 	par = info->par;
@@ -260,6 +289,10 @@ static int simplefb_probe(struct platform_device *pdev)
  error_fb_release:
 	framebuffer_release(info);
 
+ error_dt_disable:
+	if (!dev_get_platdata(&pdev->dev) && pdev->dev.of_node)
+		simplefb_dt_disable(pdev);
+
 	return ret;
 }
 
@@ -269,6 +302,8 @@ static int simplefb_remove(struct platform_device *pdev)
 
 	unregister_framebuffer(info);
 	framebuffer_release(info);
+	if (!dev_get_platdata(&pdev->dev) && pdev->dev.of_node)
+		simplefb_dt_disable(pdev);
 
 	return 0;
 }
-- 
1.7.7