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From: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
To: Rob Herring <robh@kernel.org>, Frank Rowand <frowand.list@gmail.com>
Cc: Pawel Moll <pawel.moll@arm.com>,
	Grant Likely <grant.likely@secretlab.ca>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] of/platform: depopulate devices in the reverse order of creation
Date: Mon, 12 Dec 2016 11:39:05 -0700	[thread overview]
Message-ID: <20161212183905.GA30702@obsidianresearch.com> (raw)

If the DT has inter-dependencies, then the devices need to be removed
in the right order to avoid removal problems.

Assuming the DT is constructed so that EPROBE_DEFER doesn't happen
during creating then a good way to avoid removal problems is reversing
the order during depopulation.

Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
---
 drivers/of/platform.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

In my specific case I have a gpio driver, followed by a i2c bitbang
using that driver. So gpiolib prints an error if it the gpio driver is
removed before the gpio client..

diff --git a/drivers/of/platform.c b/drivers/of/platform.c
index cd72c0156db2ba..5720fe44f991e9 100644
--- a/drivers/of/platform.c
+++ b/drivers/of/platform.c
@@ -568,7 +568,8 @@ static int of_platform_device_destroy(struct device *dev, void *data)
 void of_platform_depopulate(struct device *parent)
 {
 	if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) {
-		device_for_each_child(parent, NULL, of_platform_device_destroy);
+		device_for_each_child_reverse(parent, NULL,
+					      of_platform_device_destroy);
 		of_node_clear_flag(parent->of_node, OF_POPULATED_BUS);
 	}
 }
-- 
2.7.4

             reply	other threads:[~2016-12-12 18:39 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-12 18:39 Jason Gunthorpe [this message]
2016-12-14 20:54 ` [PATCH] of/platform: depopulate devices in the reverse order of creation Rob Herring
2016-12-14 21:40   ` Jason Gunthorpe

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