[PATCH] of/platform: depopulate devices in the reverse order of creation

From: Jason Gunthorpe
Date: Mon Dec 12 2016 - 13:39:19 EST

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@xxxxxxxxxxxxxxxxxxxx>
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);