[PATCH] spi: mark device nodes only in case of successful instantiation

From: Ralf Ramsauer
Date: Fri Oct 14 2016 - 15:40:59 EST

Instantiated SPI device nodes are marked with OF_POPULATE. This was
introduced in bd6c164. On unloading, loaded device nodes will of course
be unmarked. The problem are nodes the fail during initialisation: If a
node failed during registration, it won't be unloaded and hence never be
unmarked again.

So if a SPI driver module is unloaded and reloaded, it will skip nodes
that failed before.

Skip device nodes that are already populated and mark them only in case
of success.

Fixes: bd6c164 ("spi: Mark instantiated device nodes with OF_POPULATE")
Signed-off-by: Ralf Ramsauer <ralf@xxxxxxxxxxxxxxxxxxxxxx>
Cc: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>

imagine the following situation: you loaded a spi driver as module, but
it fails to instantiate, because of some reasons (e.g. some resources,
like gpios, might be in use in userspace).

When reloading the driver, _all_ nodes, including previously failed
ones, should be probed again. This is not the case at the moment.
Current behaviour only re-registers nodes that were previously
successfully loaded.

This small patches fixes this behaviour. I stumbled over this while
working on a spi driver.


drivers/spi/spi.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 200ca22..f96a04e 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1604,12 +1604,15 @@ static void of_register_spi_devices(struct spi_master *master)

for_each_available_child_of_node(master->dev.of_node, nc) {
- if (of_node_test_and_set_flag(nc, OF_POPULATED))
+ if (of_node_check_flag(nc, OF_POPULATED))
spi = of_register_spi_device(master, nc);
- if (IS_ERR(spi))
+ if (IS_ERR(spi)) {
dev_warn(&master->dev, "Failed to create SPI device for %s\n",
+ continue;
+ }
+ of_node_set_flag(nc, OF_POPULATED);