path: root/drivers
diff options
authorJohan Hovold <johan@kernel.org>2017-10-30 11:35:26 +0100
committerMark Brown <broonie@kernel.org>2017-10-31 11:09:43 +0000
commit68b892f1fdc493d7cd4e4067596879cd097c1f62 (patch)
tree2239373187c97df66d42397dd922c113c8a84ffa /drivers
parent2bd6bf03f4c1c59381d62c61d03f6cc3fe71f66e (diff)
spi: document odd controller reference handling
Document the fact that a reference to the controller is dropped as part of deregistration. This is an odd pattern as the reference is typically taken in __spi_alloc_controller() rather than spi_register_controller(). Most controller drivers gets it right these days and notably the device-managed interface relies on this behaviour. Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Mark Brown <broonie@kernel.org>
Diffstat (limited to 'drivers')
1 files changed, 3 insertions, 1 deletions
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 6e65524cbfd9..5673cca1d1d0 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2195,7 +2195,7 @@ static void devm_spi_unregister(struct device *dev, void *res)
* Context: can sleep
* Register a SPI device as with spi_register_controller() which will
- * automatically be unregister
+ * automatically be unregistered and freed.
* Return: zero on success, else a negative error code.
@@ -2236,6 +2236,8 @@ static int __unregister(struct device *dev, void *null)
* only ones directly touching chip registers.
* This must be called from context that can sleep.
+ *
+ * Note that this function also drops a reference to the controller.
void spi_unregister_controller(struct spi_controller *ctlr)

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