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[2/3] spi: document odd controller reference handling

Message ID 20171029115625.32385-2-johan@kernel.org (mailing list archive)
State Accepted
Commit 68b892f1fdc493d7cd4e4067596879cd097c1f62
Headers show

Commit Message

Johan Hovold Oct. 29, 2017, 11:56 a.m. UTC 
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>
---
 drivers/spi/spi.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)
diff mbox

Patch

diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 3ff0ee88c467..b33a727a0158 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2200,7 +2200,7 @@  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.
  */
@@ -2241,6 +2241,8 @@  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)
 {