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Subject[PATCH 2/3] spi: document odd controller reference handling
Date
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 --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)
{
--
2.14.3
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