spi: document the transfer_one spi_master callback

Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Mark Brown <broonie@linaro.org>
This commit is contained in:
Baruch Siach 2014-01-25 22:36:14 +02:00 committed by Mark Brown
parent 6e5f52674f
commit 18cc0adb13

View File

@ -545,6 +545,21 @@ SPI MASTER METHODS
spi_finalize_current_message() so the subsystem can issue the next
transfer. This may sleep.
master->transfer_one(struct spi_master *master, struct spi_device *spi,
struct spi_transfer *transfer)
The subsystem calls the driver to transfer a single transfer while
queuing transfers that arrive in the meantime. When the driver is
finished with this transfer, it must call
spi_finalize_current_transfer() so the subsystem can issue the next
transfer. This may sleep. Note: transfer_one and transfer_one_message
are mutually exclusive; when both are set, the generic subsystem does
not call your transfer_one callback.
Return values:
negative errno: error
0: transfer is finished
1: transfer is still in progress
DEPRECATED METHODS
master->transfer(struct spi_device *spi, struct spi_message *message)