Messages in this thread Patch in this message | | | From | Geert Uytterhoeven <> | Subject | [PATCH] spi: Clarify (a)synchronous transfer_one() | Date | Tue, 14 Jan 2014 12:34:56 +0100 |
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From: Geert Uytterhoeven <geert+renesas@linux-m68k.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@linux-m68k.org> --- include/linux/spi/spi.h | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 21a7251d85ee..5319a8510921 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -282,10 +282,12 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * @prepare_message: set up the controller to transfer a single message, * for example doing DMA mapping. Called from threaded * context. - * @transfer_one: transfer a single spi_transfer. When the - * driver is finished with this transfer it must call - * spi_finalize_current_transfer() so the subsystem can issue - * the next transfer + * @transfer_one: transfer a single spi_transfer. + * Synchronous transfer methods must return 0 on success. + * Asynchronous transfer methods must return a strict-positive + * value on successful submission, and must call + * spi_finalize_current_transfer() when the driver is finished + * so the subsystem can issue the next transfer * @unprepare_message: undo any work done by prepare_message(). * @cs_gpios: Array of GPIOs to use as chip select lines; one per CS * number. Any individual value may be -ENOENT for CS lines that -- 1.7.9.5
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