From 568d0697f42771425ae9f1e9a3db769fef7e10b6 Mon Sep 17 00:00:00 2001 From: David Brownell Date: Tue, 22 Sep 2009 16:46:18 -0700 Subject: spi: handle TX-only/RX-only Support two new half-duplex SPI implementation restrictions, for links that talk to TX-only or RX-only devices. (Existing half-duplex flavors support both transfer directions, just not at the same time.) Move spi_async() into the spi.c core, and stop inlining it. Then make that function perform error checks and reject messages that demand more than the underlying controller can support. Based on a patch from Marek Szyprowski which did this only for the bitbanged GPIO driver. Cc: Marek Szyprowski Signed-off-by: David Brownell Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/spi/spi.h | 39 +++------------------------------------ 1 file changed, 3 insertions(+), 36 deletions(-) (limited to 'include/linux/spi') diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index e2051f39f6a8..97b60b37f445 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -258,6 +258,8 @@ struct spi_master { /* other constraints relevant to this driver */ u16 flags; #define SPI_MASTER_HALF_DUPLEX BIT(0) /* can't do full duplex */ +#define SPI_MASTER_NO_RX BIT(1) /* can't do buffer read */ +#define SPI_MASTER_NO_TX BIT(2) /* can't do buffer write */ /* Setup mode and clock, etc (spi driver may call many times). * @@ -538,42 +540,7 @@ static inline void spi_message_free(struct spi_message *m) } extern int spi_setup(struct spi_device *spi); - -/** - * spi_async - asynchronous SPI transfer - * @spi: device with which data will be exchanged - * @message: describes the data transfers, including completion callback - * Context: any (irqs may be blocked, etc) - * - * This call may be used in_irq and other contexts which can't sleep, - * as well as from task contexts which can sleep. - * - * The completion callback is invoked in a context which can't sleep. - * Before that invocation, the value of message->status is undefined. - * When the callback is issued, message->status holds either zero (to - * indicate complete success) or a negative error code. After that - * callback returns, the driver which issued the transfer request may - * deallocate the associated memory; it's no longer in use by any SPI - * core or controller driver code. - * - * Note that although all messages to a spi_device are handled in - * FIFO order, messages may go to different devices in other orders. - * Some device might be higher priority, or have various "hard" access - * time requirements, for example. - * - * On detection of any fault during the transfer, processing of - * the entire message is aborted, and the device is deselected. - * Until returning from the associated message completion callback, - * no other spi_message queued to that device will be processed. - * (This rule applies equally to all the synchronous transfer calls, - * which are wrappers around this core asynchronous primitive.) - */ -static inline int -spi_async(struct spi_device *spi, struct spi_message *message) -{ - message->spi = spi; - return spi->master->transfer(spi, message); -} +extern int spi_async(struct spi_device *spi, struct spi_message *message); /*---------------------------------------------------------------------------*/ -- cgit v1.2.3-55-g7522