linux/include
Lars-Peter Clausen 6d9eecd418 spi: Add helper functions for setting up transfers
Quite often the pattern used for setting up and transferring a synchronous SPI
transaction looks very much like the following:

	struct spi_message msg;
	struct spi_transfer xfers[] = {
		...
	};

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	...
	spi_message_add_tail(&xfers[ARRAY_SIZE(xfers) - 1], &msg);

	ret = spi_sync(&msg);

This patch adds two new helper functions for handling this case. The first
helper function spi_message_init_with_transfers() takes a spi_message and an
array of spi_transfers. It will initialize the message and then call
spi_message_add_tail() for each transfer in the array. E.g. the following

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	...
	spi_message_add_tail(&xfers[ARRAY_SIZE(xfers) - 1], &msg);

can be rewritten as

	spi_message_init_with_transfers(&msg, xfers, ARRAY_SIZE(xfers));

The second function spi_sync_transfer() takes a SPI device and an array of
spi_transfers. It will allocate a new spi_message (on the stack) and add all
transfers in the array to the message. Finally it will call spi_sync() on the
message.

E.g. the follwing

	struct spi_message msg;
	struct spi_transfer xfers[] = {
		...
	};

	spi_message_init(&msg);
	spi_message_add_tail(&xfers[0], &msg);
	...
	spi_message_add_tail(&xfers[ARRAY_SIZE(xfers) - 1], &msg);

	ret = spi_sync(spi, &msg);

can be rewritten as

	struct spi_transfer xfers[] = {
		...
	};

	ret = spi_sync_transfer(spi, xfers, ARRAY_SIZE(xfers));

A coccinelle script to find such instances will follow.

Signed-off-by: Lars-Peter Clausen <lars@metafoo.de>
Reviewed-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
2013-02-09 11:02:07 +00:00
..
acpi PCI changes for the v3.8 merge window: 2012-12-13 12:14:47 -08:00
asm-generic Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k 2013-01-23 13:31:15 -08:00
clocksource
crypto crypto: cast5/cast6 - move lookup tables to shared module 2012-12-06 17:16:26 +08:00
drm Merge branch 'drm-intel-fixes' of git://people.freedesktop.org/~danvet/drm-intel 2013-01-11 07:52:48 +10:00
keys
linux spi: Add helper functions for setting up transfers 2013-02-09 11:02:07 +00:00
math-emu
media
memory
misc
net Merge branch 'master' of git://1984.lsi.us.es/nf 2012-12-28 14:28:17 -08:00
pcmcia
ras
rdma UAPI: Remove empty Kbuild files 2013-01-02 17:36:10 -08:00
rxrpc
scsi SCSI misc on 20121212 2012-12-13 19:20:31 -08:00
sound Merge remote-tracking branch 'asoc/fix/cs4271' into tmp 2013-01-10 12:22:11 +00:00
target target: Introduce TCM_NO_SENSE 2013-01-10 20:06:08 -08:00
trace Various bug fixes for ext4. Perhaps the most serious bug fixed is one 2013-01-02 09:57:34 -08:00
uapi TTY/serial fixes for 3.8-rc4 2013-01-18 14:05:59 -08:00
video Merge branch 'omap-for-v3.8/fixes-for-merge-window' into omap-for-v3.8/fixes-for-merge-window-v2 2012-12-16 11:28:10 -08:00
xen Bugfixes: 2012-12-18 12:26:54 -08:00
Kbuild UAPI: Remove empty Kbuild files 2013-01-02 17:36:10 -08:00