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Commit 7f8c7619 authored by Hans-Peter Nilsson's avatar Hans-Peter Nilsson Committed by Linus Torvalds
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[PATCH] spi_bitbang(): use overridable setup_transfer() method 



A small bug-fix for spi_bitbang: it must always call the setup_transfer
function via the overridable pointer, not assume that its
spi_bitbang_setup_transfer is sufficient.  Otherwise, if all options in the
transfers are default (0), the overrided function will never be called.

Granted, the function replacing it must call spi_bitbang_setup_transfer,
but it might also have other important things to do, even if the second
argument (the spi_transfer) is NULL.  Tested together with the other
patches on the spi_crisv32_sser and spi_crisv32_gpio drivers (not yet in
the kernel, will IIUC be submitted as part of the usual
arch-maintainer-pushes).

Signed-off-by: default avatarHans-Peter Nilsson <hp@axis.com>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ddc1e975

drivers/spi/spi_bitbang.c

+5 −4
Original line number Diff line number Diff line
@@ -210,7 +210,7 @@ int spi_bitbang_setup(struct spi_device *spi) 
	if (!cs->txrx_word)

		return -EINVAL;



	retval = spi_bitbang_setup_transfer(spi, NULL);

	retval = bitbang->setup_transfer(spi, NULL);

	if (retval < 0)

		return retval;
@@ -442,9 +442,10 @@ EXPORT_SYMBOL_GPL(spi_bitbang_transfer); 
 * hardware that basically exposes a shift register) or per-spi_transfer

 * (which takes better advantage of hardware like fifos or DMA engines).

 *

 * Drivers using per-word I/O loops should use (or call) spi_bitbang_setup and

 * spi_bitbang_cleanup to handle those spi master methods.  Those methods are

 * the defaults if the bitbang->txrx_bufs routine isn't initialized.

 * Drivers using per-word I/O loops should use (or call) spi_bitbang_setup,

 * spi_bitbang_cleanup and spi_bitbang_setup_transfer to handle those spi

 * master methods.  Those methods are the defaults if the bitbang->txrx_bufs

 * routine isn't initialized.

 *

 * This routine registers the spi_master, which will process requests in a

 * dedicated task, keeping IRQs unblocked most of the time.  To stop