spi_mpc83xx: much improved driver
The current driver may cause glitches on SPI CLK line since one must disable
the SPI controller before changing any HW settings. Fix this by implementing
a local spi_transfer function that won't change speed and/or word size while
CS is active.
While doing that heavy lifting a few other issues were addressed too:
- Make word size 16 and 32 work too.
- Honor bits_per_word and speed_hz in spi transaction.
- Optimize the common path.
This also stops using the "bitbang" framework (except for a few constants).
[Roel Kluin <12o3l@tiscali.nl>: "irq" needs to be signed]
Signed-off-by: Joakim Tjernlund <Joakim.Tjernlund@transmode.se>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2 files changed