[PATCH] SPI: Freescale iMX SPI controller driver (BIS+)

Add the SPI controller driver for Freescale i.MX(S/L/1).
Main features summary:

 > Per chip setup via board specific code and/or protocol driver.
 > Per transfer setup.
 > PIO transfers.
 > DMA transfers.
 > Managing of NULL tx / rx buffer for rd only / wr only transfers.

This patch replace patch-2.6.20-rc4-spi_imx with the following changes:
 > Few cosmetic changes.
 > Function map_dma_buffers now return 0 for success and -1 for failure.
 > Solved a bug inside spi_imx_probe function (wrong error path).
 > Solved a bug inside setup function (bad undo setup for max_speed_hz).
 > For read-only transfers, always write zero bytes.

This is almost the same as the 'BIS' version sent by Andrea, except for
updating the 'DUMMY' byte so that read-only transfers shift out zeroes.
That part of the API changed recently, since some half duplex peripheral
chips require that semantic.

Signed-off-by: Andrea Paterniani <a.paterniani@swapp-eng.it>
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>

drivers/spi/Kconfig

@@ -75,6 +75,13 @@ config SPI_BUTTERFLY
 	  inexpensive battery powered microcontroller evaluation board.
 	  This same cable can be used to flash new firmware.
 
+config SPI_IMX
+	tristate "Freescale iMX SPI controller"
+	depends on SPI_MASTER && ARCH_IMX && EXPERIMENTAL
+	help
+	  This enables using the Freescale iMX SPI controller in master
+	  mode.
+
 config SPI_MPC83xx
 	tristate "Freescale MPC83xx SPI controller"
 	depends on SPI_MASTER && PPC_83xx && EXPERIMENTAL
@@ -94,6 +101,7 @@ config SPI_OMAP_UWIRE
 	help
 	  This hooks up to the MicroWire controller on OMAP1 chips.
 
+
 config SPI_PXA2XX
 	tristate "PXA2xx SSP SPI master"
 	depends on SPI_MASTER && ARCH_PXA && EXPERIMENTAL

drivers/spi/Makefile

@@ -13,6 +13,7 @@ obj-$(CONFIG_SPI_MASTER)		+= spi.o
 # SPI master controller drivers (bus)
 obj-$(CONFIG_SPI_BITBANG)		+= spi_bitbang.o
 obj-$(CONFIG_SPI_BUTTERFLY)		+= spi_butterfly.o
+obj-$(CONFIG_SPI_IMX)			+= spi_imx.o
 obj-$(CONFIG_SPI_PXA2XX)		+= pxa2xx_spi.o
 obj-$(CONFIG_SPI_OMAP_UWIRE)		+= omap_uwire.o
 obj-$(CONFIG_SPI_MPC83xx)		+= spi_mpc83xx.o