spi: add SPI driver for most known i.MX SoCs

This driver has been tested on i.MX1/i.MX27/i.MX35 with an AT25 type
EEPROM and on i.MX27/i.MX31 with a Freescale MC13783 PMIC.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Tested-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Acked-by: David Brownell <david-b@pacbell.net>
Cc: Andrea Paterniani <a.paterniani@swapp-eng.it>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/arm/plat-mxc/include/mach/spi.h

@@ -0,0 +1,27 @@
+
+#ifndef __MACH_SPI_H_
+#define __MACH_SPI_H_
+
+/*
+ * struct spi_imx_master - device.platform_data for SPI controller devices.
+ * @chipselect: Array of chipselects for this master. Numbers >= 0 mean gpio
+ *              pins, numbers < 0 mean internal CSPI chipselects according
+ *              to MXC_SPI_CS(). Normally you want to use gpio based chip
+ *              selects as the CSPI module tries to be intelligent about
+ *              when to assert the chipselect: The CSPI module deasserts the
+ *              chipselect once it runs out of input data. The other problem
+ *              is that it is not possible to mix between high active and low
+ *              active chipselects on one single bus using the internal
+ *              chipselects. Unfortunately Freescale decided to put some
+ *              chipselects on dedicated pins which are not usable as gpios,
+ *              so we have to support the internal chipselects.
+ * @num_chipselect: ARRAY_SIZE(chipselect)
+ */
+struct spi_imx_master {
+	int	*chipselect;
+	int	num_chipselect;
+};
+
+#define MXC_SPI_CS(no)	((no) - 32)
+
+#endif /* __MACH_SPI_H_*/

drivers/spi/Kconfig

@@ -116,6 +116,14 @@ config SPI_GPIO
 	  GPIO operations, you should be able to leverage that for better
 	  speed with a custom version of this driver; see the source code.
 
+config SPI_IMX
+	tristate "Freescale i.MX SPI controllers"
+	depends on ARCH_MXC
+	select SPI_BITBANG
+	help
+	  This enables using the Freescale i.MX SPI controllers in master
+	  mode.
+
 config SPI_LM70_LLP
 	tristate "Parallel port adapter for LM70 eval board (DEVELOPMENT)"
 	depends on PARPORT && EXPERIMENTAL

drivers/spi/Makefile

@@ -17,6 +17,7 @@ obj-$(CONFIG_SPI_BITBANG)		+= spi_bitbang.o
 obj-$(CONFIG_SPI_AU1550)		+= au1550_spi.o
 obj-$(CONFIG_SPI_BUTTERFLY)		+= spi_butterfly.o
 obj-$(CONFIG_SPI_GPIO)			+= spi_gpio.o
+obj-$(CONFIG_SPI_IMX)			+= mxc_spi.o
 obj-$(CONFIG_SPI_LM70_LLP)		+= spi_lm70llp.o
 obj-$(CONFIG_SPI_PXA2XX)		+= pxa2xx_spi.o
 obj-$(CONFIG_SPI_OMAP_UWIRE)		+= omap_uwire.o