Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/spi-2.6

Documentation/spi/butterfly

+spi_butterfly - parport-to-butterfly adapter driver
+===================================================
+
+This is a hardware and software project that includes building and using
+a parallel port adapter cable, together with an "AVR Butterfly" to run
+firmware for user interfacing and/or sensors.  A Butterfly is a $US20
+battery powered card with an AVR microcontroller and lots of goodies:
+sensors, LCD, flash, toggle stick, and more.  You can use AVR-GCC to
+develop firmware for this, and flash it using this adapter cable.
+
+You can make this adapter from an old printer cable and solder things
+directly to the Butterfly.  Or (if you have the parts and skills) you
+can come up with something fancier, providing ciruit protection to the
+Butterfly and the printer port, or with a better power supply than two
+signal pins from the printer port.
+
+
+The first cable connections will hook Linux up to one SPI bus, with the
+AVR and a DataFlash chip; and to the AVR reset line.  This is all you
+need to reflash the firmware, and the pins are the standard Atmel "ISP"
+connector pins (used also on non-Butterfly AVR boards).
+
+	Signal	  Butterfly	  Parport (DB-25)
+	------	  ---------	  ---------------
+	SCK	= J403.PB1/SCK	= pin 2/D0
+	RESET	= J403.nRST	= pin 3/D1
+	VCC	= J403.VCC_EXT	= pin 8/D6
+	MOSI	= J403.PB2/MOSI	= pin 9/D7
+	MISO	= J403.PB3/MISO	= pin 11/S7,nBUSY
+	GND	= J403.GND	= pin 23/GND
+
+Then to let Linux master that bus to talk to the DataFlash chip, you must
+(a) flash new firmware that disables SPI (set PRR.2, and disable pullups
+by clearing PORTB.[0-3]); (b) configure the mtd_dataflash driver; and
+(c) cable in the chipselect.
+
+	Signal	  Butterfly	  Parport (DB-25)
+	------	  ---------	  ---------------
+	VCC	= J400.VCC_EXT	= pin 7/D5
+	SELECT	= J400.PB0/nSS	= pin 17/C3,nSELECT
+	GND	= J400.GND	= pin 24/GND
+
+The "USI" controller, using J405, can be used for a second SPI bus.  That
+would let you talk to the AVR over SPI, running firmware that makes it act
+as an SPI slave, while letting either Linux or the AVR use the DataFlash.
+There are plenty of spare parport pins to wire this one up, such as:
+
+	Signal	  Butterfly	  Parport (DB-25)
+	------	  ---------	  ---------------
+	SCK	= J403.PE4/USCK	= pin 5/D3
+	MOSI	= J403.PE5/DI	= pin 6/D4
+	MISO	= J403.PE6/DO	= pin 12/S5,nPAPEROUT
+	GND	= J403.GND	= pin 22/GND
+
+	IRQ	= J402.PF4	= pin 10/S6,ACK
+	GND	= J402.GND(P2)	= pin 25/GND
+

arch/arm/Kconfig

@@ -729,6 +729,8 @@ source "drivers/char/Kconfig"
 
 source "drivers/i2c/Kconfig"
 
+source "drivers/spi/Kconfig"
+
 source "drivers/hwmon/Kconfig"
 
 #source "drivers/l3/Kconfig"

drivers/Kconfig

@@ -44,6 +44,8 @@ source "drivers/char/Kconfig"
 
 source "drivers/i2c/Kconfig"
 
+source "drivers/spi/Kconfig"
+
 source "drivers/w1/Kconfig"
 
 source "drivers/hwmon/Kconfig"

drivers/Makefile

@@ -41,6 +41,7 @@ obj-$(CONFIG_FUSION)		+= message/
 obj-$(CONFIG_IEEE1394)		+= ieee1394/
 obj-y				+= cdrom/
 obj-$(CONFIG_MTD)		+= mtd/
+obj-$(CONFIG_SPI)		+= spi/
 obj-$(CONFIG_PCCARD)		+= pcmcia/
 obj-$(CONFIG_DIO)		+= dio/
 obj-$(CONFIG_SBUS)		+= sbus/

drivers/input/touchscreen/Kconfig

@@ -11,6 +11,19 @@ menuconfig INPUT_TOUCHSCREEN
 
 if INPUT_TOUCHSCREEN
 
+config TOUCHSCREEN_ADS7846
+	tristate "ADS 7846 based touchscreens"
+	depends on SPI_MASTER
+	help
+	  Say Y here if you have a touchscreen interface using the
+	  ADS7846 controller, and your board-specific initialization
+	  code includes that in its table of SPI devices.
+
+	  If unsure, say N (but it's safe to say "Y").
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ads7846.
+
 config TOUCHSCREEN_BITSY
 	tristate "Compaq iPAQ H3600 (Bitsy) touchscreen"
 	depends on SA1100_BITSY

drivers/input/touchscreen/Makefile

@@ -4,6 +4,7 @@
 
 # Each configuration option enables a list of files.
 
+obj-$(CONFIG_TOUCHSCREEN_ADS7846)	+= ads7846.o
 obj-$(CONFIG_TOUCHSCREEN_BITSY)	+= h3600_ts_input.o
 obj-$(CONFIG_TOUCHSCREEN_CORGI)	+= corgi_ts.o
 obj-$(CONFIG_TOUCHSCREEN_GUNZE)	+= gunze.o

drivers/mtd/devices/Kconfig

@@ -47,6 +47,22 @@ config MTD_MS02NV
 	  accelerator.  Say Y here if you have a DECstation 5000/2x0 or a
 	  DECsystem 5900 equipped with such a module.
 
+config MTD_DATAFLASH
+	tristate "Support for AT45xxx DataFlash"
+	depends on MTD && SPI_MASTER && EXPERIMENTAL
+	help
+	  This enables access to AT45xxx DataFlash chips, using SPI.
+	  Sometimes DataFlash chips are packaged inside MMC-format
+	  cards; at this writing, the MMC stack won't handle those.
+
+config MTD_M25P80
+	tristate "Support for M25 SPI Flash"
+	depends on MTD && SPI_MASTER && EXPERIMENTAL
+	help
+	  This enables access to ST M25P80 and similar SPI flash chips,
+	  used for program and data storage.  Set up your spi devices
+	  with the right board-specific platform data.
+
 config MTD_SLRAM
 	tristate "Uncached system RAM"
 	depends on MTD

drivers/mtd/devices/Makefile

@@ -23,3 +23,5 @@ obj-$(CONFIG_MTD_MTDRAM)	+= mtdram.o
 obj-$(CONFIG_MTD_LART)		+= lart.o
 obj-$(CONFIG_MTD_BLKMTD)	+= blkmtd.o
 obj-$(CONFIG_MTD_BLOCK2MTD)	+= block2mtd.o
+obj-$(CONFIG_MTD_DATAFLASH)	+= mtd_dataflash.o
+obj-$(CONFIG_MTD_M25P80)	+= m25p80.o

drivers/spi/Kconfig

+#
+# SPI driver configuration
+#
+# NOTE:  the reason this doesn't show SPI slave support is mostly that
+# nobody's needed a slave side API yet.  The master-role API is not
+# fully appropriate there, so it'd need some thought to do well.
+#
+menu "SPI support"
+
+config SPI
+	bool "SPI support"
+	help
+	  The "Serial Peripheral Interface" is a low level synchronous
+	  protocol.  Chips that support SPI can have data transfer rates
+	  up to several tens of Mbit/sec.  Chips are addressed with a
+	  controller and a chipselect.  Most SPI slaves don't support
+	  dynamic device discovery; some are even write-only or read-only.
+
+	  SPI is widely used by microcontollers to talk with sensors,
+	  eeprom and flash memory, codecs and various other controller
+	  chips, analog to digital (and d-to-a) converters, and more.
+	  MMC and SD cards can be accessed using SPI protocol; and for
+	  DataFlash cards used in MMC sockets, SPI must always be used.
+
+	  SPI is one of a family of similar protocols using a four wire
+	  interface (select, clock, data in, data out) including Microwire
+	  (half duplex), SSP, SSI, and PSP.  This driver framework should
+	  work with most such devices and controllers.
+
+config SPI_DEBUG
+	boolean "Debug support for SPI drivers"
+	depends on SPI && DEBUG_KERNEL
+	help
+	  Say "yes" to enable debug messaging (like dev_dbg and pr_debug),
+	  sysfs, and debugfs support in SPI controller and protocol drivers.
+
+#
+# MASTER side ... talking to discrete SPI slave chips including microcontrollers
+#
+
+config SPI_MASTER
+#	boolean "SPI Master Support"
+	boolean
+	default SPI
+	help
+	  If your system has an master-capable SPI controller (which
+	  provides the clock and chipselect), you can enable that
+	  controller and the protocol drivers for the SPI slave chips
+	  that are connected.
+
+comment "SPI Master Controller Drivers"
+	depends on SPI_MASTER
+
+config SPI_BITBANG
+	tristate "Bitbanging SPI master"
+	depends on SPI_MASTER && EXPERIMENTAL
+	help
+	  With a few GPIO pins, your system can bitbang the SPI protocol.
+	  Select this to get SPI support through I/O pins (GPIO, parallel
+	  port, etc).  Or, some systems' SPI master controller drivers use
+	  this code to manage the per-word or per-transfer accesses to the
+	  hardware shift registers.
+
+	  This is library code, and is automatically selected by drivers that
+	  need it.  You only need to select this explicitly to support driver
+	  modules that aren't part of this kernel tree.
+
+config SPI_BUTTERFLY
+	tristate "Parallel port adapter for AVR Butterfly (DEVELOPMENT)"
+	depends on SPI_MASTER && PARPORT && EXPERIMENTAL
+	select SPI_BITBANG
+	help
+	  This uses a custom parallel port cable to connect to an AVR
+	  Butterfly <http://www.atmel.com/products/avr/butterfly>, an
+	  inexpensive battery powered microcontroller evaluation board.
+	  This same cable can be used to flash new firmware.
+
+config SPI_BUTTERFLY
+	tristate "Parallel port adapter for AVR Butterfly (DEVELOPMENT)"
+	depends on SPI_MASTER && PARPORT && EXPERIMENTAL
+	select SPI_BITBANG
+	help
+	  This uses a custom parallel port cable to connect to an AVR
+	  Butterfly <http://www.atmel.com/products/avr/butterfly>, an
+	  inexpensive battery powered microcontroller evaluation board.
+	  This same cable can be used to flash new firmware.
+
+#
+# Add new SPI master controllers in alphabetical order above this line
+#
+
+
+#
+# There are lots of SPI device types, with sensors and memory
+# being probably the most widely used ones.
+#
+comment "SPI Protocol Masters"
+	depends on SPI_MASTER
+
+
+#
+# Add new SPI protocol masters in alphabetical order above this line
+#
+
+
+# (slave support would go here)
+
+endmenu # "SPI support"
+

drivers/spi/Makefile

+#
+# Makefile for kernel SPI drivers.
+#
+
+ifeq ($(CONFIG_SPI_DEBUG),y)
+EXTRA_CFLAGS += -DDEBUG
+endif
+
+# small core, mostly translating board-specific
+# config declarations into driver model code
+obj-$(CONFIG_SPI_MASTER)		+= spi.o
+
+# SPI master controller drivers (bus)
+obj-$(CONFIG_SPI_BITBANG)		+= spi_bitbang.o
+obj-$(CONFIG_SPI_BUTTERFLY)		+= spi_butterfly.o
+# 	... add above this line ...
+
+# SPI protocol drivers (device/link on bus)
+# 	... add above this line ...
+
+# SPI slave controller drivers (upstream link)
+# 	... add above this line ...
+
+# SPI slave drivers (protocol for that link)
+# 	... add above this line ...

include/linux/spi/ads7846.h

+/* linux/spi/ads7846.h */
+
+/* Touchscreen characteristics vary between boards and models.  The
+ * platform_data for the device's "struct device" holds this information.
+ *
+ * It's OK if the min/max values are zero.
+ */
+struct ads7846_platform_data {
+	u16	model;			/* 7843, 7845, 7846. */
+	u16	vref_delay_usecs;	/* 0 for external vref; etc */
+	u16	x_plate_ohms;
+	u16	y_plate_ohms;
+
+	u16	x_min, x_max;
+	u16	y_min, y_max;
+	u16	pressure_min, pressure_max;
+};
+

include/linux/spi/flash.h

+#ifndef LINUX_SPI_FLASH_H
+#define LINUX_SPI_FLASH_H
+
+struct mtd_partition;
+
+/**
+ * struct flash_platform_data: board-specific flash data
+ * @name: optional flash device name (eg, as used with mtdparts=)
+ * @parts: optional array of mtd_partitions for static partitioning
+ * @nr_parts: number of mtd_partitions for static partitoning
+ * @type: optional flash device type (e.g. m25p80 vs m25p64), for use
+ *	with chips that can't be queried for JEDEC or other IDs
+ *
+ * Board init code (in arch/.../mach-xxx/board-yyy.c files) can
+ * provide information about SPI flash parts (such as DataFlash) to
+ * help set up the device and its appropriate default partitioning.
+ *
+ * Note that for DataFlash, sizes for pages, blocks, and sectors are
+ * rarely powers of two; and partitions should be sector-aligned.
+ */
+struct flash_platform_data {
+	char		*name;
+	struct mtd_partition *parts;
+	unsigned int	nr_parts;
+
+	char		*type;
+
+	/* we'll likely add more ... use JEDEC IDs, etc */
+};
+
+#endif

include/linux/spi/spi_bitbang.h

+#ifndef	__SPI_BITBANG_H
+#define	__SPI_BITBANG_H
+
+/*
+ * Mix this utility code with some glue code to get one of several types of
+ * simple SPI master driver.  Two do polled word-at-a-time I/O:
+ *
+ *   -	GPIO/parport bitbangers.  Provide chipselect() and txrx_word[](),
+ *	expanding the per-word routines from the inline templates below.
+ *
+ *   -	Drivers for controllers resembling bare shift registers.  Provide
+ *	chipselect() and txrx_word[](), with custom setup()/cleanup() methods
+ *	that use your controller's clock and chipselect registers.
+ *
+ * Some hardware works well with requests at spi_transfer scope:
+ *
+ *   -	Drivers leveraging smarter hardware, with fifos or DMA; or for half
+ *	duplex (MicroWire) controllers.  Provide chipslect() and txrx_bufs(),
+ *	and custom setup()/cleanup() methods.
+ */
+struct spi_bitbang {
+	struct workqueue_struct	*workqueue;
+	struct work_struct	work;
+
+	spinlock_t		lock;
+	struct list_head	queue;
+	u8			busy;
+	u8			shutdown;
+	u8			use_dma;
+
+	struct spi_master	*master;
+
+	void	(*chipselect)(struct spi_device *spi, int is_on);
+#define	BITBANG_CS_ACTIVE	1	/* normally nCS, active low */
+#define	BITBANG_CS_INACTIVE	0
+
+	/* txrx_bufs() may handle dma mapping for transfers that don't
+	 * already have one (transfer.{tx,rx}_dma is zero), or use PIO
+	 */
+	int	(*txrx_bufs)(struct spi_device *spi, struct spi_transfer *t);
+
+	/* txrx_word[SPI_MODE_*]() just looks like a shift register */
+	u32	(*txrx_word[4])(struct spi_device *spi,
+			unsigned nsecs,
+			u32 word, u8 bits);
+};
+
+/* you can call these default bitbang->master methods from your custom
+ * methods, if you like.
+ */
+extern int spi_bitbang_setup(struct spi_device *spi);
+extern void spi_bitbang_cleanup(const struct spi_device *spi);
+extern int spi_bitbang_transfer(struct spi_device *spi, struct spi_message *m);
+
+/* start or stop queue processing */
+extern int spi_bitbang_start(struct spi_bitbang *spi);
+extern int spi_bitbang_stop(struct spi_bitbang *spi);
+
+#endif	/* __SPI_BITBANG_H */
+
+/*-------------------------------------------------------------------------*/
+
+#ifdef	EXPAND_BITBANG_TXRX
+
+/*
+ * The code that knows what GPIO pins do what should have declared four
+ * functions, ideally as inlines, before #defining EXPAND_BITBANG_TXRX
+ * and including this header:
+ *
+ *  void setsck(struct spi_device *, int is_on);
+ *  void setmosi(struct spi_device *, int is_on);
+ *  int getmiso(struct spi_device *);
+ *  void spidelay(unsigned);
+ *
+ * A non-inlined routine would call bitbang_txrx_*() routines.  The
+ * main loop could easily compile down to a handful of instructions,
+ * especially if the delay is a NOP (to run at peak speed).
+ *
+ * Since this is software, the timings may not be exactly what your board's
+ * chips need ... there may be several reasons you'd need to tweak timings
+ * in these routines, not just make to make it faster or slower to match a
+ * particular CPU clock rate.
+ */
+
+static inline u32
+bitbang_txrx_be_cpha0(struct spi_device *spi,
+		unsigned nsecs, unsigned cpol,
+		u32 word, u8 bits)
+{
+	/* if (cpol == 0) this is SPI_MODE_0; else this is SPI_MODE_2 */
+
+	/* clock starts at inactive polarity */
+	for (word <<= (32 - bits); likely(bits); bits--) {
+
+		/* setup MSB (to slave) on trailing edge */
+		setmosi(spi, word & (1 << 31));
+		spidelay(nsecs);	/* T(setup) */
+
+		setsck(spi, !cpol);
+		spidelay(nsecs);
+
+		/* sample MSB (from slave) on leading edge */
+		word <<= 1;
+		word |= getmiso(spi);
+		setsck(spi, cpol);
+	}
+	return word;
+}
+
+static inline u32
+bitbang_txrx_be_cpha1(struct spi_device *spi,
+		unsigned nsecs, unsigned cpol,
+		u32 word, u8 bits)
+{
+	/* if (cpol == 0) this is SPI_MODE_1; else this is SPI_MODE_3 */
+
+	/* clock starts at inactive polarity */
+	for (word <<= (32 - bits); likely(bits); bits--) {
+
+		/* setup MSB (to slave) on leading edge */
+		setsck(spi, !cpol);
+		setmosi(spi, word & (1 << 31));
+		spidelay(nsecs); /* T(setup) */
+
+		setsck(spi, cpol);
+		spidelay(nsecs);
+
+		/* sample MSB (from slave) on trailing edge */
+		word <<= 1;
+		word |= getmiso(spi);
+	}
+	return word;
+}
+
+#endif	/* EXPAND_BITBANG_TXRX */