mfd: dm355evm msp430 driver

Basic MFD framework for the MSP430 microcontroller firmware used
on the dm355evm board:

 - Provides an interface for other drivers: register read/write
   utilities, and register declarations.

 - Directly exports:
     * Many signals through the GPIO framework
         + LEDs
         + SW6 through gpio sysfs
	 + NTSC/nPAL jumper through gpio sysfs
	 + ... more could be added later, e.g. MMC signals
     * Child devices:
	+ LEDs, via leds-gpio child (and default triggers)
	+ RTC, via rtc-dm355evm child device
	+ Buttons and IR control, via dm355evm_keys

 - Supports power-off system call.  Use the reset button to power
   the board back up; the power supply LED will be on, but the
   MSP430 waits to re-activate the regulators.

 - On probe() this:
     * Announces firmware revision
     * Turns off the banked LEDs
     * Exports the resources noted above
     * Hooks the power-off support
     * Muxes tvp5146 -or- imager for video input

Unless the new tvp514x driver (tracked for mainline) is configured,
this assumes that some custom imager driver handles video-in.

This completely ignores the registers reporting the output voltages
on the various power supplies.  Someone could add a hwmon interface
if that seems useful.
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Samuel Ortiz <sameo@openedhand.com>

drivers/mfd/Kconfig

@@ -34,6 +34,14 @@ config MFD_ASIC3
 	  This driver supports the ASIC3 multifunction chip found on many
 	  PDAs (mainly iPAQ and HTC based ones)
 
+config MFD_DM355EVM_MSP
+	bool "DaVinci DM355 EVM microcontroller"
+	depends on I2C && MACH_DAVINCI_DM355_EVM
+	help
+	  This driver supports the MSP430 microcontroller used on these
+	  boards.  MSP430 firmware manages resets and power sequencing,
+	  inputs from buttons and the IR remote, LEDs, an RTC, and more.
+
 config HTC_EGPIO
 	bool "HTC EGPIO support"
 	depends on GENERIC_HARDIRQS && GPIOLIB && ARM

drivers/mfd/Makefile

@@ -8,6 +8,8 @@ obj-$(CONFIG_MFD_ASIC3)		+= asic3.o
 obj-$(CONFIG_HTC_EGPIO)		+= htc-egpio.o
 obj-$(CONFIG_HTC_PASIC3)	+= htc-pasic3.o
 
+obj-$(CONFIG_MFD_DM355EVM_MSP)	+= dm355evm_msp.o
+
 obj-$(CONFIG_MFD_T7L66XB)	+= t7l66xb.o
 obj-$(CONFIG_MFD_TC6387XB)	+= tc6387xb.o
 obj-$(CONFIG_MFD_TC6393XB)	+= tc6393xb.o

include/linux/i2c/dm355evm_msp.h

+/*
+ * dm355evm_msp.h - support MSP430 microcontroller on DM355EVM board
+ */
+#ifndef __LINUX_I2C_DM355EVM_MSP
+#define __LINUX_I2C_DM355EVM_MSP
+
+/*
+ * Written against Spectrum's writeup for the A4 firmware revision,
+ * and tweaked to match source and rev D2 schematics by removing CPLD
+ * and NOR flash hooks (which were last appropriate in rev B boards).
+ *
+ * Note that the firmware supports a flavor of write posting ... to be
+ * sure a write completes, issue another read or write.
+ */
+
+/* utilities to access "registers" emulated by msp430 firmware */
+extern int dm355evm_msp_write(u8 value, u8 reg);
+extern int dm355evm_msp_read(u8 reg);
+
+
+/* command/control registers */
+#define DM355EVM_MSP_COMMAND		0x00
+#	define MSP_COMMAND_NULL		0
+#	define MSP_COMMAND_RESET_COLD	1
+#	define MSP_COMMAND_RESET_WARM	2
+#	define MSP_COMMAND_RESET_WARM_I	3
+#	define MSP_COMMAND_POWEROFF	4
+#	define MSP_COMMAND_IR_REINIT	5
+#define DM355EVM_MSP_STATUS		0x01
+#	define MSP_STATUS_BAD_OFFSET	BIT(0)
+#	define MSP_STATUS_BAD_COMMAND	BIT(1)
+#	define MSP_STATUS_POWER_ERROR	BIT(2)
+#	define MSP_STATUS_RXBUF_OVERRUN	BIT(3)
+#define DM355EVM_MSP_RESET		0x02	/* 0 bits == in reset */
+#	define MSP_RESET_DC5		BIT(0)
+#	define MSP_RESET_TVP5154	BIT(2)
+#	define MSP_RESET_IMAGER		BIT(3)
+#	define MSP_RESET_ETHERNET	BIT(4)
+#	define MSP_RESET_SYS		BIT(5)
+#	define MSP_RESET_AIC33		BIT(7)
+
+/* GPIO registers ... bit patterns mostly match the source MSP ports */
+#define DM355EVM_MSP_LED		0x03	/* active low (MSP P4) */
+#define DM355EVM_MSP_SWITCH1		0x04	/* (MSP P5, masked) */
+#	define MSP_SWITCH1_SW6_1	BIT(0)
+#	define MSP_SWITCH1_SW6_2	BIT(1)
+#	define MSP_SWITCH1_SW6_3	BIT(2)
+#	define MSP_SWITCH1_SW6_4	BIT(3)
+#	define MSP_SWITCH1_J1		BIT(4)	/* NTSC/PAL */
+#	define MSP_SWITCH1_MSP_INT	BIT(5)	/* active low */
+#define DM355EVM_MSP_SWITCH2		0x05	/* (MSP P6, masked) */
+#	define MSP_SWITCH2_SW10		BIT(3)
+#	define MSP_SWITCH2_SW11		BIT(4)
+#	define MSP_SWITCH2_SW12		BIT(5)
+#	define MSP_SWITCH2_SW13		BIT(6)
+#	define MSP_SWITCH2_SW14		BIT(7)
+#define DM355EVM_MSP_SDMMC		0x06	/* (MSP P2, masked) */
+#	define MSP_SDMMC_0_WP		BIT(1)
+#	define MSP_SDMMC_0_CD		BIT(2)	/* active low */
+#	define MSP_SDMMC_1_WP		BIT(3)
+#	define MSP_SDMMC_1_CD		BIT(4)	/* active low */
+#define DM355EVM_MSP_FIRMREV		0x07	/* not a GPIO (out of order) */
+#define DM355EVM_MSP_VIDEO_IN		0x08	/* (MSP P3, masked) */
+#	define MSP_VIDEO_IMAGER		BIT(7)	/* low == tvp5146 */
+
+/* power supply registers are currently omitted */
+
+/* RTC registers */
+#define DM355EVM_MSP_RTC_0		0x12	/* LSB */
+#define DM355EVM_MSP_RTC_1		0x13
+#define DM355EVM_MSP_RTC_2		0x14
+#define DM355EVM_MSP_RTC_3		0x15	/* MSB */
+
+/* input event queue registers; code == ((HIGH << 8) | LOW) */
+#define DM355EVM_MSP_INPUT_COUNT	0x16	/* decrement by reading LOW */
+#define DM355EVM_MSP_INPUT_HIGH		0x17
+#define DM355EVM_MSP_INPUT_LOW		0x18
+
+#endif /* __LINUX_I2C_DM355EVM_MSP */