mfd: Add driver for RAVE Supervisory Processor

Add a driver for RAVE Supervisory Processor, an MCU implementing
various bits of housekeeping functionality (watchdoging, backlight
control, LED control, etc) on RAVE family of products by Zodiac
Inflight Innovations.

This driver implementes core MFD/serdev device as well as
communication subroutines necessary for commanding the device.
Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
Acked-by: Philippe Ombredanne <pombredanne@nexb.com>
Acked-by: Pavel Machek <pavel@ucw.cz>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Tested-by: Chris Healy <cphealy@gmail.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -1859,5 +1859,13 @@ config MFD_VEXPRESS_SYSREG
 	  System Registers are the platform configuration block
 	  on the ARM Ltd. Versatile Express board.
 
+config RAVE_SP_CORE
+	tristate "RAVE SP MCU core driver"
+	depends on SERIAL_DEV_BUS
+	select CRC_CCITT
+	help
+	  Select this to get support for the Supervisory Processor
+	  device found on several devices in RAVE line of hardware.
+
 endmenu
 endif

drivers/mfd/Makefile

@@ -230,3 +230,5 @@ obj-$(CONFIG_MFD_STM32_LPTIMER)	+= stm32-lptimer.o
 obj-$(CONFIG_MFD_STM32_TIMERS) 	+= stm32-timers.o
 obj-$(CONFIG_MFD_MXS_LRADC)     += mxs-lradc.o
 obj-$(CONFIG_MFD_SC27XX_PMIC)	+= sprd-sc27xx-spi.o
+obj-$(CONFIG_RAVE_SP_CORE)	+= rave-sp.o
+

include/linux/mfd/rave-sp.h

+/* SPDX-License-Identifier: GPL-2.0+ */
+
+/*
+ * Core definitions for RAVE SP MFD driver.
+ *
+ * Copyright (C) 2017 Zodiac Inflight Innovations
+ */
+
+#ifndef _LINUX_RAVE_SP_H_
+#define _LINUX_RAVE_SP_H_
+
+#include <linux/notifier.h>
+
+enum rave_sp_command {
+	RAVE_SP_CMD_GET_FIRMWARE_VERSION	= 0x20,
+	RAVE_SP_CMD_GET_BOOTLOADER_VERSION	= 0x21,
+	RAVE_SP_CMD_BOOT_SOURCE			= 0x26,
+	RAVE_SP_CMD_GET_BOARD_COPPER_REV	= 0x2B,
+	RAVE_SP_CMD_GET_GPIO_STATE		= 0x2F,
+
+	RAVE_SP_CMD_STATUS			= 0xA0,
+	RAVE_SP_CMD_SW_WDT			= 0xA1,
+	RAVE_SP_CMD_PET_WDT			= 0xA2,
+	RAVE_SP_CMD_RESET			= 0xA7,
+	RAVE_SP_CMD_RESET_REASON		= 0xA8,
+
+	RAVE_SP_CMD_REQ_COPPER_REV		= 0xB6,
+	RAVE_SP_CMD_GET_I2C_DEVICE_STATUS	= 0xBA,
+	RAVE_SP_CMD_GET_SP_SILICON_REV		= 0xB9,
+	RAVE_SP_CMD_CONTROL_EVENTS		= 0xBB,
+
+	RAVE_SP_EVNT_BASE			= 0xE0,
+};
+
+struct rave_sp;
+
+static inline unsigned long rave_sp_action_pack(u8 event, u8 value)
+{
+	return ((unsigned long)value << 8) | event;
+}
+
+static inline u8 rave_sp_action_unpack_event(unsigned long action)
+{
+	return action;
+}
+
+static inline u8 rave_sp_action_unpack_value(unsigned long action)
+{
+	return action >> 8;
+}
+
+int rave_sp_exec(struct rave_sp *sp,
+		 void *__data,  size_t data_size,
+		 void *reply_data, size_t reply_data_size);
+
+struct device;
+int devm_rave_sp_register_event_notifier(struct device *dev,
+					 struct notifier_block *nb);
+
+#endif /* _LINUX_RAVE_SP_H_ */