mfd: Add driver for Atmel Microcontroller on iPaq h3xxx

This adds a driver for the Atmel Microcontroller found on the
iPAQ h3xxx series. This device handles some keys, the
touchscreen, and the battery monitoring.

This is a port of a driver from handhelds.org 2.6.21 kernel,
written by Alessandro Gardich based on Andrew Christians
original HAL-driver. It has been heavily cleaned and
converted to mfd-core by Dmitry Artamonow and rewritten
again for the v3.x series kernels by Linus Walleij,
bringing back some of the functionality lost from Andrew's
original driver.
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Alessandro Gardich <gremlin@gremlin.it>
Signed-off-by: Dmitry Artamonow <mad_soft@inbox.ru>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Lee Jones <lee.jones@linaro.org>

drivers/mfd/Kconfig

@@ -262,6 +262,16 @@ config MFD_INTEL_MSIC
 	  Passage) chip. This chip embeds audio, battery, GPIO, etc.
 	  devices used in Intel Medfield platforms.
 
+config MFD_IPAQ_MICRO
+	bool "Atmel Micro ASIC (iPAQ h3100/h3600/h3700) Support"
+	depends on SA1100_H3100 || SA1100_H3600
+	select MFD_CORE
+	help
+	  Select this to get support for the Microcontroller found in
+	  the Compaq iPAQ handheld computers. This is an Atmel
+	  AT90LS8535 microcontroller flashed with a special iPAQ
+	  firmware using the custom protocol implemented in this driver.
+
 config MFD_JANZ_CMODIO
 	tristate "Janz CMOD-IO PCI MODULbus Carrier Board"
 	select MFD_CORE

drivers/mfd/Makefile

@@ -168,3 +168,4 @@ obj-$(CONFIG_MFD_RETU)		+= retu-mfd.o
 obj-$(CONFIG_MFD_AS3711)	+= as3711.o
 obj-$(CONFIG_MFD_AS3722)	+= as3722.o
 obj-$(CONFIG_MFD_STW481X)	+= stw481x.o
+obj-$(CONFIG_MFD_IPAQ_MICRO)	+= ipaq-micro.o

include/linux/mfd/ipaq-micro.h

+/*
+ * Header file for the compaq Micro MFD
+ */
+
+#ifndef _MFD_IPAQ_MICRO_H_
+#define _MFD_IPAQ_MICRO_H_
+
+#include <linux/spinlock.h>
+#include <linux/completion.h>
+#include <linux/list.h>
+
+#define TX_BUF_SIZE	32
+#define RX_BUF_SIZE	16
+#define CHAR_SOF	0x02
+
+/*
+ * These are the different messages that can be sent to the microcontroller
+ * to control various aspects.
+ */
+#define MSG_VERSION		0x0
+#define MSG_KEYBOARD		0x2
+#define MSG_TOUCHSCREEN		0x3
+#define MSG_EEPROM_READ		0x4
+#define MSG_EEPROM_WRITE	0x5
+#define MSG_THERMAL_SENSOR	0x6
+#define MSG_NOTIFY_LED		0x8
+#define MSG_BATTERY		0x9
+#define MSG_SPI_READ		0xb
+#define MSG_SPI_WRITE		0xc
+#define MSG_BACKLIGHT		0xd /* H3600 only */
+#define MSG_CODEC_CTRL		0xe /* H3100 only */
+#define MSG_DISPLAY_CTRL	0xf /* H3100 only */
+
+/* state of receiver parser */
+enum rx_state {
+	STATE_SOF = 0,     /* Next byte should be start of frame */
+	STATE_ID,          /* Next byte is ID & message length   */
+	STATE_DATA,        /* Next byte is a data byte           */
+	STATE_CHKSUM       /* Next byte should be checksum       */
+};
+
+/**
+ * struct ipaq_micro_txdev - TX state
+ * @len: length of message in TX buffer
+ * @index: current index into TX buffer
+ * @buf: TX buffer
+ */
+struct ipaq_micro_txdev {
+	u8 len;
+	u8 index;
+	u8 buf[TX_BUF_SIZE];
+};
+
+/**
+ * struct ipaq_micro_rxdev - RX state
+ * @state: context of RX state machine
+ * @chksum: calculated checksum
+ * @id: message ID from packet
+ * @len: RX buffer length
+ * @index: RX buffer index
+ * @buf: RX buffer
+ */
+struct ipaq_micro_rxdev {
+	enum rx_state state;
+	unsigned char chksum;
+	u8            id;
+	unsigned int  len;
+	unsigned int  index;
+	u8            buf[RX_BUF_SIZE];
+};
+
+/**
+ * struct ipaq_micro_msg - message to the iPAQ microcontroller
+ * @id: 4-bit ID of the message
+ * @tx_len: length of TX data
+ * @tx_data: TX data to send
+ * @rx_len: length of receieved RX data
+ * @rx_data: RX data to recieve
+ * @ack: a completion that will be completed when RX is complete
+ * @node: list node if message gets queued
+ */
+struct ipaq_micro_msg {
+	u8 id;
+	u8 tx_len;
+	u8 tx_data[TX_BUF_SIZE];
+	u8 rx_len;
+	u8 rx_data[RX_BUF_SIZE];
+	struct completion ack;
+	struct list_head node;
+};
+
+/**
+ * struct ipaq_micro - iPAQ microcontroller state
+ * @dev: corresponding platform device
+ * @base: virtual memory base for underlying serial device
+ * @sdlc: virtual memory base for Synchronous Data Link Controller
+ * @version: version string
+ * @tx: TX state
+ * @rx: RX state
+ * @lock: lock for this state container
+ * @msg: current message
+ * @queue: message queue
+ * @key: callback for asynchronous key events
+ * @key_data: data to pass along with key events
+ * @ts: callback for asynchronous touchscreen events
+ * @ts_data: data to pass along with key events
+ */
+struct ipaq_micro {
+	struct device *dev;
+	void __iomem *base;
+	void __iomem *sdlc;
+	char version[5];
+	struct ipaq_micro_txdev tx;	/* transmit ISR state */
+	struct ipaq_micro_rxdev rx;	/* receive ISR state */
+	spinlock_t lock;
+	struct ipaq_micro_msg *msg;
+	struct list_head queue;
+	void (*key) (void *data, int len, unsigned char *rxdata);
+	void *key_data;
+	void (*ts) (void *data, int len, unsigned char *rxdata);
+	void *ts_data;
+};
+
+extern int
+ipaq_micro_tx_msg(struct ipaq_micro *micro, struct ipaq_micro_msg *msg);
+
+static inline int
+ipaq_micro_tx_msg_sync(struct ipaq_micro *micro,
+		       struct ipaq_micro_msg *msg)
+{
+	int ret;
+
+	init_completion(&msg->ack);
+	ret = ipaq_micro_tx_msg(micro, msg);
+	wait_for_completion(&msg->ack);
+
+	return ret;
+}
+
+static inline int
+ipaq_micro_tx_msg_async(struct ipaq_micro *micro,
+			struct ipaq_micro_msg *msg)
+{
+	init_completion(&msg->ack);
+	return ipaq_micro_tx_msg(micro, msg);
+}
+
+#endif /* _MFD_IPAQ_MICRO_H_ */