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 <[e-mail]>
Signed-off-by: Alessandro Gardich <[e-mail]>
Signed-off-by: Dmitry Artamonow <[e-mail]>
Signed-off-by: Linus Walleij <[e-mail]>
Signed-off-by: Lee Jones <[e-mail]>

drivers/mfd/Kconfig

···
 	  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

···
 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

drivers/mfd/ipaq-micro.c

···
+/*
+ * Compaq iPAQ h3xxx Atmel microcontroller companion support
+ *
+ * This is an Atmel AT90LS8535 with a special flashed-in firmware that
+ * implements the special protocol used by this driver.
+ *
+ * based on previous kernel 2.4 version by Andrew Christian
+ * Author : Alessandro Gardich <[e-mail]>
+ * Author : Dmitry Artamonow <[e-mail]>
+ * Author : Linus Walleij <[e-mail]>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/pm.h>
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/mfd/core.h>
+#include <linux/mfd/ipaq-micro.h>
+#include <linux/string.h>
+#include <linux/random.h>
+#include <linux/slab.h>
+#include <linux/list.h>
+
+#include <mach/hardware.h>
+
+static void ipaq_micro_trigger_tx(struct ipaq_micro *micro)
+{
+	struct ipaq_micro_txdev *tx = &micro->tx;
+	struct ipaq_micro_msg *msg = micro->msg;
+	int i, bp;
+	u8 checksum;
+	u32 val;
+
+	bp = 0;
+	tx->buf[bp++] = CHAR_SOF;
+
+	checksum = ((msg->id & 0x0f) << 4) | (msg->tx_len & 0x0f);
+	tx->buf[bp++] = checksum;
+
+	for (i = 0; i < msg->tx_len; i++) {
+		tx->buf[bp++] = msg->tx_data[i];
+		checksum += msg->tx_data[i];
+	}
+
+	tx->buf[bp++] = checksum;
+	tx->len = bp;
+	tx->index = 0;
+	print_hex_dump(KERN_DEBUG, "data: ", DUMP_PREFIX_OFFSET, 16, 1,
+		       tx->buf, tx->len, true);
+
+	/* Enable interrupt */
+	val = readl(micro->base + UTCR3);
+	val |= UTCR3_TIE;
+	writel(val, micro->base + UTCR3);
+}
+
+int ipaq_micro_tx_msg(struct ipaq_micro *micro, struct ipaq_micro_msg *msg)
+{
+	unsigned long flags;
+
+	dev_dbg(micro->dev, "TX msg: %02x, %d bytes\n", msg->id, msg->tx_len);
+
+	spin_lock_irqsave(&micro->lock, flags);
+	if (micro->msg) {
+		list_add_tail(&msg->node, &micro->queue);
+		spin_unlock_irqrestore(&micro->lock, flags);
+		return 0;
+	}
+	micro->msg = msg;
+	ipaq_micro_trigger_tx(micro);
+	spin_unlock_irqrestore(&micro->lock, flags);
+	return 0;
+}
+EXPORT_SYMBOL(ipaq_micro_tx_msg);
+
+static void micro_rx_msg(struct ipaq_micro *micro, u8 id, int len, u8 *data)
+{
+	int i;
+
+	dev_dbg(micro->dev, "RX msg: %02x, %d bytes\n", id, len);
+
+	spin_lock(&micro->lock);
+	switch (id) {
+	case MSG_VERSION:
+	case MSG_EEPROM_READ:
+	case MSG_EEPROM_WRITE:
+	case MSG_BACKLIGHT:
+	case MSG_NOTIFY_LED:
+	case MSG_THERMAL_SENSOR:
+	case MSG_BATTERY:
+		/* Handle synchronous messages */
+		if (micro->msg && micro->msg->id == id) {
+			struct ipaq_micro_msg *msg = micro->msg;
+
+			memcpy(msg->rx_data, data, len);
+			msg->rx_len = len;
+			complete(&micro->msg->ack);
+			if (!list_empty(&micro->queue)) {
+				micro->msg = list_entry(micro->queue.next,
+							struct ipaq_micro_msg,
+							node);
+				list_del_init(&micro->msg->node);
+				ipaq_micro_trigger_tx(micro);
+			} else
+				micro->msg = NULL;
+			dev_dbg(micro->dev, "OK RX message 0x%02x\n", id);
+		} else {
+			dev_err(micro->dev,
+				"out of band RX message 0x%02x\n", id);
+			if(!micro->msg)
+				dev_info(micro->dev, "no message queued\n");
+			else
+				dev_info(micro->dev, "expected message %02x\n",
+					 micro->msg->id);
+		}
+		break;
+	case MSG_KEYBOARD:
+		if (micro->key)
+			micro->key(micro->key_data, len, data);
+		else
+			dev_dbg(micro->dev, "key message ignored, no handle \n");
+		break;
+	case MSG_TOUCHSCREEN:
+		if (micro->ts)
+			micro->ts(micro->ts_data, len, data);
+		else
+			dev_dbg(micro->dev, "touchscreen message ignored, no handle \n");
+		break;
+	default:
+		dev_err(micro->dev,
+			"unknown msg %d [%d] ", id, len);
+		for (i = 0; i < len; ++i)
+			pr_cont("0x%02x ", data[i]);
+		pr_cont("\n");
+	}
+	spin_unlock(&micro->lock);
+}
+
+static void micro_process_char(struct ipaq_micro *micro, u8 ch)
+{
+	struct ipaq_micro_rxdev *rx = &micro->rx;
+
+	switch (rx->state) {
+	case STATE_SOF:	/* Looking for SOF */
+		if (ch == CHAR_SOF)
+			rx->state = STATE_ID; /* Next byte is the id and len */
+		break;
+	case STATE_ID: /* Looking for id and len byte */
+		rx->id = (ch & 0xf0) >> 4 ;
+		rx->len = (ch & 0x0f);
+		rx->index = 0;
+		rx->chksum = ch;
+		rx->state = (rx->len > 0) ? STATE_DATA : STATE_CHKSUM;
+		break;
+	case STATE_DATA: /* Looking for 'len' data bytes */
+		rx->chksum += ch;
+		rx->buf[rx->index] = ch;
+		if (++rx->index == rx->len)
+			rx->state = STATE_CHKSUM;
+		break;
+	case STATE_CHKSUM: /* Looking for the checksum */
+		if (ch == rx->chksum)
+			micro_rx_msg(micro, rx->id, rx->len, rx->buf);
+		rx->state = STATE_SOF;
+		break;
+	}
+}
+
+static void micro_rx_chars(struct ipaq_micro *micro)
+{
+	u32 status, ch;
+
+	while ((status = readl(micro->base + UTSR1)) & UTSR1_RNE) {
+		ch = readl(micro->base + UTDR);
+		if (status & UTSR1_PRE)
+			dev_err(micro->dev, "rx: parity error\n");
+		else if (status & UTSR1_FRE)
+			dev_err(micro->dev, "rx: framing error\n");
+		else if (status & UTSR1_ROR)
+			dev_err(micro->dev, "rx: overrun error\n");
+		micro_process_char(micro, ch);
+	}
+}
+
+static void ipaq_micro_get_version(struct ipaq_micro *micro)
+{
+	struct ipaq_micro_msg msg = {
+		.id = MSG_VERSION,
+	};
+
+	ipaq_micro_tx_msg_sync(micro, &msg);
+	if (msg.rx_len == 4) {
+		memcpy(micro->version, msg.rx_data, 4);
+		micro->version[4] = '\0';
+	} else if (msg.rx_len == 9) {
+		memcpy(micro->version, msg.rx_data, 4);
+		micro->version[4] = '\0';
+		/* Bytes 4-7 are "pack", byte 8 is "boot type" */
+	} else {
+		dev_err(micro->dev,
+			"illegal version message %d bytes\n", msg.rx_len);
+	}
+}
+
+static void ipaq_micro_eeprom_read(struct ipaq_micro *micro,
+				   u8 address, u8 len, u8 *data)
+{
+	struct ipaq_micro_msg msg = {
+		.id = MSG_EEPROM_READ,
+	};
+	u8 i;
+
+	for (i = 0; i < len; i++) {
+		msg.tx_data[0] = address + i;
+		msg.tx_data[1] = 1;
+		msg.tx_len = 2;
+		ipaq_micro_tx_msg_sync(micro, &msg);
+		memcpy(data + (i * 2), msg.rx_data, 2);
+	}
+}
+
+static char *ipaq_micro_str(u8 *wchar, u8 len)
+{
+	char retstr[256];
+	u8 i;
+
+	for (i = 0; i < len / 2; i++)
+		retstr[i] = wchar[i * 2];
+	return kstrdup(retstr, GFP_KERNEL);
+}
+
+static u16 ipaq_micro_to_u16(u8 *data)
+{
+	return data[1] << 8 | data[0];
+}
+
+static void ipaq_micro_eeprom_dump(struct ipaq_micro *micro)
+{
+	u8 dump[256];
+	char *str;
+
+	ipaq_micro_eeprom_read(micro, 0, 128, dump);
+	str = ipaq_micro_str(dump, 10);
+	if (str) {
+		dev_info(micro->dev, "HM version %s\n", str);
+		kfree(str);
+	}
+	str = ipaq_micro_str(dump+10, 40);
+	if (str) {
+		dev_info(micro->dev, "serial number: %s\n", str);
+		/* Feed the random pool with this */
+		add_device_randomness(str, strlen(str));
+		kfree(str);
+	}
+	str = ipaq_micro_str(dump+50, 20);
+	if (str) {
+		dev_info(micro->dev, "module ID: %s\n", str);
+		kfree(str);
+	}
+	str = ipaq_micro_str(dump+70, 10);
+	if (str) {
+		dev_info(micro->dev, "product revision: %s\n", str);
+		kfree(str);
+	}
+	dev_info(micro->dev, "product ID: %u\n", ipaq_micro_to_u16(dump+80));
+	dev_info(micro->dev, "frame rate: %u fps\n",
+		 ipaq_micro_to_u16(dump+82));
+	dev_info(micro->dev, "page mode: %u\n", ipaq_micro_to_u16(dump+84));
+	dev_info(micro->dev, "country ID: %u\n", ipaq_micro_to_u16(dump+86));
+	dev_info(micro->dev, "color display: %s\n",
+		 ipaq_micro_to_u16(dump+88) ? "yes" : "no");
+	dev_info(micro->dev, "ROM size: %u MiB\n", ipaq_micro_to_u16(dump+90));
+	dev_info(micro->dev, "RAM size: %u KiB\n", ipaq_micro_to_u16(dump+92));
+	dev_info(micro->dev, "screen: %u x %u\n",
+		 ipaq_micro_to_u16(dump+94), ipaq_micro_to_u16(dump+96));
+	print_hex_dump(KERN_DEBUG, "eeprom: ", DUMP_PREFIX_OFFSET, 16, 1,
+		       dump, 256, true);
+
+}
+
+static void micro_tx_chars(struct ipaq_micro *micro)
+{
+	struct ipaq_micro_txdev *tx = &micro->tx;
+	u32 val;
+
+	while ((tx->index < tx->len) &&
+	       (readl(micro->base + UTSR1) & UTSR1_TNF)) {
+		writel(tx->buf[tx->index], micro->base + UTDR);
+		tx->index++;
+	}
+
+	/* Stop interrupts */
+	val = readl(micro->base + UTCR3);
+	val &= ~UTCR3_TIE;
+	writel(val, micro->base + UTCR3);
+}
+
+static void micro_reset_comm(struct ipaq_micro *micro)
+{
+	struct ipaq_micro_rxdev *rx = &micro->rx;
+	u32 val;
+
+	if (micro->msg)
+		complete(&micro->msg->ack);
+
+	/* Initialize Serial channel protocol frame */
+	rx->state = STATE_SOF;  /* Reset the state machine */
+
+	/* Set up interrupts */
+	writel(0x01, micro->sdlc + 0x0); /* Select UART mode */
+
+	/* Clean up CR3 */
+	writel(0x0, micro->base + UTCR3);
+
+	/* Format: 8N1 */
+	writel(UTCR0_8BitData | UTCR0_1StpBit, micro->base + UTCR0);
+
+	/* Baud rate: 115200 */
+	writel(0x0, micro->base + UTCR1);
+	writel(0x1, micro->base + UTCR2);
+
+	/* Clear SR0 */
+	writel(0xff, micro->base + UTSR0);
+
+	/* Enable RX int, disable TX int */
+	writel(UTCR3_TXE | UTCR3_RXE | UTCR3_RIE, micro->base + UTCR3);
+	val = readl(micro->base + UTCR3);
+	val &= ~UTCR3_TIE;
+	writel(val, micro->base + UTCR3);
+}
+
+static irqreturn_t micro_serial_isr(int irq, void *dev_id)
+{
+	struct ipaq_micro *micro = dev_id;
+	struct ipaq_micro_txdev *tx = &micro->tx;
+	u32 status;
+
+	status = readl(micro->base + UTSR0);
+	do {
+		if (status & (UTSR0_RID | UTSR0_RFS)) {
+			if (status & UTSR0_RID)
+				/* Clear the Receiver IDLE bit */
+				writel(UTSR0_RID, micro->base + UTSR0);
+			micro_rx_chars(micro);
+		}
+
+		/* Clear break bits */
+		if (status & (UTSR0_RBB | UTSR0_REB))
+			writel(status & (UTSR0_RBB | UTSR0_REB),
+			       micro->base + UTSR0);
+
+		if (status & UTSR0_TFS)
+			micro_tx_chars(micro);
+
+		status = readl(micro->base + UTSR0);
+
+	} while (((tx->index < tx->len) && (status & UTSR0_TFS)) ||
+		 (status & (UTSR0_RFS | UTSR0_RID)));
+
+	return IRQ_HANDLED;
+}
+
+static struct mfd_cell micro_cells[] = {
+	{ .name = "ipaq-micro-backlight", },
+	{ .name = "ipaq-micro-battery", },
+	{ .name = "ipaq-micro-keys", },
+	{ .name = "ipaq-micro-ts", },
+	{ .name = "ipaq-micro-leds", },
+};
+
+static int micro_resume(struct device *dev)
+{
+	struct ipaq_micro *micro = dev_get_drvdata(dev);
+
+	micro_reset_comm(micro);
+	mdelay(10);
+
+	return 0;
+}
+
+static int micro_probe(struct platform_device *pdev)
+{
+	struct ipaq_micro *micro;
+	struct resource *res;
+	int ret;
+	int irq;
+
+	micro = devm_kzalloc(&pdev->dev, sizeof(*micro), GFP_KERNEL);
+	if (!micro)
+		return -ENOMEM;
+
+	micro->dev = &pdev->dev;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res)
+		return -EINVAL;
+
+	micro->base = devm_request_and_ioremap(&pdev->dev, res);
+	if (!micro->base)
+		return -ENOMEM;
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 1);
+	if (!res)
+		return -EINVAL;
+
+	micro->sdlc = devm_request_and_ioremap(&pdev->dev, res);
+	if (!micro->sdlc)
+		return -ENOMEM;
+
+	micro_reset_comm(micro);
+
+	irq = platform_get_irq(pdev, 0);
+	if (!irq)
+		return -EINVAL;
+	ret = devm_request_irq(&pdev->dev, irq, micro_serial_isr,
+			       IRQF_SHARED, "ipaq-micro",
+			       micro);
+	if (ret) {
+		dev_err(&pdev->dev, "unable to grab serial port IRQ\n");
+		return ret;
+	} else
+		dev_info(&pdev->dev, "grabbed serial port IRQ\n");
+
+	spin_lock_init(&micro->lock);
+	INIT_LIST_HEAD(&micro->queue);
+	platform_set_drvdata(pdev, micro);
+
+	ret = mfd_add_devices(&pdev->dev, pdev->id, micro_cells,
+			      ARRAY_SIZE(micro_cells), NULL, 0, NULL);
+	if (ret) {
+		dev_err(&pdev->dev, "error adding MFD cells");
+		return ret;
+	}
+
+	/* Check version */
+	ipaq_micro_get_version(micro);
+	dev_info(&pdev->dev, "Atmel micro ASIC version %s\n", micro->version);
+	ipaq_micro_eeprom_dump(micro);
+
+	return 0;
+}
+
+static int micro_remove(struct platform_device *pdev)
+{
+	struct ipaq_micro *micro = platform_get_drvdata(pdev);
+	u32 val;
+
+	mfd_remove_devices(&pdev->dev);
+
+	val = readl(micro->base + UTCR3);
+	val &= ~(UTCR3_RXE | UTCR3_RIE); /* disable receive interrupt */
+	val &= ~(UTCR3_TXE | UTCR3_TIE); /* disable transmit interrupt */
+	writel(val, micro->base + UTCR3);
+
+	return 0;
+}
+
+static const struct dev_pm_ops micro_dev_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(NULL, micro_resume)
+};
+
+static struct platform_driver micro_device_driver = {
+	.driver   = {
+		.name	= "ipaq-h3xxx-micro",
+		.pm	= &micro_dev_pm_ops,
+	},
+	.probe    = micro_probe,
+	.remove   = micro_remove,
+	/* .shutdown = micro_suspend, // FIXME */
+};
+module_platform_driver(micro_device_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("driver for iPAQ Atmel micro core and backlight");

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_ */