ifx6x60: SPI protocol driver for Infineon 6x60 modem

Prototype driver for the IFX6x60 series of SPI attached modems by Jim
Stanley and Russ Gorby
Signed-off-by: Russ Gorby <richardx.r.gorby@intel.com>

[Some reworking and a major cleanup]
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/serial/Kconfig

@@ -1632,4 +1632,10 @@ config SERIAL_ALTERA_UART_CONSOLE
 	help
 	  Enable a Altera UART port to be the system console.
 
+config SERIAL_IFX6X60
+        tristate "SPI protocol driver for Infineon 6x60 modem (EXPERIMENTAL)"
+	depends on GPIOLIB && EXPERIMENTAL
+	help
+	  Support for the IFX6x60 modem devices on Intel MID platforms.
+
 endmenu

drivers/serial/Makefile

@@ -89,3 +89,4 @@ obj-$(CONFIG_SERIAL_ALTERA_UART) += altera_uart.o
 obj-$(CONFIG_SERIAL_MRST_MAX3110)	+= mrst_max3110.o
 obj-$(CONFIG_SERIAL_MFD_HSU)	+= mfd.o
 obj-$(CONFIG_SERIAL_OMAP) += omap-serial.o
+obj-$(CONFIG_SERIAL_IFX6X60)  	+= ifx6x60.o

drivers/serial/ifx6x60.c

+/****************************************************************************
+ *
+ * Driver for the IFX 6x60 spi modem.
+ *
+ * Copyright (C) 2008 Option International
+ * Copyright (C) 2008 Filip Aben <f.aben@option.com>
+ *		      Denis Joseph Barrow <d.barow@option.com>
+ *		      Jan Dumon <j.dumon@option.com>
+ *
+ * Copyright (C) 2009, 2010 Intel Corp
+ * Russ Gorby <richardx.r.gorby@intel.com>
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
+ * USA
+ *
+ * Driver modified by Intel from Option gtm501l_spi.c
+ *
+ * Notes
+ * o	The driver currently assumes a single device only. If you need to
+ *	change this then look for saved_ifx_dev and add a device lookup
+ * o	The driver is intended to be big-endian safe but has never been
+ *	tested that way (no suitable hardware). There are a couple of FIXME
+ *	notes by areas that may need addressing
+ * o	Some of the GPIO naming/setup assumptions may need revisiting if
+ *	you need to use this driver for another platform.
+ *
+ *****************************************************************************/
+#include <linux/module.h>
+#include <linux/termios.h>
+#include <linux/tty.h>
+#include <linux/device.h>
+#include <linux/spi/spi.h>
+#include <linux/tty.h>
+#include <linux/kfifo.h>
+#include <linux/tty_flip.h>
+#include <linux/timer.h>
+#include <linux/serial.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/rfkill.h>
+#include <linux/fs.h>
+#include <linux/ip.h>
+#include <linux/dmapool.h>
+#include <linux/gpio.h>
+#include <linux/sched.h>
+#include <linux/time.h>
+#include <linux/wait.h>
+#include <linux/tty.h>
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+#include <linux/spi/ifx_modem.h>
+
+#include "ifx6x60.h"
+
+#define IFX_SPI_MORE_MASK		0x10
+#define IFX_SPI_MORE_BIT		12	/* bit position in u16 */
+#define IFX_SPI_CTS_BIT			13	/* bit position in u16 */
+#define IFX_SPI_TTY_ID			0
+#define IFX_SPI_TIMEOUT_SEC		2
+#define IFX_SPI_HEADER_0		(-1)
+#define IFX_SPI_HEADER_F		(-2)
+
+/* forward reference */
+static void ifx_spi_handle_srdy(struct ifx_spi_device *ifx_dev);
+
+/* local variables */
+static int spi_b16 = 1;			/* 8 or 16 bit word length */
+static struct tty_driver *tty_drv;
+static struct ifx_spi_device *saved_ifx_dev;
+static struct lock_class_key ifx_spi_key;
+
+/* GPIO/GPE settings */
+
+/**
+ *	mrdy_set_high		-	set MRDY GPIO
+ *	@ifx: device we are controlling
+ *
+ */
+static inline void mrdy_set_high(struct ifx_spi_device *ifx)
+{
+	gpio_set_value(ifx->gpio.mrdy, 1);
+}
+
+/**
+ *	mrdy_set_low		-	clear MRDY GPIO
+ *	@ifx: device we are controlling
+ *
+ */
+static inline void mrdy_set_low(struct ifx_spi_device *ifx)
+{
+	gpio_set_value(ifx->gpio.mrdy, 0);
+}
+
+/**
+ *	ifx_spi_power_state_set
+ *	@ifx_dev: our SPI device
+ *	@val: bits to set
+ *
+ *	Set bit in power status and signal power system if status becomes non-0
+ */
+static void
+ifx_spi_power_state_set(struct ifx_spi_device *ifx_dev, unsigned char val)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&ifx_dev->power_lock, flags);
+
+	/*
+	 * if power status is already non-0, just update, else
+	 * tell power system
+	 */
+	if (!ifx_dev->power_status)
+		pm_runtime_get(&ifx_dev->spi_dev->dev);
+	ifx_dev->power_status |= val;
+
+	spin_unlock_irqrestore(&ifx_dev->power_lock, flags);
+}
+
+/**
+ *	ifx_spi_power_state_clear	-	clear power bit
+ *	@ifx_dev: our SPI device
+ *	@val: bits to clear
+ *
+ *	clear bit in power status and signal power system if status becomes 0
+ */
+static void
+ifx_spi_power_state_clear(struct ifx_spi_device *ifx_dev, unsigned char val)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&ifx_dev->power_lock, flags);
+
+	if (ifx_dev->power_status) {
+		ifx_dev->power_status &= ~val;
+		if (!ifx_dev->power_status)
+			pm_runtime_put(&ifx_dev->spi_dev->dev);
+	}
+
+	spin_unlock_irqrestore(&ifx_dev->power_lock, flags);
+}
+
+/**
+ *	swap_buf
+ *	@buf: our buffer
+ *	@len : number of bytes (not words) in the buffer
+ *	@end: end of buffer
+ *
+ *	Swap the contents of a buffer into big endian format
+ */
+static inline void swap_buf(u16 *buf, int len, void *end)
+{
+	int n;
+
+	len = ((len + 1) >> 1);
+	if ((void *)&buf[len] > end) {
+		pr_err("swap_buf: swap exceeds boundary (%p > %p)!",
+		       &buf[len], end);
+		return;
+	}
+	for (n = 0; n < len; n++) {
+		*buf = cpu_to_be16(*buf);
+		buf++;
+	}
+}
+
+/**
+ *	mrdy_assert		-	assert MRDY line
+ *	@ifx_dev: our SPI device
+ *
+ *	Assert mrdy and set timer to wait for SRDY interrupt, if SRDY is low
+ *	now.
+ *
+ *	FIXME: Can SRDY even go high as we are running this code ?
+ */
+static void mrdy_assert(struct ifx_spi_device *ifx_dev)
+{
+	int val = gpio_get_value(ifx_dev->gpio.srdy);
+	if (!val) {
+		if (!test_and_set_bit(IFX_SPI_STATE_TIMER_PENDING,
+				      &ifx_dev->flags)) {
+			ifx_dev->spi_timer.expires =
+				jiffies + IFX_SPI_TIMEOUT_SEC*HZ;
+			add_timer(&ifx_dev->spi_timer);
+
+		}
+	}
+	ifx_spi_power_state_set(ifx_dev, IFX_SPI_POWER_DATA_PENDING);
+	mrdy_set_high(ifx_dev);
+}
+
+/**
+ *	ifx_spi_hangup		-	hang up an IFX device
+ *	@ifx_dev: our SPI device
+ *
+ *	Hang up the tty attached to the IFX device if one is currently
+ *	open. If not take no action
+ */
+static void ifx_spi_ttyhangup(struct ifx_spi_device *ifx_dev)
+{
+	struct tty_port *pport = &ifx_dev->tty_port;
+	struct tty_struct *tty = tty_port_tty_get(pport);
+	if (tty) {
+		tty_hangup(tty);
+		tty_kref_put(tty);
+	}
+}
+
+/**
+ *	ifx_spi_timeout		-	SPI timeout
+ *	@arg: our SPI device
+ *
+ *	The SPI has timed out: hang up the tty. Users will then see a hangup
+ *	and error events.
+ */
+static void ifx_spi_timeout(unsigned long arg)
+{
+	struct ifx_spi_device *ifx_dev = (struct ifx_spi_device *)arg;
+
+	dev_warn(&ifx_dev->spi_dev->dev, "*** SPI Timeout ***");
+	ifx_spi_ttyhangup(ifx_dev);
+	mrdy_set_low(ifx_dev);
+	clear_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags);
+}
+
+/* char/tty operations */
+
+/**
+ *	ifx_spi_tiocmget	-	get modem lines
+ *	@tty: our tty device
+ *	@filp: file handle issuing the request
+ *
+ *	Map the signal state into Linux modem flags and report the value
+ *	in Linux terms
+ */
+static int ifx_spi_tiocmget(struct tty_struct *tty, struct file *filp)
+{
+	unsigned int value;
+	struct ifx_spi_device *ifx_dev = tty->driver_data;
+
+	value =
+	(test_bit(IFX_SPI_RTS, &ifx_dev->signal_state) ? TIOCM_RTS : 0) |
+	(test_bit(IFX_SPI_DTR, &ifx_dev->signal_state) ? TIOCM_DTR : 0) |
+	(test_bit(IFX_SPI_CTS, &ifx_dev->signal_state) ? TIOCM_CTS : 0) |
+	(test_bit(IFX_SPI_DSR, &ifx_dev->signal_state) ? TIOCM_DSR : 0) |
+	(test_bit(IFX_SPI_DCD, &ifx_dev->signal_state) ? TIOCM_CAR : 0) |
+	(test_bit(IFX_SPI_RI, &ifx_dev->signal_state) ? TIOCM_RNG : 0);
+	return value;
+}
+
+/**
+ *	ifx_spi_tiocmset	-	set modem bits
+ *	@tty: the tty structure
+ *	@filp: file handle issuing the request
+ *	@set: bits to set
+ *	@clear: bits to clear
+ *
+ *	The IFX6x60 only supports DTR and RTS. Set them accordingly
+ *	and flag that an update to the modem is needed.
+ *
+ *	FIXME: do we need to kick the tranfers when we do this ?
+ */
+static int ifx_spi_tiocmset(struct tty_struct *tty, struct file *filp,
+			    unsigned int set, unsigned int clear)
+{
+	struct ifx_spi_device *ifx_dev = tty->driver_data;
+
+	if (set & TIOCM_RTS)
+		set_bit(IFX_SPI_RTS, &ifx_dev->signal_state);
+	if (set & TIOCM_DTR)
+		set_bit(IFX_SPI_DTR, &ifx_dev->signal_state);
+	if (clear & TIOCM_RTS)
+		clear_bit(IFX_SPI_RTS, &ifx_dev->signal_state);
+	if (clear & TIOCM_DTR)
+		clear_bit(IFX_SPI_DTR, &ifx_dev->signal_state);
+
+	set_bit(IFX_SPI_UPDATE, &ifx_dev->signal_state);
+	return 0;
+}
+
+/**
+ *	ifx_spi_open	-	called on tty open
+ *	@tty: our tty device
+ *	@filp: file handle being associated with the tty
+ *
+ *	Open the tty interface. We let the tty_port layer do all the work
+ *	for us.
+ *
+ *	FIXME: Remove single device assumption and saved_ifx_dev
+ */
+static int ifx_spi_open(struct tty_struct *tty, struct file *filp)
+{
+	return tty_port_open(&saved_ifx_dev->tty_port, tty, filp);
+}
+
+/**
+ *	ifx_spi_close	-	called when our tty closes
+ *	@tty: the tty being closed
+ *	@filp: the file handle being closed
+ *
+ *	Perform the close of the tty. We use the tty_port layer to do all
+ *	our hard work.
+ */
+static void ifx_spi_close(struct tty_struct *tty, struct file *filp)
+{
+	struct ifx_spi_device *ifx_dev = tty->driver_data;
+	tty_port_close(&ifx_dev->tty_port, tty, filp);
+	/* FIXME: should we do an ifx_spi_reset here ? */
+}
+
+/**
+ *	ifx_decode_spi_header	-	decode received header
+ *	@buffer: the received data
+ *	@length: decoded length
+ *	@more: decoded more flag
+ *	@received_cts: status of cts we received
+ *
+ *	Note how received_cts is handled -- if header is all F it is left
+ *	the same as it was, if header is all 0 it is set to 0 otherwise it is
+ *	taken from the incoming header.
+ *
+ *	FIXME: endianness
+ */
+static int ifx_spi_decode_spi_header(unsigned char *buffer, int *length,
+			unsigned char *more, unsigned char *received_cts)
+{
+	u16 h1;
+	u16 h2;
+	u16 *in_buffer = (u16 *)buffer;
+
+	h1 = *in_buffer;
+	h2 = *(in_buffer+1);
+
+	if (h1 == 0 && h2 == 0) {
+		*received_cts = 0;
+		return IFX_SPI_HEADER_0;
+	} else if (h1 == 0xffff && h2 == 0xffff) {
+		/* spi_slave_cts remains as it was */
+		return IFX_SPI_HEADER_F;
+	}
+
+	*length = h1 & 0xfff;	/* upper bits of byte are flags */
+	*more = (buffer[1] >> IFX_SPI_MORE_BIT) & 1;
+	*received_cts = (buffer[3] >> IFX_SPI_CTS_BIT) & 1;
+	return 0;
+}
+
+/**
+ *	ifx_setup_spi_header	-	set header fields
+ *	@txbuffer: pointer to start of SPI buffer
+ *	@tx_count: bytes
+ *	@more: indicate if more to follow
+ *
+ *	Format up an SPI header for a transfer
+ *
+ *	FIXME: endianness?
+ */
+static void ifx_spi_setup_spi_header(unsigned char *txbuffer, int tx_count,
+					unsigned char more)
+{
+	*(u16 *)(txbuffer) = tx_count;
+	*(u16 *)(txbuffer+2) = IFX_SPI_PAYLOAD_SIZE;
+	txbuffer[1] |= (more << IFX_SPI_MORE_BIT) & IFX_SPI_MORE_MASK;
+}
+
+/**
+ *	ifx_spi_wakeup_serial	-	SPI space made
+ *	@port_data: our SPI device
+ *
+ *	We have emptied the FIFO enough that we want to get more data
+ *	queued into it. Poke the line discipline via tty_wakeup so that
+ *	it will feed us more bits
+ */
+static void ifx_spi_wakeup_serial(struct ifx_spi_device *ifx_dev)
+{
+	struct tty_struct *tty;
+
+	tty = tty_port_tty_get(&ifx_dev->tty_port);
+	if (!tty)
+		return;
+	tty_wakeup(tty);
+	tty_kref_put(tty);
+}
+
+/**
+ *	ifx_spi_prepare_tx_buffer	-	prepare transmit frame
+ *	@ifx_dev: our SPI device
+ *
+ *	The transmit buffr needs a header and various other bits of
+ *	information followed by as much data as we can pull from the FIFO
+ *	and transfer. This function formats up a suitable buffer in the
+ *	ifx_dev->tx_buffer
+ *
+ *	FIXME: performance - should we wake the tty when the queue is half
+ *			     empty ?
+ */
+static int ifx_spi_prepare_tx_buffer(struct ifx_spi_device *ifx_dev)
+{
+	int temp_count;
+	int queue_length;
+	int tx_count;
+	unsigned char *tx_buffer;
+
+	tx_buffer = ifx_dev->tx_buffer;
+	memset(tx_buffer, 0, IFX_SPI_TRANSFER_SIZE);
+
+	/* make room for required SPI header */
+	tx_buffer += IFX_SPI_HEADER_OVERHEAD;
+	tx_count = IFX_SPI_HEADER_OVERHEAD;
+
+	/* clear to signal no more data if this turns out to be the
+	 * last buffer sent in a sequence */
+	ifx_dev->spi_more = 0;
+
+	/* if modem cts is set, just send empty buffer */
+	if (!ifx_dev->spi_slave_cts) {
+		/* see if there's tx data */
+		queue_length = kfifo_len(&ifx_dev->tx_fifo);
+		if (queue_length != 0) {
+			/* data to mux -- see if there's room for it */
+			temp_count = min(queue_length, IFX_SPI_PAYLOAD_SIZE);
+			temp_count = kfifo_out_locked(&ifx_dev->tx_fifo,
+					tx_buffer, temp_count,
+					&ifx_dev->fifo_lock);
+
+			/* update buffer pointer and data count in message */
+			tx_buffer += temp_count;
+			tx_count += temp_count;
+			if (temp_count == queue_length)
+				/* poke port to get more data */
+				ifx_spi_wakeup_serial(ifx_dev);
+			else /* more data in port, use next SPI message */
+				ifx_dev->spi_more = 1;
+		}
+	}
+	/* have data and info for header -- set up SPI header in buffer */
+	/* spi header needs payload size, not entire buffer size */
+	ifx_spi_setup_spi_header(ifx_dev->tx_buffer,
+					tx_count-IFX_SPI_HEADER_OVERHEAD,
+					ifx_dev->spi_more);
+	/* swap actual data in the buffer */
+	swap_buf((u16 *)(ifx_dev->tx_buffer), tx_count,
+		&ifx_dev->tx_buffer[IFX_SPI_TRANSFER_SIZE]);
+	return tx_count;
+}
+
+/**
+ *	ifx_spi_write		-	line discipline write
+ *	@tty: our tty device
+ *	@buf: pointer to buffer to write (kernel space)
+ *	@count: size of buffer
+ *
+ *	Write the characters we have been given into the FIFO. If the device
+ *	is not active then activate it, when the SRDY line is asserted back
+ *	this will commence I/O
+ */
+static int ifx_spi_write(struct tty_struct *tty, const unsigned char *buf,
+			 int count)
+{
+	struct ifx_spi_device *ifx_dev = tty->driver_data;
+	unsigned char *tmp_buf = (unsigned char *)buf;
+	int tx_count = kfifo_in_locked(&ifx_dev->tx_fifo, tmp_buf, count,
+				   &ifx_dev->fifo_lock);
+	mrdy_assert(ifx_dev);
+	return tx_count;
+}
+
+/**
+ *	ifx_spi_chars_in_buffer	-	line discipline helper
+ *	@tty: our tty device
+ *
+ *	Report how much data we can accept before we drop bytes. As we use
+ *	a simple FIFO this is nice and easy.
+ */
+static int ifx_spi_write_room(struct tty_struct *tty)
+{
+	struct ifx_spi_device *ifx_dev = tty->driver_data;
+	return IFX_SPI_FIFO_SIZE - kfifo_len(&ifx_dev->tx_fifo);
+}
+
+/**
+ *	ifx_spi_chars_in_buffer	-	line discipline helper
+ *	@tty: our tty device
+ *
+ *	Report how many characters we have buffered. In our case this is the
+ *	number of bytes sitting in our transmit FIFO.
+ */
+static int ifx_spi_chars_in_buffer(struct tty_struct *tty)
+{
+	struct ifx_spi_device *ifx_dev = tty->driver_data;
+	return kfifo_len(&ifx_dev->tx_fifo);
+}
+
+/**
+ *	ifx_port_hangup
+ *	@port: our tty port
+ *
+ *	tty port hang up. Called when tty_hangup processing is invoked either
+ *	by loss of carrier, or by software (eg vhangup). Serialized against
+ *	activate/shutdown by the tty layer.
+ */
+static void ifx_spi_hangup(struct tty_struct *tty)
+{
+	struct ifx_spi_device *ifx_dev = tty->driver_data;
+	tty_port_hangup(&ifx_dev->tty_port);
+}
+
+/**
+ *	ifx_port_activate
+ *	@port: our tty port
+ *
+ *	tty port activate method - called for first open. Serialized
+ *	with hangup and shutdown by the tty layer.
+ */
+static int ifx_port_activate(struct tty_port *port, struct tty_struct *tty)
+{
+	struct ifx_spi_device *ifx_dev =
+		container_of(port, struct ifx_spi_device, tty_port);
+
+	/* clear any old data; can't do this in 'close' */
+	kfifo_reset(&ifx_dev->tx_fifo);
+
+	/* put port data into this tty */
+	tty->driver_data = ifx_dev;
+
+	/* allows flip string push from int context */
+	tty->low_latency = 1;
+
+	return 0;
+}
+
+/**
+ *	ifx_port_shutdown
+ *	@port: our tty port
+ *
+ *	tty port shutdown method - called for last port close. Serialized
+ *	with hangup and activate by the tty layer.
+ */
+static void ifx_port_shutdown(struct tty_port *port)
+{
+	struct ifx_spi_device *ifx_dev =
+		container_of(port, struct ifx_spi_device, tty_port);
+
+	mrdy_set_low(ifx_dev);
+	clear_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags);
+	tasklet_kill(&ifx_dev->io_work_tasklet);
+}
+
+static const struct tty_port_operations ifx_tty_port_ops = {
+	.activate = ifx_port_activate,
+	.shutdown = ifx_port_shutdown,
+};
+
+static const struct tty_operations ifx_spi_serial_ops = {
+	.open = ifx_spi_open,
+	.close = ifx_spi_close,
+	.write = ifx_spi_write,
+	.hangup = ifx_spi_hangup,
+	.write_room = ifx_spi_write_room,
+	.chars_in_buffer = ifx_spi_chars_in_buffer,
+	.tiocmget = ifx_spi_tiocmget,
+	.tiocmset = ifx_spi_tiocmset,
+};
+
+/**
+ *	ifx_spi_insert_fip_string	-	queue received data
+ *	@ifx_ser: our SPI device
+ *	@chars: buffer we have received
+ *	@size: number of chars reeived
+ *
+ *	Queue bytes to the tty assuming the tty side is currently open. If
+ *	not the discard the data.
+ */
+static void ifx_spi_insert_flip_string(struct ifx_spi_device *ifx_dev,
+				    unsigned char *chars, size_t size)
+{
+	struct tty_struct *tty = tty_port_tty_get(&ifx_dev->tty_port);
+	if (!tty)
+		return;
+	tty_insert_flip_string(tty, chars, size);
+	tty_flip_buffer_push(tty);
+	tty_kref_put(tty);
+}
+
+/**
+ *	ifx_spi_complete	-	SPI transfer completed
+ *	@ctx: our SPI device
+ *
+ *	An SPI transfer has completed. Process any received data and kick off
+ *	any further transmits we can commence.
+ */
+static void ifx_spi_complete(void *ctx)
+{
+	struct ifx_spi_device *ifx_dev = ctx;
+	struct tty_struct *tty;
+	struct tty_ldisc *ldisc = NULL;
+	int length;
+	int actual_length;
+	unsigned char more;
+	unsigned char cts;
+	int local_write_pending = 0;
+	int queue_length;
+	int srdy;
+	int decode_result;
+
+	mrdy_set_low(ifx_dev);
+
+	if (!ifx_dev->spi_msg.status) {
+		/* check header validity, get comm flags */
+		swap_buf((u16 *)ifx_dev->rx_buffer, IFX_SPI_HEADER_OVERHEAD,
+			&ifx_dev->rx_buffer[IFX_SPI_HEADER_OVERHEAD]);
+		decode_result = ifx_spi_decode_spi_header(ifx_dev->rx_buffer,
+				&length, &more, &cts);
+		if (decode_result == IFX_SPI_HEADER_0) {
+			dev_dbg(&ifx_dev->spi_dev->dev,
+				"ignore input: invalid header 0");
+			ifx_dev->spi_slave_cts = 0;
+			goto complete_exit;
+		} else if (decode_result == IFX_SPI_HEADER_F) {
+			dev_dbg(&ifx_dev->spi_dev->dev,
+				"ignore input: invalid header F");
+			goto complete_exit;
+		}
+
+		ifx_dev->spi_slave_cts = cts;
+
+		actual_length = min((unsigned int)length,
+					ifx_dev->spi_msg.actual_length);
+		swap_buf((u16 *)(ifx_dev->rx_buffer + IFX_SPI_HEADER_OVERHEAD),
+			 actual_length,
+			 &ifx_dev->rx_buffer[IFX_SPI_TRANSFER_SIZE]);
+		ifx_spi_insert_flip_string(
+			ifx_dev,
+			ifx_dev->rx_buffer + IFX_SPI_HEADER_OVERHEAD,
+			(size_t)actual_length);
+	} else {
+		dev_dbg(&ifx_dev->spi_dev->dev, "SPI transfer error %d",
+		       ifx_dev->spi_msg.status);
+	}
+
+complete_exit:
+	if (ifx_dev->write_pending) {
+		ifx_dev->write_pending = 0;
+		local_write_pending = 1;
+	}
+
+	clear_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &(ifx_dev->flags));
+
+	queue_length = kfifo_len(&ifx_dev->tx_fifo);
+	srdy = gpio_get_value(ifx_dev->gpio.srdy);
+	if (!srdy)
+		ifx_spi_power_state_clear(ifx_dev, IFX_SPI_POWER_SRDY);
+
+	/* schedule output if there is more to do */
+	if (test_and_clear_bit(IFX_SPI_STATE_IO_READY, &ifx_dev->flags))
+		tasklet_schedule(&ifx_dev->io_work_tasklet);
+	else {
+		if (more || ifx_dev->spi_more || queue_length > 0 ||
+			local_write_pending) {
+			if (ifx_dev->spi_slave_cts) {
+				if (more)
+					mrdy_assert(ifx_dev);
+			} else
+				mrdy_assert(ifx_dev);
+		} else {
+			/*
+			 * poke line discipline driver if any for more data
+			 * may or may not get more data to write
+			 * for now, say not busy
+			 */
+			ifx_spi_power_state_clear(ifx_dev,
+						  IFX_SPI_POWER_DATA_PENDING);
+			tty = tty_port_tty_get(&ifx_dev->tty_port);
+			if (tty) {
+				ldisc = tty_ldisc_ref(tty);
+				if (ldisc) {
+					ldisc->ops->write_wakeup(tty);
+					tty_ldisc_deref(ldisc);
+				}
+				tty_kref_put(tty);
+			}
+		}
+	}
+}
+
+/**
+ *	ifx_spio_io		-	I/O tasklet
+ *	@data: our SPI device
+ *
+ *	Queue data for transmission if possible and then kick off the
+ *	transfer.
+ */
+static void ifx_spi_io(unsigned long data)
+{
+	int retval;
+	struct ifx_spi_device *ifx_dev = (struct ifx_spi_device *) data;
+
+	if (!test_and_set_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &ifx_dev->flags)) {
+		if (ifx_dev->gpio.unack_srdy_int_nb > 0)
+			ifx_dev->gpio.unack_srdy_int_nb--;
+
+		ifx_spi_prepare_tx_buffer(ifx_dev);
+
+		spi_message_init(&ifx_dev->spi_msg);
+		INIT_LIST_HEAD(&ifx_dev->spi_msg.queue);
+
+		ifx_dev->spi_msg.context = ifx_dev;
+		ifx_dev->spi_msg.complete = ifx_spi_complete;
+
+		/* set up our spi transfer */
+		/* note len is BYTES, not transfers */
+		ifx_dev->spi_xfer.len = IFX_SPI_TRANSFER_SIZE;
+		ifx_dev->spi_xfer.cs_change = 0;
+		ifx_dev->spi_xfer.speed_hz = 12500000;
+		/* ifx_dev->spi_xfer.speed_hz = 390625; */
+		ifx_dev->spi_xfer.bits_per_word = spi_b16 ? 16 : 8;
+
+		ifx_dev->spi_xfer.tx_buf = ifx_dev->tx_buffer;
+		ifx_dev->spi_xfer.rx_buf = ifx_dev->rx_buffer;
+
+		/*
+		 * setup dma pointers
+		 */
+		if (ifx_dev->is_6160) {
+			ifx_dev->spi_msg.is_dma_mapped = 1;
+			ifx_dev->tx_dma = ifx_dev->tx_bus;
+			ifx_dev->rx_dma = ifx_dev->rx_bus;
+			ifx_dev->spi_xfer.tx_dma = ifx_dev->tx_dma;
+			ifx_dev->spi_xfer.rx_dma = ifx_dev->rx_dma;
+		} else {
+			ifx_dev->spi_msg.is_dma_mapped = 0;
+			ifx_dev->tx_dma = (dma_addr_t)0;
+			ifx_dev->rx_dma = (dma_addr_t)0;
+			ifx_dev->spi_xfer.tx_dma = (dma_addr_t)0;
+			ifx_dev->spi_xfer.rx_dma = (dma_addr_t)0;
+		}
+
+		spi_message_add_tail(&ifx_dev->spi_xfer, &ifx_dev->spi_msg);
+
+		/* Assert MRDY. This may have already been done by the write
+		 * routine.
+		 */
+		mrdy_assert(ifx_dev);
+
+		retval = spi_async(ifx_dev->spi_dev, &ifx_dev->spi_msg);
+		if (retval) {
+			clear_bit(IFX_SPI_STATE_IO_IN_PROGRESS,
+				  &ifx_dev->flags);
+			tasklet_schedule(&ifx_dev->io_work_tasklet);
+			return;
+		}
+	} else
+		ifx_dev->write_pending = 1;
+}
+
+/**
+ *	ifx_spi_free_port	-	free up the tty side
+ *	@ifx_dev: IFX device going away
+ *
+ *	Unregister and free up a port when the device goes away
+ */
+static void ifx_spi_free_port(struct ifx_spi_device *ifx_dev)
+{
+	if (ifx_dev->tty_dev)
+		tty_unregister_device(tty_drv, ifx_dev->minor);
+	kfifo_free(&ifx_dev->tx_fifo);
+}
+
+/**
+ *	ifx_spi_create_port	-	create a new port
+ *	@ifx_dev: our spi device
+ *
+ *	Allocate and initialise the tty port that goes with this interface
+ *	and add it to the tty layer so that it can be opened.
+ */
+static int ifx_spi_create_port(struct ifx_spi_device *ifx_dev)
+{
+	int ret = 0;
+	struct tty_port *pport = &ifx_dev->tty_port;
+
+	spin_lock_init(&ifx_dev->fifo_lock);
+	lockdep_set_class_and_subclass(&ifx_dev->fifo_lock,
+		&ifx_spi_key, 0);
+
+	if (kfifo_alloc(&ifx_dev->tx_fifo, IFX_SPI_FIFO_SIZE, GFP_KERNEL)) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	pport->ops = &ifx_tty_port_ops;
+	tty_port_init(pport);
+	ifx_dev->minor = IFX_SPI_TTY_ID;
+	ifx_dev->tty_dev = tty_register_device(tty_drv, ifx_dev->minor,
+					       &ifx_dev->spi_dev->dev);
+	if (IS_ERR(ifx_dev->tty_dev)) {
+		dev_dbg(&ifx_dev->spi_dev->dev,
+			"%s: registering tty device failed", __func__);
+		ret = PTR_ERR(ifx_dev->tty_dev);
+		goto error_ret;
+	}
+	return 0;
+
+error_ret:
+	ifx_spi_free_port(ifx_dev);
+	return ret;
+}
+
+/**
+ *	ifx_spi_handle_srdy		-	handle SRDY
+ *	@ifx_dev: device asserting SRDY
+ *
+ *	Check our device state and see what we need to kick off when SRDY
+ *	is asserted. This usually means killing the timer and firing off the
+ *	I/O processing.
+ */
+static void ifx_spi_handle_srdy(struct ifx_spi_device *ifx_dev)
+{
+	if (test_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags)) {
+		del_timer_sync(&ifx_dev->spi_timer);
+		clear_bit(IFX_SPI_STATE_TIMER_PENDING, &ifx_dev->flags);
+	}
+
+	ifx_spi_power_state_set(ifx_dev, IFX_SPI_POWER_SRDY);
+
+	if (!test_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &ifx_dev->flags))
+		tasklet_schedule(&ifx_dev->io_work_tasklet);
+	else
+		set_bit(IFX_SPI_STATE_IO_READY, &ifx_dev->flags);
+}
+
+/**
+ *	ifx_spi_srdy_interrupt	-	SRDY asserted
+ *	@irq: our IRQ number
+ *	@dev: our ifx device
+ *
+ *	The modem asserted SRDY. Handle the srdy event
+ */
+static irqreturn_t ifx_spi_srdy_interrupt(int irq, void *dev)
+{
+	struct ifx_spi_device *ifx_dev = dev;
+	ifx_dev->gpio.unack_srdy_int_nb++;
+	ifx_spi_handle_srdy(ifx_dev);
+	return IRQ_HANDLED;
+}
+
+/**
+ *	ifx_spi_reset_interrupt	-	Modem has changed reset state
+ *	@irq: interrupt number
+ *	@dev: our device pointer
+ *
+ *	The modem has either entered or left reset state. Check the GPIO
+ *	line to see which.
+ *
+ *	FIXME: review locking on MR_INPROGRESS versus
+ *	parallel unsolicited reset/solicited reset
+ */
+static irqreturn_t ifx_spi_reset_interrupt(int irq, void *dev)
+{
+	struct ifx_spi_device *ifx_dev = dev;
+	int val = gpio_get_value(ifx_dev->gpio.reset_out);
+	int solreset = test_bit(MR_START, &ifx_dev->mdm_reset_state);
+
+	if (val == 0) {
+		/* entered reset */
+		set_bit(MR_INPROGRESS, &ifx_dev->mdm_reset_state);
+		if (!solreset) {
+			/* unsolicited reset  */
+			ifx_spi_ttyhangup(ifx_dev);
+		}
+	} else {
+		/* exited reset */
+		clear_bit(MR_INPROGRESS, &ifx_dev->mdm_reset_state);
+		if (solreset) {
+			set_bit(MR_COMPLETE, &ifx_dev->mdm_reset_state);
+			wake_up(&ifx_dev->mdm_reset_wait);
+		}
+	}
+	return IRQ_HANDLED;
+}
+
+/**
+ *	ifx_spi_free_device - free device
+ *	@ifx_dev: device to free
+ *
+ *	Free the IFX device
+ */
+static void ifx_spi_free_device(struct ifx_spi_device *ifx_dev)
+{
+	ifx_spi_free_port(ifx_dev);
+	dma_free_coherent(&ifx_dev->spi_dev->dev,
+				IFX_SPI_TRANSFER_SIZE,
+				ifx_dev->tx_buffer,
+				ifx_dev->tx_bus);
+	dma_free_coherent(&ifx_dev->spi_dev->dev,
+				IFX_SPI_TRANSFER_SIZE,
+				ifx_dev->rx_buffer,
+				ifx_dev->rx_bus);
+}
+
+/**
+ *	ifx_spi_reset	-	reset modem
+ *	@ifx_dev: modem to reset
+ *
+ *	Perform a reset on the modem
+ */
+static int ifx_spi_reset(struct ifx_spi_device *ifx_dev)
+{
+	int ret;
+	/*
+	 * set up modem power, reset
+	 *
+	 * delays are required on some platforms for the modem
+	 * to reset properly
+	 */
+	set_bit(MR_START, &ifx_dev->mdm_reset_state);
+	gpio_set_value(ifx_dev->gpio.po, 0);
+	gpio_set_value(ifx_dev->gpio.reset, 0);
+	msleep(25);
+	gpio_set_value(ifx_dev->gpio.reset, 1);
+	msleep(1);
+	gpio_set_value(ifx_dev->gpio.po, 1);
+	msleep(1);
+	gpio_set_value(ifx_dev->gpio.po, 0);
+	ret = wait_event_timeout(ifx_dev->mdm_reset_wait,
+				 test_bit(MR_COMPLETE,
+					  &ifx_dev->mdm_reset_state),
+				 IFX_RESET_TIMEOUT);
+	if (!ret)
+		dev_warn(&ifx_dev->spi_dev->dev, "Modem reset timeout: (state:%lx)",
+			 ifx_dev->mdm_reset_state);
+
+	ifx_dev->mdm_reset_state = 0;
+	return ret;
+}
+
+/**
+ *	ifx_spi_spi_probe	-	probe callback
+ *	@spi: our possible matching SPI device
+ *
+ *	Probe for a 6x60 modem on SPI bus. Perform any needed device and
+ *	GPIO setup.
+ *
+ *	FIXME:
+ *	-	Support for multiple devices
+ *	-	Split out MID specific GPIO handling eventually
+ */
+
+static int ifx_spi_spi_probe(struct spi_device *spi)
+{
+	int ret;
+	int srdy;
+	struct ifx_modem_platform_data *pl_data = NULL;
+	struct ifx_spi_device *ifx_dev;
+
+	if (saved_ifx_dev) {
+		dev_dbg(&spi->dev, "ignoring subsequent detection");
+		return -ENODEV;
+	}
+
+	/* initialize structure to hold our device variables */
+	ifx_dev = kzalloc(sizeof(struct ifx_spi_device), GFP_KERNEL);
+	if (!ifx_dev) {
+		dev_err(&spi->dev, "spi device allocation failed");
+		return -ENOMEM;
+	}
+	saved_ifx_dev = ifx_dev;
+	ifx_dev->spi_dev = spi;
+	clear_bit(IFX_SPI_STATE_IO_IN_PROGRESS, &ifx_dev->flags);
+	spin_lock_init(&ifx_dev->write_lock);
+	spin_lock_init(&ifx_dev->power_lock);
+	ifx_dev->power_status = 0;
+	init_timer(&ifx_dev->spi_timer);
+	ifx_dev->spi_timer.function = ifx_spi_timeout;
+	ifx_dev->spi_timer.data = (unsigned long)ifx_dev;
+	ifx_dev->is_6160 = pl_data->is_6160;
+
+	/* ensure SPI protocol flags are initialized to enable transfer */
+	ifx_dev->spi_more = 0;
+	ifx_dev->spi_slave_cts = 0;
+
+	/*initialize transfer and dma buffers */
+	ifx_dev->tx_buffer = dma_alloc_coherent(&ifx_dev->spi_dev->dev,
+				IFX_SPI_TRANSFER_SIZE,
+				&ifx_dev->tx_bus,
+				GFP_KERNEL);
+	if (!ifx_dev->tx_buffer) {
+		dev_err(&spi->dev, "DMA-TX buffer allocation failed");
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+	ifx_dev->rx_buffer = dma_alloc_coherent(&ifx_dev->spi_dev->dev,
+				IFX_SPI_TRANSFER_SIZE,
+				&ifx_dev->rx_bus,
+				GFP_KERNEL);
+	if (!ifx_dev->rx_buffer) {
+		dev_err(&spi->dev, "DMA-RX buffer allocation failed");
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	/* initialize waitq for modem reset */
+	init_waitqueue_head(&ifx_dev->mdm_reset_wait);
+
+	spi_set_drvdata(spi, ifx_dev);
+	tasklet_init(&ifx_dev->io_work_tasklet, ifx_spi_io,
+						(unsigned long)ifx_dev);
+
+	set_bit(IFX_SPI_STATE_PRESENT, &ifx_dev->flags);
+
+	/* create our tty port */
+	ret = ifx_spi_create_port(ifx_dev);
+	if (ret != 0) {
+		dev_err(&spi->dev, "create default tty port failed");
+		goto error_ret;
+	}
+
+	pl_data = (struct ifx_modem_platform_data *)spi->dev.platform_data;
+	if (pl_data) {
+		ifx_dev->gpio.reset = pl_data->rst_pmu;
+		ifx_dev->gpio.po = pl_data->pwr_on;
+		ifx_dev->gpio.mrdy = pl_data->mrdy;
+		ifx_dev->gpio.srdy = pl_data->srdy;
+		ifx_dev->gpio.reset_out = pl_data->rst_out;
+	} else {
+		dev_err(&spi->dev, "missing platform data!");
+		ret = -ENODEV;
+		goto error_ret;
+	}
+
+	dev_info(&spi->dev, "gpios %d, %d, %d, %d, %d",
+		 ifx_dev->gpio.reset, ifx_dev->gpio.po, ifx_dev->gpio.mrdy,
+		 ifx_dev->gpio.srdy, ifx_dev->gpio.reset_out);
+
+	/* Configure gpios */
+	ret = gpio_request(ifx_dev->gpio.reset, "ifxModem");
+	if (ret < 0) {
+		dev_err(&spi->dev, "Unable to allocate GPIO%d (RESET)",
+			ifx_dev->gpio.reset);
+		goto error_ret;
+	}
+	ret += gpio_direction_output(ifx_dev->gpio.reset, 0);
+	ret += gpio_export(ifx_dev->gpio.reset, 1);
+	if (ret) {
+		dev_err(&spi->dev, "Unable to configure GPIO%d (RESET)",
+			ifx_dev->gpio.reset);
+		ret = -EBUSY;
+		goto error_ret2;
+	}
+
+	ret = gpio_request(ifx_dev->gpio.po, "ifxModem");
+	ret += gpio_direction_output(ifx_dev->gpio.po, 0);
+	ret += gpio_export(ifx_dev->gpio.po, 1);
+	if (ret) {
+		dev_err(&spi->dev, "Unable to configure GPIO%d (ON)",
+			ifx_dev->gpio.po);
+		ret = -EBUSY;
+		goto error_ret3;
+	}
+
+	ret = gpio_request(ifx_dev->gpio.mrdy, "ifxModem");
+	if (ret < 0) {
+		dev_err(&spi->dev, "Unable to allocate GPIO%d (MRDY)",
+			ifx_dev->gpio.mrdy);
+		goto error_ret3;
+	}
+	ret += gpio_export(ifx_dev->gpio.mrdy, 1);
+	ret += gpio_direction_output(ifx_dev->gpio.mrdy, 0);
+	if (ret) {
+		dev_err(&spi->dev, "Unable to configure GPIO%d (MRDY)",
+			ifx_dev->gpio.mrdy);
+		ret = -EBUSY;
+		goto error_ret4;
+	}
+
+	ret = gpio_request(ifx_dev->gpio.srdy, "ifxModem");
+	if (ret < 0) {
+		dev_err(&spi->dev, "Unable to allocate GPIO%d (SRDY)",
+			ifx_dev->gpio.srdy);
+		ret = -EBUSY;
+		goto error_ret4;
+	}
+	ret += gpio_export(ifx_dev->gpio.srdy, 1);
+	ret += gpio_direction_input(ifx_dev->gpio.srdy);
+	if (ret) {
+		dev_err(&spi->dev, "Unable to configure GPIO%d (SRDY)",
+			ifx_dev->gpio.srdy);
+		ret = -EBUSY;
+		goto error_ret5;
+	}
+
+	ret = gpio_request(ifx_dev->gpio.reset_out, "ifxModem");
+	if (ret < 0) {
+		dev_err(&spi->dev, "Unable to allocate GPIO%d (RESET_OUT)",
+			ifx_dev->gpio.reset_out);
+		goto error_ret5;
+	}
+	ret += gpio_export(ifx_dev->gpio.reset_out, 1);
+	ret += gpio_direction_input(ifx_dev->gpio.reset_out);
+	if (ret) {
+		dev_err(&spi->dev, "Unable to configure GPIO%d (RESET_OUT)",
+			ifx_dev->gpio.reset_out);
+		ret = -EBUSY;
+		goto error_ret6;
+	}
+
+	ret = request_irq(gpio_to_irq(ifx_dev->gpio.reset_out),
+			  ifx_spi_reset_interrupt,
+			  IRQF_TRIGGER_RISING|IRQF_TRIGGER_FALLING, DRVNAME,
+		(void *)ifx_dev);
+	if (ret) {
+		dev_err(&spi->dev, "Unable to get irq %x\n",
+			gpio_to_irq(ifx_dev->gpio.reset_out));
+		goto error_ret6;
+	}
+
+	ret = ifx_spi_reset(ifx_dev);
+
+	ret = request_irq(gpio_to_irq(ifx_dev->gpio.srdy),
+			  ifx_spi_srdy_interrupt,
+			  IRQF_TRIGGER_RISING, DRVNAME,
+			  (void *)ifx_dev);
+	if (ret) {
+		dev_err(&spi->dev, "Unable to get irq %x",
+			gpio_to_irq(ifx_dev->gpio.srdy));
+		goto error_ret6;
+	}
+
+	/* set pm runtime power state and register with power system */
+	pm_runtime_set_active(&spi->dev);
+	pm_runtime_enable(&spi->dev);
+
+	/* handle case that modem is already signaling SRDY */
+	/* no outgoing tty open at this point, this just satisfies the
+	 * modem's read and should reset communication properly
+	 */
+	srdy = gpio_get_value(ifx_dev->gpio.srdy);
+
+	if (srdy) {
+		mrdy_assert(ifx_dev);
+		ifx_spi_handle_srdy(ifx_dev);
+	} else
+		mrdy_set_low(ifx_dev);
+	return 0;
+
+error_ret6:
+	gpio_free(ifx_dev->gpio.srdy);
+error_ret5:
+	gpio_free(ifx_dev->gpio.mrdy);
+error_ret4:
+	gpio_free(ifx_dev->gpio.reset);
+error_ret3:
+	gpio_free(ifx_dev->gpio.po);
+error_ret2:
+	gpio_free(ifx_dev->gpio.reset_out);
+error_ret:
+	ifx_spi_free_device(ifx_dev);
+	saved_ifx_dev = NULL;
+	return ret;
+}
+
+/**
+ *	ifx_spi_spi_remove	-	SPI device was removed
+ *	@spi: SPI device
+ *
+ *	FIXME: We should be shutting the device down here not in
+ *	the module unload path.
+ */
+
+static int ifx_spi_spi_remove(struct spi_device *spi)
+{
+	struct ifx_spi_device *ifx_dev = spi_get_drvdata(spi);
+	/* stop activity */
+	tasklet_kill(&ifx_dev->io_work_tasklet);
+	/* free irq */
+	free_irq(gpio_to_irq(ifx_dev->gpio.reset_out), (void *)ifx_dev);
+	free_irq(gpio_to_irq(ifx_dev->gpio.srdy), (void *)ifx_dev);
+
+	gpio_free(ifx_dev->gpio.srdy);
+	gpio_free(ifx_dev->gpio.mrdy);
+	gpio_free(ifx_dev->gpio.reset);
+	gpio_free(ifx_dev->gpio.po);
+	gpio_free(ifx_dev->gpio.reset_out);
+
+	/* free allocations */
+	ifx_spi_free_device(ifx_dev);
+
+	saved_ifx_dev = NULL;
+	return 0;
+}
+
+/**
+ *	ifx_spi_spi_shutdown	-	called on SPI shutdown
+ *	@spi: SPI device
+ *
+ *	No action needs to be taken here
+ */
+
+static void ifx_spi_spi_shutdown(struct spi_device *spi)
+{
+}
+
+/*
+ * various suspends and resumes have nothing to do
+ * no hardware to save state for
+ */
+
+/**
+ *	ifx_spi_spi_suspend	-	suspend SPI on system suspend
+ *	@dev: device being suspended
+ *
+ *	Suspend the SPI side. No action needed on Intel MID platforms, may
+ *	need extending for other systems.
+ */
+static int ifx_spi_spi_suspend(struct spi_device *spi, pm_message_t msg)
+{
+	return 0;
+}
+
+/**
+ *	ifx_spi_spi_resume	-	resume SPI side on system resume
+ *	@dev: device being suspended
+ *
+ *	Suspend the SPI side. No action needed on Intel MID platforms, may
+ *	need extending for other systems.
+ */
+static int ifx_spi_spi_resume(struct spi_device *spi)
+{
+	return 0;
+}
+
+/**
+ *	ifx_spi_pm_suspend	-	suspend modem on system suspend
+ *	@dev: device being suspended
+ *
+ *	Suspend the modem. No action needed on Intel MID platforms, may
+ *	need extending for other systems.
+ */
+static int ifx_spi_pm_suspend(struct device *dev)
+{
+	return 0;
+}
+
+/**
+ *	ifx_spi_pm_resume	-	resume modem on system resume
+ *	@dev: device being suspended
+ *
+ *	Allow the modem to resume. No action needed.
+ *
+ *	FIXME: do we need to reset anything here ?
+ */
+static int ifx_spi_pm_resume(struct device *dev)
+{
+	return 0;
+}
+
+/**
+ *	ifx_spi_pm_runtime_resume	-	suspend modem
+ *	@dev: device being suspended
+ *
+ *	Allow the modem to resume. No action needed.
+ */
+static int ifx_spi_pm_runtime_resume(struct device *dev)
+{
+	return 0;
+}
+
+/**
+ *	ifx_spi_pm_runtime_suspend	-	suspend modem
+ *	@dev: device being suspended
+ *
+ *	Allow the modem to suspend and thus suspend to continue up the
+ *	device tree.
+ */
+static int ifx_spi_pm_runtime_suspend(struct device *dev)
+{
+	return 0;
+}
+
+/**
+ *	ifx_spi_pm_runtime_idle		-	check if modem idle
+ *	@dev: our device
+ *
+ *	Check conditions and queue runtime suspend if idle.
+ */
+static int ifx_spi_pm_runtime_idle(struct device *dev)
+{
+	struct spi_device *spi = to_spi_device(dev);
+	struct ifx_spi_device *ifx_dev = spi_get_drvdata(spi);
+
+	if (!ifx_dev->power_status)
+		pm_runtime_suspend(dev);
+
+	return 0;
+}
+
+static const struct dev_pm_ops ifx_spi_pm = {
+	.resume = ifx_spi_pm_resume,
+	.suspend = ifx_spi_pm_suspend,
+	.runtime_resume = ifx_spi_pm_runtime_resume,
+	.runtime_suspend = ifx_spi_pm_runtime_suspend,
+	.runtime_idle = ifx_spi_pm_runtime_idle
+};
+
+static const struct spi_device_id ifx_id_table[] = {
+	{"ifx6160", 0},
+	{"ifx6260", 0},
+	{ }
+};
+MODULE_DEVICE_TABLE(spi, ifx_id_table);
+
+/* spi operations */
+static const struct spi_driver ifx_spi_driver_6160 = {
+	.driver = {
+		.name = "ifx6160",
+		.bus = &spi_bus_type,
+		.pm = &ifx_spi_pm,
+		.owner = THIS_MODULE},
+	.probe = ifx_spi_spi_probe,
+	.shutdown = ifx_spi_spi_shutdown,
+	.remove = __devexit_p(ifx_spi_spi_remove),
+	.suspend = ifx_spi_spi_suspend,
+	.resume = ifx_spi_spi_resume,
+	.id_table = ifx_id_table
+};
+
+/**
+ *	ifx_spi_exit	-	module exit
+ *
+ *	Unload the module.
+ */
+
+static void __exit ifx_spi_exit(void)
+{
+	/* unregister */
+	tty_unregister_driver(tty_drv);
+	spi_unregister_driver((void *)&ifx_spi_driver_6160);
+}
+
+/**
+ *	ifx_spi_init		-	module entry point
+ *
+ *	Initialise the SPI and tty interfaces for the IFX SPI driver
+ *	We need to initialize upper-edge spi driver after the tty
+ *	driver because otherwise the spi probe will race
+ */
+
+static int __init ifx_spi_init(void)
+{
+	int result;
+
+	tty_drv = alloc_tty_driver(1);
+	if (!tty_drv) {
+		pr_err("%s: alloc_tty_driver failed", DRVNAME);
+		return -ENOMEM;
+	}
+
+	tty_drv->magic = TTY_DRIVER_MAGIC;
+	tty_drv->owner = THIS_MODULE;
+	tty_drv->driver_name = DRVNAME;
+	tty_drv->name = TTYNAME;
+	tty_drv->minor_start = IFX_SPI_TTY_ID;
+	tty_drv->num = 1;
+	tty_drv->type = TTY_DRIVER_TYPE_SERIAL;
+	tty_drv->subtype = SERIAL_TYPE_NORMAL;
+	tty_drv->flags = TTY_DRIVER_REAL_RAW | TTY_DRIVER_DYNAMIC_DEV;
+	tty_drv->init_termios = tty_std_termios;
+
+	tty_set_operations(tty_drv, &ifx_spi_serial_ops);
+
+	result = tty_register_driver(tty_drv);
+	if (result) {
+		pr_err("%s: tty_register_driver failed(%d)",
+			DRVNAME, result);
+		return result;
+	}
+
+	result = spi_register_driver((void *)&ifx_spi_driver_6160);
+	if (result) {
+		pr_err("%s: spi_register_driver failed(%d)",
+			DRVNAME, result);
+		tty_unregister_driver(tty_drv);
+	}
+	return result;
+}
+
+module_init(ifx_spi_init);
+module_exit(ifx_spi_exit);
+
+MODULE_AUTHOR("Intel");
+MODULE_DESCRIPTION("IFX6x60 spi driver");
+MODULE_LICENSE("GPL");
+MODULE_INFO(Version, "0.1-IFX6x60");

drivers/serial/ifx6x60.h

+/****************************************************************************
+ *
+ * Driver for the IFX spi modem.
+ *
+ * Copyright (C) 2009, 2010 Intel Corp
+ * Jim Stanley <jim.stanley@intel.com>
+ *
+ *
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301,
+ * USA
+ *
+ *
+ *
+ *****************************************************************************/
+#ifndef _IFX6X60_H
+#define _IFX6X60_H
+
+#define DRVNAME				"ifx6x60"
+#define TTYNAME				"ttyIFX"
+
+/* #define IFX_THROTTLE_CODE */
+
+#define IFX_SPI_MAX_MINORS		1
+#define IFX_SPI_TRANSFER_SIZE		2048
+#define IFX_SPI_FIFO_SIZE		4096
+
+#define IFX_SPI_HEADER_OVERHEAD		4
+#define IFX_RESET_TIMEOUT		msecs_to_jiffies(50)
+
+/* device flags bitfield definitions */
+#define IFX_SPI_STATE_PRESENT		0
+#define IFX_SPI_STATE_IO_IN_PROGRESS	1
+#define IFX_SPI_STATE_IO_READY		2
+#define IFX_SPI_STATE_TIMER_PENDING	3
+
+/* flow control bitfields */
+#define IFX_SPI_DCD			0
+#define IFX_SPI_CTS			1
+#define IFX_SPI_DSR			2
+#define IFX_SPI_RI			3
+#define IFX_SPI_DTR			4
+#define IFX_SPI_RTS			5
+#define IFX_SPI_TX_FC			6
+#define IFX_SPI_RX_FC			7
+#define IFX_SPI_UPDATE			8
+
+#define IFX_SPI_PAYLOAD_SIZE		(IFX_SPI_TRANSFER_SIZE - \
+						IFX_SPI_HEADER_OVERHEAD)
+
+#define IFX_SPI_IRQ_TYPE		DETECT_EDGE_RISING
+#define IFX_SPI_GPIO_TARGET		0
+#define IFX_SPI_GPIO0			0x105
+
+#define IFX_SPI_STATUS_TIMEOUT		(2000*HZ)
+
+/* values for bits in power status byte */
+#define IFX_SPI_POWER_DATA_PENDING	1
+#define IFX_SPI_POWER_SRDY		2
+
+struct ifx_spi_device {
+	/* Our SPI device */
+	struct spi_device *spi_dev;
+
+	/* Port specific data */
+	struct kfifo tx_fifo;
+	spinlock_t fifo_lock;
+	unsigned long signal_state;
+
+	/* TTY Layer logic */
+	struct tty_port tty_port;
+	struct device *tty_dev;
+	int minor;
+
+	/* Low level I/O work */
+	struct tasklet_struct io_work_tasklet;
+	unsigned long flags;
+	dma_addr_t rx_dma;
+	dma_addr_t tx_dma;
+
+	int is_6160;				/* Modem type */
+
+	spinlock_t write_lock;
+	int write_pending;
+	spinlock_t power_lock;
+	unsigned char power_status;
+
+	unsigned char *rx_buffer;
+	unsigned char *tx_buffer;
+	dma_addr_t rx_bus;
+	dma_addr_t tx_bus;
+	unsigned char spi_more;
+	unsigned char spi_slave_cts;
+
+	struct timer_list spi_timer;
+
+	struct spi_message spi_msg;
+	struct spi_transfer spi_xfer;
+
+	struct {
+		/* gpio lines */
+		unsigned short srdy;		/* slave-ready gpio */
+		unsigned short mrdy;		/* master-ready gpio */
+		unsigned short reset;		/* modem-reset gpio */
+		unsigned short po;		/* modem-on gpio */
+		unsigned short reset_out;	/* modem-in-reset gpio */
+		/* state/stats */
+		int unack_srdy_int_nb;
+	} gpio;
+
+	/* modem reset */
+	unsigned long mdm_reset_state;
+#define MR_START	0
+#define MR_INPROGRESS	1
+#define MR_COMPLETE	2
+	wait_queue_head_t mdm_reset_wait;
+};
+
+#endif /* _IFX6X60_H */

include/linux/spi/ifx_modem.h

+#ifndef LINUX_IFX_MODEM_H
+#define LINUX_IFX_MODEM_H
+
+struct ifx_modem_platform_data {
+	unsigned short rst_out; /* modem reset out */
+	unsigned short pwr_on;  /* power on */
+	unsigned short rst_pmu; /* reset modem */
+	unsigned short tx_pwr;  /* modem power threshold */
+	unsigned short srdy;    /* SRDY */
+	unsigned short mrdy;    /* MRDY */
+	unsigned short is_6160;	/* Modem type */
+};
+
+#endif