modem: Port M6718 modem state driver

Adds the modem state driver to the M6718 modem IPC interface.

ST-Ericsson ID: 369397
ST-Ericsson FOSS-OUT ID: STETL-FOSS-OUT-12224
ST-Ericsson Linux next: NA

Change-Id: I5566277b950aa0be954f4350bdc1ed38c7afd7d8
Signed-off-by: Chris Blair <chris.blair@stericsson.com>
Reviewed-on: http://gerrit.lud.stericsson.com/gerrit/36434
Reviewed-by: Derek MORTON <derek.morton@stericsson.com>
Reviewed-by: QATOOLS
Reviewed-by: Andrew LYNN <andrew.lynn@stericsson.com>
Reviewed-by: QABUILD
Reviewed-by: Jonas ABERG <jonas.aberg@stericsson.com>

3 files changed, 1340 insertions, 0 deletions

diff --git a/drivers/modem/m6718_spi/Makefile b/drivers/modem/m6718_spi/Makefile
index 96bf481e986..492995bc753 100644
--- a/drivers/modem/m6718_spi/Makefile
+++ b/drivers/modem/m6718_spi/Makefile
@@ -7,4 +7,8 @@ endif
 
 m6718_modem_spi-objs := modem_driver.o
 
+ifeq ($(CONFIG_MODEM_M6718_SPI_ENABLE_FEATURE_MODEM_STATE),y)
+m6718_modem_spi-objs += modem_state.o
+endif
+
 obj-$(CONFIG_MODEM_M6718_SPI) += m6718_modem_spi.o
diff --git a/drivers/modem/m6718_spi/modem_state.c b/drivers/modem/m6718_spi/modem_state.c
new file mode 100644
index 00000000000..266f75a7a71
--- /dev/null
+++ b/drivers/modem/m6718_spi/modem_state.c
@@ -0,0 +1,1300 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ *
+ * Author: Derek Morton <derek.morton@stericsson.com>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Power state driver for M6718 MODEM
+ */
+
+/* define DEBUG to enable debug logging */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/modem/m6718_spi/modem_state.h>
+#include <linux/gpio.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/timer.h>
+#include <linux/gpio/nomadik.h>
+#include <plat/pincfg.h>
+#include <linux/workqueue.h>
+#include <linux/list.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/uaccess.h>
+
+/*
+ * To enable this driver add a struct platform_device in the board
+ * configuration file (e.g. board-*.c) with name="modemstate"
+ * optionally specify dev.initname="m6718" to define the driver
+ * name as it will appear in the file system.
+ * e.g.
+ * static struct platform_device modem_state_device =
+ * {
+ *    .name = "modemstate",
+ *    .dev =
+ *    {
+ *       .init_name = "m6718" // Name that will appear in FS
+ *    },
+ *    .num_resources = ARRAY_SIZE(modem_state_resources),
+ *    .resource = modem_state_resources
+ * };
+ *
+ * This driver uses gpio pins which should be specified as resources *
+ * e.g.
+ * static struct resource modem_state_resources[] =  .......
+ * Output pins are specified as IORESOURCE_IO
+ * Currently supported Output pins are:
+ * onkey_pin
+ * reset_pin
+ * vbat_pin
+ * Input pins are specified as IORESOURCE_IRQ
+ * Currently supported input pins are:
+ * rsthc_pin
+ * rstext_pin
+ * crash_pin
+ * Currently only the start value is used as the gpio pin number but
+ * end should also be specified as the gpio pin number in case gpio ranges
+ * are used in the future.
+ * e.g. if gpio 161 is used as the onkey pin
+ * {
+ *    .start = 161,
+ *    .end = 161,
+ *    .name = "onkey_pin",
+ *    .flags = IORESOURCE_IO,
+ * },
+ */
+
+struct modem_state_dev {
+	int onkey_pin;
+	int rsthc_pin;
+	int rstext_pin;
+	int crash_pin;
+	int reset_pin;
+	int vbat_pin;
+	int power_state;
+	int irq_state;
+	int busy;
+	struct timer_list onkey_timer;
+	struct timer_list reset_timer;
+	struct timer_list onkey_debounce_timer;
+	struct timer_list vbat_off_timer;
+	struct timer_list busy_timer;
+	spinlock_t lock;
+	struct device *dev;
+	struct workqueue_struct *workqueue;
+	struct work_struct wq_rsthc;
+	struct work_struct wq_rstext;
+	struct work_struct wq_crash;
+#ifdef CONFIG_DEBUG_FS
+	struct dentry *debugfsdir;
+	struct dentry *debugfs_debug;
+#endif
+};
+
+struct callback_list {
+	struct list_head node;
+	int (*callback) (unsigned long);
+	unsigned long data;
+};
+LIST_HEAD(callback_list);
+
+static char *modem_state_str[] = {
+	"off",
+	"reset",
+	"crash",
+	"on",
+	/*
+	 * Add new states before error and update enum modem_states
+	 * in modem_state.h
+	 */
+	"error"
+};
+
+static struct modem_state_dev *modem_state;
+
+static void set_on_config(struct modem_state_dev *msdev)
+{
+	if (msdev->crash_pin)
+		nmk_config_pin(PIN_CFG(msdev->crash_pin, GPIO) |
+			       PIN_INPUT_PULLDOWN, false);
+	if (msdev->rstext_pin)
+		nmk_config_pin(PIN_CFG(msdev->rstext_pin, GPIO) |
+			       PIN_INPUT_PULLDOWN, false);
+	if (msdev->rsthc_pin)
+		nmk_config_pin(PIN_CFG(msdev->rsthc_pin, GPIO) |
+			       PIN_INPUT_PULLDOWN, false);
+	if (msdev->reset_pin)
+		nmk_config_pin(PIN_CFG(msdev->reset_pin, GPIO) |
+			       PIN_OUTPUT_HIGH, false);
+}
+
+static void set_off_config(struct modem_state_dev *msdev)
+{
+	if (msdev->crash_pin)
+		nmk_config_pin(PIN_CFG(msdev->crash_pin, GPIO) |
+			       PIN_INPUT_PULLDOWN, false);
+	if (msdev->rstext_pin)
+		nmk_config_pin(PIN_CFG(msdev->rstext_pin, GPIO) |
+			       PIN_OUTPUT_LOW, false);
+	if (msdev->rsthc_pin)
+		nmk_config_pin(PIN_CFG(msdev->rsthc_pin, GPIO) | PIN_OUTPUT_LOW,
+			       false);
+	if (msdev->reset_pin)
+		nmk_config_pin(PIN_CFG(msdev->reset_pin, GPIO) |
+			       PIN_OUTPUT_HIGH, false);
+}
+
+static void enable_irq_all(struct modem_state_dev *msdev)
+{
+	if (msdev->rsthc_pin) {
+		enable_irq(GPIO_TO_IRQ(msdev->rsthc_pin));
+		if ((0 > enable_irq_wake(GPIO_TO_IRQ(msdev->rsthc_pin))))
+			dev_err(msdev->dev,
+				"Request for wake on pin %d failed\n",
+				msdev->rsthc_pin);
+	}
+	if (msdev->rstext_pin) {
+		enable_irq(GPIO_TO_IRQ(msdev->rstext_pin));
+		if ((0 > enable_irq_wake(GPIO_TO_IRQ(msdev->rstext_pin))))
+			dev_err(msdev->dev,
+				"Request for wake on pin %d failed\n",
+				msdev->rstext_pin);
+	}
+	if (msdev->crash_pin) {
+		enable_irq(GPIO_TO_IRQ(msdev->crash_pin));
+		if ((0 > enable_irq_wake(GPIO_TO_IRQ(msdev->crash_pin))))
+			dev_err(msdev->dev,
+				"Request for wake on pin %d failed\n",
+				msdev->crash_pin);
+	}
+}
+
+static void disable_irq_all(struct modem_state_dev *msdev)
+{
+	if (msdev->rsthc_pin) {
+		disable_irq_wake(GPIO_TO_IRQ(msdev->rsthc_pin));
+		disable_irq(GPIO_TO_IRQ(msdev->rsthc_pin));
+	}
+	if (msdev->rstext_pin) {
+		disable_irq_wake(GPIO_TO_IRQ(msdev->rstext_pin));
+		disable_irq(GPIO_TO_IRQ(msdev->rstext_pin));
+	}
+	if (msdev->crash_pin) {
+		disable_irq_wake(GPIO_TO_IRQ(msdev->crash_pin));
+		disable_irq(GPIO_TO_IRQ(msdev->crash_pin));
+	}
+}
+
+/*
+ * These functions which access GPIO must only be called
+ * with spinlock enabled.
+ */
+
+/*
+ * Toggle ONKEY pin high then low to turn modem on or off. Modem expects
+ * ONKEY line to be pulled low then high. GPIO needs to be driven high then
+ * low as logic is inverted through a transistor.
+ */
+static void toggle_modem_power(struct modem_state_dev *msdev)
+{
+	dev_info(msdev->dev, "Modem power toggle\n");
+	msdev->busy = 1;
+	gpio_set_value(msdev->onkey_pin, 1);
+	msdev->onkey_timer.data = (unsigned long)msdev;
+	/* Timeout of at least 1 second */
+	mod_timer(&msdev->onkey_timer, jiffies + (1 * HZ) + 1);
+}
+
+/* Modem is forced into reset when its reset line is pulled low */
+/* Drive GPIO low then high to reset modem */
+static void modem_reset(struct modem_state_dev *msdev)
+{
+	dev_info(msdev->dev, "Modem reset\n");
+	msdev->busy = 1;
+	gpio_set_value(msdev->reset_pin, 0);
+	msdev->reset_timer.data = (unsigned long)msdev;
+	/* Wait a couple of Jiffies */
+	mod_timer(&msdev->reset_timer, jiffies + 2);
+}
+
+static void modem_vbat_set_value(struct modem_state_dev *msdev, int vbat_val)
+{
+	switch (vbat_val) {
+	case 0:
+		msdev->power_state = 0;
+		dev_info(msdev->dev, "Modem vbat off\n");
+		gpio_set_value(msdev->vbat_pin, vbat_val);
+		if (1 == msdev->irq_state) {
+			msdev->irq_state = 0;
+			disable_irq_all(msdev);
+			set_off_config(msdev);
+		}
+		break;
+	case 1:
+		dev_info(msdev->dev, "Modem vbat on\n");
+		if (0 == msdev->irq_state) {
+			msdev->irq_state = 1;
+			set_on_config(msdev);
+			enable_irq_all(msdev);
+		}
+		gpio_set_value(msdev->vbat_pin, vbat_val);
+		break;
+	default:
+		return;
+		break;
+	}
+}
+
+static void modem_power_on(struct modem_state_dev *msdev)
+{
+	int rsthc = gpio_get_value(msdev->rsthc_pin);
+	msdev->power_state = 1;
+	del_timer(&msdev->vbat_off_timer);
+	if (rsthc == 0) {
+		modem_vbat_set_value(msdev, 1);
+		toggle_modem_power(msdev);
+	}
+}
+
+static void modem_power_off(struct modem_state_dev *msdev)
+{
+	int rsthc = gpio_get_value(msdev->rsthc_pin);
+
+	msdev->power_state = 0;
+	if (rsthc == 1) {
+		toggle_modem_power(msdev);
+		/* Cut power to modem after 10 seconds */
+		msdev->vbat_off_timer.data = (unsigned long)msdev;
+		mod_timer(&msdev->vbat_off_timer, jiffies + (10 * HZ));
+	}
+}
+/* End of functions requiring spinlock */
+
+static void call_callbacks(void)
+{
+	struct callback_list *item;
+
+	list_for_each_entry(item, &callback_list, node)
+		item->callback(item->data);
+}
+
+static int get_modem_state(struct modem_state_dev *msdev)
+{
+	int state;
+	unsigned long flags;
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	if (0 == gpio_get_value(msdev->rsthc_pin))
+		state = MODEM_STATE_OFF;
+	else if (0 == gpio_get_value(msdev->rstext_pin))
+		state = MODEM_STATE_RESET;
+	else if (1 == gpio_get_value(msdev->crash_pin))
+		state = MODEM_STATE_CRASH;
+	else
+		state = MODEM_STATE_ON;
+	spin_unlock_irqrestore(&msdev->lock, flags);
+
+	return state;
+}
+
+/* modempower read handler */
+static ssize_t modem_state_power_get(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	int rsthc;
+	int power_state;
+	unsigned long flags;
+	struct modem_state_dev *msdev =
+		platform_get_drvdata(to_platform_device(dev));
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	rsthc = gpio_get_value(msdev->rsthc_pin);
+	power_state = msdev->power_state;
+	spin_unlock_irqrestore(&msdev->lock, flags);
+
+	return sprintf(buf, "state=%d, expected=%d\n", rsthc, power_state);
+}
+
+/*
+ * modempower write handler
+ * Write '0' to /sys/devices/platform/modemstate/modempower to turn modem off
+ * Write '1' to /sys/devices/platform/modemstate/modempower to turn modem on
+ */
+static ssize_t modem_state_power_set(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	unsigned long flags;
+	int ret = count;
+	struct modem_state_dev *msdev =
+		platform_get_drvdata(to_platform_device(dev));
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	if (msdev->busy) {
+		ret = -EAGAIN;
+	} else if (count > 0) {
+		switch (buf[0]) {
+		case '0':
+			modem_power_off(msdev);
+			break;
+		case '1':
+			modem_power_on(msdev);
+			break;
+		default:
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&msdev->lock, flags);
+	return ret;
+}
+
+/* reset read handler */
+static ssize_t modem_state_reset_get(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	int rstext;
+	struct modem_state_dev *msdev =
+		platform_get_drvdata(to_platform_device(dev));
+
+	/* No need for spinlocks here as there is only 1 value */
+	rstext = gpio_get_value(msdev->rstext_pin);
+
+	return sprintf(buf, "state=%d\n", rstext);
+}
+
+/* reset write handler */
+/* Write '1' to /sys/devices/platform/modemstate/reset to reset modem */
+static ssize_t modem_state_reset_set(struct device *dev,
+				     struct device_attribute *attr,
+				     const char *buf, size_t count)
+{
+	unsigned long flags;
+	int ret = count;
+	struct modem_state_dev *msdev =
+		platform_get_drvdata(to_platform_device(dev));
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	if (msdev->busy) {
+		ret = -EAGAIN;
+	} else if (count > 0) {
+		if (buf[0] == '1')
+			modem_reset(msdev);
+	}
+	spin_unlock_irqrestore(&msdev->lock, flags);
+
+	return ret;
+}
+
+/* crash read handler */
+static ssize_t modem_state_crash_get(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	int crash;
+	struct modem_state_dev *msdev =
+		platform_get_drvdata(to_platform_device(dev));
+
+	/* No need for spinlocks here as there is only 1 value */
+	crash = gpio_get_value(msdev->crash_pin);
+
+	return sprintf(buf, "state=%d\n", crash);
+}
+
+/* state read handler */
+static ssize_t modem_state_state_get(struct device *dev,
+				     struct device_attribute *attr, char *buf)
+{
+	int state;
+	struct modem_state_dev *msdev =
+		platform_get_drvdata(to_platform_device(dev));
+
+	state = get_modem_state(msdev);
+	if (state > MODEM_STATE_END_MARKER)
+		state = MODEM_STATE_END_MARKER;
+
+	return sprintf(buf, "%s\n", modem_state_str[state]);
+}
+
+#ifdef CONFIG_DEBUG_FS
+static int modem_state_debug_get(struct seq_file *s, void *data)
+{
+	int onkey;
+	int rsthc;
+	int rstext;
+	int reset;
+	int crash;
+	int vbat;
+	unsigned long flags;
+	struct modem_state_dev *msdev = s->private;
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	onkey = gpio_get_value(msdev->onkey_pin);
+	rsthc = gpio_get_value(msdev->rsthc_pin);
+	rstext = gpio_get_value(msdev->rstext_pin);
+	reset = gpio_get_value(msdev->reset_pin);
+	crash = gpio_get_value(msdev->crash_pin);
+	vbat = gpio_get_value(msdev->vbat_pin);
+	spin_unlock_irqrestore(&msdev->lock, flags);
+
+	seq_printf(s, "onkey=%d, rsthc=%d, rstext=%d, "
+			"reset=%d, crash=%d, vbat=%d\n",
+			onkey, rsthc, rstext, reset, crash, vbat);
+	return 0;
+}
+
+/*
+ * debug write handler
+ * Write o['0'|'1'] to /sys/devices/platform/modemstate/debug to set
+ * onkey line low or high.
+ * Write r['0'|'1'] to /sys/devices/platform/modemstate/debug to set
+ * reset line low or high.
+ * Write v['0'|'1'] to /sys/devices/platform/modemstate/debug to set
+ * vbat line low or high.
+ */
+static ssize_t modem_state_debug_set(struct file *file,
+	const char __user *user_buf,
+	size_t count,
+	loff_t *ppos)
+{
+	unsigned long flags;
+	int bufsize;
+	char buf[128];
+
+	bufsize = min(count, sizeof(buf) - 1);
+	if (copy_from_user(buf, user_buf, bufsize))
+		return -EFAULT;
+	buf[bufsize] = 0;
+
+	spin_lock_irqsave(&modem_state->lock, flags);
+	if (modem_state->busy) {
+		return -EAGAIN;
+	} else if (count > 1) {
+		switch (buf[1]) {
+		case '0':	/* fallthrough */
+		case '1':
+			switch (buf[0]) {
+			case 'o':
+				gpio_set_value(modem_state->onkey_pin,
+					buf[1] - '0');
+				break;
+			case 'r':
+				gpio_set_value(modem_state->reset_pin,
+					buf[1] - '0');
+				break;
+			case 'v':
+				gpio_set_value(modem_state->vbat_pin,
+				buf[1] - '0');
+				break;
+			default:
+				break;
+			}
+			break;
+		default:
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&modem_state->lock, flags);
+
+	return bufsize;
+}
+
+static int modem_state_debug_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, modem_state_debug_get, inode->i_private);
+}
+#endif /* CONFIG_DEBUG_FS */
+
+static DEVICE_ATTR(modempower, S_IRUSR | S_IWUSR,
+		   modem_state_power_get, modem_state_power_set);
+static DEVICE_ATTR(reset, S_IRUSR | S_IWUSR,
+		   modem_state_reset_get, modem_state_reset_set);
+static DEVICE_ATTR(crash, S_IRUSR, modem_state_crash_get, NULL);
+static DEVICE_ATTR(state, S_IRUSR, modem_state_state_get, NULL);
+
+static struct attribute *modemstate_attributes[] = {
+	&dev_attr_modempower.attr,
+	&dev_attr_reset.attr,
+	&dev_attr_crash.attr,
+	&dev_attr_state.attr,
+	NULL
+};
+
+static struct attribute_group modemstate_attr_group = {
+	.attrs = modemstate_attributes,
+	.name = "modemstate"
+};
+
+#ifdef CONFIG_DEBUG_FS
+static const struct file_operations debugfs_debug_fops = {
+	.open = modem_state_debug_open,
+	.read = seq_read,
+	.write = modem_state_debug_set,
+	.llseek = seq_lseek,
+	.release = single_release
+};
+#endif
+
+static void sysfs_notify_rsthc(struct modem_state_dev *msdev)
+{
+	sysfs_notify(&msdev->dev->kobj, NULL, dev_attr_modempower.attr.name);
+	sysfs_notify(&msdev->dev->kobj, NULL, dev_attr_state.attr.name);
+}
+
+static void sysfs_notify_rstext(struct modem_state_dev *msdev)
+{
+	sysfs_notify(&msdev->dev->kobj, NULL, dev_attr_reset.attr.name);
+	sysfs_notify(&msdev->dev->kobj, NULL, dev_attr_state.attr.name);
+}
+
+static void sysfs_notify_crash(struct modem_state_dev *msdev)
+{
+	sysfs_notify(&msdev->dev->kobj, NULL, dev_attr_crash.attr.name);
+	sysfs_notify(&msdev->dev->kobj, NULL, dev_attr_state.attr.name);
+}
+
+static void wq_rsthc(struct work_struct *work)
+{
+	unsigned long flags;
+	int rsthc;
+	struct modem_state_dev *msdev =
+		container_of(work, struct modem_state_dev, wq_rsthc);
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	rsthc = gpio_get_value(msdev->rsthc_pin);
+	dev_dbg(msdev->dev, "RSTHC interrupt detected, rsthc=%d\n", rsthc);
+	if (msdev->power_state == rsthc) {
+		if (!rsthc) {
+			/* Modem has turned off, and we were expecting it to.
+			   turn vbat to the modem off now */
+			del_timer(&msdev->vbat_off_timer);
+			modem_vbat_set_value(msdev, 0);
+		}
+	} else {
+		dev_dbg(msdev->dev,
+			 "Modem power state is %d, expected %d\n", rsthc,
+			 msdev->power_state);
+		dev_dbg(msdev->dev,
+			"Attempting to change modem power state "
+			"in 2 seconds\n");
+
+		msdev->onkey_debounce_timer.data = (unsigned long)msdev;
+		/* Wait > 2048ms due to debounce timer */
+		mod_timer(&msdev->onkey_debounce_timer,
+			jiffies + ((2050 * HZ) / 1000));
+	}
+	spin_unlock_irqrestore(&msdev->lock, flags);
+
+	call_callbacks();
+	sysfs_notify_rsthc(msdev);
+}
+
+static void wq_rstext(struct work_struct *work)
+{
+	struct modem_state_dev *msdev =
+		container_of(work, struct modem_state_dev, wq_rstext);
+
+	dev_dbg(msdev->dev, "RSTEXT interrupt detected, rstext=%d\n",
+		 gpio_get_value(msdev->rstext_pin));
+
+	call_callbacks();
+	sysfs_notify_rstext(msdev);
+}
+
+static void wq_crash(struct work_struct *work)
+{
+	struct modem_state_dev *msdev =
+		container_of(work, struct modem_state_dev, wq_rstext);
+
+	dev_dbg(msdev->dev, "modem crash interrupt detected. crash=%d\n",
+		 gpio_get_value(msdev->crash_pin));
+
+	call_callbacks();
+	sysfs_notify_crash(msdev);
+}
+
+/* Populate device structure used by the driver */
+static int modem_state_dev_init(struct platform_device *pdev,
+				struct modem_state_dev *msdev)
+{
+	int err = 0;
+	struct resource *r;
+
+	r = platform_get_resource_byname(pdev, IORESOURCE_IO, "onkey_pin");
+	if (r == NULL) {
+		err = -ENXIO;
+		dev_err(&pdev->dev,
+			"Could not get GPIO number for onkey pin\n");
+		goto err_resource;
+	}
+	msdev->onkey_pin = r->start;
+
+	r = platform_get_resource_byname(pdev, IORESOURCE_IO, "reset_pin");
+	if (r == NULL) {
+		err = -ENXIO;
+		dev_err(&pdev->dev,
+			"Could not get GPIO number for reset pin\n");
+		goto err_resource;
+	}
+	msdev->reset_pin = r->start;
+
+	r = platform_get_resource_byname(pdev, IORESOURCE_IO, "vbat_pin");
+	if (r == NULL) {
+		err = -ENXIO;
+		dev_err(&pdev->dev, "Could not get GPIO number for vbat pin\n");
+		goto err_resource;
+	}
+	msdev->vbat_pin = r->start;
+
+	msdev->rsthc_pin = platform_get_irq_byname(pdev, "rsthc_pin");
+	if (msdev->rsthc_pin < 0) {
+		err = msdev->rsthc_pin;
+		dev_err(&pdev->dev,
+			"Could not get GPIO number for rsthc pin\n");
+		goto err_resource;
+	}
+
+	msdev->rstext_pin = platform_get_irq_byname(pdev, "rstext_pin");
+	if (msdev->rstext_pin < 0) {
+		err = msdev->rstext_pin;
+		dev_err(&pdev->dev,
+			"Could not get GPIO number for retext pin\n");
+		goto err_resource;
+	}
+
+	msdev->crash_pin = platform_get_irq_byname(pdev, "crash_pin");
+	if (msdev->crash_pin < 0) {
+		err = msdev->crash_pin;
+		dev_err(&pdev->dev,
+			"Could not get GPIO number for crash pin\n");
+		goto err_resource;
+	}
+err_resource:
+	return err;
+}
+
+/* IRQ handlers */
+
+/* Handlers for rsthc (modem power off indication) IRQ */
+static irqreturn_t rsthc_irq(int irq, void *dev)
+{
+	struct modem_state_dev *msdev = (struct modem_state_dev *)dev;
+
+	/* check it's our interrupt */
+	if (irq != GPIO_TO_IRQ(msdev->rsthc_pin)) {
+		dev_err(msdev->dev, "Spurious RSTHC irq\n");
+		return IRQ_NONE;
+	}
+
+	queue_work(msdev->workqueue, &msdev->wq_rsthc);
+	return IRQ_HANDLED;
+}
+
+/* Handlers for rstext (modem reset indication) IRQ */
+static irqreturn_t rstext_irq(int irq, void *dev)
+{
+	struct modem_state_dev *msdev = (struct modem_state_dev *)dev;
+
+	/* check it's our interrupt */
+	if (irq != GPIO_TO_IRQ(msdev->rstext_pin)) {
+		dev_err(msdev->dev, "Spurious RSTEXT irq\n");
+		return IRQ_NONE;
+	}
+
+	queue_work(msdev->workqueue, &msdev->wq_rstext);
+	return IRQ_HANDLED;
+}
+
+/* Handlers for modem crash indication IRQ */
+static irqreturn_t crash_irq(int irq, void *dev)
+{
+	struct modem_state_dev *msdev = (struct modem_state_dev *)dev;
+
+	/* check it's our interrupt */
+	if (irq != GPIO_TO_IRQ(msdev->crash_pin)) {
+		dev_err(msdev->dev, "Spurious modem crash irq\n");
+		return IRQ_NONE;
+	}
+
+	queue_work(msdev->workqueue, &msdev->wq_crash);
+	return IRQ_HANDLED;
+}
+
+static int request_irq_pin(int pin, irq_handler_t handler, unsigned long flags,
+			   struct modem_state_dev *msdev)
+{
+	int err = 0;
+	if (pin) {
+		err = request_irq(GPIO_TO_IRQ(pin), handler, flags,
+				  dev_name(msdev->dev), msdev);
+		if (err == 0) {
+			err = enable_irq_wake(GPIO_TO_IRQ(pin));
+			if (err < 0) {
+				dev_err(msdev->dev,
+					"Request for wake on pin %d failed\n",
+					pin);
+				free_irq(GPIO_TO_IRQ(pin), NULL);
+			}
+		} else {
+			dev_err(msdev->dev,
+				"Request for irq on pin %d failed\n", pin);
+		}
+	}
+	return err;
+}
+
+static void free_irq_pin(int pin)
+{
+	disable_irq_wake(GPIO_TO_IRQ(pin));
+	free_irq(GPIO_TO_IRQ(pin), NULL);
+}
+
+static int request_irq_all(struct modem_state_dev *msdev)
+{
+	int err;
+
+	err = request_irq_pin(msdev->rsthc_pin, rsthc_irq,
+				IRQF_TRIGGER_RISING |
+				IRQF_TRIGGER_FALLING |
+				IRQF_NO_SUSPEND, msdev);
+	if (err < 0)
+		goto err_rsthc_irq_req;
+
+	err = request_irq_pin(msdev->rstext_pin, rstext_irq,
+				IRQF_TRIGGER_RISING |
+				IRQF_TRIGGER_FALLING |
+				IRQF_NO_SUSPEND, msdev);
+	if (err < 0)
+		goto err_rstext_irq_req;
+
+	err = request_irq_pin(msdev->crash_pin, crash_irq,
+				IRQF_TRIGGER_RISING |
+				IRQF_TRIGGER_FALLING |
+				IRQF_NO_SUSPEND, msdev);
+	if (err < 0)
+		goto err_crash_irq_req;
+
+	return 0;
+
+err_crash_irq_req:
+	free_irq_pin(msdev->rstext_pin);
+err_rstext_irq_req:
+	free_irq_pin(msdev->rsthc_pin);
+err_rsthc_irq_req:
+	return err;
+}
+
+/* Configure GPIO used by the driver */
+static int modem_state_gpio_init(struct platform_device *pdev,
+				 struct modem_state_dev *msdev)
+{
+	int err = 0;
+
+	/* Reserve gpio pins */
+	if (msdev->onkey_pin != 0) {
+		err = gpio_request(msdev->onkey_pin, dev_name(msdev->dev));
+		if (err < 0) {
+			dev_err(&pdev->dev, "Request for onkey pin failed\n");
+			goto err_onkey_req;
+		}
+	}
+	if (msdev->reset_pin != 0) {
+		err = gpio_request(msdev->reset_pin, dev_name(msdev->dev));
+		if (err < 0) {
+			dev_err(&pdev->dev, "Request for reset pin failed\n");
+			goto err_reset_req;
+		}
+	}
+	if (msdev->rsthc_pin != 0) {
+		err = gpio_request(msdev->rsthc_pin, dev_name(msdev->dev));
+		if (err < 0) {
+			dev_err(&pdev->dev, "Request for rsthc pin failed\n");
+			goto err_rsthc_req;
+		}
+	}
+	if (msdev->rstext_pin != 0) {
+		err = gpio_request(msdev->rstext_pin, dev_name(msdev->dev));
+		if (err < 0) {
+			dev_err(&pdev->dev, "Request for rstext pin failed\n");
+			goto err_rstext_req;
+		}
+	}
+	if (msdev->crash_pin != 0) {
+		err = gpio_request(msdev->crash_pin, dev_name(msdev->dev));
+		if (err < 0) {
+			dev_err(&pdev->dev, "Request for crash pin failed\n");
+			goto err_crash_req;
+		}
+	}
+	if (msdev->vbat_pin != 0) {
+		err = gpio_request(msdev->vbat_pin, dev_name(msdev->dev));
+		if (err < 0) {
+			dev_err(&pdev->dev, "Request for vbat pin failed\n");
+			goto err_vbat_req;
+		}
+	}
+
+	/* Set initial pin config */
+	set_on_config(msdev);
+	if (msdev->onkey_pin)
+		nmk_config_pin(PIN_CFG(msdev->onkey_pin, GPIO) |
+			       PIN_OUTPUT_LOW, false);
+	if (msdev->vbat_pin)
+		nmk_config_pin(PIN_CFG(msdev->vbat_pin, GPIO) | PIN_OUTPUT_HIGH,
+			       false);
+
+	/* Configure IRQs for GPIO pins */
+	err = request_irq_all(msdev);
+	if (err < 0) {
+		dev_err(&pdev->dev, "Request for irqs failed, err = %d\n", err);
+		goto err_irq_req;
+	}
+	msdev->irq_state = 1;
+
+	/* Save current modem state */
+	msdev->power_state = gpio_get_value(msdev->rsthc_pin);
+
+	return 0;
+
+err_irq_req:
+	gpio_free(msdev->vbat_pin);
+err_vbat_req:
+	gpio_free(msdev->crash_pin);
+err_crash_req:
+	gpio_free(msdev->rstext_pin);
+err_rstext_req:
+	gpio_free(msdev->rsthc_pin);
+err_rsthc_req:
+	gpio_free(msdev->reset_pin);
+err_reset_req:
+	gpio_free(msdev->onkey_pin);
+err_onkey_req:
+	return err;
+}
+
+/* Timer handlers */
+
+static void modem_power_timeout(unsigned long data)
+{
+	unsigned long flags;
+	struct modem_state_dev *msdev = (struct modem_state_dev *)data;
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	if (msdev->busy)
+		msdev->busy = 0;
+	else
+		dev_err(msdev->dev,
+			"onkey timer expired and busy flag not set\n");
+
+	gpio_set_value(msdev->onkey_pin, 0);
+	spin_unlock_irqrestore(&msdev->lock, flags);
+}
+
+static void modem_reset_timeout(unsigned long data)
+{
+	unsigned long flags;
+	struct modem_state_dev *msdev = (struct modem_state_dev *)data;
+
+	spin_lock_irqsave(&modem_state->lock, flags);
+	if (msdev->busy)
+		msdev->busy = 0;
+	else
+		dev_err(msdev->dev,
+			"reset timer expired and busy flag not set\n");
+
+	gpio_set_value(msdev->reset_pin, 1);
+	spin_unlock_irqrestore(&modem_state->lock, flags);
+}
+
+static void modem_onkey_debounce_timeout(unsigned long data)
+{
+	unsigned long flags;
+	struct modem_state_dev *msdev = (struct modem_state_dev *)data;
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	if (msdev->busy) {
+		dev_info(msdev->dev,
+			 "Delayed onkey change aborted. "
+			 "Another action in progress\n");
+	} else {
+		if (gpio_get_value(msdev->rsthc_pin) != msdev->power_state) {
+			if (0 == msdev->power_state)
+				modem_power_off(msdev);
+			else
+				modem_power_on(msdev);
+		}
+	}
+	spin_unlock_irqrestore(&msdev->lock, flags);
+}
+
+static void modem_vbat_off_timeout(unsigned long data)
+{
+	struct modem_state_dev *msdev = (struct modem_state_dev *)data;
+	unsigned long flags;
+	spin_lock_irqsave(&msdev->lock, flags);
+	if (0 == msdev->power_state)
+		modem_vbat_set_value(msdev, 0);
+	spin_unlock_irqrestore(&msdev->lock, flags);
+}
+
+static void modem_busy_on_timeout(unsigned long data)
+{
+	unsigned long flags;
+	struct modem_state_dev *msdev = (struct modem_state_dev *)data;
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	if (msdev->busy) {
+		mod_timer(&msdev->busy_timer, jiffies + 1);
+	} else {
+		msdev->busy_timer.function = NULL;
+		modem_power_on(msdev);
+	}
+	spin_unlock_irqrestore(&msdev->lock, flags);
+}
+
+static void modem_busy_off_timeout(unsigned long data)
+{
+	unsigned long flags;
+	struct modem_state_dev *msdev = (struct modem_state_dev *)data;
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	if (msdev->busy) {
+		mod_timer(&msdev->busy_timer, jiffies + 1);
+	} else {
+		msdev->busy_timer.function = NULL;
+		modem_power_off(msdev);
+	}
+	spin_unlock_irqrestore(&msdev->lock, flags);
+}
+
+static void modem_busy_reset_timeout(unsigned long data)
+{
+	unsigned long flags;
+	struct modem_state_dev *msdev = (struct modem_state_dev *)data;
+
+	spin_lock_irqsave(&msdev->lock, flags);
+	if (msdev->busy) {
+		mod_timer(&msdev->busy_timer, jiffies + 1);
+	} else {
+		msdev->busy_timer.function = NULL;
+		modem_reset(msdev);
+	}
+	spin_unlock_irqrestore(&msdev->lock, flags);
+}
+
+#ifdef DEBUG
+static int callback_test(unsigned long data)
+{
+	struct modem_state_dev *msdev = (struct modem_state_dev *)data;
+	dev_info(msdev->dev, "Test callback. Modem state is %s\n",
+		 modem_state_to_str(modem_state_get_state()));
+	return 0;
+}
+#endif
+
+/* Exported functions */
+
+void modem_state_power_on(void)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&modem_state->lock, flags);
+	if (modem_state->busy) {
+		/*
+		 * Ignore on request if turning off is queued,
+		 * cancel any queued reset request
+		 */
+		if (modem_busy_reset_timeout ==
+		    modem_state->busy_timer.function) {
+			del_timer_sync(&modem_state->busy_timer);
+			modem_state->busy_timer.function = NULL;
+		}
+		if (NULL == modem_state->busy_timer.function) {
+			modem_state->busy_timer.function =
+			    modem_busy_on_timeout;
+			modem_state->busy_timer.data =
+			    (unsigned long)modem_state;
+			mod_timer(&modem_state->busy_timer, jiffies + 1);
+		}
+	} else {
+		modem_power_on(modem_state);
+	}
+	spin_unlock_irqrestore(&modem_state->lock, flags);
+}
+
+void modem_state_power_off(void)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&modem_state->lock, flags);
+	if (modem_state->busy) {
+		/*
+		 * Prioritize off request if others are queued.
+		 * Must turn modem off if system is shutting down
+		 */
+		if (NULL != modem_state->busy_timer.function)
+			del_timer_sync(&modem_state->busy_timer);
+
+		modem_state->busy_timer.function = modem_busy_off_timeout;
+		modem_state->busy_timer.data = (unsigned long)modem_state;
+		mod_timer(&modem_state->busy_timer, jiffies + 1);
+	} else {
+		modem_power_off(modem_state);
+	}
+	spin_unlock_irqrestore(&modem_state->lock, flags);
+}
+
+void modem_state_force_reset(void)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&modem_state->lock, flags);
+	if (modem_state->busy) {
+		/* Ignore reset request if turning on or off is queued */
+		if (NULL == modem_state->busy_timer.function) {
+			modem_state->busy_timer.function =
+			    modem_busy_reset_timeout;
+			modem_state->busy_timer.data =
+			    (unsigned long)modem_state;
+			mod_timer(&modem_state->busy_timer, jiffies + 1);
+		}
+	} else {
+		modem_reset(modem_state);
+	}
+	spin_unlock_irqrestore(&modem_state->lock, flags);
+}
+
+int modem_state_get_state(void)
+{
+	return get_modem_state(modem_state);
+}
+
+char *modem_state_to_str(int state)
+{
+	if (state > MODEM_STATE_END_MARKER)
+		state = MODEM_STATE_END_MARKER;
+
+	return modem_state_str[state];
+}
+
+int modem_state_register_callback(int (*callback) (unsigned long),
+				  unsigned long data)
+{
+	struct callback_list *item;
+	unsigned long flags;
+
+	if (NULL == modem_state)
+		return -EAGAIN;
+
+	if (NULL == callback)
+		return -EINVAL;
+
+	item = kzalloc(sizeof(*item), GFP_KERNEL);
+	if (NULL == item) {
+		dev_err(modem_state->dev,
+			"Could not allocate memory for struct callback_list\n");
+		return -ENOMEM;
+	}
+	item->callback = callback;
+	item->data = data;
+
+	spin_lock_irqsave(&modem_state->lock, flags);
+	list_add_tail(&item->node, &callback_list);
+	spin_unlock_irqrestore(&modem_state->lock, flags);
+
+	return 0;
+}
+
+int modem_state_remove_callback(int (*callback) (unsigned long))
+{
+	struct callback_list *iterator;
+	struct callback_list *item;
+	unsigned long flags;
+	int ret = -ENXIO;
+
+	if (NULL == callback)
+		return -EINVAL;
+
+	spin_lock_irqsave(&modem_state->lock, flags);
+	list_for_each_entry_safe(iterator, item, &callback_list, node) {
+		if (callback == item->callback) {
+			list_del(&item->node);
+			kfree(item);
+			ret = 0;
+			break;
+		}
+	}
+	spin_unlock_irqrestore(&modem_state->lock, flags);
+
+	return ret;
+}
+
+#ifdef CONFIG_PM
+int modem_state_suspend(struct device *dev)
+{
+	struct modem_state_dev *msdev =
+		platform_get_drvdata(to_platform_device(dev));
+
+	if (msdev->busy) {
+		dev_info(dev, "Driver is busy\n");
+		return -EBUSY;
+	} else {
+		return 0;
+	}
+}
+
+int modem_state_resume(struct device *dev)
+{
+	return 0;
+}
+#endif
+
+static int __devinit modem_state_probe(struct platform_device *pdev)
+{
+	int err = 0;
+
+	dev_info(&pdev->dev, "Starting probe\n");
+
+	modem_state = kzalloc(sizeof(struct modem_state_dev), GFP_KERNEL);
+	if (NULL == modem_state) {
+		dev_err(&pdev->dev,
+			"Could not allocate memory for modem_state_dev\n");
+		return -ENOMEM;
+	}
+	modem_state->dev = &pdev->dev;
+
+	spin_lock_init(&modem_state->lock);
+
+	INIT_WORK(&modem_state->wq_rsthc, wq_rsthc);
+	INIT_WORK(&modem_state->wq_rstext, wq_rstext);
+	INIT_WORK(&modem_state->wq_crash, wq_crash);
+	modem_state->workqueue =
+		create_singlethread_workqueue(dev_name(&pdev->dev));
+	if (modem_state->workqueue == NULL) {
+		dev_err(&pdev->dev, "Failed to create workqueue\n");
+		goto err_queue;
+	}
+
+	err = modem_state_dev_init(pdev, modem_state);
+	if (err != 0) {
+		dev_err(&pdev->dev, "Could not initialize device structure\n");
+		goto err_dev;
+	}
+
+	init_timer(&modem_state->onkey_timer);
+	init_timer(&modem_state->reset_timer);
+	init_timer(&modem_state->onkey_debounce_timer);
+	init_timer(&modem_state->vbat_off_timer);
+	init_timer(&modem_state->busy_timer);
+	modem_state->onkey_timer.function = modem_power_timeout;
+	modem_state->reset_timer.function = modem_reset_timeout;
+	modem_state->onkey_debounce_timer.function =
+	    modem_onkey_debounce_timeout;
+	modem_state->vbat_off_timer.function = modem_vbat_off_timeout;
+	modem_state->busy_timer.function = NULL;
+
+	platform_set_drvdata(pdev, modem_state);
+
+	err = modem_state_gpio_init(pdev, modem_state);
+	if (err != 0) {
+		dev_err(&pdev->dev, "Could not initialize GPIO\n");
+		goto err_gpio;
+	}
+
+	if (sysfs_create_group(&pdev->dev.kobj, &modemstate_attr_group) < 0) {
+		dev_err(&pdev->dev, "failed to create sysfs nodes\n");
+		goto err_sysfs;
+	}
+
+#ifdef CONFIG_DEBUG_FS
+	modem_state->debugfsdir = debugfs_create_dir("modemstate", NULL);
+	modem_state->debugfs_debug = debugfs_create_file("debug",
+					S_IRUGO | S_IWUGO,
+					modem_state->debugfsdir,
+					modem_state,
+					&debugfs_debug_fops);
+#endif
+
+#ifdef DEBUG
+	modem_state_register_callback(callback_test,
+				      (unsigned long)modem_state);
+#endif
+	return 0;
+
+err_sysfs:
+err_gpio:
+err_dev:
+	destroy_workqueue(modem_state->workqueue);
+err_queue:
+	kfree(modem_state);
+	return err;
+}
+
+static int __devexit modem_state_remove(struct platform_device *pdev)
+{
+	struct modem_state_dev *msdev = platform_get_drvdata(pdev);
+
+	sysfs_remove_group(&pdev->dev.kobj, &modemstate_attr_group);
+	destroy_workqueue(msdev->workqueue);
+	kfree(msdev);
+	return 0;
+}
+
+static void modem_state_shutdown(struct platform_device *pdev)
+{
+	/*
+	 * Trigger software shutdown of the modem and then wait until
+	 * modem-off state is detected. If the modem does not power off
+	 * when requested power will be removed and we will detect the
+	 * modem-off state that way.
+	 */
+	modem_state_power_off();
+	if (MODEM_STATE_OFF != modem_state_get_state())
+		dev_alert(&pdev->dev, "Waiting for modem to power down\n");
+	while (MODEM_STATE_OFF != modem_state_get_state())
+		cond_resched();
+}
+
+#ifdef CONFIG_PM
+static const struct dev_pm_ops modem_state_dev_pm_ops = {
+	.suspend_noirq = modem_state_suspend,
+	.resume_noirq = modem_state_resume,
+};
+#endif
+
+static struct platform_driver modem_state_driver = {
+	.probe = modem_state_probe,
+	.remove = __devexit_p(modem_state_remove),
+	.shutdown = modem_state_shutdown,
+	.driver = {
+		   .name = "modemstate",
+		   .owner = THIS_MODULE,
+#ifdef CONFIG_PM
+		   .pm = &modem_state_dev_pm_ops,
+#endif
+		   },
+};
+
+static int __init modem_state_init(void)
+{
+#ifdef DEBUG
+	printk(KERN_ALERT "Modem state driver init\n");
+#endif
+	return platform_driver_probe(&modem_state_driver, modem_state_probe);
+}
+
+static void __exit modem_state_exit(void)
+{
+	platform_driver_unregister(&modem_state_driver);
+}
+
+module_init(modem_state_init);
+module_exit(modem_state_exit);
+
+MODULE_AUTHOR("Derek Morton");
+MODULE_DESCRIPTION("M6718 modem power state driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/modem/m6718_spi/modem_state.h b/include/linux/modem/m6718_spi/modem_state.h
new file mode 100644
index 00000000000..a2f1d9fbe3e
--- /dev/null
+++ b/include/linux/modem/m6718_spi/modem_state.h
@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) ST-Ericsson SA 2011
+ *
+ * Author: Derek Morton <derek.morton@stericsson.com>
+ *
+ * License terms: GNU General Public License (GPL) version 2
+ *
+ * Power state driver for M6718 MODEM
+ */
+#ifndef MODEM_STATE_H
+#define MODEM_STATE_H
+
+enum modem_states {
+	MODEM_STATE_OFF,
+	MODEM_STATE_RESET,
+	MODEM_STATE_CRASH,
+	MODEM_STATE_ON,
+	/*
+	 * Add new states before end marker and update modem_state_str[]
+	 * in modem_state.c
+	 */
+	MODEM_STATE_END_MARKER
+};
+
+void modem_state_power_on(void);
+void modem_state_power_off(void);
+void modem_state_force_reset(void);
+int modem_state_get_state(void);
+char *modem_state_to_str(int state);
+
+/* Callbacks will be running in tasklet context */
+int modem_state_register_callback(int (*callback) (unsigned long),
+	unsigned long data);
+int modem_state_remove_callback(int (*callback) (unsigned long));
+
+#endif