misc: add akm8975 compass driver

Originally written by HTC. Contributions by Motorola and AKM.
  misc: Import akm8975 from Motorola

Major style and code cleanups by Praveen Bharathi <pbharathi@motorola.com>
  misc: akm8975: clean up code violations in akm8975.c
  misc: akm8975: Clean up coding style, add suspend and resume

Change-Id: I4196913f15aec2dfbed47506d3dc085aada8e92d
Signed-off-by: Dima Zavin <dima@android.com>

4 files changed, 828 insertions, 0 deletions

diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
index 66c13042dda..1a0254a15c5 100644
--- a/drivers/misc/Kconfig
+++ b/drivers/misc/Kconfig
@@ -382,6 +382,14 @@ config HMC6352
 	  This driver provides support for the Honeywell HMC6352 compass,
 	  providing configuration and heading data via sysfs.
 
+config SENSORS_AK8975
+	tristate "AK8975 compass support"
+	default n
+	depends on I2C
+	help
+	  If you say yes here you get support for Asahi Kasei's
+	  orientation sensor AK8975.
+
 config EP93XX_PWM
 	tristate "EP93xx PWM support"
 	depends on ARCH_EP93XX
diff --git a/drivers/misc/Makefile b/drivers/misc/Makefile
index a8159930334..89540d14f84 100644
--- a/drivers/misc/Makefile
+++ b/drivers/misc/Makefile
@@ -51,3 +51,4 @@ obj-$(CONFIG_USB_SWITCH_FSA9480) += fsa9480.o
 obj-$(CONFIG_ALTERA_STAPL)	+=altera-stapl/
 obj-$(CONFIG_MAX8997_MUIC)	+= max8997-muic.o
 obj-$(CONFIG_WL127X_RFKILL)	+= wl127x-rfkill.o
+obj-$(CONFIG_SENSORS_AK8975)	+= akm8975.o
diff --git a/drivers/misc/akm8975.c b/drivers/misc/akm8975.c
new file mode 100644
index 00000000000..830d2897afd
--- /dev/null
+++ b/drivers/misc/akm8975.c
@@ -0,0 +1,732 @@
+/* drivers/misc/akm8975.c - akm8975 compass driver
+ *
+ * Copyright (C) 2007-2008 HTC Corporation.
+ * Author: Hou-Kun Chen <houkun.chen@gmail.com>
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * 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.
+ *
+ */
+
+/*
+ * Revised by AKM 2009/04/02
+ * Revised by Motorola 2010/05/27
+ *
+ */
+
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/slab.h>
+#include <linux/irq.h>
+#include <linux/miscdevice.h>
+#include <linux/gpio.h>
+#include <linux/uaccess.h>
+#include <linux/delay.h>
+#include <linux/input.h>
+#include <linux/workqueue.h>
+#include <linux/freezer.h>
+#include <linux/akm8975.h>
+#include <linux/earlysuspend.h>
+
+#define AK8975DRV_CALL_DBG 0
+#if AK8975DRV_CALL_DBG
+#define FUNCDBG(msg)	pr_err("%s:%s\n", __func__, msg);
+#else
+#define FUNCDBG(msg)
+#endif
+
+#define AK8975DRV_DATA_DBG 0
+#define MAX_FAILURE_COUNT 10
+
+struct akm8975_data {
+	struct i2c_client *this_client;
+	struct akm8975_platform_data *pdata;
+	struct input_dev *input_dev;
+	struct work_struct work;
+	struct mutex flags_lock;
+#ifdef CONFIG_HAS_EARLYSUSPEND
+	struct early_suspend early_suspend;
+#endif
+};
+
+/*
+* Because misc devices can not carry a pointer from driver register to
+* open, we keep this global. This limits the driver to a single instance.
+*/
+struct akm8975_data *akmd_data;
+
+static DECLARE_WAIT_QUEUE_HEAD(open_wq);
+
+static atomic_t open_flag;
+
+static short m_flag;
+static short a_flag;
+static short t_flag;
+static short mv_flag;
+
+static short akmd_delay;
+
+static ssize_t akm8975_show(struct device *dev, struct device_attribute *attr,
+				 char *buf)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	return sprintf(buf, "%u\n", i2c_smbus_read_byte_data(client,
+							     AK8975_REG_CNTL));
+}
+static ssize_t akm8975_store(struct device *dev, struct device_attribute *attr,
+			    const char *buf, size_t count)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	unsigned long val;
+	strict_strtoul(buf, 10, &val);
+	if (val > 0xff)
+		return -EINVAL;
+	i2c_smbus_write_byte_data(client, AK8975_REG_CNTL, val);
+	return count;
+}
+static DEVICE_ATTR(akm_ms1, S_IWUSR | S_IRUGO, akm8975_show, akm8975_store);
+
+static int akm8975_i2c_rxdata(struct akm8975_data *akm, char *buf, int length)
+{
+	struct i2c_msg msgs[] = {
+		{
+			.addr = akm->this_client->addr,
+			.flags = 0,
+			.len = 1,
+			.buf = buf,
+		},
+		{
+			.addr = akm->this_client->addr,
+			.flags = I2C_M_RD,
+			.len = length,
+			.buf = buf,
+		},
+	};
+
+	FUNCDBG("called");
+
+	if (i2c_transfer(akm->this_client->adapter, msgs, 2) < 0) {
+		pr_err("akm8975_i2c_rxdata: transfer error\n");
+		return EIO;
+	} else
+		return 0;
+}
+
+static int akm8975_i2c_txdata(struct akm8975_data *akm, char *buf, int length)
+{
+	struct i2c_msg msgs[] = {
+		{
+			.addr = akm->this_client->addr,
+			.flags = 0,
+			.len = length,
+			.buf = buf,
+		},
+	};
+
+	FUNCDBG("called");
+
+	if (i2c_transfer(akm->this_client->adapter, msgs, 1) < 0) {
+		pr_err("akm8975_i2c_txdata: transfer error\n");
+		return -EIO;
+	} else
+		return 0;
+}
+
+static void akm8975_ecs_report_value(struct akm8975_data *akm, short *rbuf)
+{
+	struct akm8975_data *data = i2c_get_clientdata(akm->this_client);
+
+	FUNCDBG("called");
+
+#if AK8975DRV_DATA_DBG
+	pr_info("akm8975_ecs_report_value: yaw = %d, pitch = %d, roll = %d\n",
+				 rbuf[0], rbuf[1], rbuf[2]);
+	pr_info("tmp = %d, m_stat= %d, g_stat=%d\n", rbuf[3], rbuf[4], rbuf[5]);
+	pr_info("Acceleration:	 x = %d LSB, y = %d LSB, z = %d LSB\n",
+				 rbuf[6], rbuf[7], rbuf[8]);
+	pr_info("Magnetic:	 x = %d LSB, y = %d LSB, z = %d LSB\n\n",
+				 rbuf[9], rbuf[10], rbuf[11]);
+#endif
+	mutex_lock(&akm->flags_lock);
+	/* Report magnetic sensor information */
+	if (m_flag) {
+		input_report_abs(data->input_dev, ABS_RX, rbuf[0]);
+		input_report_abs(data->input_dev, ABS_RY, rbuf[1]);
+		input_report_abs(data->input_dev, ABS_RZ, rbuf[2]);
+		input_report_abs(data->input_dev, ABS_RUDDER, rbuf[4]);
+	}
+
+	/* Report acceleration sensor information */
+	if (a_flag) {
+		input_report_abs(data->input_dev, ABS_X, rbuf[6]);
+		input_report_abs(data->input_dev, ABS_Y, rbuf[7]);
+		input_report_abs(data->input_dev, ABS_Z, rbuf[8]);
+		input_report_abs(data->input_dev, ABS_WHEEL, rbuf[5]);
+	}
+
+	/* Report temperature information */
+	if (t_flag)
+		input_report_abs(data->input_dev, ABS_THROTTLE, rbuf[3]);
+
+	if (mv_flag) {
+		input_report_abs(data->input_dev, ABS_HAT0X, rbuf[9]);
+		input_report_abs(data->input_dev, ABS_HAT0Y, rbuf[10]);
+		input_report_abs(data->input_dev, ABS_BRAKE, rbuf[11]);
+	}
+	mutex_unlock(&akm->flags_lock);
+
+	input_sync(data->input_dev);
+}
+
+static void akm8975_ecs_close_done(struct akm8975_data *akm)
+{
+	FUNCDBG("called");
+	mutex_lock(&akm->flags_lock);
+	m_flag = 1;
+	a_flag = 1;
+	t_flag = 1;
+	mv_flag = 1;
+	mutex_unlock(&akm->flags_lock);
+}
+
+static int akm_aot_open(struct inode *inode, struct file *file)
+{
+	int ret = -1;
+
+	FUNCDBG("called");
+	if (atomic_cmpxchg(&open_flag, 0, 1) == 0) {
+		wake_up(&open_wq);
+		ret = 0;
+	}
+
+	ret = nonseekable_open(inode, file);
+	if (ret)
+		return ret;
+
+	file->private_data = akmd_data;
+
+	return ret;
+}
+
+static int akm_aot_release(struct inode *inode, struct file *file)
+{
+	FUNCDBG("called");
+	atomic_set(&open_flag, 0);
+	wake_up(&open_wq);
+	return 0;
+}
+
+static int akm_aot_ioctl(struct inode *inode, struct file *file,
+	      unsigned int cmd, unsigned long arg)
+{
+	void __user *argp = (void __user *) arg;
+	short flag;
+	struct akm8975_data *akm = file->private_data;
+
+	FUNCDBG("called");
+
+	switch (cmd) {
+	case ECS_IOCTL_APP_SET_MFLAG:
+	case ECS_IOCTL_APP_SET_AFLAG:
+	case ECS_IOCTL_APP_SET_MVFLAG:
+		if (copy_from_user(&flag, argp, sizeof(flag)))
+			return -EFAULT;
+		if (flag < 0 || flag > 1)
+			return -EINVAL;
+		break;
+	case ECS_IOCTL_APP_SET_DELAY:
+		if (copy_from_user(&flag, argp, sizeof(flag)))
+			return -EFAULT;
+		break;
+	default:
+		break;
+	}
+
+	mutex_lock(&akm->flags_lock);
+	switch (cmd) {
+	case ECS_IOCTL_APP_SET_MFLAG:
+	  m_flag = flag;
+		break;
+	case ECS_IOCTL_APP_GET_MFLAG:
+		flag = m_flag;
+		break;
+	case ECS_IOCTL_APP_SET_AFLAG:
+		a_flag = flag;
+		break;
+	case ECS_IOCTL_APP_GET_AFLAG:
+		flag = a_flag;
+		break;
+	case ECS_IOCTL_APP_SET_MVFLAG:
+		mv_flag = flag;
+		break;
+	case ECS_IOCTL_APP_GET_MVFLAG:
+		flag = mv_flag;
+		break;
+	case ECS_IOCTL_APP_SET_DELAY:
+		akmd_delay = flag;
+		break;
+	case ECS_IOCTL_APP_GET_DELAY:
+		flag = akmd_delay;
+		break;
+	default:
+		return -ENOTTY;
+	}
+	mutex_unlock(&akm->flags_lock);
+
+	switch (cmd) {
+	case ECS_IOCTL_APP_GET_MFLAG:
+	case ECS_IOCTL_APP_GET_AFLAG:
+	case ECS_IOCTL_APP_GET_MVFLAG:
+	case ECS_IOCTL_APP_GET_DELAY:
+		if (copy_to_user(argp, &flag, sizeof(flag)))
+			return -EFAULT;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+static int akmd_open(struct inode *inode, struct file *file)
+{
+	int err = 0;
+
+	FUNCDBG("called");
+	err = nonseekable_open(inode, file);
+	if (err)
+		return err;
+
+	file->private_data = akmd_data;
+	return 0;
+}
+
+static int akmd_release(struct inode *inode, struct file *file)
+{
+	struct akm8975_data *akm = file->private_data;
+
+	FUNCDBG("called");
+	akm8975_ecs_close_done(akm);
+	return 0;
+}
+
+static int akmd_ioctl(struct inode *inode, struct file *file, unsigned int cmd,
+		      unsigned long arg)
+{
+	void __user *argp = (void __user *) arg;
+
+	char rwbuf[16];
+	int ret = -1;
+	int status;
+	short value[12];
+	short delay;
+	struct akm8975_data *akm = file->private_data;
+
+	FUNCDBG("called");
+
+	switch (cmd) {
+	case ECS_IOCTL_READ:
+	case ECS_IOCTL_WRITE:
+		if (copy_from_user(&rwbuf, argp, sizeof(rwbuf)))
+			return -EFAULT;
+		break;
+
+	case ECS_IOCTL_SET_YPR:
+		if (copy_from_user(&value, argp, sizeof(value)))
+			return -EFAULT;
+		break;
+
+	default:
+		break;
+	}
+
+	switch (cmd) {
+	case ECS_IOCTL_READ:
+		if (rwbuf[0] < 1)
+			return -EINVAL;
+
+		ret = akm8975_i2c_rxdata(akm, &rwbuf[1], rwbuf[0]);
+		if (ret < 0)
+			return ret;
+		break;
+
+	case ECS_IOCTL_WRITE:
+		if (rwbuf[0] < 2)
+			return -EINVAL;
+
+		ret = akm8975_i2c_txdata(akm, &rwbuf[1], rwbuf[0]);
+		if (ret < 0)
+			return ret;
+		break;
+	case ECS_IOCTL_SET_YPR:
+		akm8975_ecs_report_value(akm, value);
+		break;
+
+	case ECS_IOCTL_GET_OPEN_STATUS:
+		wait_event_interruptible(open_wq,
+					 (atomic_read(&open_flag) != 0));
+		status = atomic_read(&open_flag);
+		break;
+	case ECS_IOCTL_GET_CLOSE_STATUS:
+		wait_event_interruptible(open_wq,
+					 (atomic_read(&open_flag) == 0));
+		status = atomic_read(&open_flag);
+		break;
+
+	case ECS_IOCTL_GET_DELAY:
+		delay = akmd_delay;
+		break;
+
+	default:
+		FUNCDBG("Unknown cmd\n");
+		return -ENOTTY;
+	}
+
+	switch (cmd) {
+	case ECS_IOCTL_READ:
+		if (copy_to_user(argp, &rwbuf, sizeof(rwbuf)))
+			return -EFAULT;
+		break;
+	case ECS_IOCTL_GET_OPEN_STATUS:
+	case ECS_IOCTL_GET_CLOSE_STATUS:
+		if (copy_to_user(argp, &status, sizeof(status)))
+			return -EFAULT;
+		break;
+	case ECS_IOCTL_GET_DELAY:
+		if (copy_to_user(argp, &delay, sizeof(delay)))
+			return -EFAULT;
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+/* needed to clear the int. pin */
+static void akm_work_func(struct work_struct *work)
+{
+	struct akm8975_data *akm =
+	    container_of(work, struct akm8975_data, work);
+
+	FUNCDBG("called");
+	enable_irq(akm->this_client->irq);
+}
+
+static irqreturn_t akm8975_interrupt(int irq, void *dev_id)
+{
+	struct akm8975_data *akm = dev_id;
+	FUNCDBG("called");
+
+	disable_irq_nosync(akm->this_client->irq);
+	schedule_work(&akm->work);
+	return IRQ_HANDLED;
+}
+
+static int akm8975_power_off(struct akm8975_data *akm)
+{
+#if AK8975DRV_CALL_DBG
+	pr_info("%s\n", __func__);
+#endif
+	if (akm->pdata->power_off)
+		akm->pdata->power_off();
+
+	return 0;
+}
+
+static int akm8975_power_on(struct akm8975_data *akm)
+{
+	int err;
+
+#if AK8975DRV_CALL_DBG
+	pr_info("%s\n", __func__);
+#endif
+	if (akm->pdata->power_on) {
+		err = akm->pdata->power_on();
+		if (err < 0)
+			return err;
+	}
+	return 0;
+}
+
+static int akm8975_suspend(struct i2c_client *client, pm_message_t mesg)
+{
+	struct akm8975_data *akm = i2c_get_clientdata(client);
+
+#if AK8975DRV_CALL_DBG
+	pr_info("%s\n", __func__);
+#endif
+	/* TO DO: might need more work after power mgmt
+	   is enabled */
+	return akm8975_power_off(akm);
+}
+
+static int akm8975_resume(struct i2c_client *client)
+{
+	struct akm8975_data *akm = i2c_get_clientdata(client);
+
+#if AK8975DRV_CALL_DBG
+	pr_info("%s\n", __func__);
+#endif
+	/* TO DO: might need more work after power mgmt
+	   is enabled */
+	return akm8975_power_on(akm);
+}
+
+#ifdef CONFIG_HAS_EARLYSUSPEND
+static void akm8975_early_suspend(struct early_suspend *handler)
+{
+	struct akm8975_data *akm;
+	akm = container_of(handler, struct akm8975_data, early_suspend);
+
+#if AK8975DRV_CALL_DBG
+	pr_info("%s\n", __func__);
+#endif
+	akm8975_suspend(akm->this_client, PMSG_SUSPEND);
+}
+
+static void akm8975_early_resume(struct early_suspend *handler)
+{
+	struct akm8975_data *akm;
+	akm = container_of(handler, struct akm8975_data, early_suspend);
+
+#if AK8975DRV_CALL_DBG
+	pr_info("%s\n", __func__);
+#endif
+	akm8975_resume(akm->this_client);
+}
+#endif
+
+
+static int akm8975_init_client(struct i2c_client *client)
+{
+	struct akm8975_data *data;
+	int ret;
+
+	data = i2c_get_clientdata(client);
+
+	ret = request_irq(client->irq, akm8975_interrupt, IRQF_TRIGGER_RISING,
+				"akm8975", data);
+
+	if (ret < 0) {
+		pr_err("akm8975_init_client: request irq failed\n");
+		goto err;
+	}
+
+	init_waitqueue_head(&open_wq);
+
+	mutex_lock(&data->flags_lock);
+	m_flag = 1;
+	a_flag = 1;
+	t_flag = 1;
+	mv_flag = 1;
+	mutex_unlock(&data->flags_lock);
+
+	return 0;
+err:
+  return ret;
+}
+
+static const struct file_operations akmd_fops = {
+	.owner = THIS_MODULE,
+	.open = akmd_open,
+	.release = akmd_release,
+	.ioctl = akmd_ioctl,
+};
+
+static const struct file_operations akm_aot_fops = {
+	.owner = THIS_MODULE,
+	.open = akm_aot_open,
+	.release = akm_aot_release,
+	.ioctl = akm_aot_ioctl,
+};
+
+static struct miscdevice akm_aot_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "akm8975_aot",
+	.fops = &akm_aot_fops,
+};
+
+static struct miscdevice akmd_device = {
+	.minor = MISC_DYNAMIC_MINOR,
+	.name = "akm8975_dev",
+	.fops = &akmd_fops,
+};
+
+int akm8975_probe(struct i2c_client *client,
+		  const struct i2c_device_id *devid)
+{
+	struct akm8975_data *akm;
+	int err;
+	FUNCDBG("called");
+
+	if (client->dev.platform_data == NULL) {
+		dev_err(&client->dev, "platform data is NULL. exiting.\n");
+		err = -ENODEV;
+		goto exit_platform_data_null;
+	}
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
+		dev_err(&client->dev, "platform data is NULL. exiting.\n");
+		err = -ENODEV;
+		goto exit_check_functionality_failed;
+	}
+
+	akm = kzalloc(sizeof(struct akm8975_data), GFP_KERNEL);
+	if (!akm) {
+		dev_err(&client->dev,
+			"failed to allocate memory for module data\n");
+		err = -ENOMEM;
+		goto exit_alloc_data_failed;
+	}
+
+	akm->pdata = client->dev.platform_data;
+
+	mutex_init(&akm->flags_lock);
+	INIT_WORK(&akm->work, akm_work_func);
+	i2c_set_clientdata(client, akm);
+
+	err = akm8975_power_on(akm);
+	if (err < 0)
+		goto exit_power_on_failed;
+
+	akm8975_init_client(client);
+	akm->this_client = client;
+	akmd_data = akm;
+
+	akm->input_dev = input_allocate_device();
+	if (!akm->input_dev) {
+		err = -ENOMEM;
+		dev_err(&akm->this_client->dev,
+			"input device allocate failed\n");
+		goto exit_input_dev_alloc_failed;
+	}
+
+	set_bit(EV_ABS, akm->input_dev->evbit);
+
+	/* yaw */
+	input_set_abs_params(akm->input_dev, ABS_RX, 0, 23040, 0, 0);
+	/* pitch */
+	input_set_abs_params(akm->input_dev, ABS_RY, -11520, 11520, 0, 0);
+	/* roll */
+	input_set_abs_params(akm->input_dev, ABS_RZ, -5760, 5760, 0, 0);
+	/* x-axis acceleration */
+	input_set_abs_params(akm->input_dev, ABS_X, -5760, 5760, 0, 0);
+	/* y-axis acceleration */
+	input_set_abs_params(akm->input_dev, ABS_Y, -5760, 5760, 0, 0);
+	/* z-axis acceleration */
+	input_set_abs_params(akm->input_dev, ABS_Z, -5760, 5760, 0, 0);
+	/* temparature */
+	input_set_abs_params(akm->input_dev, ABS_THROTTLE, -30, 85, 0, 0);
+	/* status of magnetic sensor */
+	input_set_abs_params(akm->input_dev, ABS_RUDDER, 0, 3, 0, 0);
+	/* status of acceleration sensor */
+	input_set_abs_params(akm->input_dev, ABS_WHEEL, 0, 3, 0, 0);
+	/* x-axis of raw magnetic vector */
+	input_set_abs_params(akm->input_dev, ABS_HAT0X, -20480, 20479, 0, 0);
+	/* y-axis of raw magnetic vector */
+	input_set_abs_params(akm->input_dev, ABS_HAT0Y, -20480, 20479, 0, 0);
+	/* z-axis of raw magnetic vector */
+	input_set_abs_params(akm->input_dev, ABS_BRAKE, -20480, 20479, 0, 0);
+
+	akm->input_dev->name = "compass";
+
+	err = input_register_device(akm->input_dev);
+	if (err) {
+		pr_err("akm8975_probe: Unable to register input device: %s\n",
+					 akm->input_dev->name);
+		goto exit_input_register_device_failed;
+	}
+
+	err = misc_register(&akmd_device);
+	if (err) {
+		pr_err("akm8975_probe: akmd_device register failed\n");
+		goto exit_misc_device_register_failed;
+	}
+
+	err = misc_register(&akm_aot_device);
+	if (err) {
+		pr_err("akm8975_probe: akm_aot_device register failed\n");
+		goto exit_misc_device_register_failed;
+	}
+
+	err = device_create_file(&client->dev, &dev_attr_akm_ms1);
+
+#ifdef CONFIG_HAS_EARLYSUSPEND
+	akm->early_suspend.suspend = akm8975_early_suspend;
+	akm->early_suspend.resume = akm8975_early_resume;
+	register_early_suspend(&akm->early_suspend);
+#endif
+	return 0;
+
+exit_misc_device_register_failed:
+exit_input_register_device_failed:
+	input_free_device(akm->input_dev);
+exit_input_dev_alloc_failed:
+	akm8975_power_off(akm);
+exit_power_on_failed:
+	kfree(akm);
+exit_alloc_data_failed:
+exit_check_functionality_failed:
+exit_platform_data_null:
+	return err;
+}
+
+static int __devexit akm8975_remove(struct i2c_client *client)
+{
+	struct akm8975_data *akm = i2c_get_clientdata(client);
+	FUNCDBG("called");
+	free_irq(client->irq, NULL);
+	input_unregister_device(akm->input_dev);
+	misc_deregister(&akmd_device);
+	misc_deregister(&akm_aot_device);
+	akm8975_power_off(akm);
+	kfree(akm);
+	return 0;
+}
+
+static const struct i2c_device_id akm8975_id[] = {
+	{ "akm8975", 0 },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, akm8975_id);
+
+static struct i2c_driver akm8975_driver = {
+	.probe = akm8975_probe,
+	.remove = akm8975_remove,
+#ifndef CONFIG_HAS_EARLYSUSPEND
+	.resume = akm8975_resume,
+	.suspend = akm8975_suspend,
+#endif
+	.id_table = akm8975_id,
+	.driver = {
+		.name = "akm8975",
+	},
+};
+
+static int __init akm8975_init(void)
+{
+	pr_info("AK8975 compass driver: init\n");
+	FUNCDBG("AK8975 compass driver: init\n");
+	return i2c_add_driver(&akm8975_driver);
+}
+
+static void __exit akm8975_exit(void)
+{
+	FUNCDBG("AK8975 compass driver: exit\n");
+	i2c_del_driver(&akm8975_driver);
+}
+
+module_init(akm8975_init);
+module_exit(akm8975_exit);
+
+MODULE_AUTHOR("Hou-Kun Chen <hk_chen@htc.com>");
+MODULE_DESCRIPTION("AK8975 compass driver");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/akm8975.h b/include/linux/akm8975.h
new file mode 100644
index 00000000000..6a7c4326001
--- /dev/null
+++ b/include/linux/akm8975.h
@@ -0,0 +1,87 @@
+/*
+ * Definitions for akm8975 compass chip.
+ */
+#ifndef AKM8975_H
+#define AKM8975_H
+
+#include <linux/ioctl.h>
+
+/*! \name AK8975 operation mode
+ \anchor AK8975_Mode
+ Defines an operation mode of the AK8975.*/
+/*! @{*/
+#define AK8975_MODE_SNG_MEASURE   0x01
+#define	AK8975_MODE_SELF_TEST     0x08
+#define	AK8975_MODE_FUSE_ACCESS   0x0F
+#define	AK8975_MODE_POWER_DOWN    0x00
+/*! @}*/
+
+#define RBUFF_SIZE		8	/* Rx buffer size */
+
+/*! \name AK8975 register address
+\anchor AK8975_REG
+Defines a register address of the AK8975.*/
+/*! @{*/
+#define AK8975_REG_WIA		0x00
+#define AK8975_REG_INFO		0x01
+#define AK8975_REG_ST1		0x02
+#define AK8975_REG_HXL		0x03
+#define AK8975_REG_HXH		0x04
+#define AK8975_REG_HYL		0x05
+#define AK8975_REG_HYH		0x06
+#define AK8975_REG_HZL		0x07
+#define AK8975_REG_HZH		0x08
+#define AK8975_REG_ST2		0x09
+#define AK8975_REG_CNTL		0x0A
+#define AK8975_REG_RSV		0x0B
+#define AK8975_REG_ASTC		0x0C
+#define AK8975_REG_TS1		0x0D
+#define AK8975_REG_TS2		0x0E
+#define AK8975_REG_I2CDIS	0x0F
+/*! @}*/
+
+/*! \name AK8975 fuse-rom address
+\anchor AK8975_FUSE
+Defines a read-only address of the fuse ROM of the AK8975.*/
+/*! @{*/
+#define AK8975_FUSE_ASAX	0x10
+#define AK8975_FUSE_ASAY	0x11
+#define AK8975_FUSE_ASAZ	0x12
+/*! @}*/
+
+#define AKMIO                   0xA1
+
+/* IOCTLs for AKM library */
+#define ECS_IOCTL_WRITE                 _IOW(AKMIO, 0x02, char[5])
+#define ECS_IOCTL_READ                  _IOWR(AKMIO, 0x03, char[5])
+#define ECS_IOCTL_GETDATA               _IOR(AKMIO, 0x08, char[RBUFF_SIZE])
+#define ECS_IOCTL_SET_YPR               _IOW(AKMIO, 0x0C, short[12])
+#define ECS_IOCTL_GET_OPEN_STATUS       _IOR(AKMIO, 0x0D, int)
+#define ECS_IOCTL_GET_CLOSE_STATUS      _IOR(AKMIO, 0x0E, int)
+#define ECS_IOCTL_GET_DELAY             _IOR(AKMIO, 0x30, short)
+
+/* IOCTLs for APPs */
+#define ECS_IOCTL_APP_SET_MFLAG		_IOW(AKMIO, 0x11, short)
+#define ECS_IOCTL_APP_GET_MFLAG		_IOW(AKMIO, 0x12, short)
+#define ECS_IOCTL_APP_SET_AFLAG		_IOW(AKMIO, 0x13, short)
+#define ECS_IOCTL_APP_GET_AFLAG		_IOR(AKMIO, 0x14, short)
+#define ECS_IOCTL_APP_SET_DELAY		_IOW(AKMIO, 0x18, short)
+#define ECS_IOCTL_APP_GET_DELAY		ECS_IOCTL_GET_DELAY
+/* Set raw magnetic vector flag */
+#define ECS_IOCTL_APP_SET_MVFLAG	_IOW(AKMIO, 0x19, short)
+/* Get raw magnetic vector flag */
+#define ECS_IOCTL_APP_GET_MVFLAG	_IOR(AKMIO, 0x1A, short)
+#define ECS_IOCTL_APP_SET_TFLAG         _IOR(AKMIO, 0x15, short)
+
+
+struct akm8975_platform_data {
+	int intr;
+
+	int (*init)(void);
+	void (*exit)(void);
+	int (*power_on)(void);
+	int (*power_off)(void);
+};
+
+#endif
+