drivers/input/misc/gp2a.c - kernel/omap - Git at Google

 /* linux/driver/input/misc/gp2a.c
  * Copyright (C) 2010 Samsung Electronics. All rights reserved.
  *
  * 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 St, Fifth Floor, Boston, MA
  * 02110-1301 USA
  */

 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/i2c.h>
 #include <linux/fs.h>
 #include <linux/errno.h>
 #include <linux/device.h>
 #include <linux/delay.h>
 #include <linux/miscdevice.h>
 #include <linux/platform_device.h>
 #include <linux/leds.h>
 #include <linux/gpio.h>
 #include <linux/wakelock.h>
 #include <linux/slab.h>
 #include <linux/input.h>
 #include <linux/workqueue.h>
 #include <linux/uaccess.h>
 #include <linux/gp2a.h>


 /* Note about power vs enable/disable:
  *  The chip has two functions, proximity and ambient light sensing.
  *  There is no separate power enablement to the two functions (unlike
  *  the Capella CM3602/3623).
  *  This module implements two drivers: /dev/proximity and /dev/light.
  *  When either driver is enabled (via sysfs attributes), we give power
  *  to the chip.  When both are disabled, we remove power from the chip.
  *  In suspend, we remove power if light is disabled but not if proximity is
  *  enabled (proximity is allowed to wakeup from suspend).
  *
  *  There are no ioctls for either driver interfaces.  Output is via
  *  input device framework and control via sysfs attributes.
  */


 #define gp2a_dbgmsg(str, args...) pr_debug("%s: " str, __func__, ##args)

 /* ADDSEL is LOW */
 #define REGS_PROX		0x0 /* Read  Only */
 #define REGS_GAIN		0x1 /* Write Only */
 #define REGS_HYS		0x2 /* Write Only */
 #define REGS_CYCLE		0x3 /* Write Only */
 #define REGS_OPMOD		0x4 /* Write Only */

 /* sensor type */
 #define LIGHT           0
 #define PROXIMITY	1
 #define ALL		2

 #define DELAY_LOWBOUND	(5 * NSEC_PER_MSEC)

 /* start time delay for light sensor in nano seconds */
 #define LIGHT_SENSOR_START_TIME_DELAY 50000000

 static u8 reg_defaults[5] = {
 	0x00, /* PROX: read only register */
 	0x08, /* GAIN: large LED drive level */
 	0xC2, /* HYS: receiver sensitivity */
 	0x04, /* CYCLE: */
 	0x01, /* OPMOD: normal operating mode */
 };

 enum {
 	LIGHT_ENABLED = BIT(0),
 	PROXIMITY_ENABLED = BIT(1),
 };

 /* driver data */
 struct gp2a_data {
 	struct input_dev *proximity_input_dev;
 	struct input_dev *light_input_dev;
 	struct gp2a_platform_data *pdata;
 	struct i2c_client *i2c_client;
 	int irq;
 	struct work_struct work_light;
 	struct hrtimer timer;
 	ktime_t light_poll_delay;
 	bool on;
 	u8 power_state;
 	struct mutex power_lock;
 	struct wake_lock prx_wake_lock;
 	struct workqueue_struct *wq;
 };

 int gp2a_i2c_write(struct gp2a_data *gp2a, u8 reg, u8 *val)
 {
 	int err = 0;
 	struct i2c_msg msg[1];
 	unsigned char data[2];
 	int retry = 10;
 	struct i2c_client *client = gp2a->i2c_client;

 	if ((client == NULL) || (!client->adapter))
 		return -ENODEV;

 	while (retry--) {
 		data[0] = reg;
 		data[1] = *val;

 		msg->addr = client->addr;
 		msg->flags = 0; /* write */
 		msg->len = 2;
 		msg->buf = data;

 		err = i2c_transfer(client->adapter, msg, 1);

 		if (err >= 0)
 			return 0;
 	}
 	return err;
 }

 static void gp2a_light_enable(struct gp2a_data *gp2a)
 {
 	gp2a_dbgmsg("starting poll timer, delay %lldns\n",
 		    ktime_to_ns(gp2a->light_poll_delay));
 	/*
 	 * Set far out of range ABS_MISC value, -1024, to enable real value to
 	 * go through next.
 	 */
 	input_abs_set_val(gp2a->light_input_dev, ABS_MISC, -1024);
 	hrtimer_start(&gp2a->timer, ktime_set(0, LIGHT_SENSOR_START_TIME_DELAY),
 					HRTIMER_MODE_REL);
 }

 static void gp2a_light_disable(struct gp2a_data *gp2a)
 {
 	gp2a_dbgmsg("cancelling poll timer\n");
 	hrtimer_cancel(&gp2a->timer);
 	cancel_work_sync(&gp2a->work_light);
 }

 static ssize_t poll_delay_show(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
 	struct gp2a_data *gp2a = dev_get_drvdata(dev);
 	return sprintf(buf, "%lld\n", ktime_to_ns(gp2a->light_poll_delay));
 }


 static ssize_t poll_delay_store(struct device *dev,
 				struct device_attribute *attr,
 				const char *buf, size_t size)
 {
 	struct gp2a_data *gp2a = dev_get_drvdata(dev);
 	int64_t new_delay;
 	int err;

 	err = strict_strtoll(buf, 10, &new_delay);
 	if (err < 0)
 		return err;

 	gp2a_dbgmsg("new delay = %lldns, old delay = %lldns\n",
 		    new_delay, ktime_to_ns(gp2a->light_poll_delay));

 	if (new_delay < DELAY_LOWBOUND) {
 		gp2a_dbgmsg("new delay less than low bound, so set delay "
 			"to %lld\n", (int64_t)DELAY_LOWBOUND);
 		new_delay = DELAY_LOWBOUND;
 	}

 	mutex_lock(&gp2a->power_lock);
 	if (new_delay != ktime_to_ns(gp2a->light_poll_delay)) {
 		gp2a->light_poll_delay = ns_to_ktime(new_delay);
 		if (gp2a->power_state & LIGHT_ENABLED) {
 			gp2a_light_disable(gp2a);
 			gp2a_light_enable(gp2a);
 		}
 	}
 	mutex_unlock(&gp2a->power_lock);

 	return size;
 }

 static ssize_t light_enable_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
 {
 	struct gp2a_data *gp2a = dev_get_drvdata(dev);
 	return sprintf(buf, "%d\n",
 		       (gp2a->power_state & LIGHT_ENABLED) ? 1 : 0);
 }

 static ssize_t proximity_enable_show(struct device *dev,
 				 struct device_attribute *attr, char *buf)
 {
 	struct gp2a_data *gp2a = dev_get_drvdata(dev);
 	return sprintf(buf, "%d\n",
 		       (gp2a->power_state & PROXIMITY_ENABLED) ? 1 : 0);
 }

 static ssize_t light_enable_store(struct device *dev,
 				  struct device_attribute *attr,
 				  const char *buf, size_t size)
 {
 	struct gp2a_data *gp2a = dev_get_drvdata(dev);
 	bool new_value;

 	if (sysfs_streq(buf, "1"))
 		new_value = true;
 	else if (sysfs_streq(buf, "0"))
 		new_value = false;
 	else {
 		pr_err("%s: invalid value %d\n", __func__, *buf);
 		return -EINVAL;
 	}

 	mutex_lock(&gp2a->power_lock);
 	gp2a_dbgmsg("new_value = %d, old state = %d\n",
 		    new_value, (gp2a->power_state & LIGHT_ENABLED) ? 1 : 0);
 	if (new_value && !(gp2a->power_state & LIGHT_ENABLED)) {
 		if (!gp2a->power_state)
 			gp2a->pdata->power(true);
 		gp2a->power_state |= LIGHT_ENABLED;
 		gp2a_light_enable(gp2a);
 	} else if (!new_value && (gp2a->power_state & LIGHT_ENABLED)) {
 		gp2a_light_disable(gp2a);
 		gp2a->power_state &= ~LIGHT_ENABLED;
 		if (!gp2a->power_state)
 			gp2a->pdata->power(false);
 	}
 	mutex_unlock(&gp2a->power_lock);
 	return size;
 }

 static ssize_t proximity_enable_store(struct device *dev,
 				      struct device_attribute *attr,
 				      const char *buf, size_t size)
 {
 	struct gp2a_data *gp2a = dev_get_drvdata(dev);
 	bool new_value;

 	if (sysfs_streq(buf, "1"))
 		new_value = true;
 	else if (sysfs_streq(buf, "0"))
 		new_value = false;
 	else {
 		pr_err("%s: invalid value %d\n", __func__, *buf);
 		return -EINVAL;
 	}

 	mutex_lock(&gp2a->power_lock);
 	gp2a_dbgmsg("new_value = %d, old state = %d\n",
 		    new_value, (gp2a->power_state & PROXIMITY_ENABLED) ? 1 : 0);
 	if (new_value && !(gp2a->power_state & PROXIMITY_ENABLED)) {
 		if (!gp2a->power_state)
 			gp2a->pdata->power(true);
 		gp2a->power_state |= PROXIMITY_ENABLED;
 		enable_irq(gp2a->irq);
 		enable_irq_wake(gp2a->irq);
 		gp2a_i2c_write(gp2a, REGS_GAIN, &reg_defaults[1]);
 		gp2a_i2c_write(gp2a, REGS_HYS, &reg_defaults[2]);
 		gp2a_i2c_write(gp2a, REGS_CYCLE, &reg_defaults[3]);
 		gp2a_i2c_write(gp2a, REGS_OPMOD, &reg_defaults[4]);
 	} else if (!new_value && (gp2a->power_state & PROXIMITY_ENABLED)) {
 		disable_irq_wake(gp2a->irq);
 		disable_irq(gp2a->irq);
 		gp2a_i2c_write(gp2a, REGS_OPMOD, &reg_defaults[0]);
 		gp2a->power_state &= ~PROXIMITY_ENABLED;
 		if (!gp2a->power_state)
 			gp2a->pdata->power(false);
 	}
 	mutex_unlock(&gp2a->power_lock);
 	return size;
 }

 static DEVICE_ATTR(poll_delay, S_IRUGO | S_IWUSR | S_IWGRP,
 		   poll_delay_show, poll_delay_store);

 static struct device_attribute dev_attr_light_enable =
 	__ATTR(enable, S_IRUGO | S_IWUSR | S_IWGRP,
 	       light_enable_show, light_enable_store);

 static struct device_attribute dev_attr_proximity_enable =
 	__ATTR(enable, S_IRUGO | S_IWUSR | S_IWGRP,
 	       proximity_enable_show, proximity_enable_store);

 static struct attribute *light_sysfs_attrs[] = {
 	&dev_attr_light_enable.attr,
 	&dev_attr_poll_delay.attr,
 	NULL
 };

 static struct attribute_group light_attribute_group = {
 	.attrs = light_sysfs_attrs,
 };

 static struct attribute *proximity_sysfs_attrs[] = {
 	&dev_attr_proximity_enable.attr,
 	NULL
 };

 static struct attribute_group proximity_attribute_group = {
 	.attrs = proximity_sysfs_attrs,
 };

 static void gp2a_work_func_light(struct work_struct *work)
 {
 	struct gp2a_data *gp2a = container_of(work, struct gp2a_data,
 					      work_light);
 	int adc = gp2a->pdata->light_adc_value();
 	if (adc < 0) {
 		pr_err("adc returned error %d\n", adc);
 		return;
 	}
 	gp2a_dbgmsg("adc returned light value %d\n", adc);
 	input_report_abs(gp2a->light_input_dev, ABS_MISC, adc);
 	input_sync(gp2a->light_input_dev);
 }

 /* This function is for light sensor.  It operates every a few seconds.
  * It asks for work to be done on a thread because i2c needs a thread
  * context (slow and blocking) and then reschedules the timer to run again.
  */
 static enum hrtimer_restart gp2a_timer_func(struct hrtimer *timer)
 {
 	struct gp2a_data *gp2a = container_of(timer, struct gp2a_data, timer);
 	queue_work(gp2a->wq, &gp2a->work_light);
 	hrtimer_forward_now(&gp2a->timer, gp2a->light_poll_delay);
 	return HRTIMER_RESTART;
 }

 /* interrupt happened due to transition/change of near/far proximity state */
 irqreturn_t gp2a_irq_handler(int irq, void *data)
 {
 	struct gp2a_data *ip = data;
 	int val = gpio_get_value(ip->pdata->p_out);
 	if (val < 0) {
 		pr_err("%s: gpio_get_value error %d\n", __func__, val);
 		return IRQ_HANDLED;
 	}

 	gp2a_dbgmsg("gp2a: proximity val=%d\n", val);

 	/* 0 is close, 1 is far */
 	input_report_abs(ip->proximity_input_dev, ABS_DISTANCE, val);
 	input_sync(ip->proximity_input_dev);
 	wake_lock_timeout(&ip->prx_wake_lock, 3*HZ);
 	return IRQ_HANDLED;
 }

 static int gp2a_setup_irq(struct gp2a_data *gp2a)
 {
 	int rc = -EIO;
 	struct gp2a_platform_data *pdata = gp2a->pdata;
 	int irq;

 	gp2a_dbgmsg("start\n");

 	rc = gpio_request(pdata->p_out, "gpio_proximity_out");
 	if (rc < 0) {
 		pr_err("%s: gpio %d request failed (%d)\n",
 			__func__, pdata->p_out, rc);
 		return rc;
 	}

 	rc = gpio_direction_input(pdata->p_out);
 	if (rc < 0) {
 		pr_err("%s: failed to set gpio %d as input (%d)\n",
 			__func__, pdata->p_out, rc);
 		goto err_gpio_direction_input;
 	}

 	irq = gpio_to_irq(pdata->p_out);
 	rc = request_irq(irq,
 			 gp2a_irq_handler,
 			 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
 			 "proximity_int",
 			 gp2a);
 	if (rc < 0) {
 		pr_err("%s: request_irq(%d) failed for gpio %d (%d)\n",
 			__func__, irq,
 			pdata->p_out, rc);
 		goto err_request_irq;
 	}

 	/* start with interrupts disabled */
 	disable_irq(irq);
 	gp2a->irq = irq;

 	/* sync input device with proximity gpio pin default value */
 	gp2a_irq_handler(gp2a->irq, gp2a);

 	gp2a_dbgmsg("success\n");

 	goto done;

 err_request_irq:
 err_gpio_direction_input:
 	gpio_free(pdata->p_out);
 done:
 	return rc;
 }

 static int gp2a_i2c_probe(struct i2c_client *client,
 			  const struct i2c_device_id *id)
 {
 	int ret = -ENODEV;
 	struct input_dev *input_dev;
 	struct gp2a_data *gp2a;
 	struct gp2a_platform_data *pdata = client->dev.platform_data;

 	if (!pdata) {
 		pr_err("%s: missing pdata!\n", __func__);
 		return ret;
 	}
 	if (!pdata->power || !pdata->light_adc_value) {
 		pr_err("%s: incomplete pdata!\n", __func__);
 		return ret;
 	}
 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
 		pr_err("%s: i2c functionality check failed!\n", __func__);
 		return ret;
 	}

 	gp2a = kzalloc(sizeof(struct gp2a_data), GFP_KERNEL);
 	if (!gp2a) {
 		pr_err("%s: failed to alloc memory for module data\n",
 		       __func__);
 		return -ENOMEM;
 	}

 	gp2a->pdata = pdata;
 	gp2a->i2c_client = client;
 	i2c_set_clientdata(client, gp2a);


 	wake_lock_init(&gp2a->prx_wake_lock, WAKE_LOCK_SUSPEND,
 		"prx_wake_lock");
 	mutex_init(&gp2a->power_lock);

 	/* allocate proximity input_device */
 	input_dev = input_allocate_device();
 	if (!input_dev) {
 		pr_err("%s: could not allocate input device\n", __func__);
 		goto err_input_allocate_device_proximity;
 	}
 	gp2a->proximity_input_dev = input_dev;
 	input_set_drvdata(input_dev, gp2a);
 	input_dev->name = "proximity";
 	input_set_capability(input_dev, EV_ABS, ABS_DISTANCE);
 	input_set_abs_params(input_dev, ABS_DISTANCE, 0, 1, 0, 0);

 	ret = gp2a_setup_irq(gp2a);
 	if (ret) {
 		pr_err("%s: could not setup irq\n", __func__);
 		input_free_device(input_dev);
 		goto err_setup_irq;
 	}

 	gp2a_dbgmsg("registering proximity input device\n");
 	ret = input_register_device(input_dev);
 	if (ret < 0) {
 		pr_err("%s: could not register input device\n", __func__);
 		input_free_device(input_dev);
 		goto err_input_register_device_proximity;
 	}
 	ret = sysfs_create_group(&input_dev->dev.kobj,
 				 &proximity_attribute_group);
 	if (ret) {
 		pr_err("%s: could not create sysfs group\n", __func__);
 		goto err_sysfs_create_group_proximity;
 	}

 	/* hrtimer settings.  we poll for light values using a timer. */
 	hrtimer_init(&gp2a->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
 	gp2a->light_poll_delay = ns_to_ktime(200 * NSEC_PER_MSEC);
 	gp2a->timer.function = gp2a_timer_func;

 	/* the timer just fires off a work queue request.  we need a thread
 	 * to read the i2c (can be slow and blocking)
 	 */
 	gp2a->wq = create_singlethread_workqueue("gp2a_wq");
 	if (!gp2a->wq) {
 		ret = -ENOMEM;
 		pr_err("%s: could not create workqueue\n", __func__);
 		goto err_create_workqueue;
 	}
 	/* this is the thread function we run on the work queue */
 	INIT_WORK(&gp2a->work_light, gp2a_work_func_light);

 	/* allocate lightsensor-level input_device */
 	input_dev = input_allocate_device();
 	if (!input_dev) {
 		pr_err("%s: could not allocate input device\n", __func__);
 		ret = -ENOMEM;
 		goto err_input_allocate_device_light;
 	}
 	input_set_drvdata(input_dev, gp2a);
 	input_dev->name = "lightsensor-level";
 	input_set_capability(input_dev, EV_ABS, ABS_MISC);
 	input_set_abs_params(input_dev, ABS_MISC, 0, 1023, 8, 0);

 	gp2a_dbgmsg("registering lightsensor-level input device\n");
 	ret = input_register_device(input_dev);
 	if (ret < 0) {
 		pr_err("%s: could not register input device\n", __func__);
 		input_free_device(input_dev);
 		goto err_input_register_device_light;
 	}
 	gp2a->light_input_dev = input_dev;
 	ret = sysfs_create_group(&input_dev->dev.kobj,
 				 &light_attribute_group);
 	if (ret) {
 		pr_err("%s: could not create sysfs group\n", __func__);
 		goto err_sysfs_create_group_light;
 	}
 	goto done;

 	/* error, unwind it all */
 err_sysfs_create_group_light:
 	input_unregister_device(gp2a->light_input_dev);
 err_input_register_device_light:
 err_input_allocate_device_light:
 	destroy_workqueue(gp2a->wq);
 err_create_workqueue:
 	sysfs_remove_group(&gp2a->proximity_input_dev->dev.kobj,
 			   &proximity_attribute_group);
 err_sysfs_create_group_proximity:
 	input_unregister_device(gp2a->proximity_input_dev);
 err_input_register_device_proximity:
 	free_irq(gp2a->irq, gp2a);
 	gpio_free(gp2a->pdata->p_out);
 err_setup_irq:
 err_input_allocate_device_proximity:
 	mutex_destroy(&gp2a->power_lock);
 	wake_lock_destroy(&gp2a->prx_wake_lock);
 	kfree(gp2a);
 done:
 	return ret;
 }

 static int gp2a_suspend(struct device *dev)
 {
 	/* We disable power only if proximity is disabled.  If proximity
 	 * is enabled, we leave power on because proximity is allowed
 	 * to wake up device.  We remove power without changing
 	 * gp2a->power_state because we use that state in resume
 	 */
 	struct i2c_client *client = to_i2c_client(dev);
 	struct gp2a_data *gp2a = i2c_get_clientdata(client);
 	if (gp2a->power_state & LIGHT_ENABLED)
 		gp2a_light_disable(gp2a);
 	if (gp2a->power_state == LIGHT_ENABLED)
 		gp2a->pdata->power(false);
 	return 0;
 }

 static int gp2a_resume(struct device *dev)
 {
 	/* Turn power back on if we were before suspend. */
 	struct i2c_client *client = to_i2c_client(dev);
 	struct gp2a_data *gp2a = i2c_get_clientdata(client);
 	if (gp2a->power_state == LIGHT_ENABLED)
 		gp2a->pdata->power(true);
 	if (gp2a->power_state & LIGHT_ENABLED)
 		gp2a_light_enable(gp2a);
 	return 0;
 }

 static int gp2a_i2c_remove(struct i2c_client *client)
 {
 	struct gp2a_data *gp2a = i2c_get_clientdata(client);
 	sysfs_remove_group(&gp2a->light_input_dev->dev.kobj,
 			   &light_attribute_group);
 	sysfs_remove_group(&gp2a->proximity_input_dev->dev.kobj,
 			   &proximity_attribute_group);
 	free_irq(gp2a->irq, gp2a);
 	destroy_workqueue(gp2a->wq);
 	input_unregister_device(gp2a->light_input_dev);
 	input_unregister_device(gp2a->proximity_input_dev);
 	gpio_free(gp2a->pdata->p_out);
 	if (gp2a->power_state) {
 		gp2a->power_state = 0;
 		if (gp2a->power_state & LIGHT_ENABLED)
 			gp2a_light_disable(gp2a);
 		gp2a->pdata->power(false);
 	}
 	mutex_destroy(&gp2a->power_lock);
 	wake_lock_destroy(&gp2a->prx_wake_lock);
 	kfree(gp2a);
 	return 0;
 }

 static const struct i2c_device_id gp2a_device_id[] = {
 	{"gp2a", 0},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, gp2a_device_id);

 static const struct dev_pm_ops gp2a_pm_ops = {
 	.suspend = gp2a_suspend,
 	.resume = gp2a_resume
 };

 static struct i2c_driver gp2a_i2c_driver = {
 	.driver = {
 		.name = "gp2a",
 		.owner = THIS_MODULE,
 		.pm = &gp2a_pm_ops
 	},
 	.probe		= gp2a_i2c_probe,
 	.remove		= gp2a_i2c_remove,
 	.id_table	= gp2a_device_id,
 };


 static int __init gp2a_init(void)
 {
 	return i2c_add_driver(&gp2a_i2c_driver);
 }

 static void __exit gp2a_exit(void)
 {
 	i2c_del_driver(&gp2a_i2c_driver);
 }

 module_init(gp2a_init);
 module_exit(gp2a_exit);

 MODULE_AUTHOR("[email protected]");
 MODULE_DESCRIPTION("Optical Sensor driver for gp2ap002a00f");
 MODULE_LICENSE("GPL");
	/* linux/driver/input/misc/gp2a.c
	* Copyright (C) 2010 Samsung Electronics. All rights reserved.
	*
	* 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 St, Fifth Floor, Boston, MA
	* 02110-1301 USA
	*/

	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/i2c.h>
	#include <linux/fs.h>
	#include <linux/errno.h>
	#include <linux/device.h>
	#include <linux/delay.h>
	#include <linux/miscdevice.h>
	#include <linux/platform_device.h>
	#include <linux/leds.h>
	#include <linux/gpio.h>
	#include <linux/wakelock.h>
	#include <linux/slab.h>
	#include <linux/input.h>
	#include <linux/workqueue.h>
	#include <linux/uaccess.h>
	#include <linux/gp2a.h>


	/* Note about power vs enable/disable:
	* The chip has two functions, proximity and ambient light sensing.
	* There is no separate power enablement to the two functions (unlike
	* the Capella CM3602/3623).
	* This module implements two drivers: /dev/proximity and /dev/light.
	* When either driver is enabled (via sysfs attributes), we give power
	* to the chip. When both are disabled, we remove power from the chip.
	* In suspend, we remove power if light is disabled but not if proximity is
	* enabled (proximity is allowed to wakeup from suspend).
	*
	* There are no ioctls for either driver interfaces. Output is via
	* input device framework and control via sysfs attributes.
	*/


	#define gp2a_dbgmsg(str, args...) pr_debug("%s: " str, __func__, ##args)

	/* ADDSEL is LOW */
	#define REGS_PROX 0x0 /* Read Only */
	#define REGS_GAIN 0x1 /* Write Only */
	#define REGS_HYS 0x2 /* Write Only */
	#define REGS_CYCLE 0x3 /* Write Only */
	#define REGS_OPMOD 0x4 /* Write Only */

	/* sensor type */
	#define LIGHT 0
	#define PROXIMITY 1
	#define ALL 2

	#define DELAY_LOWBOUND (5 * NSEC_PER_MSEC)

	/* start time delay for light sensor in nano seconds */
	#define LIGHT_SENSOR_START_TIME_DELAY 50000000

	static u8 reg_defaults[5] = {
	0x00, /* PROX: read only register */
	0x08, /* GAIN: large LED drive level */
	0xC2, /* HYS: receiver sensitivity */
	0x04, /* CYCLE: */
	0x01, /* OPMOD: normal operating mode */
	};

	enum {
	LIGHT_ENABLED = BIT(0),
	PROXIMITY_ENABLED = BIT(1),
	};

	/* driver data */
	struct gp2a_data {
	struct input_dev *proximity_input_dev;
	struct input_dev *light_input_dev;
	struct gp2a_platform_data *pdata;
	struct i2c_client *i2c_client;
	int irq;
	struct work_struct work_light;
	struct hrtimer timer;
	ktime_t light_poll_delay;
	bool on;
	u8 power_state;
	struct mutex power_lock;
	struct wake_lock prx_wake_lock;
	struct workqueue_struct *wq;
	};

	int gp2a_i2c_write(struct gp2a_data gp2a, u8 reg, u8 val)
	{
	int err = 0;
	struct i2c_msg msg[1];
	unsigned char data[2];
	int retry = 10;
	struct i2c_client *client = gp2a->i2c_client;

	if ((client == NULL) \|\| (!client->adapter))
	return -ENODEV;

	while (retry--) {
	data[0] = reg;
	data[1] = *val;

	msg->addr = client->addr;
	msg->flags = 0; /* write */
	msg->len = 2;
	msg->buf = data;

	err = i2c_transfer(client->adapter, msg, 1);

	if (err >= 0)
	return 0;
	}
	return err;
	}

	static void gp2a_light_enable(struct gp2a_data *gp2a)
	{
	gp2a_dbgmsg("starting poll timer, delay %lldns\n",
	ktime_to_ns(gp2a->light_poll_delay));
	/*
	* Set far out of range ABS_MISC value, -1024, to enable real value to
	* go through next.
	*/
	input_abs_set_val(gp2a->light_input_dev, ABS_MISC, -1024);
	hrtimer_start(&gp2a->timer, ktime_set(0, LIGHT_SENSOR_START_TIME_DELAY),
	HRTIMER_MODE_REL);
	}

	static void gp2a_light_disable(struct gp2a_data *gp2a)
	{
	gp2a_dbgmsg("cancelling poll timer\n");
	hrtimer_cancel(&gp2a->timer);
	cancel_work_sync(&gp2a->work_light);
	}

	static ssize_t poll_delay_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct gp2a_data *gp2a = dev_get_drvdata(dev);
	return sprintf(buf, "%lld\n", ktime_to_ns(gp2a->light_poll_delay));
	}


	static ssize_t poll_delay_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t size)
	{
	struct gp2a_data *gp2a = dev_get_drvdata(dev);
	int64_t new_delay;
	int err;

	err = strict_strtoll(buf, 10, &new_delay);
	if (err < 0)
	return err;

	gp2a_dbgmsg("new delay = %lldns, old delay = %lldns\n",
	new_delay, ktime_to_ns(gp2a->light_poll_delay));

	if (new_delay < DELAY_LOWBOUND) {
	gp2a_dbgmsg("new delay less than low bound, so set delay "
	"to %lld\n", (int64_t)DELAY_LOWBOUND);
	new_delay = DELAY_LOWBOUND;
	}

	mutex_lock(&gp2a->power_lock);
	if (new_delay != ktime_to_ns(gp2a->light_poll_delay)) {
	gp2a->light_poll_delay = ns_to_ktime(new_delay);
	if (gp2a->power_state & LIGHT_ENABLED) {
	gp2a_light_disable(gp2a);
	gp2a_light_enable(gp2a);
	}
	}
	mutex_unlock(&gp2a->power_lock);

	return size;
	}

	static ssize_t light_enable_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct gp2a_data *gp2a = dev_get_drvdata(dev);
	return sprintf(buf, "%d\n",
	(gp2a->power_state & LIGHT_ENABLED) ? 1 : 0);
	}

	static ssize_t proximity_enable_show(struct device *dev,
	struct device_attribute attr, char buf)
	{
	struct gp2a_data *gp2a = dev_get_drvdata(dev);
	return sprintf(buf, "%d\n",
	(gp2a->power_state & PROXIMITY_ENABLED) ? 1 : 0);
	}

	static ssize_t light_enable_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t size)
	{
	struct gp2a_data *gp2a = dev_get_drvdata(dev);
	bool new_value;

	if (sysfs_streq(buf, "1"))
	new_value = true;
	else if (sysfs_streq(buf, "0"))
	new_value = false;
	else {
	pr_err("%s: invalid value %d\n", __func__, *buf);
	return -EINVAL;
	}

	mutex_lock(&gp2a->power_lock);
	gp2a_dbgmsg("new_value = %d, old state = %d\n",
	new_value, (gp2a->power_state & LIGHT_ENABLED) ? 1 : 0);
	if (new_value && !(gp2a->power_state & LIGHT_ENABLED)) {
	if (!gp2a->power_state)
	gp2a->pdata->power(true);
	gp2a->power_state \|= LIGHT_ENABLED;
	gp2a_light_enable(gp2a);
	} else if (!new_value && (gp2a->power_state & LIGHT_ENABLED)) {
	gp2a_light_disable(gp2a);
	gp2a->power_state &= ~LIGHT_ENABLED;
	if (!gp2a->power_state)
	gp2a->pdata->power(false);
	}
	mutex_unlock(&gp2a->power_lock);
	return size;
	}

	static ssize_t proximity_enable_store(struct device *dev,
	struct device_attribute *attr,
	const char *buf, size_t size)
	{
	struct gp2a_data *gp2a = dev_get_drvdata(dev);
	bool new_value;

	if (sysfs_streq(buf, "1"))
	new_value = true;
	else if (sysfs_streq(buf, "0"))
	new_value = false;
	else {
	pr_err("%s: invalid value %d\n", __func__, *buf);
	return -EINVAL;
	}

	mutex_lock(&gp2a->power_lock);
	gp2a_dbgmsg("new_value = %d, old state = %d\n",
	new_value, (gp2a->power_state & PROXIMITY_ENABLED) ? 1 : 0);
	if (new_value && !(gp2a->power_state & PROXIMITY_ENABLED)) {
	if (!gp2a->power_state)
	gp2a->pdata->power(true);
	gp2a->power_state \|= PROXIMITY_ENABLED;
	enable_irq(gp2a->irq);
	enable_irq_wake(gp2a->irq);
	gp2a_i2c_write(gp2a, REGS_GAIN, &reg_defaults[1]);
	gp2a_i2c_write(gp2a, REGS_HYS, &reg_defaults[2]);
	gp2a_i2c_write(gp2a, REGS_CYCLE, &reg_defaults[3]);
	gp2a_i2c_write(gp2a, REGS_OPMOD, &reg_defaults[4]);
	} else if (!new_value && (gp2a->power_state & PROXIMITY_ENABLED)) {
	disable_irq_wake(gp2a->irq);
	disable_irq(gp2a->irq);
	gp2a_i2c_write(gp2a, REGS_OPMOD, &reg_defaults[0]);
	gp2a->power_state &= ~PROXIMITY_ENABLED;
	if (!gp2a->power_state)
	gp2a->pdata->power(false);
	}
	mutex_unlock(&gp2a->power_lock);
	return size;
	}

	static DEVICE_ATTR(poll_delay, S_IRUGO \| S_IWUSR \| S_IWGRP,
	poll_delay_show, poll_delay_store);

	static struct device_attribute dev_attr_light_enable =
	__ATTR(enable, S_IRUGO \| S_IWUSR \| S_IWGRP,
	light_enable_show, light_enable_store);

	static struct device_attribute dev_attr_proximity_enable =
	__ATTR(enable, S_IRUGO \| S_IWUSR \| S_IWGRP,
	proximity_enable_show, proximity_enable_store);

	static struct attribute *light_sysfs_attrs[] = {
	&dev_attr_light_enable.attr,
	&dev_attr_poll_delay.attr,
	NULL
	};

	static struct attribute_group light_attribute_group = {
	.attrs = light_sysfs_attrs,
	};

	static struct attribute *proximity_sysfs_attrs[] = {
	&dev_attr_proximity_enable.attr,
	NULL
	};

	static struct attribute_group proximity_attribute_group = {
	.attrs = proximity_sysfs_attrs,
	};

	static void gp2a_work_func_light(struct work_struct *work)
	{
	struct gp2a_data *gp2a = container_of(work, struct gp2a_data,
	work_light);
	int adc = gp2a->pdata->light_adc_value();
	if (adc < 0) {
	pr_err("adc returned error %d\n", adc);
	return;
	}
	gp2a_dbgmsg("adc returned light value %d\n", adc);
	input_report_abs(gp2a->light_input_dev, ABS_MISC, adc);
	input_sync(gp2a->light_input_dev);
	}

	/* This function is for light sensor. It operates every a few seconds.
	* It asks for work to be done on a thread because i2c needs a thread
	* context (slow and blocking) and then reschedules the timer to run again.
	*/
	static enum hrtimer_restart gp2a_timer_func(struct hrtimer *timer)
	{
	struct gp2a_data *gp2a = container_of(timer, struct gp2a_data, timer);
	queue_work(gp2a->wq, &gp2a->work_light);
	hrtimer_forward_now(&gp2a->timer, gp2a->light_poll_delay);
	return HRTIMER_RESTART;
	}

	/* interrupt happened due to transition/change of near/far proximity state */
	irqreturn_t gp2a_irq_handler(int irq, void *data)
	{
	struct gp2a_data *ip = data;
	int val = gpio_get_value(ip->pdata->p_out);
	if (val < 0) {
	pr_err("%s: gpio_get_value error %d\n", __func__, val);
	return IRQ_HANDLED;
	}

	gp2a_dbgmsg("gp2a: proximity val=%d\n", val);

	/* 0 is close, 1 is far */
	input_report_abs(ip->proximity_input_dev, ABS_DISTANCE, val);
	input_sync(ip->proximity_input_dev);
	wake_lock_timeout(&ip->prx_wake_lock, 3*HZ);
	return IRQ_HANDLED;
	}

	static int gp2a_setup_irq(struct gp2a_data *gp2a)
	{
	int rc = -EIO;
	struct gp2a_platform_data *pdata = gp2a->pdata;
	int irq;

	gp2a_dbgmsg("start\n");

	rc = gpio_request(pdata->p_out, "gpio_proximity_out");
	if (rc < 0) {
	pr_err("%s: gpio %d request failed (%d)\n",
	__func__, pdata->p_out, rc);
	return rc;
	}

	rc = gpio_direction_input(pdata->p_out);
	if (rc < 0) {
	pr_err("%s: failed to set gpio %d as input (%d)\n",
	__func__, pdata->p_out, rc);
	goto err_gpio_direction_input;
	}

	irq = gpio_to_irq(pdata->p_out);
	rc = request_irq(irq,
	gp2a_irq_handler,
	IRQF_TRIGGER_RISING \| IRQF_TRIGGER_FALLING,
	"proximity_int",
	gp2a);
	if (rc < 0) {
	pr_err("%s: request_irq(%d) failed for gpio %d (%d)\n",
	__func__, irq,
	pdata->p_out, rc);
	goto err_request_irq;
	}

	/* start with interrupts disabled */
	disable_irq(irq);
	gp2a->irq = irq;

	/* sync input device with proximity gpio pin default value */
	gp2a_irq_handler(gp2a->irq, gp2a);

	gp2a_dbgmsg("success\n");

	goto done;

	err_request_irq:
	err_gpio_direction_input:
	gpio_free(pdata->p_out);
	done:
	return rc;
	}

	static int gp2a_i2c_probe(struct i2c_client *client,
	const struct i2c_device_id *id)
	{
	int ret = -ENODEV;
	struct input_dev *input_dev;
	struct gp2a_data *gp2a;
	struct gp2a_platform_data *pdata = client->dev.platform_data;

	if (!pdata) {
	pr_err("%s: missing pdata!\n", __func__);
	return ret;
	}
	if (!pdata->power \|\| !pdata->light_adc_value) {
	pr_err("%s: incomplete pdata!\n", __func__);
	return ret;
	}
	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
	pr_err("%s: i2c functionality check failed!\n", __func__);
	return ret;
	}

	gp2a = kzalloc(sizeof(struct gp2a_data), GFP_KERNEL);
	if (!gp2a) {
	pr_err("%s: failed to alloc memory for module data\n",
	__func__);
	return -ENOMEM;
	}

	gp2a->pdata = pdata;
	gp2a->i2c_client = client;
	i2c_set_clientdata(client, gp2a);


	wake_lock_init(&gp2a->prx_wake_lock, WAKE_LOCK_SUSPEND,
	"prx_wake_lock");
	mutex_init(&gp2a->power_lock);

	/* allocate proximity input_device */
	input_dev = input_allocate_device();
	if (!input_dev) {
	pr_err("%s: could not allocate input device\n", __func__);
	goto err_input_allocate_device_proximity;
	}
	gp2a->proximity_input_dev = input_dev;
	input_set_drvdata(input_dev, gp2a);
	input_dev->name = "proximity";
	input_set_capability(input_dev, EV_ABS, ABS_DISTANCE);
	input_set_abs_params(input_dev, ABS_DISTANCE, 0, 1, 0, 0);

	ret = gp2a_setup_irq(gp2a);
	if (ret) {
	pr_err("%s: could not setup irq\n", __func__);
	input_free_device(input_dev);
	goto err_setup_irq;
	}

	gp2a_dbgmsg("registering proximity input device\n");
	ret = input_register_device(input_dev);
	if (ret < 0) {
	pr_err("%s: could not register input device\n", __func__);
	input_free_device(input_dev);
	goto err_input_register_device_proximity;
	}
	ret = sysfs_create_group(&input_dev->dev.kobj,
	&proximity_attribute_group);
	if (ret) {
	pr_err("%s: could not create sysfs group\n", __func__);
	goto err_sysfs_create_group_proximity;
	}

	/* hrtimer settings. we poll for light values using a timer. */
	hrtimer_init(&gp2a->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
	gp2a->light_poll_delay = ns_to_ktime(200 * NSEC_PER_MSEC);
	gp2a->timer.function = gp2a_timer_func;

	/* the timer just fires off a work queue request. we need a thread
	* to read the i2c (can be slow and blocking)
	*/
	gp2a->wq = create_singlethread_workqueue("gp2a_wq");
	if (!gp2a->wq) {
	ret = -ENOMEM;
	pr_err("%s: could not create workqueue\n", __func__);
	goto err_create_workqueue;
	}
	/* this is the thread function we run on the work queue */
	INIT_WORK(&gp2a->work_light, gp2a_work_func_light);

	/* allocate lightsensor-level input_device */
	input_dev = input_allocate_device();
	if (!input_dev) {
	pr_err("%s: could not allocate input device\n", __func__);
	ret = -ENOMEM;
	goto err_input_allocate_device_light;
	}
	input_set_drvdata(input_dev, gp2a);
	input_dev->name = "lightsensor-level";
	input_set_capability(input_dev, EV_ABS, ABS_MISC);
	input_set_abs_params(input_dev, ABS_MISC, 0, 1023, 8, 0);

	gp2a_dbgmsg("registering lightsensor-level input device\n");
	ret = input_register_device(input_dev);
	if (ret < 0) {
	pr_err("%s: could not register input device\n", __func__);
	input_free_device(input_dev);
	goto err_input_register_device_light;
	}
	gp2a->light_input_dev = input_dev;
	ret = sysfs_create_group(&input_dev->dev.kobj,
	&light_attribute_group);
	if (ret) {
	pr_err("%s: could not create sysfs group\n", __func__);
	goto err_sysfs_create_group_light;
	}
	goto done;

	/* error, unwind it all */
	err_sysfs_create_group_light:
	input_unregister_device(gp2a->light_input_dev);
	err_input_register_device_light:
	err_input_allocate_device_light:
	destroy_workqueue(gp2a->wq);
	err_create_workqueue:
	sysfs_remove_group(&gp2a->proximity_input_dev->dev.kobj,
	&proximity_attribute_group);
	err_sysfs_create_group_proximity:
	input_unregister_device(gp2a->proximity_input_dev);
	err_input_register_device_proximity:
	free_irq(gp2a->irq, gp2a);
	gpio_free(gp2a->pdata->p_out);
	err_setup_irq:
	err_input_allocate_device_proximity:
	mutex_destroy(&gp2a->power_lock);
	wake_lock_destroy(&gp2a->prx_wake_lock);
	kfree(gp2a);
	done:
	return ret;
	}

	static int gp2a_suspend(struct device *dev)
	{
	/* We disable power only if proximity is disabled. If proximity
	* is enabled, we leave power on because proximity is allowed
	* to wake up device. We remove power without changing
	* gp2a->power_state because we use that state in resume
	*/
	struct i2c_client *client = to_i2c_client(dev);
	struct gp2a_data *gp2a = i2c_get_clientdata(client);
	if (gp2a->power_state & LIGHT_ENABLED)
	gp2a_light_disable(gp2a);
	if (gp2a->power_state == LIGHT_ENABLED)
	gp2a->pdata->power(false);
	return 0;
	}

	static int gp2a_resume(struct device *dev)
	{
	/* Turn power back on if we were before suspend. */
	struct i2c_client *client = to_i2c_client(dev);
	struct gp2a_data *gp2a = i2c_get_clientdata(client);
	if (gp2a->power_state == LIGHT_ENABLED)
	gp2a->pdata->power(true);
	if (gp2a->power_state & LIGHT_ENABLED)
	gp2a_light_enable(gp2a);
	return 0;
	}

	static int gp2a_i2c_remove(struct i2c_client *client)
	{
	struct gp2a_data *gp2a = i2c_get_clientdata(client);
	sysfs_remove_group(&gp2a->light_input_dev->dev.kobj,
	&light_attribute_group);
	sysfs_remove_group(&gp2a->proximity_input_dev->dev.kobj,
	&proximity_attribute_group);
	free_irq(gp2a->irq, gp2a);
	destroy_workqueue(gp2a->wq);
	input_unregister_device(gp2a->light_input_dev);
	input_unregister_device(gp2a->proximity_input_dev);
	gpio_free(gp2a->pdata->p_out);
	if (gp2a->power_state) {
	gp2a->power_state = 0;
	if (gp2a->power_state & LIGHT_ENABLED)
	gp2a_light_disable(gp2a);
	gp2a->pdata->power(false);
	}
	mutex_destroy(&gp2a->power_lock);
	wake_lock_destroy(&gp2a->prx_wake_lock);
	kfree(gp2a);
	return 0;
	}

	static const struct i2c_device_id gp2a_device_id[] = {
	{"gp2a", 0},
	{}
	};
	MODULE_DEVICE_TABLE(i2c, gp2a_device_id);

	static const struct dev_pm_ops gp2a_pm_ops = {
	.suspend = gp2a_suspend,
	.resume = gp2a_resume
	};

	static struct i2c_driver gp2a_i2c_driver = {
	.driver = {
	.name = "gp2a",
	.owner = THIS_MODULE,
	.pm = &gp2a_pm_ops
	},
	.probe = gp2a_i2c_probe,
	.remove = gp2a_i2c_remove,
	.id_table = gp2a_device_id,
	};


	static int __init gp2a_init(void)
	{
	return i2c_add_driver(&gp2a_i2c_driver);
	}

	static void __exit gp2a_exit(void)
	{
	i2c_del_driver(&gp2a_i2c_driver);
	}

	module_init(gp2a_init);
	module_exit(gp2a_exit);

	MODULE_AUTHOR("[email protected]");
	MODULE_DESCRIPTION("Optical Sensor driver for gp2ap002a00f");
	MODULE_LICENSE("GPL");