staging: iio: remove specific chrdev for event reading. Get fd from ioctl on buffer.

Change suggested by Arnd Bergmann.

No real reason to have two chrdevs per device. This step merges them into one.
Currently this means that events will only work on devices with buffers. THat will
be remedied shortly.

V2: set name for event attribute groups.  Otherwise they all sorts of fun occurs on
dynamic channel event attribute creation.
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Acked-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/accel/sca3000_core.c

@@ -1036,6 +1036,7 @@ static struct attribute *sca3000_event_attributes[] = {
 
 static struct attribute_group sca3000_event_attribute_group = {
 	.attrs = sca3000_event_attributes,
+	.name = "events",
 };
 
 /**

drivers/staging/iio/adc/ad7150.c

@@ -700,6 +700,7 @@ static struct attribute *ad7150_event_attributes[] = {
 
 static struct attribute_group ad7150_event_attribute_group = {
 	.attrs = ad7150_event_attributes,
+	.name = "events",
 };
 
 static const struct iio_info ad7150_info = {

drivers/staging/iio/adc/ad7745.c

@@ -563,6 +563,7 @@ static struct attribute *ad774x_event_attributes[] = {
 
 static struct attribute_group ad774x_event_attribute_group = {
 	.attrs = ad774x_event_attributes,
+	.name = "events",
 };
 
 static const struct iio_info ad774x_info = {

drivers/staging/iio/adc/ad7816.c

@@ -329,6 +329,7 @@ static struct attribute *ad7816_event_attributes[] = {
 
 static struct attribute_group ad7816_event_attribute_group = {
 	.attrs = ad7816_event_attributes,
+	.name = "events",
 };
 
 static const struct iio_info ad7816_info = {

drivers/staging/iio/adc/ad799x_core.c

@@ -447,6 +447,7 @@ static struct attribute *ad7993_4_7_8_event_attributes[] = {
 
 static struct attribute_group ad7993_4_7_8_event_attrs_group = {
 	.attrs = ad7993_4_7_8_event_attributes,
+	.name = "events",
 };
 
 static struct attribute *ad7992_event_attributes[] = {
@@ -463,6 +464,7 @@ static struct attribute *ad7992_event_attributes[] = {
 
 static struct attribute_group ad7992_event_attrs_group = {
 	.attrs = ad7992_event_attributes,
+	.name = "events",
 };
 
 static const struct iio_info ad7991_info = {

drivers/staging/iio/adc/adt7310.c

@@ -741,8 +741,10 @@ static struct attribute *adt7310_event_ct_attributes[] = {
 static struct attribute_group adt7310_event_attribute_group[ADT7310_IRQS] = {
 	{
 		.attrs = adt7310_event_int_attributes,
+		.name = "events",
 	}, {
 		.attrs = adt7310_event_ct_attributes,
+		.name = "events",
 	}
 };
 

drivers/staging/iio/adc/adt7410.c

@@ -708,8 +708,10 @@ static struct attribute *adt7410_event_ct_attributes[] = {
 static struct attribute_group adt7410_event_attribute_group[ADT7410_IRQS] = {
 	{
 		.attrs = adt7410_event_int_attributes,
+		.name = "events",
 	}, {
 		.attrs = adt7410_event_ct_attributes,
+		.name = "events",
 	}
 };
 

drivers/staging/iio/adc/adt75.c

@@ -530,6 +530,7 @@ static struct attribute *adt75_event_attributes[] = {
 
 static struct attribute_group adt75_event_attribute_group = {
 	.attrs = adt75_event_attributes,
+	.name = "events",
 };
 
 static const struct iio_info adt75_info = {

drivers/staging/iio/adc/max1363_core.c

@@ -827,6 +827,7 @@ static struct attribute *max1363_event_attributes[] = {
 
 static struct attribute_group max1363_event_attribute_group = {
 	.attrs = max1363_event_attributes,
+	.name = "events",
 };
 
 #define MAX1363_EVENT_FUNCS						\
@@ -1296,7 +1297,8 @@ static int __devinit max1363_probe(struct i2c_client *client,
 	/* Estabilish that the iio_dev is a child of the i2c device */
 	indio_dev->dev.parent = &client->dev;
 	indio_dev->name = id->name;
-
+	indio_dev->channels = st->chip_info->channels;
+	indio_dev->num_channels = st->chip_info->num_channels;
 	indio_dev->info = st->chip_info->info;
 	indio_dev->modes = INDIO_DIRECT_MODE;
 	indio_dev->channels = st->chip_info->channels;

drivers/staging/iio/addac/adt7316.c

@@ -2064,6 +2064,7 @@ static struct attribute *adt7316_event_attributes[] = {
 
 static struct attribute_group adt7316_event_attribute_group = {
 	.attrs = adt7316_event_attributes,
+	.name = "events",
 };
 
 static struct attribute *adt7516_event_attributes[] = {
@@ -2084,6 +2085,7 @@ static struct attribute *adt7516_event_attributes[] = {
 
 static struct attribute_group adt7516_event_attribute_group = {
 	.attrs = adt7516_event_attributes,
+	.name = "events",
 };
 
 #ifdef CONFIG_PM

drivers/staging/iio/chrdev.h

@@ -40,4 +40,5 @@ struct iio_event_data {
 	s64	timestamp;
 };
 
+#define IIO_GET_EVENT_FD_IOCTL _IOR('i', 0x90, int)
 #endif

drivers/staging/iio/dac/ad5504.c

@@ -247,6 +247,7 @@ static struct attribute *ad5504_ev_attributes[] = {
 
 static struct attribute_group ad5504_ev_attribute_group = {
 	.attrs = ad5504_ev_attributes,
+	.name = "events",
 };
 
 static irqreturn_t ad5504_event_handler(int irq, void *private)

drivers/staging/iio/iio.h

@@ -245,6 +245,7 @@ struct iio_info {
 
 };
 
+int iio_event_getfd(struct iio_dev *indio_dev);
 /**
  * struct iio_dev - industrial I/O device
  * @id:			[INTERN] used to identify device internally

drivers/staging/iio/industrialio-core.c

@@ -21,6 +21,7 @@
 #include <linux/wait.h>
 #include <linux/cdev.h>
 #include <linux/slab.h>
+#include <linux/anon_inodes.h>
 #include "iio.h"
 #include "iio_core.h"
 #include "iio_core_trigger.h"
@@ -128,6 +129,7 @@ struct iio_detected_event_list {
 	struct iio_event_data		ev;
 };
 
+
 /**
  * struct iio_event_interface - chrdev interface for an event line
  * @dev:		device assocated with event interface
@@ -139,7 +141,6 @@ struct iio_detected_event_list {
  * @current_events:	number of events in detected list
  */
 struct iio_event_interface {
-	struct device				dev;
 	struct iio_handler			handler;
 	wait_queue_head_t			wait;
 	struct mutex				event_list_lock;
@@ -187,7 +188,6 @@ int iio_push_event(struct iio_dev *dev_info,
 }
 EXPORT_SYMBOL(iio_push_event);
 
-
 /* This turns up an awful lot */
 ssize_t iio_read_const_attr(struct device *dev,
 			    struct device_attribute *attr,
@@ -207,7 +207,6 @@ static ssize_t iio_event_chrdev_read(struct file *filep,
 	struct iio_detected_event_list *el;
 	int ret;
 	size_t len;
-
 	mutex_lock(&ev_int->event_list_lock);
 	if (list_empty(&ev_int->det_events)) {
 		if (filep->f_flags & O_NONBLOCK) {
@@ -249,10 +248,8 @@ static ssize_t iio_event_chrdev_read(struct file *filep,
 
 static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
 {
-	struct iio_handler *hand = iio_cdev_to_handler(inode->i_cdev);
-	struct iio_event_interface *ev_int = hand->private;
+	struct iio_event_interface *ev_int = filep->private_data;
 	struct iio_detected_event_list *el, *t;
-
 	mutex_lock(&ev_int->event_list_lock);
 	clear_bit(IIO_BUSY_BIT_POS, &ev_int->handler.flags);
 	/*
@@ -264,23 +261,7 @@ static int iio_event_chrdev_release(struct inode *inode, struct file *filep)
 		list_del(&el->list);
 		kfree(el);
 	}
-	mutex_unlock(&ev_int->event_list_lock);
-
-	return 0;
-}
-
-static int iio_event_chrdev_open(struct inode *inode, struct file *filep)
-{
-	struct iio_handler *hand = iio_cdev_to_handler(inode->i_cdev);
-	struct iio_event_interface *ev_int = hand->private;
-
-	mutex_lock(&ev_int->event_list_lock);
-	if (test_and_set_bit(IIO_BUSY_BIT_POS, &hand->flags)) {
-		fops_put(filep->f_op);
-		mutex_unlock(&ev_int->event_list_lock);
-		return -EBUSY;
-	}
-	filep->private_data = hand->private;
+	ev_int->current_events = 0;
 	mutex_unlock(&ev_int->event_list_lock);
 
 	return 0;
@@ -289,23 +270,10 @@ static int iio_event_chrdev_open(struct inode *inode, struct file *filep)
 static const struct file_operations iio_event_chrdev_fileops = {
 	.read =  iio_event_chrdev_read,
 	.release = iio_event_chrdev_release,
-	.open = iio_event_chrdev_open,
 	.owner = THIS_MODULE,
 	.llseek = noop_llseek,
 };
 
-static void iio_event_dev_release(struct device *dev)
-{
-	struct iio_event_interface *ev_int
-		= container_of(dev, struct iio_event_interface, dev);
-	cdev_del(&ev_int->handler.chrdev);
-	iio_device_free_chrdev_minor(MINOR(dev->devt));
-};
-
-static struct device_type iio_event_type = {
-	.release = iio_event_dev_release,
-};
-
 int iio_device_get_chrdev_minor(void)
 {
 	int ret;
@@ -322,34 +290,29 @@ void iio_device_free_chrdev_minor(int val)
 	iio_free_ida_val(&iio_chrdev_ida, val);
 }
 
-static int iio_setup_ev_int(struct iio_event_interface *ev_int,
+int iio_event_getfd(struct iio_dev *indio_dev)
+{
+	if (indio_dev->event_interfaces == NULL)
+		return -ENODEV;
+
+	mutex_lock(&indio_dev->event_interfaces->event_list_lock);
+	if (test_and_set_bit(IIO_BUSY_BIT_POS,
+			     &indio_dev->event_interfaces->handler.flags)) {
+		mutex_unlock(&indio_dev->event_interfaces->event_list_lock);
+		return -EBUSY;
+	}
+	mutex_unlock(&indio_dev->event_interfaces->event_list_lock);
+	return anon_inode_getfd("iio:event",
+				&iio_event_chrdev_fileops,
+				&indio_dev->event_interfaces[0], O_RDONLY);
+}
+
+static void iio_setup_ev_int(struct iio_event_interface *ev_int,
 			    const char *dev_name,
 			    int index,
 			    struct module *owner,
 			    struct device *dev)
 {
-	int ret, minor;
-
-	ev_int->dev.bus = &iio_bus_type;
-	ev_int->dev.parent = dev;
-	ev_int->dev.type = &iio_event_type;
-	device_initialize(&ev_int->dev);
-
-	minor = iio_device_get_chrdev_minor();
-	if (minor < 0) {
-		ret = minor;
-		goto error_device_put;
-	}
-	ev_int->dev.devt = MKDEV(MAJOR(iio_devt), minor);
-	dev_set_name(&ev_int->dev, "%s:event%d", dev_name, index);
-
-	ret = device_add(&ev_int->dev);
-	if (ret)
-		goto error_free_minor;
-
-	cdev_init(&ev_int->handler.chrdev, &iio_event_chrdev_fileops);
-	ev_int->handler.chrdev.owner = owner;
-
 	mutex_init(&ev_int->event_list_lock);
 	/* discussion point - make this variable? */
 	ev_int->max_events = 10;
@@ -358,27 +321,6 @@ static int iio_setup_ev_int(struct iio_event_interface *ev_int,
 	init_waitqueue_head(&ev_int->wait);
 	ev_int->handler.private = ev_int;
 	ev_int->handler.flags = 0;
-
-	ret = cdev_add(&ev_int->handler.chrdev, ev_int->dev.devt, 1);
-	if (ret)
-		goto error_unreg_device;
-
-	return 0;
-
-error_unreg_device:
-	device_unregister(&ev_int->dev);
-error_free_minor:
-	iio_device_free_chrdev_minor(minor);
-error_device_put:
-	put_device(&ev_int->dev);
-
-	return ret;
-}
-
-static void iio_free_ev_int(struct iio_event_interface *ev_int)
-{
-	device_unregister(&ev_int->dev);
-	put_device(&ev_int->dev);
 }
 
 static int __init iio_init(void)
@@ -970,7 +912,7 @@ static int iio_device_add_event_sysfs(struct iio_dev *dev_info,
 			continue;
 		}
 		ret = __iio_add_chan_devattr(postfix,
-					     NULL,
+					     "events",
 					     chan,
 					     &iio_ev_state_show,
 					     iio_ev_state_store,
@@ -980,7 +922,7 @@ static int iio_device_add_event_sysfs(struct iio_dev *dev_info,
 					       extending the bitmask - but
 					       how far*/
 					     0,
-					     &dev_info->event_interfaces[0].dev,
+					     &dev_info->dev,
 					     &dev_info->event_interfaces[0].
 					     dev_attr_list);
 		kfree(postfix);
@@ -994,13 +936,12 @@ static int iio_device_add_event_sysfs(struct iio_dev *dev_info,
 			ret = -ENOMEM;
 			goto error_ret;
 		}
-		ret = __iio_add_chan_devattr(postfix, NULL, chan,
+		ret = __iio_add_chan_devattr(postfix, "events", chan,
 					     iio_ev_value_show,
 					     iio_ev_value_store,
 					     mask,
 					     0,
-					     &dev_info->event_interfaces[0]
-					     .dev,
+					     &dev_info->dev,
 					     &dev_info->event_interfaces[0]
 					     .dev_attr_list);
 		kfree(postfix);
@@ -1020,8 +961,7 @@ static inline void __iio_remove_event_config_attrs(struct iio_dev *dev_info,
 	list_for_each_entry_safe(p, n,
 				 &dev_info->event_interfaces[i].
 				 dev_attr_list, l) {
-		sysfs_remove_file_from_group(&dev_info
-					     ->event_interfaces[i].dev.kobj,
+		sysfs_remove_file_from_group(&dev_info->dev.kobj,
 					     &p->dev_attr.attr,
 					     NULL);
 		kfree(p->dev_attr.attr.name);
@@ -1052,6 +992,15 @@ static inline int __iio_add_event_config_attrs(struct iio_dev *dev_info, int i)
 	return ret;
 }
 
+static struct attribute *iio_events_dummy_attrs[] = {
+	NULL
+};
+
+static struct attribute_group iio_events_dummy_group = {
+	.name = "events",
+	.attrs = iio_events_dummy_attrs
+};
+
 static int iio_device_register_eventset(struct iio_dev *dev_info)
 {
 	int ret = 0, i, j;
@@ -1069,42 +1018,33 @@ static int iio_device_register_eventset(struct iio_dev *dev_info)
 	}
 
 	for (i = 0; i < dev_info->info->num_interrupt_lines; i++) {
-		ret = iio_setup_ev_int(&dev_info->event_interfaces[i],
+		iio_setup_ev_int(&dev_info->event_interfaces[i],
 				 dev_name(&dev_info->dev),
 				 i,
 				 dev_info->info->driver_module,
 				 &dev_info->dev);
-		if (ret) {
-			dev_err(&dev_info->dev,
-				"Could not get chrdev interface\n");
-			goto error_free_setup_event_lines;
-		}
-
-		dev_set_drvdata(&dev_info->event_interfaces[i].dev,
-				(void *)dev_info);
 
 		if (dev_info->info->event_attrs != NULL)
-			ret = sysfs_create_group(&dev_info
-						 ->event_interfaces[i]
-						 .dev.kobj,
+			ret = sysfs_create_group(&dev_info->dev.kobj,
 						 &dev_info->info
 						 ->event_attrs[i]);
-
+		else
+			ret = sysfs_create_group(&dev_info->dev.kobj,
+						 &iio_events_dummy_group);
 		if (ret) {
 			dev_err(&dev_info->dev,
 				"Failed to register sysfs for event attrs");
-			iio_free_ev_int(&dev_info->event_interfaces[i]);
 			goto error_free_setup_event_lines;
 		}
 		ret = __iio_add_event_config_attrs(dev_info, i);
 		if (ret) {
 			if (dev_info->info->event_attrs != NULL)
-				sysfs_remove_group(&dev_info
-						   ->event_interfaces[i]
-						   .dev.kobj,
+				sysfs_remove_group(&dev_info->dev.kobj,
 						   &dev_info->info
 						   ->event_attrs[i]);
-			iio_free_ev_int(&dev_info->event_interfaces[i]);
+			else
+				sysfs_remove_group(&dev_info->dev.kobj,
+						   &iio_events_dummy_group);
 			goto error_free_setup_event_lines;
 		}
 	}
@@ -1114,11 +1054,12 @@ static int iio_device_register_eventset(struct iio_dev *dev_info)
 error_free_setup_event_lines:
 	for (j = 0; j < i; j++) {
 		__iio_remove_event_config_attrs(dev_info, j);
-		if (dev_info->info->event_attrs != NULL)
-			sysfs_remove_group(&dev_info
-					   ->event_interfaces[j].dev.kobj,
+		if (dev_info->info->event_attrs != NULL) {
+			sysfs_remove_group(&dev_info->dev.kobj,
 					   &dev_info->info->event_attrs[j]);
-		iio_free_ev_int(&dev_info->event_interfaces[j]);
+			sysfs_remove_group(&dev_info->dev.kobj,
+					   &iio_events_dummy_group);
+		}
 	}
 	kfree(dev_info->event_interfaces);
 error_ret:
@@ -1135,10 +1076,11 @@ static void iio_device_unregister_eventset(struct iio_dev *dev_info)
 	for (i = 0; i < dev_info->info->num_interrupt_lines; i++) {
 		__iio_remove_event_config_attrs(dev_info, i);
 		if (dev_info->info->event_attrs != NULL)
-			sysfs_remove_group(&dev_info
-					   ->event_interfaces[i].dev.kobj,
+			sysfs_remove_group(&dev_info->dev.kobj,
 					   &dev_info->info->event_attrs[i]);
-		iio_free_ev_int(&dev_info->event_interfaces[i]);
+		else
+			sysfs_remove_group(&dev_info->dev.kobj,
+					   &iio_events_dummy_group);
 	}
 	kfree(dev_info->event_interfaces);
 }

drivers/staging/iio/industrialio-ring.c

@@ -93,6 +93,25 @@ static unsigned int iio_ring_poll(struct file *filp,
 	return 0;
 }
 
+/* Somewhat of a cross file organization violation - ioctls here are actually
+ * event related */
+static long iio_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
+{
+
+	struct iio_ring_buffer *rb = f->private_data;
+	struct iio_dev *indio_dev = rb->indio_dev;
+	int __user *ip = (int __user *)arg;
+
+	if (cmd == IIO_GET_EVENT_FD_IOCTL) {
+		int fd;
+		fd = iio_event_getfd(indio_dev);
+		if (copy_to_user(ip, &fd, sizeof(fd)))
+			return -EFAULT;
+		return 0;
+	}
+	return -EINVAL;
+}
+
 static const struct file_operations iio_ring_fileops = {
 	.read = iio_ring_read_first_n_outer,
 	.release = iio_ring_release,
@@ -100,6 +119,8 @@ static const struct file_operations iio_ring_fileops = {
 	.poll = iio_ring_poll,
 	.owner = THIS_MODULE,
 	.llseek = noop_llseek,
+	.unlocked_ioctl = iio_ioctl,
+	.compat_ioctl = iio_ioctl,
 };
 
 void iio_ring_access_release(struct device *dev)