iio: core: A few code cleanups and documentation fixes

index c117f50d0cf3..6cca86fd0ef9 100644
@@ -1617,6 +1617,28 @@ const struct device_type iio_device_type = {
 	.release = iio_dev_release,
 };
 
+/**
+ * opaque_struct_size() - Calculate size of opaque structure with trailing aligned data.
+ * @p: Pointer to the opaque structure.
+ * @a: Alignment in bytes before trailing data.
+ * @s: Data size in bytes (can be 0).
+ *
+ * Calculates size of memory needed for structure of @p followed by the aligned data
+ * of size @s. When @s is 0, the alignment @a is not taken into account and the result
+ * is an equivalent to sizeof(*(@p)).
+ *
+ * Returns: Number of bytes needed or SIZE_MAX on overflow.
+ */
+#define opaque_struct_size(p, a, s)	({		\
+	size_t _psize = sizeof(*(p));			\
+	size_t _asize = ALIGN(_psize, (a));		\
+	size_t _ssize = s;				\
+	_ssize ? size_add(_asize, _ssize) : _psize;	\
+})
+
+#define opaque_struct_data(p, a)			\
+	((void *)(p) + ALIGN(sizeof(*(p)), (a)))
+
 /**
  * iio_device_alloc() - allocate an iio_dev from a driver
  * @parent:		Parent device.

@@ -1628,19 +1650,13 @@ struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv)
 	struct iio_dev *indio_dev;
 	size_t alloc_size;
 
-	alloc_size = sizeof(struct iio_dev_opaque);
-	if (sizeof_priv) {
-		alloc_size = ALIGN(alloc_size, IIO_DMA_MINALIGN);
-		alloc_size += sizeof_priv;
-	}
-
+	alloc_size = opaque_struct_size(iio_dev_opaque, IIO_DMA_MINALIGN, sizeof_priv);
 	iio_dev_opaque = kzalloc(alloc_size, GFP_KERNEL);
 	if (!iio_dev_opaque)
 		return NULL;
 
 	indio_dev = &iio_dev_opaque->indio_dev;
-	indio_dev->priv = (char *)iio_dev_opaque +
-		ALIGN(sizeof(struct iio_dev_opaque), IIO_DMA_MINALIGN);
+	indio_dev->priv = opaque_struct_data(iio_dev_opaque, IIO_DMA_MINALIGN);
 
 	indio_dev->dev.parent = parent;
 	indio_dev->dev.type = &iio_device_type;

index 6cca86fd0ef9..90e59223b178 100644
@@ -1400,50 +1400,32 @@ static ssize_t label_show(struct device *dev, struct device_attribute *attr,
 
 static DEVICE_ATTR_RO(label);
 
+static const char * const clock_names[] = {
+	[CLOCK_REALTIME]	 	= "realtime",
+	[CLOCK_MONOTONIC]	 	= "monotonic",
+	[CLOCK_PROCESS_CPUTIME_ID]	= "process_cputime_id",
+	[CLOCK_THREAD_CPUTIME_ID]	= "thread_cputime_id",
+	[CLOCK_MONOTONIC_RAW]	 	= "monotonic_raw",
+	[CLOCK_REALTIME_COARSE]	 	= "realtime_coarse",
+	[CLOCK_MONOTONIC_COARSE] 	= "monotonic_coarse",
+	[CLOCK_BOOTTIME]	 	= "boottime",
+	[CLOCK_REALTIME_ALARM]		= "realtime_alarm",
+	[CLOCK_BOOTTIME_ALARM]		= "boottime_alarm",
+	[CLOCK_SGI_CYCLE]		= "sgi_cycle",
+	[CLOCK_TAI]		 	= "tai",
+};
+
 static ssize_t current_timestamp_clock_show(struct device *dev,
 					    struct device_attribute *attr,
 					    char *buf)
 {
 	const struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	const clockid_t clk = iio_device_get_clock(indio_dev);
-	const char *name;
-	ssize_t sz;
 
-	switch (clk) {
-	case CLOCK_REALTIME:
-		name = "realtime\n";
-		sz = sizeof("realtime\n");
-		break;
-	case CLOCK_MONOTONIC:
-		name = "monotonic\n";
-		sz = sizeof("monotonic\n");
-		break;
-	case CLOCK_MONOTONIC_RAW:
-		name = "monotonic_raw\n";
-		sz = sizeof("monotonic_raw\n");
-		break;
-	case CLOCK_REALTIME_COARSE:
-		name = "realtime_coarse\n";
-		sz = sizeof("realtime_coarse\n");
-		break;
-	case CLOCK_MONOTONIC_COARSE:
-		name = "monotonic_coarse\n";
-		sz = sizeof("monotonic_coarse\n");
-		break;
-	case CLOCK_BOOTTIME:
-		name = "boottime\n";
-		sz = sizeof("boottime\n");
-		break;
-	case CLOCK_TAI:
-		name = "tai\n";
-		sz = sizeof("tai\n");
-		break;
-	default:
+	if (clk < 0 && clk >= ARRAY_SIZE(clock_names))
 		BUG();
-	}
 
-	memcpy(buf, name, sz);
-	return sz;
+	return sprintf(buf, "%s\n", clock_names[clk]);
 }
 
 static ssize_t current_timestamp_clock_store(struct device *dev,

@@ -1453,22 +1435,21 @@ static ssize_t current_timestamp_clock_store(struct device *dev,
 	clockid_t clk;
 	int ret;
 
-	if (sysfs_streq(buf, "realtime"))
-		clk = CLOCK_REALTIME;
-	else if (sysfs_streq(buf, "monotonic"))
-		clk = CLOCK_MONOTONIC;
-	else if (sysfs_streq(buf, "monotonic_raw"))
-		clk = CLOCK_MONOTONIC_RAW;
-	else if (sysfs_streq(buf, "realtime_coarse"))
-		clk = CLOCK_REALTIME_COARSE;
-	else if (sysfs_streq(buf, "monotonic_coarse"))
-		clk = CLOCK_MONOTONIC_COARSE;
-	else if (sysfs_streq(buf, "boottime"))
-		clk = CLOCK_BOOTTIME;
-	else if (sysfs_streq(buf, "tai"))
-		clk = CLOCK_TAI;
-	else
+	ret = sysfs_match_string(clock_names, buf);
+	if (ret < 0)
+		return ret;
+
+	switch (ret) {
+	case CLOCK_PROCESS_CPUTIME_ID:
+	case CLOCK_THREAD_CPUTIME_ID:
+	case CLOCK_REALTIME_ALARM:
+	case CLOCK_BOOTTIME_ALARM:
+	case CLOCK_SGI_CYCLE:
 		return -EINVAL;
+	default:
+		clk = ret;
+		break;
+	}
 
 	ret = iio_device_set_clock(dev_to_iio_dev(dev), clk);
 	if (ret)

index 90e59223b178..be154879983e 100644
@@ -1465,7 +1465,7 @@ int iio_device_register_sysfs_group(struct iio_dev *indio_dev,
 	const struct attribute_group **new, **old = iio_dev_opaque->groups;
 	unsigned int cnt = iio_dev_opaque->groupcounter;
 
-	new = krealloc(old, sizeof(*new) * (cnt + 2), GFP_KERNEL);
+	new = krealloc_array(old, cnt + 2, sizeof(*new), GFP_KERNEL);
 	if (!new)
 		return -ENOMEM;
 

@@ -1483,13 +1483,13 @@ static int iio_device_register_sysfs(struct iio_dev *indio_dev)
 {
 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 	int i, ret = 0, attrcount, attrn, attrcount_orig = 0;
+	struct attribute **attrs, **attr, *clk = NULL;
 	struct iio_dev_attr *p;
-	struct attribute **attr, *clk = NULL;
 
 	/* First count elements in any existing group */
-	if (indio_dev->info->attrs) {
-		attr = indio_dev->info->attrs->attrs;
-		while (*attr++ != NULL)
+	attrs = indio_dev->info->attrs ? indio_dev->info->attrs->attrs : NULL;
+	if (attrs) {
+		for (attr = attrs; *attr; attr++)
 			attrcount_orig++;
 	}
 	attrcount = attrcount_orig;

@@ -1521,20 +1521,14 @@ static int iio_device_register_sysfs(struct iio_dev *indio_dev)
 	if (clk)
 		attrcount++;
 
+	/* Copy across original attributes, and point to original binary attributes */
 	iio_dev_opaque->chan_attr_group.attrs =
-		kcalloc(attrcount + 1,
-			sizeof(iio_dev_opaque->chan_attr_group.attrs[0]),
-			GFP_KERNEL);
+		krealloc_array(attrs, attrcount + 1, sizeof(*attrs), GFP_KERNEL);
 	if (iio_dev_opaque->chan_attr_group.attrs == NULL) {
 		ret = -ENOMEM;
 		goto error_clear_attrs;
 	}
-	/* Copy across original attributes, and point to original binary attributes */
 	if (indio_dev->info->attrs) {
-		memcpy(iio_dev_opaque->chan_attr_group.attrs,
-		       indio_dev->info->attrs->attrs,
-		       sizeof(iio_dev_opaque->chan_attr_group.attrs[0])
-		       *attrcount_orig);
 		iio_dev_opaque->chan_attr_group.is_visible =
 			indio_dev->info->attrs->is_visible;
 		iio_dev_opaque->chan_attr_group.bin_attrs =

index be154879983e..9753f6552db4 100644
@@ -389,7 +389,7 @@ static ssize_t iio_debugfs_write_reg(struct file *file,
 	char buf[80];
 	int ret;
 
-	count = min_t(size_t, count, (sizeof(buf)-1));
+	count = min(count, sizeof(buf) - 1);
 	if (copy_from_user(buf, userbuf, count))
 		return -EFAULT;
 

index 9753f6552db4..ab9c6db69625 100644
@@ -524,7 +524,7 @@ ssize_t iio_enum_read(struct iio_dev *indio_dev,
 	i = e->get(indio_dev, chan);
 	if (i < 0)
 		return i;
-	else if (i >= e->num_items || !e->items[i])
+	if (i >= e->num_items || !e->items[i])
 		return -EINVAL;
 
 	return sysfs_emit(buf, "%s\n", e->items[i]);

@@ -1217,7 +1217,7 @@ static int iio_device_add_info_mask_type(struct iio_dev *indio_dev,
 					     &iio_dev_opaque->channel_attr_list);
 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
 			continue;
-		else if (ret < 0)
+		if (ret < 0)
 			return ret;
 		attrcount++;
 	}

@@ -1255,7 +1255,7 @@ static int iio_device_add_info_mask_type_avail(struct iio_dev *indio_dev,
 		kfree(avail_postfix);
 		if ((ret == -EBUSY) && (shared_by != IIO_SEPARATE))
 			continue;
-		else if (ret < 0)
+		if (ret < 0)
 			return ret;
 		attrcount++;
 	}

index ab9c6db69625..e29772940886 100644
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0-only
-/* The industrial I/O core
+/*
+ * The industrial I/O core
  *
  * Copyright (c) 2008 Jonathan Cameron
  *

@@ -183,7 +184,9 @@ static const char * const iio_chan_info_postfix[] = {
  * @indio_dev:		Device structure whose ID is being queried
  *
  * The IIO device ID is a unique index used for example for the naming
- * of the character device /dev/iio\:device[ID]
+ * of the character device /dev/iio\:device[ID].
+ *
+ * Returns: Unique ID for the device.
  */
 int iio_device_id(struct iio_dev *indio_dev)
 {

@@ -196,6 +199,8 @@ EXPORT_SYMBOL_GPL(iio_device_id);
 /**
  * iio_buffer_enabled() - helper function to test if the buffer is enabled
  * @indio_dev:		IIO device structure for device
+ *
+ * Returns: True, if the buffer is enabled.
  */
 bool iio_buffer_enabled(struct iio_dev *indio_dev)
 {

@@ -225,6 +230,9 @@ EXPORT_SYMBOL_GPL(iio_get_debugfs_dentry);
  * iio_find_channel_from_si() - get channel from its scan index
  * @indio_dev:		device
  * @si:			scan index to match
+ *
+ * Returns:
+ * Constant pointer to iio_chan_spec, if scan index matches, NULL on failure.
  */
 const struct iio_chan_spec
 *iio_find_channel_from_si(struct iio_dev *indio_dev, int si)

@@ -249,7 +257,9 @@ EXPORT_SYMBOL(iio_read_const_attr);
 /**
  * iio_device_set_clock() - Set current timestamping clock for the device
  * @indio_dev: IIO device structure containing the device
- * @clock_id: timestamping clock posix identifier to set.
+ * @clock_id: timestamping clock POSIX identifier to set.
+ *
+ * Returns: 0 on success, or a negative error code.
  */
 int iio_device_set_clock(struct iio_dev *indio_dev, clockid_t clock_id)
 {

@@ -275,6 +285,8 @@ EXPORT_SYMBOL(iio_device_set_clock);
 /**
  * iio_device_get_clock() - Retrieve current timestamping clock for the device
  * @indio_dev: IIO device structure containing the device
+ *
+ * Returns: Clock ID of the current timestamping clock for the device.
  */
 clockid_t iio_device_get_clock(const struct iio_dev *indio_dev)
 {

@@ -287,6 +299,8 @@ EXPORT_SYMBOL(iio_device_get_clock);
 /**
  * iio_get_time_ns() - utility function to get a time stamp for events etc
  * @indio_dev: device
+ *
+ * Returns: Timestamp of the event in nanoseconds.
  */
 s64 iio_get_time_ns(const struct iio_dev *indio_dev)
 {

@@ -594,7 +608,7 @@ EXPORT_SYMBOL_GPL(iio_show_mount_matrix);
  * If device is assigned no mounting matrix property, a default 3x3 identity
  * matrix will be filled in.
  *
- * Return: 0 if success, or a negative error code on failure.
+ * Returns: 0 if success, or a negative error code on failure.
  */
 int iio_read_mount_matrix(struct device *dev, struct iio_mount_matrix *matrix)
 {

@@ -692,9 +706,9 @@ static ssize_t __iio_format_value(char *buf, size_t offset, unsigned int type,
  * @vals:	Pointer to the values, exact meaning depends on the
  *		type parameter.
  *
- * Return: 0 by default, a negative number on failure or the
- *	   total number of characters written for a type that belongs
- *	   to the IIO_VAL_* constant.
+ * Returns:
+ * 0 by default, a negative number on failure or the total number of characters
+ * written for a type that belongs to the IIO_VAL_* constant.
  */
 ssize_t iio_format_value(char *buf, unsigned int type, int size, int *vals)
 {

@@ -847,8 +861,8 @@ static ssize_t iio_read_channel_info_avail(struct device *dev,
  * @fract: The fractional part of the number
  * @scale_db: True if this should parse as dB
  *
- * Returns 0 on success, or a negative error code if the string could not be
- * parsed.
+ * Returns:
+ * 0 on success, or a negative error code if the string could not be parsed.
  */
 static int __iio_str_to_fixpoint(const char *str, int fract_mult,
 				 int *integer, int *fract, bool scale_db)

@@ -917,8 +931,8 @@ static int __iio_str_to_fixpoint(const char *str, int fract_mult,
  * @integer: The integer part of the number
  * @fract: The fractional part of the number
  *
- * Returns 0 on success, or a negative error code if the string could not be
- * parsed.
+ * Returns:
+ * 0 on success, or a negative error code if the string could not be parsed.
  */
 int iio_str_to_fixpoint(const char *str, int fract_mult,
 			int *integer, int *fract)

@@ -1618,7 +1632,10 @@ const struct device_type iio_device_type = {
  * iio_device_alloc() - allocate an iio_dev from a driver
  * @parent:		Parent device.
  * @sizeof_priv:	Space to allocate for private structure.
- **/
+ *
+ * Returns:
+ * Pointer to allocated iio_dev on success, NULL on failure.
+ */
 struct iio_dev *iio_device_alloc(struct device *parent, int sizeof_priv)
 {
 	struct iio_dev_opaque *iio_dev_opaque;

@@ -1668,7 +1685,7 @@ EXPORT_SYMBOL(iio_device_alloc);
 /**
  * iio_device_free() - free an iio_dev from a driver
  * @dev:		the iio_dev associated with the device
- **/
+ */
 void iio_device_free(struct iio_dev *dev)
 {
 	if (dev)

@@ -1689,7 +1706,7 @@ static void devm_iio_device_release(void *iio_dev)
  * Managed iio_device_alloc. iio_dev allocated with this function is
  * automatically freed on driver detach.
  *
- * RETURNS:
+ * Returns:
  * Pointer to allocated iio_dev on success, NULL on failure.
  */
 struct iio_dev *devm_iio_device_alloc(struct device *parent, int sizeof_priv)

@@ -1716,8 +1733,8 @@ EXPORT_SYMBOL_GPL(devm_iio_device_alloc);
  * @filp:	File structure for iio device used to keep and later access
  *		private data
  *
- * Return: 0 on success or -EBUSY if the device is already opened
- **/
+ * Returns: 0 on success or -EBUSY if the device is already opened
+ */
 static int iio_chrdev_open(struct inode *inode, struct file *filp)
 {
 	struct iio_dev_opaque *iio_dev_opaque =

@@ -1750,7 +1767,7 @@ static int iio_chrdev_open(struct inode *inode, struct file *filp)
  * @inode:	Inode structure pointer for the char device
  * @filp:	File structure pointer for the char device
  *
- * Return: 0 for successful release
+ * Returns: 0 for successful release.
  */
 static int iio_chrdev_release(struct inode *inode, struct file *filp)
 {

@@ -1789,7 +1806,7 @@ static long iio_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
 
 	mutex_lock(&iio_dev_opaque->info_exist_lock);
 
-	/**
+	/*
 	 * The NULL check here is required to prevent crashing when a device
 	 * is being removed while userspace would still have open file handles
 	 * to try to access this device.

@@ -1966,7 +1983,7 @@ EXPORT_SYMBOL(__iio_device_register);
 /**
  * iio_device_unregister() - unregister a device from the IIO subsystem
  * @indio_dev:		Device structure representing the device.
- **/
+ */
 void iio_device_unregister(struct iio_dev *indio_dev)
 {
 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);

@@ -2017,7 +2034,7 @@ EXPORT_SYMBOL_GPL(__devm_iio_device_register);
  *
  * Use with iio_device_release_direct_mode()
  *
- * Returns: 0 on success, -EBUSY on failure
+ * Returns: 0 on success, -EBUSY on failure.
  */
 int iio_device_claim_direct_mode(struct iio_dev *indio_dev)
 {

index e29772940886..202a1a67ba98 100644
@@ -354,6 +354,7 @@ static int __init iio_init(void)
 error_nothing:
 	return ret;
 }
+subsys_initcall(iio_init);
 
 static void __exit iio_exit(void)
 {

@@ -362,6 +363,7 @@ static void __exit iio_exit(void)
 	bus_unregister(&iio_bus_type);
 	debugfs_remove(iio_debugfs_dentry);
 }
+module_exit(iio_exit);
 
 #if defined(CONFIG_DEBUG_FS)
 static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,

@@ -2118,9 +2120,6 @@ int iio_device_get_current_mode(struct iio_dev *indio_dev)
 }
 EXPORT_SYMBOL_GPL(iio_device_get_current_mode);
 
-subsys_initcall(iio_init);
-module_exit(iio_exit);
-
 MODULE_AUTHOR("Jonathan Cameron <[email protected]>");
 MODULE_DESCRIPTION("Industrial I/O core");
 MODULE_LICENSE("GPL");

index 202a1a67ba98..1918da2a70ad 100644
@@ -206,9 +206,9 @@ bool iio_buffer_enabled(struct iio_dev *indio_dev)
 {
 	struct iio_dev_opaque *iio_dev_opaque = to_iio_dev_opaque(indio_dev);
 
-	return iio_dev_opaque->currentmode
-		& (INDIO_BUFFER_TRIGGERED | INDIO_BUFFER_HARDWARE |
-		   INDIO_BUFFER_SOFTWARE);
+	return iio_dev_opaque->currentmode &
+	       (INDIO_BUFFER_HARDWARE | INDIO_BUFFER_SOFTWARE |
+		INDIO_BUFFER_TRIGGERED);
 }
 EXPORT_SYMBOL_GPL(iio_buffer_enabled);
 

@@ -388,8 +388,8 @@ static ssize_t iio_debugfs_read_reg(struct file *file, char __user *userbuf,
 	}
 
 	iio_dev_opaque->read_buf_len = snprintf(iio_dev_opaque->read_buf,
-					      sizeof(iio_dev_opaque->read_buf),
-					      "0x%X\n", val);
+						sizeof(iio_dev_opaque->read_buf),
+						"0x%X\n", val);
 
 	return simple_read_from_buffer(userbuf, count, ppos,
 				       iio_dev_opaque->read_buf,

@@ -492,8 +492,7 @@ static ssize_t iio_read_channel_ext_info(struct device *dev,
 
 static ssize_t iio_write_channel_ext_info(struct device *dev,
 				     struct device_attribute *attr,
-				     const char *buf,
-					 size_t len)
+				     const char *buf, size_t len)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);

@@ -585,9 +584,9 @@ static int iio_setup_mount_idmatrix(const struct device *dev,
 ssize_t iio_show_mount_matrix(struct iio_dev *indio_dev, uintptr_t priv,
 			      const struct iio_chan_spec *chan, char *buf)
 {
-	const struct iio_mount_matrix *mtx = ((iio_get_mount_matrix_t *)
-					      priv)(indio_dev, chan);
+	const struct iio_mount_matrix *mtx;
 
+	mtx = ((iio_get_mount_matrix_t *)priv)(indio_dev, chan);
 	if (IS_ERR(mtx))
 		return PTR_ERR(mtx);
 

@@ -1025,14 +1024,12 @@ int __iio_device_attr_init(struct device_attribute *dev_attr,
 	if (chan->modified && (shared_by == IIO_SEPARATE)) {
 		if (chan->extend_name)
 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s_%s",
-						 iio_modifier_names[chan
-								    ->channel2],
+						 iio_modifier_names[chan->channel2],
 						 chan->extend_name,
 						 postfix);
 		else
 			full_postfix = kasprintf(GFP_KERNEL, "%s_%s",
-						 iio_modifier_names[chan
-								    ->channel2],
+						 iio_modifier_names[chan->channel2],
 						 postfix);
 	} else {
 		if (chan->extend_name == NULL || shared_by != IIO_SEPARATE)