drivers/base/regmap/regmap-debugfs.c - maze/linux - Git at Google

 /*
  * Register map access API - debugfs
  *
  * Copyright 2011 Wolfson Microelectronics plc
  *
  * Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
  *
  * 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.
  */

 #include <linux/slab.h>
 #include <linux/mutex.h>
 #include <linux/debugfs.h>
 #include <linux/uaccess.h>
 #include <linux/device.h>

 #include "internal.h"

 static struct dentry *regmap_debugfs_root;

 /* Calculate the length of a fixed format  */
 static size_t regmap_calc_reg_len(int max_val, char *buf, size_t buf_size)
 {
 	snprintf(buf, buf_size, "%x", max_val);
 	return strlen(buf);
 }

 static ssize_t regmap_name_read_file(struct file *file,
 				     char __user *user_buf, size_t count,
 				     loff_t *ppos)
 {
 	struct regmap *map = file->private_data;
 	int ret;
 	char *buf;

 	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
 	if (ret < 0) {
 		kfree(buf);
 		return ret;
 	}

 	ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
 	kfree(buf);
 	return ret;
 }

 static const struct file_operations regmap_name_fops = {
 	.open = simple_open,
 	.read = regmap_name_read_file,
 	.llseek = default_llseek,
 };

 static void regmap_debugfs_free_dump_cache(struct regmap *map)
 {
 	struct regmap_debugfs_off_cache *c;

 	while (!list_empty(&map->debugfs_off_cache)) {
 		c = list_first_entry(&map->debugfs_off_cache,
 				     struct regmap_debugfs_off_cache,
 				     list);
 		list_del(&c->list);
 		kfree(c);
 	}
 }

 /*
  * Work out where the start offset maps into register numbers, bearing
  * in mind that we suppress hidden registers.
  */
 static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
 						  unsigned int base,
 						  loff_t from,
 						  loff_t *pos)
 {
 	struct regmap_debugfs_off_cache *c = NULL;
 	loff_t p = 0;
 	unsigned int i, ret;
 	unsigned int fpos_offset;
 	unsigned int reg_offset;

 	/*
 	 * If we don't have a cache build one so we don't have to do a
 	 * linear scan each time.
 	 */
 	mutex_lock(&map->cache_lock);
 	i = base;
 	if (list_empty(&map->debugfs_off_cache)) {
 		for (; i <= map->max_register; i += map->reg_stride) {
 			/* Skip unprinted registers, closing off cache entry */
 			if (!regmap_readable(map, i) ||
 			    regmap_precious(map, i)) {
 				if (c) {
 					c->max = p - 1;
 					c->max_reg = i - map->reg_stride;
 					list_add_tail(&c->list,
 						      &map->debugfs_off_cache);
 					c = NULL;
 				}

 				continue;
 			}

 			/* No cache entry?  Start a new one */
 			if (!c) {
 				c = kzalloc(sizeof(*c), GFP_KERNEL);
 				if (!c) {
 					regmap_debugfs_free_dump_cache(map);
 					mutex_unlock(&map->cache_lock);
 					return base;
 				}
 				c->min = p;
 				c->base_reg = i;
 			}

 			p += map->debugfs_tot_len;
 		}
 	}

 	/* Close the last entry off if we didn't scan beyond it */
 	if (c) {
 		c->max = p - 1;
 		c->max_reg = i - map->reg_stride;
 		list_add_tail(&c->list,
 			      &map->debugfs_off_cache);
 	}

 	/*
 	 * This should never happen; we return above if we fail to
 	 * allocate and we should never be in this code if there are
 	 * no registers at all.
 	 */
 	WARN_ON(list_empty(&map->debugfs_off_cache));
 	ret = base;

 	/* Find the relevant block:offset */
 	list_for_each_entry(c, &map->debugfs_off_cache, list) {
 		if (from >= c->min && from <= c->max) {
 			fpos_offset = from - c->min;
 			reg_offset = fpos_offset / map->debugfs_tot_len;
 			*pos = c->min + (reg_offset * map->debugfs_tot_len);
 			mutex_unlock(&map->cache_lock);
 			return c->base_reg + reg_offset;
 		}

 		*pos = c->max;
 		ret = c->max_reg;
 	}
 	mutex_unlock(&map->cache_lock);

 	return ret;
 }

 static inline void regmap_calc_tot_len(struct regmap *map,
 				       void *buf, size_t count)
 {
 	/* Calculate the length of a fixed format  */
 	if (!map->debugfs_tot_len) {
 		map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
 							   buf, count);
 		map->debugfs_val_len = 2 * map->format.val_bytes;
 		map->debugfs_tot_len = map->debugfs_reg_len +
 			map->debugfs_val_len + 3;      /* : \n */
 	}
 }

 static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
 				   unsigned int to, char __user *user_buf,
 				   size_t count, loff_t *ppos)
 {
 	size_t buf_pos = 0;
 	loff_t p = *ppos;
 	ssize_t ret;
 	int i;
 	char *buf;
 	unsigned int val, start_reg;

 	if (*ppos < 0 || !count)
 		return -EINVAL;

 	buf = kmalloc(count, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	regmap_calc_tot_len(map, buf, count);

 	/* Work out which register we're starting at */
 	start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);

 	for (i = start_reg; i <= to; i += map->reg_stride) {
 		if (!regmap_readable(map, i))
 			continue;

 		if (regmap_precious(map, i))
 			continue;

 		/* If we're in the region the user is trying to read */
 		if (p >= *ppos) {
 			/* ...but not beyond it */
 			if (buf_pos + map->debugfs_tot_len > count)
 				break;

 			/* Format the register */
 			snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
 				 map->debugfs_reg_len, i - from);
 			buf_pos += map->debugfs_reg_len + 2;

 			/* Format the value, write all X if we can't read */
 			ret = regmap_read(map, i, &val);
 			if (ret == 0)
 				snprintf(buf + buf_pos, count - buf_pos,
 					 "%.*x", map->debugfs_val_len, val);
 			else
 				memset(buf + buf_pos, 'X',
 				       map->debugfs_val_len);
 			buf_pos += 2 * map->format.val_bytes;

 			buf[buf_pos++] = '\n';
 		}
 		p += map->debugfs_tot_len;
 	}

 	ret = buf_pos;

 	if (copy_to_user(user_buf, buf, buf_pos)) {
 		ret = -EFAULT;
 		goto out;
 	}

 	*ppos += buf_pos;

 out:
 	kfree(buf);
 	return ret;
 }

 static ssize_t regmap_map_read_file(struct file *file, char __user *user_buf,
 				    size_t count, loff_t *ppos)
 {
 	struct regmap *map = file->private_data;

 	return regmap_read_debugfs(map, 0, map->max_register, user_buf,
 				   count, ppos);
 }

 #undef REGMAP_ALLOW_WRITE_DEBUGFS
 #ifdef REGMAP_ALLOW_WRITE_DEBUGFS
 /*
  * This can be dangerous especially when we have clients such as
  * PMICs, therefore don't provide any real compile time configuration option
  * for this feature, people who want to use this will need to modify
  * the source code directly.
  */
 static ssize_t regmap_map_write_file(struct file *file,
 				     const char __user *user_buf,
 				     size_t count, loff_t *ppos)
 {
 	char buf[32];
 	size_t buf_size;
 	char *start = buf;
 	unsigned long reg, value;
 	struct regmap *map = file->private_data;
 	int ret;

 	buf_size = min(count, (sizeof(buf)-1));
 	if (copy_from_user(buf, user_buf, buf_size))
 		return -EFAULT;
 	buf[buf_size] = 0;

 	while (*start == ' ')
 		start++;
 	reg = simple_strtoul(start, &start, 16);
 	while (*start == ' ')
 		start++;
 	if (strict_strtoul(start, 16, &value))
 		return -EINVAL;

 	/* Userspace has been fiddling around behind the kernel's back */
 	add_taint(TAINT_USER, LOCKDEP_NOW_UNRELIABLE);

 	ret = regmap_write(map, reg, value);
 	if (ret < 0)
 		return ret;
 	return buf_size;
 }
 #else
 #define regmap_map_write_file NULL
 #endif

 static const struct file_operations regmap_map_fops = {
 	.open = simple_open,
 	.read = regmap_map_read_file,
 	.write = regmap_map_write_file,
 	.llseek = default_llseek,
 };

 static ssize_t regmap_range_read_file(struct file *file, char __user *user_buf,
 				      size_t count, loff_t *ppos)
 {
 	struct regmap_range_node *range = file->private_data;
 	struct regmap *map = range->map;

 	return regmap_read_debugfs(map, range->range_min, range->range_max,
 				   user_buf, count, ppos);
 }

 static const struct file_operations regmap_range_fops = {
 	.open = simple_open,
 	.read = regmap_range_read_file,
 	.llseek = default_llseek,
 };

 static ssize_t regmap_reg_ranges_read_file(struct file *file,
 					   char __user *user_buf, size_t count,
 					   loff_t *ppos)
 {
 	struct regmap *map = file->private_data;
 	struct regmap_debugfs_off_cache *c;
 	loff_t p = 0;
 	size_t buf_pos = 0;
 	char *buf;
 	char *entry;
 	int ret;

 	if (*ppos < 0 || !count)
 		return -EINVAL;

 	buf = kmalloc(count, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
 	if (!entry) {
 		kfree(buf);
 		return -ENOMEM;
 	}

 	/* While we are at it, build the register dump cache
 	 * now so the read() operation on the `registers' file
 	 * can benefit from using the cache.  We do not care
 	 * about the file position information that is contained
 	 * in the cache, just about the actual register blocks */
 	regmap_calc_tot_len(map, buf, count);
 	regmap_debugfs_get_dump_start(map, 0, *ppos, &p);

 	/* Reset file pointer as the fixed-format of the `registers'
 	 * file is not compatible with the `range' file */
 	p = 0;
 	mutex_lock(&map->cache_lock);
 	list_for_each_entry(c, &map->debugfs_off_cache, list) {
 		snprintf(entry, PAGE_SIZE, "%x-%x",
 			 c->base_reg, c->max_reg);
 		if (p >= *ppos) {
 			if (buf_pos + 1 + strlen(entry) > count)
 				break;
 			snprintf(buf + buf_pos, count - buf_pos,
 				 "%s", entry);
 			buf_pos += strlen(entry);
 			buf[buf_pos] = '\n';
 			buf_pos++;
 		}
 		p += strlen(entry) + 1;
 	}
 	mutex_unlock(&map->cache_lock);

 	kfree(entry);
 	ret = buf_pos;

 	if (copy_to_user(user_buf, buf, buf_pos)) {
 		ret = -EFAULT;
 		goto out_buf;
 	}

 	*ppos += buf_pos;
 out_buf:
 	kfree(buf);
 	return ret;
 }

 static const struct file_operations regmap_reg_ranges_fops = {
 	.open = simple_open,
 	.read = regmap_reg_ranges_read_file,
 	.llseek = default_llseek,
 };

 static ssize_t regmap_access_read_file(struct file *file,
 				       char __user *user_buf, size_t count,
 				       loff_t *ppos)
 {
 	int reg_len, tot_len;
 	size_t buf_pos = 0;
 	loff_t p = 0;
 	ssize_t ret;
 	int i;
 	struct regmap *map = file->private_data;
 	char *buf;

 	if (*ppos < 0 || !count)
 		return -EINVAL;

 	buf = kmalloc(count, GFP_KERNEL);
 	if (!buf)
 		return -ENOMEM;

 	/* Calculate the length of a fixed format  */
 	reg_len = regmap_calc_reg_len(map->max_register, buf, count);
 	tot_len = reg_len + 10; /* ': R W V P\n' */

 	for (i = 0; i <= map->max_register; i += map->reg_stride) {
 		/* Ignore registers which are neither readable nor writable */
 		if (!regmap_readable(map, i) && !regmap_writeable(map, i))
 			continue;

 		/* If we're in the region the user is trying to read */
 		if (p >= *ppos) {
 			/* ...but not beyond it */
 			if (buf_pos >= count - 1 - tot_len)
 				break;

 			/* Format the register */
 			snprintf(buf + buf_pos, count - buf_pos,
 				 "%.*x: %c %c %c %c\n",
 				 reg_len, i,
 				 regmap_readable(map, i) ? 'y' : 'n',
 				 regmap_writeable(map, i) ? 'y' : 'n',
 				 regmap_volatile(map, i) ? 'y' : 'n',
 				 regmap_precious(map, i) ? 'y' : 'n');

 			buf_pos += tot_len;
 		}
 		p += tot_len;
 	}

 	ret = buf_pos;

 	if (copy_to_user(user_buf, buf, buf_pos)) {
 		ret = -EFAULT;
 		goto out;
 	}

 	*ppos += buf_pos;

 out:
 	kfree(buf);
 	return ret;
 }

 static const struct file_operations regmap_access_fops = {
 	.open = simple_open,
 	.read = regmap_access_read_file,
 	.llseek = default_llseek,
 };

 void regmap_debugfs_init(struct regmap *map, const char *name)
 {
 	struct rb_node *next;
 	struct regmap_range_node *range_node;

 	INIT_LIST_HEAD(&map->debugfs_off_cache);
 	mutex_init(&map->cache_lock);

 	if (name) {
 		map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
 					      dev_name(map->dev), name);
 		name = map->debugfs_name;
 	} else {
 		name = dev_name(map->dev);
 	}

 	map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
 	if (!map->debugfs) {
 		dev_warn(map->dev, "Failed to create debugfs directory\n");
 		return;
 	}

 	debugfs_create_file("name", 0400, map->debugfs,
 			    map, &regmap_name_fops);

 	debugfs_create_file("range", 0400, map->debugfs,
 			    map, &regmap_reg_ranges_fops);

 	if (map->max_register) {
 		debugfs_create_file("registers", 0400, map->debugfs,
 				    map, &regmap_map_fops);
 		debugfs_create_file("access", 0400, map->debugfs,
 				    map, &regmap_access_fops);
 	}

 	if (map->cache_type) {
 		debugfs_create_bool("cache_only", 0400, map->debugfs,
 				    &map->cache_only);
 		debugfs_create_bool("cache_dirty", 0400, map->debugfs,
 				    &map->cache_dirty);
 		debugfs_create_bool("cache_bypass", 0400, map->debugfs,
 				    &map->cache_bypass);
 	}

 	next = rb_first(&map->range_tree);
 	while (next) {
 		range_node = rb_entry(next, struct regmap_range_node, node);

 		if (range_node->name)
 			debugfs_create_file(range_node->name, 0400,
 					    map->debugfs, range_node,
 					    &regmap_range_fops);

 		next = rb_next(&range_node->node);
 	}
 }

 void regmap_debugfs_exit(struct regmap *map)
 {
 	debugfs_remove_recursive(map->debugfs);
 	mutex_lock(&map->cache_lock);
 	regmap_debugfs_free_dump_cache(map);
 	mutex_unlock(&map->cache_lock);
 	kfree(map->debugfs_name);
 }

 void regmap_debugfs_initcall(void)
 {
 	regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
 	if (!regmap_debugfs_root) {
 		pr_warn("regmap: Failed to create debugfs root\n");
 		return;
 	}
 }
	/*
	* Register map access API - debugfs
	*
	* Copyright 2011 Wolfson Microelectronics plc
	*
	* Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
	*
	* 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.
	*/

	#include <linux/slab.h>
	#include <linux/mutex.h>
	#include <linux/debugfs.h>
	#include <linux/uaccess.h>
	#include <linux/device.h>

	#include "internal.h"

	static struct dentry *regmap_debugfs_root;

	/* Calculate the length of a fixed format */
	static size_t regmap_calc_reg_len(int max_val, char *buf, size_t buf_size)
	{
	snprintf(buf, buf_size, "%x", max_val);
	return strlen(buf);
	}

	static ssize_t regmap_name_read_file(struct file *file,
	char __user *user_buf, size_t count,
	loff_t *ppos)
	{
	struct regmap *map = file->private_data;
	int ret;
	char *buf;

	buf = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	ret = snprintf(buf, PAGE_SIZE, "%s\n", map->dev->driver->name);
	if (ret < 0) {
	kfree(buf);
	return ret;
	}

	ret = simple_read_from_buffer(user_buf, count, ppos, buf, ret);
	kfree(buf);
	return ret;
	}

	static const struct file_operations regmap_name_fops = {
	.open = simple_open,
	.read = regmap_name_read_file,
	.llseek = default_llseek,
	};

	static void regmap_debugfs_free_dump_cache(struct regmap *map)
	{
	struct regmap_debugfs_off_cache *c;

	while (!list_empty(&map->debugfs_off_cache)) {
	c = list_first_entry(&map->debugfs_off_cache,
	struct regmap_debugfs_off_cache,
	list);
	list_del(&c->list);
	kfree(c);
	}
	}

	/*
	* Work out where the start offset maps into register numbers, bearing
	* in mind that we suppress hidden registers.
	*/
	static unsigned int regmap_debugfs_get_dump_start(struct regmap *map,
	unsigned int base,
	loff_t from,
	loff_t *pos)
	{
	struct regmap_debugfs_off_cache *c = NULL;
	loff_t p = 0;
	unsigned int i, ret;
	unsigned int fpos_offset;
	unsigned int reg_offset;

	/*
	* If we don't have a cache build one so we don't have to do a
	* linear scan each time.
	*/
	mutex_lock(&map->cache_lock);
	i = base;
	if (list_empty(&map->debugfs_off_cache)) {
	for (; i <= map->max_register; i += map->reg_stride) {
	/* Skip unprinted registers, closing off cache entry */
	if (!regmap_readable(map, i) \|\|
	regmap_precious(map, i)) {
	if (c) {
	c->max = p - 1;
	c->max_reg = i - map->reg_stride;
	list_add_tail(&c->list,
	&map->debugfs_off_cache);
	c = NULL;
	}

	continue;
	}

	/* No cache entry? Start a new one */
	if (!c) {
	c = kzalloc(sizeof(*c), GFP_KERNEL);
	if (!c) {
	regmap_debugfs_free_dump_cache(map);
	mutex_unlock(&map->cache_lock);
	return base;
	}
	c->min = p;
	c->base_reg = i;
	}

	p += map->debugfs_tot_len;
	}
	}

	/* Close the last entry off if we didn't scan beyond it */
	if (c) {
	c->max = p - 1;
	c->max_reg = i - map->reg_stride;
	list_add_tail(&c->list,
	&map->debugfs_off_cache);
	}

	/*
	* This should never happen; we return above if we fail to
	* allocate and we should never be in this code if there are
	* no registers at all.
	*/
	WARN_ON(list_empty(&map->debugfs_off_cache));
	ret = base;

	/* Find the relevant block:offset */
	list_for_each_entry(c, &map->debugfs_off_cache, list) {
	if (from >= c->min && from <= c->max) {
	fpos_offset = from - c->min;
	reg_offset = fpos_offset / map->debugfs_tot_len;
	pos = c->min + (reg_offset map->debugfs_tot_len);
	mutex_unlock(&map->cache_lock);
	return c->base_reg + reg_offset;
	}

	*pos = c->max;
	ret = c->max_reg;
	}
	mutex_unlock(&map->cache_lock);

	return ret;
	}

	static inline void regmap_calc_tot_len(struct regmap *map,
	void *buf, size_t count)
	{
	/* Calculate the length of a fixed format */
	if (!map->debugfs_tot_len) {
	map->debugfs_reg_len = regmap_calc_reg_len(map->max_register,
	buf, count);
	map->debugfs_val_len = 2 * map->format.val_bytes;
	map->debugfs_tot_len = map->debugfs_reg_len +
	map->debugfs_val_len + 3; /* : \n */
	}
	}

	static ssize_t regmap_read_debugfs(struct regmap *map, unsigned int from,
	unsigned int to, char __user *user_buf,
	size_t count, loff_t *ppos)
	{
	size_t buf_pos = 0;
	loff_t p = *ppos;
	ssize_t ret;
	int i;
	char *buf;
	unsigned int val, start_reg;

	if (*ppos < 0 \|\| !count)
	return -EINVAL;

	buf = kmalloc(count, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	regmap_calc_tot_len(map, buf, count);

	/* Work out which register we're starting at */
	start_reg = regmap_debugfs_get_dump_start(map, from, *ppos, &p);

	for (i = start_reg; i <= to; i += map->reg_stride) {
	if (!regmap_readable(map, i))
	continue;

	if (regmap_precious(map, i))
	continue;

	/* If we're in the region the user is trying to read */
	if (p >= *ppos) {
	/* ...but not beyond it */
	if (buf_pos + map->debugfs_tot_len > count)
	break;

	/* Format the register */
	snprintf(buf + buf_pos, count - buf_pos, "%.*x: ",
	map->debugfs_reg_len, i - from);
	buf_pos += map->debugfs_reg_len + 2;

	/* Format the value, write all X if we can't read */
	ret = regmap_read(map, i, &val);
	if (ret == 0)
	snprintf(buf + buf_pos, count - buf_pos,
	"%.*x", map->debugfs_val_len, val);
	else
	memset(buf + buf_pos, 'X',
	map->debugfs_val_len);
	buf_pos += 2 * map->format.val_bytes;

	buf[buf_pos++] = '\n';
	}
	p += map->debugfs_tot_len;
	}

	ret = buf_pos;

	if (copy_to_user(user_buf, buf, buf_pos)) {
	ret = -EFAULT;
	goto out;
	}

	*ppos += buf_pos;

	out:
	kfree(buf);
	return ret;
	}

	static ssize_t regmap_map_read_file(struct file file, char __user user_buf,
	size_t count, loff_t *ppos)
	{
	struct regmap *map = file->private_data;

	return regmap_read_debugfs(map, 0, map->max_register, user_buf,
	count, ppos);
	}

	#undef REGMAP_ALLOW_WRITE_DEBUGFS
	#ifdef REGMAP_ALLOW_WRITE_DEBUGFS
	/*
	* This can be dangerous especially when we have clients such as
	* PMICs, therefore don't provide any real compile time configuration option
	* for this feature, people who want to use this will need to modify
	* the source code directly.
	*/
	static ssize_t regmap_map_write_file(struct file *file,
	const char __user *user_buf,
	size_t count, loff_t *ppos)
	{
	char buf[32];
	size_t buf_size;
	char *start = buf;
	unsigned long reg, value;
	struct regmap *map = file->private_data;
	int ret;

	buf_size = min(count, (sizeof(buf)-1));
	if (copy_from_user(buf, user_buf, buf_size))
	return -EFAULT;
	buf[buf_size] = 0;

	while (*start == ' ')
	start++;
	reg = simple_strtoul(start, &start, 16);
	while (*start == ' ')
	start++;
	if (strict_strtoul(start, 16, &value))
	return -EINVAL;

	/* Userspace has been fiddling around behind the kernel's back */
	add_taint(TAINT_USER, LOCKDEP_NOW_UNRELIABLE);

	ret = regmap_write(map, reg, value);
	if (ret < 0)
	return ret;
	return buf_size;
	}
	#else
	#define regmap_map_write_file NULL
	#endif

	static const struct file_operations regmap_map_fops = {
	.open = simple_open,
	.read = regmap_map_read_file,
	.write = regmap_map_write_file,
	.llseek = default_llseek,
	};

	static ssize_t regmap_range_read_file(struct file file, char __user user_buf,
	size_t count, loff_t *ppos)
	{
	struct regmap_range_node *range = file->private_data;
	struct regmap *map = range->map;

	return regmap_read_debugfs(map, range->range_min, range->range_max,
	user_buf, count, ppos);
	}

	static const struct file_operations regmap_range_fops = {
	.open = simple_open,
	.read = regmap_range_read_file,
	.llseek = default_llseek,
	};

	static ssize_t regmap_reg_ranges_read_file(struct file *file,
	char __user *user_buf, size_t count,
	loff_t *ppos)
	{
	struct regmap *map = file->private_data;
	struct regmap_debugfs_off_cache *c;
	loff_t p = 0;
	size_t buf_pos = 0;
	char *buf;
	char *entry;
	int ret;

	if (*ppos < 0 \|\| !count)
	return -EINVAL;

	buf = kmalloc(count, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	entry = kmalloc(PAGE_SIZE, GFP_KERNEL);
	if (!entry) {
	kfree(buf);
	return -ENOMEM;
	}

	/* While we are at it, build the register dump cache
	* now so the read() operation on the `registers' file
	* can benefit from using the cache. We do not care
	* about the file position information that is contained
	* in the cache, just about the actual register blocks */
	regmap_calc_tot_len(map, buf, count);
	regmap_debugfs_get_dump_start(map, 0, *ppos, &p);

	/* Reset file pointer as the fixed-format of the `registers'
	* file is not compatible with the `range' file */
	p = 0;
	mutex_lock(&map->cache_lock);
	list_for_each_entry(c, &map->debugfs_off_cache, list) {
	snprintf(entry, PAGE_SIZE, "%x-%x",
	c->base_reg, c->max_reg);
	if (p >= *ppos) {
	if (buf_pos + 1 + strlen(entry) > count)
	break;
	snprintf(buf + buf_pos, count - buf_pos,
	"%s", entry);
	buf_pos += strlen(entry);
	buf[buf_pos] = '\n';
	buf_pos++;
	}
	p += strlen(entry) + 1;
	}
	mutex_unlock(&map->cache_lock);

	kfree(entry);
	ret = buf_pos;

	if (copy_to_user(user_buf, buf, buf_pos)) {
	ret = -EFAULT;
	goto out_buf;
	}

	*ppos += buf_pos;
	out_buf:
	kfree(buf);
	return ret;
	}

	static const struct file_operations regmap_reg_ranges_fops = {
	.open = simple_open,
	.read = regmap_reg_ranges_read_file,
	.llseek = default_llseek,
	};

	static ssize_t regmap_access_read_file(struct file *file,
	char __user *user_buf, size_t count,
	loff_t *ppos)
	{
	int reg_len, tot_len;
	size_t buf_pos = 0;
	loff_t p = 0;
	ssize_t ret;
	int i;
	struct regmap *map = file->private_data;
	char *buf;

	if (*ppos < 0 \|\| !count)
	return -EINVAL;

	buf = kmalloc(count, GFP_KERNEL);
	if (!buf)
	return -ENOMEM;

	/* Calculate the length of a fixed format */
	reg_len = regmap_calc_reg_len(map->max_register, buf, count);
	tot_len = reg_len + 10; /* ': R W V P\n' */

	for (i = 0; i <= map->max_register; i += map->reg_stride) {
	/* Ignore registers which are neither readable nor writable */
	if (!regmap_readable(map, i) && !regmap_writeable(map, i))
	continue;

	/* If we're in the region the user is trying to read */
	if (p >= *ppos) {
	/* ...but not beyond it */
	if (buf_pos >= count - 1 - tot_len)
	break;

	/* Format the register */
	snprintf(buf + buf_pos, count - buf_pos,
	"%.*x: %c %c %c %c\n",
	reg_len, i,
	regmap_readable(map, i) ? 'y' : 'n',
	regmap_writeable(map, i) ? 'y' : 'n',
	regmap_volatile(map, i) ? 'y' : 'n',
	regmap_precious(map, i) ? 'y' : 'n');

	buf_pos += tot_len;
	}
	p += tot_len;
	}

	ret = buf_pos;

	if (copy_to_user(user_buf, buf, buf_pos)) {
	ret = -EFAULT;
	goto out;
	}

	*ppos += buf_pos;

	out:
	kfree(buf);
	return ret;
	}

	static const struct file_operations regmap_access_fops = {
	.open = simple_open,
	.read = regmap_access_read_file,
	.llseek = default_llseek,
	};

	void regmap_debugfs_init(struct regmap map, const char name)
	{
	struct rb_node *next;
	struct regmap_range_node *range_node;

	INIT_LIST_HEAD(&map->debugfs_off_cache);
	mutex_init(&map->cache_lock);

	if (name) {
	map->debugfs_name = kasprintf(GFP_KERNEL, "%s-%s",
	dev_name(map->dev), name);
	name = map->debugfs_name;
	} else {
	name = dev_name(map->dev);
	}

	map->debugfs = debugfs_create_dir(name, regmap_debugfs_root);
	if (!map->debugfs) {
	dev_warn(map->dev, "Failed to create debugfs directory\n");
	return;
	}

	debugfs_create_file("name", 0400, map->debugfs,
	map, &regmap_name_fops);

	debugfs_create_file("range", 0400, map->debugfs,
	map, &regmap_reg_ranges_fops);

	if (map->max_register) {
	debugfs_create_file("registers", 0400, map->debugfs,
	map, &regmap_map_fops);
	debugfs_create_file("access", 0400, map->debugfs,
	map, &regmap_access_fops);
	}

	if (map->cache_type) {
	debugfs_create_bool("cache_only", 0400, map->debugfs,
	&map->cache_only);
	debugfs_create_bool("cache_dirty", 0400, map->debugfs,
	&map->cache_dirty);
	debugfs_create_bool("cache_bypass", 0400, map->debugfs,
	&map->cache_bypass);
	}

	next = rb_first(&map->range_tree);
	while (next) {
	range_node = rb_entry(next, struct regmap_range_node, node);

	if (range_node->name)
	debugfs_create_file(range_node->name, 0400,
	map->debugfs, range_node,
	&regmap_range_fops);

	next = rb_next(&range_node->node);
	}
	}

	void regmap_debugfs_exit(struct regmap *map)
	{
	debugfs_remove_recursive(map->debugfs);
	mutex_lock(&map->cache_lock);
	regmap_debugfs_free_dump_cache(map);
	mutex_unlock(&map->cache_lock);
	kfree(map->debugfs_name);
	}

	void regmap_debugfs_initcall(void)
	{
	regmap_debugfs_root = debugfs_create_dir("regmap", NULL);
	if (!regmap_debugfs_root) {
	pr_warn("regmap: Failed to create debugfs root\n");
	return;
	}
	}