regmap.c

/*
 * Register map access API
 *
 * 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/device.h>
#include <linux/slab.h>
#include <linux/export.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/of.h>
#include <linux/rbtree.h>
#include <linux/sched.h>

#define CREATE_TRACE_POINTS
#include "trace.h"

#include "internal.h"

/*
 * Sometimes for failures during very early init the trace
 * infrastructure isn't available early enough to be used.  For this
 * sort of problem defining LOG_DEVICE will add printks for basic
 * register I/O on a specific device.
 */
#undef LOG_DEVICE

static int _regmap_update_bits(struct regmap *map, unsigned int reg,
			       unsigned int mask, unsigned int val,
			       bool *change);

static int _regmap_bus_reg_read(void *context, unsigned int reg,
				unsigned int *val);
static int _regmap_bus_read(void *context, unsigned int reg,
			    unsigned int *val);
static int _regmap_bus_formatted_write(void *context, unsigned int reg,
				       unsigned int val);
static int _regmap_bus_reg_write(void *context, unsigned int reg,
				 unsigned int val);
static int _regmap_bus_raw_write(void *context, unsigned int reg,
				 unsigned int val);

bool regmap_reg_in_ranges(unsigned int reg,
			  const struct regmap_range *ranges,
			  unsigned int nranges)
{
	const struct regmap_range *r;
	int i;

	for (i = 0, r = ranges; i < nranges; i++, r++)
		if (regmap_reg_in_range(reg, r))
			return true;
	return false;
}
EXPORT_SYMBOL_GPL(regmap_reg_in_ranges);

bool regmap_check_range_table(struct regmap *map, unsigned int reg,
			      const struct regmap_access_table *table)
{
	/* Check "no ranges" first */
	if (regmap_reg_in_ranges(reg, table->no_ranges, table->n_no_ranges))
		return false;

	/* In case zero "yes ranges" are supplied, any reg is OK */
	if (!table->n_yes_ranges)
		return true;

	return regmap_reg_in_ranges(reg, table->yes_ranges,
				    table->n_yes_ranges);
}
EXPORT_SYMBOL_GPL(regmap_check_range_table);

bool regmap_writeable(struct regmap *map, unsigned int reg)
{
	if (map->max_register && reg > map->max_register)
		return false;

	if (map->writeable_reg)
		return map->writeable_reg(map->dev, reg);

	if (map->wr_table)
		return regmap_check_range_table(map, reg, map->wr_table);

	return true;
}

bool regmap_readable(struct regmap *map, unsigned int reg)
{
	if (map->max_register && reg > map->max_register)
		return false;

	if (map->format.format_write)
		return false;

	if (map->readable_reg)
		return map->readable_reg(map->dev, reg);

	if (map->rd_table)
		return regmap_check_range_table(map, reg, map->rd_table);

	return true;
}

bool regmap_volatile(struct regmap *map, unsigned int reg)
{
	if (!map->format.format_write && !regmap_readable(map, reg))
		return false;

	if (map->volatile_reg)
		return map->volatile_reg(map->dev, reg);

	if (map->volatile_table)
		return regmap_check_range_table(map, reg, map->volatile_table);

	if (map->cache_ops)
		return false;
	else
		return true;
}

bool regmap_precious(struct regmap *map, unsigned int reg)
{
	if (!regmap_readable(map, reg))
		return false;

	if (map->precious_reg)
		return map->precious_reg(map->dev, reg);

	if (map->precious_table)
		return regmap_check_range_table(map, reg, map->precious_table);

	return false;
}

static bool regmap_volatile_range(struct regmap *map, unsigned int reg,
	size_t num)
{
	unsigned int i;

	for (i = 0; i < num; i++)
		if (!regmap_volatile(map, reg + i))
			return false;

	return true;
}

static void regmap_format_2_6_write(struct regmap *map,
				     unsigned int reg, unsigned int val)
{
	u8 *out = map->work_buf;

	*out = (reg << 6) | val;
}

static void regmap_format_4_12_write(struct regmap *map,
				     unsigned int reg, unsigned int val)
{
	__be16 *out = map->work_buf;
	*out = cpu_to_be16((reg << 12) | val);
}

static void regmap_format_7_9_write(struct regmap *map,
				    unsigned int reg, unsigned int val)
{
	__be16 *out = map->work_buf;
	*out = cpu_to_be16((reg << 9) | val);
}

static void regmap_format_10_14_write(struct regmap *map,
				    unsigned int reg, unsigned int val)
{
	u8 *out = map->work_buf;

	out[2] = val;
	out[1] = (val >> 8) | (reg << 6);
	out[0] = reg >> 2;
}

static void regmap_format_8(void *buf, unsigned int val, unsigned int shift)
{
	u8 *b = buf;

	b[0] = val << shift;
}

static void regmap_format_16_be(void *buf, unsigned int val, unsigned int shift)
{
	__be16 *b = buf;

	b[0] = cpu_to_be16(val << shift);
}

static void regmap_format_16_le(void *buf, unsigned int val, unsigned int shift)
{
	__le16 *b = buf;

	b[0] = cpu_to_le16(val << shift);
}

static void regmap_format_16_native(void *buf, unsigned int val,
				    unsigned int shift)
{
	*(u16 *)buf = val << shift;
}

static void regmap_format_24(void *buf, unsigned int val, unsigned int shift)
{
	u8 *b = buf;

	val <<= shift;

	b[0] = val >> 16;
	b[1] = val >> 8;
	b[2] = val;
}

static void regmap_format_32_be(void *buf, unsigned int val, unsigned int shift)
{
	__be32 *b = buf;

	b[0] = cpu_to_be32(val << shift);
}

static void regmap_format_32_le(void *buf, unsigned int val, unsigned int shift)
{
	__le32 *b = buf;

	b[0] = cpu_to_le32(val << shift);
}

static void regmap_format_32_native(void *buf, unsigned int val,
				    unsigned int shift)
{
	*(u32 *)buf = val << shift;
}

static void regmap_parse_inplace_noop(void *buf)
{
}

static unsigned int regmap_parse_8(const void *buf)
{
	const u8 *b = buf;

	return b[0];
}

static unsigned int regmap_parse_16_be(const void *buf)
{
	const __be16 *b = buf;

	return be16_to_cpu(b[0]);
}

static unsigned int regmap_parse_16_le(const void *buf)
{
	const __le16 *b = buf;

	return le16_to_cpu(b[0]);
}

static void regmap_parse_16_be_inplace(void *buf)
{
	__be16 *b = buf;

	b[0] = be16_to_cpu(b[0]);
}

static void regmap_parse_16_le_inplace(void *buf)
{
	__le16 *b = buf;

	b[0] = le16_to_cpu(b[0]);
}

static unsigned int regmap_parse_16_native(const void *buf)
{
	return *(u16 *)buf;
}

static unsigned int regmap_parse_24(const void *buf)
{
	const u8 *b = buf;
	unsigned int ret = b[2];
	ret |= ((unsigned int)b[1]) << 8;
	ret |= ((unsigned int)b[0]) << 16;

	return ret;
}

static unsigned int regmap_parse_32_be(const void *buf)
{
	const __be32 *b = buf;

	return be32_to_cpu(b[0]);
}

static unsigned int regmap_parse_32_le(const void *buf)
{
	const __le32 *b = buf;

	return le32_to_cpu(b[0]);
}

static void regmap_parse_32_be_inplace(void *buf)
{
	__be32 *b = buf;

	b[0] = be32_to_cpu(b[0]);
}

static void regmap_parse_32_le_inplace(void *buf)
{
	__le32 *b = buf;

	b[0] = le32_to_cpu(b[0]);
}

static unsigned int regmap_parse_32_native(const void *buf)
{
	return *(u32 *)buf;
}

static void regmap_lock_mutex(void *__map)
{
	struct regmap *map = __map;
	mutex_lock(&map->mutex);
}

static void regmap_unlock_mutex(void *__map)
{
	struct regmap *map = __map;
	mutex_unlock(&map->mutex);
}

static void regmap_lock_spinlock(void *__map)
__acquires(&map->spinlock)
{
	struct regmap *map = __map;
	unsigned long flags;

	spin_lock_irqsave(&map->spinlock, flags);
	map->spinlock_flags = flags;
}

static void regmap_unlock_spinlock(void *__map)
__releases(&map->spinlock)
{
	struct regmap *map = __map;
	spin_unlock_irqrestore(&map->spinlock, map->spinlock_flags);
}

static void dev_get_regmap_release(struct device *dev, void *res)
{
	/*
	 * We don't actually have anything to do here; the goal here
	 * is not to manage the regmap but to provide a simple way to
	 * get the regmap back given a struct device.
	 */
}

static bool _regmap_range_add(struct regmap *map,
			      struct regmap_range_node *data)
{
	struct rb_root *root = &map->range_tree;
	struct rb_node **new = &(root->rb_node), *parent = NULL;

	while (*new) {
		struct regmap_range_node *this =
			container_of(*new, struct regmap_range_node, node);

		parent = *new;
		if (data->range_max < this->range_min)
			new = &((*new)->rb_left);
		else if (data->range_min > this->range_max)
			new = &((*new)->rb_right);
		else
			return false;
	}

	rb_link_node(&data->node, parent, new);
	rb_insert_color(&data->node, root);

	return true;
}

static struct regmap_range_node *_regmap_range_lookup(struct regmap *map,
						      unsigned int reg)
{
	struct rb_node *node = map->range_tree.rb_node;

	while (node) {
		struct regmap_range_node *this =
			container_of(node, struct regmap_range_node, node);

		if (reg < this->range_min)
			node = node->rb_left;
		else if (reg > this->range_max)
			node = node->rb_right;
		else
			return this;
	}

	return NULL;
}

static void regmap_range_exit(struct regmap *map)
{
	struct rb_node *next;
	struct regmap_range_node *range_node;

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

	kfree(map->selector_work_buf);
}

int regmap_attach_dev(struct device *dev, struct regmap *map,
		      const struct regmap_config *config)
{
	struct regmap **m;

	map->dev = dev;

	regmap_debugfs_init(map, config->name);

	/* Add a devres resource for dev_get_regmap() */
	m = devres_alloc(dev_get_regmap_release, sizeof(*m), GFP_KERNEL);
	if (!m) {
		regmap_debugfs_exit(map);
		return -ENOMEM;
	}
	*m = map;
	devres_add(dev, m);

	return 0;
}
EXPORT_SYMBOL_GPL(regmap_attach_dev);

static enum regmap_endian regmap_get_reg_endian(const struct regmap_bus *bus,
					const struct regmap_config *config)
{
	enum regmap_endian endian;

	/* Retrieve the endianness specification from the regmap config */
	endian = config->reg_format_endian;

	/* If the regmap config specified a non-default value, use that */
	if (endian != REGMAP_ENDIAN_DEFAULT)
		return endian;

	/* Retrieve the endianness specification from the bus config */
	if (bus && bus->reg_format_endian_default)
		endian = bus->reg_format_endian_default;

	/* If the bus specified a non-default value, use that */
	if (endian != REGMAP_ENDIAN_DEFAULT)
		return endian;

	/* Use this if no other value was found */
	return REGMAP_ENDIAN_BIG;
}

enum regmap_endian regmap_get_val_endian(struct device *dev,
					 const struct regmap_bus *bus,
					 const struct regmap_config *config)
{
	struct device_node *np;
	enum regmap_endian endian;

	/* Retrieve the endianness specification from the regmap config */
	endian = config->val_format_endian;

	/* If the regmap config specified a non-default value, use that */
	if (endian != REGMAP_ENDIAN_DEFAULT)
		return endian;

	/* If the dev and dev->of_node exist try to get endianness from DT */
	if (dev && dev->of_node) {
		np = dev->of_node;

		/* Parse the device's DT node for an endianness specification */
		if (of_property_read_bool(np, "big-endian"))
			endian = REGMAP_ENDIAN_BIG;
		else if (of_property_read_bool(np, "little-endian"))
			endian = REGMAP_ENDIAN_LITTLE;

		/* If the endianness was specified in DT, use that */
		if (endian != REGMAP_ENDIAN_DEFAULT)
			return endian;
	}

	/* Retrieve the endianness specification from the bus config */
	if (bus && bus->val_format_endian_default)
		endian = bus->val_format_endian_default;

	/* If the bus specified a non-default value, use that */
	if (endian != REGMAP_ENDIAN_DEFAULT)
		return endian;

	/* Use this if no other value was found */
	return REGMAP_ENDIAN_BIG;
}
EXPORT_SYMBOL_GPL(regmap_get_val_endian);

/**
 * regmap_init(): Initialise register map
 *
 * @dev: Device that will be interacted with
 * @bus: Bus-specific callbacks to use with device
 * @bus_context: Data passed to bus-specific callbacks
 * @config: Configuration for register map
 *
 * The return value will be an ERR_PTR() on error or a valid pointer to
 * a struct regmap.  This function should generally not be called
 * directly, it should be called by bus-specific init functions.
 */
struct regmap *regmap_init(struct device *dev,
			   const struct regmap_bus *bus,
			   void *bus_context,
			   const struct regmap_config *config)
{
	struct regmap *map;
	int ret = -EINVAL;
	enum regmap_endian reg_endian, val_endian;
	int i, j;

	if (!config)
		goto err;

	map = kzalloc(sizeof(*map), GFP_KERNEL);
	if (map == NULL) {
		ret = -ENOMEM;
		goto err;
	}

	if (config->lock && config->unlock) {
		map->lock = config->lock;
		map->unlock = config->unlock;
		map->lock_arg = config->lock_arg;
	} else {
		if ((bus && bus->fast_io) ||
		    config->fast_io) {
			spin_lock_init(&map->spinlock);
			map->lock = regmap_lock_spinlock;
			map->unlock = regmap_unlock_spinlock;
		} else {
			mutex_init(&map->mutex);
			map->lock = regmap_lock_mutex;
			map->unlock = regmap_unlock_mutex;
		}
		map->lock_arg = map;
	}
	map->format.reg_bytes = DIV_ROUND_UP(config->reg_bits, 8);
	map->format.pad_bytes = config->pad_bits / 8;
	map->format.val_bytes = DIV_ROUND_UP(config->val_bits, 8);
	map->format.buf_size = DIV_ROUND_UP(config->reg_bits +
			config->val_bits + config->pad_bits, 8);
	map->reg_shift = config->pad_bits % 8;
	if (config->reg_stride)
		map->reg_stride = config->reg_stride;
	else
		map->reg_stride = 1;
	map->use_single_rw = config->use_single_rw;
	map->can_multi_write = config->can_multi_write;
	map->dev = dev;
	map->bus = bus;
	map->bus_context = bus_context;
	map->max_register = config->max_register;
	map->wr_table = config->wr_table;
	map->rd_table = config->rd_table;
	map->volatile_table = config->volatile_table;
	map->precious_table = config->precious_table;
	map->writeable_reg = config->writeable_reg;
	map->readable_reg = config->readable_reg;
	map->volatile_reg = config->volatile_reg;
	map->precious_reg = config->precious_reg;
	map->cache_type = config->cache_type;
	map->name = config->name;

	spin_lock_init(&map->async_lock);
	INIT_LIST_HEAD(&map->async_list);
	INIT_LIST_HEAD(&map->async_free);
	init_waitqueue_head(&map->async_waitq);

	if (config->read_flag_mask || config->write_flag_mask) {
		map->read_flag_mask = config->read_flag_mask;
		map->write_flag_mask = config->write_flag_mask;
	} else if (bus) {
		map->read_flag_mask = bus->read_flag_mask;
	}

	if (!bus) {
		map->reg_read  = config->reg_read;
		map->reg_write = config->reg_write;

		map->defer_caching = false;
		goto skip_format_initialization;
	} else if (!bus->read || !bus->write) {
		map->reg_read = _regmap_bus_reg_read;
		map->reg_write = _regmap_bus_reg_write;

		map->defer_caching = false;
		goto skip_format_initialization;
	} else {
		map->reg_read  = _regmap_bus_read;
	}

	reg_endian = regmap_get_reg_endian(bus, config);
	val_endian = regmap_get_val_endian(dev, bus, config);

	switch (config->reg_bits + map->reg_shift) {
	case 2:
		switch (config->val_bits) {
		case 6:
			map->format.format_write = regmap_format_2_6_write;
			break;
		default:
			goto err_map;
		}
		break;

	case 4:
		switch (config->val_bits) {
		case 12:
			map->format.format_write = regmap_format_4_12_write;
			break;
		default:
			goto err_map;
		}
		break;

	case 7:
		switch (config->val_bits) {
		case 9:
			map->format.format_write = regmap_format_7_9_write;
			break;
		default:
			goto err_map;
		}
		break;

	case 10:
		switch (config->val_bits) {
		case 14:
			map->format.format_write = regmap_format_10_14_write;
			break;
		default:
			goto err_map;
		}
		break;

	case 8:
		map->format.format_reg = regmap_format_8;
		break;

	case 16:
		switch (reg_endian) {
		case REGMAP_ENDIAN_BIG:
			map->format.format_reg = regmap_format_16_be;
			break;
		case REGMAP_ENDIAN_NATIVE:
			map->format.format_reg = regmap_format_16_native;
			break;
		default:
			goto err_map;
		}
		break;

	case 24:
		if (reg_endian != REGMAP_ENDIAN_BIG)
			goto err_map;
		map->format.format_reg = regmap_format_24;
		break;

	case 32:
		switch (reg_endian) {
		case REGMAP_ENDIAN_BIG:
			map->format.format_reg = regmap_format_32_be;
			break;
		case REGMAP_ENDIAN_NATIVE:
			map->format.format_reg = regmap_format_32_native;
			break;
		default:
			goto err_map;
		}
		break;

	default:
		goto err_map;
	}

	if (val_endian == REGMAP_ENDIAN_NATIVE)
		map->format.parse_inplace = regmap_parse_inplace_noop;

	switch (config->val_bits) {
	case 8:
		map->format.format_val = regmap_format_8;
		map->format.parse_val = regmap_parse_8;
		map->format.parse_inplace = regmap_parse_inplace_noop;
		break;
	case 16:
		switch (val_endian) {
		case REGMAP_ENDIAN_BIG:
			map->format.format_val = regmap_format_16_be;
			map->format.parse_val = regmap_parse_16_be;
			map->format.parse_inplace = regmap_parse_16_be_inplace;
			break;
		case REGMAP_ENDIAN_LITTLE:
			map->format.format_val = regmap_format_16_le;
			map->format.parse_val = regmap_parse_16_le;
			map->format.parse_inplace = regmap_parse_16_le_inplace;
			break;
		case REGMAP_ENDIAN_NATIVE:
			map->format.format_val = regmap_format_16_native;
			map->format.parse_val = regmap_parse_16_native;
			break;
		default:
			goto err_map;
		}
		break;
	case 24:
		if (val_endian != REGMAP_ENDIAN_BIG)
			goto err_map;
		map->format.format_val = regmap_format_24;
		map->format.parse_val = regmap_parse_24;
		break;
	case 32:
		switch (val_endian) {
		case REGMAP_ENDIAN_BIG:
			map->format.format_val = regmap_format_32_be;
			map->format.parse_val = regmap_parse_32_be;
			map->format.parse_inplace = regmap_parse_32_be_inplace;
			break;
		case REGMAP_ENDIAN_LITTLE:
			map->format.format_val = regmap_format_32_le;
			map->format.parse_val = regmap_parse_32_le;
			map->format.parse_inplace = regmap_parse_32_le_inplace;
			break;
		case REGMAP_ENDIAN_NATIVE:
			map->format.format_val = regmap_format_32_native;
			map->format.parse_val = regmap_parse_32_native;
			break;
		default:
			goto err_map;
		}
		break;
	}

	if (map->format.format_write) {
		if ((reg_endian != REGMAP_ENDIAN_BIG) ||
		    (val_endian != REGMAP_ENDIAN_BIG))
			goto err_map;
		map->use_single_rw = true;
	}

	if (!map->format.format_write &&
	    !(map->format.format_reg && map->format.format_val))
		goto err_map;

	map->work_buf = kzalloc(map->format.buf_size, GFP_KERNEL);
	if (map->work_buf == NULL) {
		ret = -ENOMEM;
		goto err_map;
	}

	if (map->format.format_write) {
		map->defer_caching = false;
		map->reg_write = _regmap_bus_formatted_write;
	} else if (map->format.format_val) {
		map->defer_caching = true;
		map->reg_write = _regmap_bus_raw_write;
	}

skip_format_initialization:

	map->range_tree = RB_ROOT;
	for (i = 0; i < config->num_ranges; i++) {
		const struct regmap_range_cfg *range_cfg = &config->ranges[i];
		struct regmap_range_node *new;

		/* Sanity check */
		if (range_cfg->range_max < range_cfg->range_min) {
			dev_err(map->dev, "Invalid range %d: %d < %d\n", i,
				range_cfg->range_max, range_cfg->range_min);
			goto err_range;
		}

		if (range_cfg->range_max > map->max_register) {
			dev_err(map->dev, "Invalid range %d: %d > %d\n", i,
				range_cfg->range_max, map->max_register);
			goto err_range;
		}

		if (range_cfg->selector_reg > map->max_register) {
			dev_err(map->dev,
				"Invalid range %d: selector out of map\n", i);
			goto err_range;
		}

		if (range_cfg->window_len == 0) {
			dev_err(map->dev, "Invalid range %d: window_len 0\n",
				i);
			goto err_range;
		}

		/* Make sure, that this register range has no selector
		   or data window within its boundary */
		for (j = 0; j < config->num_ranges; j++) {
			unsigned sel_reg = config->ranges[j].selector_reg;
			unsigned win_min = config->ranges[j].window_start;
			unsigned win_max = win_min +
					   config->ranges[j].window_len - 1;

			/* Allow data window inside its own virtual range */
			if (j == i)
				continue;

			if (range_cfg->range_min <= sel_reg &&
			    sel_reg <= range_cfg->range_max) {
				dev_err(map->dev,
					"Range %d: selector for %d in window\n",
					i, j);
				goto err_range;
			}

			if (!(win_max < range_cfg->range_min ||
			      win_min > range_cfg->range_max)) {
				dev_err(map->dev,
					"Range %d: window for %d in window\n",
					i, j);
				goto err_range;
			}
		}

		new = kzalloc(sizeof(*new), GFP_KERNEL);
		if (new == NULL) {
			ret = -ENOMEM;
			goto err_range;
		}

		new->map = map;
		new->name = range_cfg->name;
		new->range_min = range_cfg->range_min;
		new->range_max = range_cfg->range_max;
		new->selector_reg = range_cfg->selector_reg;
		new->selector_mask = range_cfg->selector_mask;
		new->selector_shift = range_cfg->selector_shift;
		new->window_start = range_cfg->window_start;
		new->window_len = range_cfg->window_len;

		if (!_regmap_range_add(map, new)) {
			dev_err(map->dev, "Failed to add range %d\n", i);
			kfree(new);
			goto err_range;
		}

		if (map->selector_work_buf == NULL) {
			map->selector_work_buf =
				kzalloc(map->format.buf_size, GFP_KERNEL);
			if (map->selector_work_buf == NULL) {
				ret = -ENOMEM;
				goto err_range;
			}
		}
	}

	ret = regcache_init(map, config);
	if (ret != 0)
		goto err_range;

	if (dev) {
		ret = regmap_attach_dev(dev, map, config);
		if (ret != 0)
			goto err_regcache;
	}

	return map;

err_regcache:
	regcache_exit(map);
err_range:
	regmap_range_exit(map);
	kfree(map->work_buf);
err_map:
	kfree(map);
err:
	return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(regmap_init);

static void devm_regmap_release(struct device *dev, void *res)
{
	regmap_exit(*(struct regmap **)res);
}

/**
 * devm_regmap_init(): Initialise managed register map
 *
 * @dev: Device that will be interacted with
 * @bus: Bus-specific callbacks to use with device
 * @bus_context: Data passed to bus-specific callbacks
 * @config: Configuration for register map
 *
 * The return value will be an ERR_PTR() on error or a valid pointer
 * to a struct regmap.  This function should generally not be called
 * directly, it should be called by bus-specific init functions.  The
 * map will be automatically freed by the device management code.
 */
struct regmap *devm_regmap_init(struct device *dev,
				const struct regmap_bus *bus,
				void *bus_context,
				const struct regmap_config *config)
{
	struct regmap **ptr, *regmap;

	ptr = devres_alloc(devm_regmap_release, sizeof(*ptr), GFP_KERNEL);
	if (!ptr)
		return ERR_PTR(-ENOMEM);

	regmap = regmap_init(dev, bus, bus_context, config);
	if (!IS_ERR(regmap)) {
		*ptr = regmap;
		devres_add(dev, ptr);
	} else {
		devres_free(ptr);
	}

	return regmap;
}
EXPORT_SYMBOL_GPL(devm_regmap_init);

static void regmap_field_init(struct regmap_field *rm_field,
	struct regmap *regmap, struct reg_field reg_field)
{
	rm_field->regmap = regmap;
	rm_field->reg = reg_field.reg;
	rm_field->shift = reg_field.lsb;
	rm_field->mask = GENMASK(reg_field.msb, reg_field.lsb);
	rm_field->id_size = reg_field.id_size;
	rm_field->id_offset = reg_field.id_offset;
}

/**
 * devm_regmap_field_alloc(): Allocate and initialise a register field
 * in a register map.
 *
 * @dev: Device that will be interacted with
 * @regmap: regmap bank in which this register field is located.
 * @reg_field: Register field with in the bank.
 *
 * The return value will be an ERR_PTR() on error or a valid pointer
 * to a struct regmap_field. The regmap_field will be automatically freed
 * by the device management code.
 */
struct regmap_field *devm_regmap_field_alloc(struct device *dev,
		struct regmap *regmap, struct reg_field reg_field)
{
	struct regmap_field *rm_field = devm_kzalloc(dev,
					sizeof(*rm_field), GFP_KERNEL);
	if (!rm_field)
		return ERR_PTR(-ENOMEM);

	regmap_field_init(rm_field, regmap, reg_field);

	return rm_field;

}
EXPORT_SYMBOL_GPL(devm_regmap_field_alloc);

/**
 * devm_regmap_field_free(): Free register field allocated using
 * devm_regmap_field_alloc. Usally drivers need not call this function,
 * as the memory allocated via devm will be freed as per device-driver
 * life-cyle.
 *
 * @dev: Device that will be interacted with
 * @field: regmap field which should be freed.
 */
void devm_regmap_field_free(struct device *dev,
	struct regmap_field *field)
{
	devm_kfree(dev, field);
}
EXPORT_SYMBOL_GPL(devm_regmap_field_free);

/**
 * regmap_field_alloc(): Allocate and initialise a register field