/*
* 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/slab.h>
#include <linux/module.h>
#include <linux/mutex.h>
#include <linux/err.h>
#include <linux/regmap.h>
struct regmap;
struct regmap_format {
size_t buf_size;
size_t reg_bytes;
size_t val_bytes;
void (*format_write)(struct regmap *map,
unsigned int reg, unsigned int val);
void (*format_reg)(void *buf, unsigned int reg);
void (*format_val)(void *buf, unsigned int val);
unsigned int (*parse_val)(void *buf);
};
struct regmap {
struct mutex lock;
struct device *dev; /* Device we do I/O on */
void *work_buf; /* Scratch buffer used to format I/O */
struct regmap_format format; /* Buffer format */
const struct regmap_bus *bus;
};
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_8(void *buf, unsigned int val)
{
u8 *b = buf;
b[0] = val;
}
static void regmap_format_16(void *buf, unsigned int val)
{
__be16 *b = buf;
b[0] = cpu_to_be16(val);
}
static unsigned int regmap_parse_8(void *buf)
{
u8 *b = buf;
return b[0];
}
static unsigned int regmap_parse_16(void *buf)
{
__be16 *b = buf;
b[0] = be16_to_cpu(b[0]);
return b[0];
}
/**
* regmap_init(): Initialise register map
*
* @dev: Device that will be interacted with
* @bus: Bus-specific callbacks to use with device
* @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,
const struct regmap_config *config)
{
struct regmap *map;
int ret = -EINVAL;
if (!bus || !config)
return NULL;
map = kzalloc(sizeof(*map), GFP_KERNEL);
if (map == NULL) {
ret = -ENOMEM;
goto err;
}
mutex_init(&map->lock);
map->format.buf_size = (config->reg_bits + config->val_bits) / 8;
map->format.reg_bytes = config->reg_bits / 8;
map->format.val_bytes = config->val_bits / 8;
map->dev = dev;
map->bus = bus;
switch (config->reg_bits) {
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 8:
map->format.format_reg = regmap_format_8;
break;
case 16:
map->format.format_reg = regmap_format_16;
break;
default:
goto err_map;
}
switch (config->val_bits) {
case 8:
map->format.format_val = regmap_format_8;
map->format.parse_val = regmap_parse_8;
break;
case 16:
map->format.format_val = regmap_format_16;
map->format.parse_val = regmap_parse_16;
break;
}
if (!map->format.format_write &&
!(map->format.format_reg && map->format.format_val))
goto err_map;
map->work_buf = kmalloc(map->format.buf_size, GFP_KERNEL);
if (map->work_buf == NULL) {
ret = -ENOMEM;
goto err_bus;
}
return map;
err_bus:
module_put(map->bus->owner);
err_map:
kfree(map);
err:
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(regmap_init);
/**
* regmap_exit(): Free a previously allocated register map
*/
void regmap_exit(struct regmap *map)
{
kfree(map->work_buf);
module_put(map->bus->owner);
kfree(map);
}
EXPORT_SYMBOL_GPL(regmap_exit);
static int _regmap_raw_write(struct regmap *map, unsigned int reg,
const void *val, size_t val_len)
{
void *buf;
int ret = -ENOTSUPP;
size_t len;
map->format.format_reg(map->work_buf, reg);
/* Try to do a gather write if we can */
if (map->bus->gather_write)
ret = map->bus->gather_write(map->dev, map->work_buf,
map->format.reg_bytes,
val, val_len);
/* Otherwise fall back on linearising by hand. */
if (ret == -ENOTSUPP) {
len = map->format.reg_bytes + val_len;
buf = kmalloc(len, GFP_KERNEL);
if (!buf)
return -ENOMEM;
memcpy(buf, map->work_buf, map->format.reg_bytes);
memcpy(buf + map->format.reg_bytes, val, val_len);
ret = map->bus->write(map->dev, buf, len);
kfree(buf);
}
return ret;
}
static int _regmap_write(struct regmap *map, unsigned int reg,
unsigned int val)
{
BUG_ON(!map->format.format_write && !map->format.format_val);
if (map->format.format_write) {
map->format.format_write(map, reg, val);
return map->bus->write(map->dev, map->work_buf,
map->format.buf_size);
} else {
map->format.format_val(map->work_buf + map->format.reg_bytes,
val);
return _regmap_raw_write(map, reg,
map->work_buf + map->format.reg_bytes,
map->format.val_bytes);
}
}
/**
* regmap_write(): Write a value to a single register
*
* @map: Register map to write to
* @reg: Register to write to
* @val: Value to be written
*
* A value of zero will be returned on success, a negative errno will
* be returned in error cases.
*/
int regmap_write(struct regmap *map, unsigned int reg, unsigned int val)
{
int ret;
mutex_lock(&map->lock);
ret = _regmap_write(map, reg, val);
mutex_unlock(&map->lock);
return ret;
}
EXPORT_SYMBOL_GPL(regmap_write);
/**
* regmap_raw_write(): Write raw values to one or more registers
*
* @map: Register map to write to
* @reg: Initial register to write to
* @val: Block of data to be written, laid out for direct transmission to the
* device
* @val_len: Length of data pointed to by val.
*
* This function is intended to be used for things like firmware
* download where a large block of data needs to be transferred to the
* device. No formatting will be done on the data provided.
*
* A value of zero will be returned on success, a negative errno will
* be returned in error cases.
*/
int regmap_raw_write(struct regmap *map, unsigned int reg,
const void *val, size_t val_len)
{
int ret;
mutex_lock(&map->lock);
ret = _regmap_raw_write(map, reg, val, val_len);
mutex_unlock(&map->lock);
return ret;
}
EXPORT_SYMBOL_GPL(regmap_raw_write);
static int _regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
unsigned int val_len)
{
u8 *u8 = map->work_buf;
int ret;
map->format.format_reg(map->work_buf, reg);
/*
* Some buses flag reads by setting the high bits in the
* register addresss; since it's always the high bits for all
* current formats we can do this here rather than in
* formatting. This may break if we get interesting formats.
*/
if (map->bus->read_flag_mask)
u8[0] |= map->bus->read_flag_mask;
ret = map->bus->read(map->dev, map->work_buf, map->format.reg_bytes,
val, val_len);
if (ret != 0)
return ret;
return 0;
}
static int _regmap_read(struct regmap *map, unsigned int reg,
unsigned int *val)
{
int ret;
if (!map->format.parse_val)
return -EINVAL;
ret = _regmap_raw_read(map, reg, map->work_buf, map->format.val_bytes);
if (ret == 0)
*val = map->format.parse_val(map->work_buf);
return ret;
}
/**
* regmap_read(): Read a value from a single register
*
* @map: Register map to write to
* @reg: Register to be read from
* @val: Pointer to store read value
*
* A value of zero will be returned on success, a negative errno will
* be returned in error cases.
*/
int regmap_read(struct regmap *map, unsigned int reg, unsigned int *val)
{
int ret;
mutex_lock(&map->lock);
ret = _regmap_read(map, reg, val);
mutex_unlock(&map->lock);
return ret;
}
EXPORT_SYMBOL_GPL(regmap_read);
/**
* regmap_raw_read(): Read raw data from the device
*
* @map: Register map to write to
* @reg: First register to be read from
* @val: Pointer to store read value
* @val_len: Size of data to read
*
* A value of zero will be returned on success, a negative errno will
* be returned in error cases.
*/
int regmap_raw_read(struct regmap *map, unsigned int reg, void *val,
size_t val_len)
{
int ret;
mutex_lock(&map->lock);
ret = _regmap_raw_read(map, reg, val, val_len);
mutex_unlock(&map->lock);
return ret;
}
EXPORT_SYMBOL_GPL(regmap_raw_read);
/**
* regmap_bulk_read(): Read multiple registers from the device
*
* @map: Register map to write to
* @reg: First register to be read from
* @val: Pointer to store read value, in native register size for device
* @val_count: Number of registers to read
*
* A value of zero will be returned on success, a negative errno will
* be returned in error cases.
*/
int regmap_bulk_read(struct regmap *map, unsigned int reg, void *val,
size_t val_count)
{
int ret, i;
size_t val_bytes = map->format.val_bytes;
if (!map->format.parse_val)
return -EINVAL;
ret = regmap_raw_read(map, reg, val, val_bytes * val_count);
if (ret != 0)
return ret;
for (i = 0; i < val_count * val_bytes; i += val_bytes)
map->format.parse_val(val + i);
return 0;
}
EXPORT_SYMBOL_GPL(regmap_bulk_read);
/**
* remap_update_bits: Perform a read/modify/write cycle on the register map
*
* @map: Register map to update
* @reg: Register to update
* @mask: Bitmask to change
* @val: New value for bitmask
*
* Returns zero for success, a negative number on error.
*/
int regmap_update_bits(struct regmap *map, unsigned int reg,
unsigned int mask, unsigned int val)
{
int ret;
unsigned int tmp;
mutex_lock(&map->lock);
ret = _regmap_read(map, reg, &tmp);
if (ret != 0)
goto out;
tmp &= ~mask;
tmp |= val & mask;
ret = _regmap_write(map, reg, tmp);
out:
mutex_unlock(&map->lock);
return ret;
}
EXPORT_SYMBOL_GPL(regmap_update_bits);
