leandrof/linux
1
0
Fork 0
forked from Minki/linux
Code Issues Pull Requests Packages Projects Releases Wiki Activity
a45f1d4331
linux/drivers/base/regmap/regmap-i2c.c
AceLan Kao 82f25bd73c
regmap-i2c: add 16-bit width registers support 
This allows to access data with 16-bit width of registers
via i2c SMBus block functions.

The multi-command sequence of the reading function is not safe
and may read the wrong data from other address if other commands
are sent in-between the SMBus commands in the read function.

Read performance:
   32768 bytes (33 kB, 32 KiB) copied, 11.4869 s, 2.9 kB/s
Write performance(with 1-byte page):
   32768 bytes (33 kB, 32 KiB) copied, 129.591 s, 0.3 kB/s

The implementation is inspired by below commit
https://patchwork.ozlabs.org/patch/545292/

v2: add more descriptions about the issue that maybe introduced
    by this commit

Signed-off-by: AceLan Kao <acelan.kao@canonical.com>
Link: https://lore.kernel.org/r/20200424123358.144850-1-acelan.kao@canonical.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2020-04-24 14:32:07 +01:00

369 lines
8.4 KiB
C
Raw Blame History

// SPDX-License-Identifier: GPL-2.0
//
// Register map access API - I2C support
//
// Copyright 2011 Wolfson Microelectronics plc
//
// Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
#include <linux/regmap.h>
#include <linux/i2c.h>
#include <linux/module.h>
#include "internal.h"
static int regmap_smbus_byte_reg_read(void *context, unsigned int reg,
unsigned int *val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
int ret;
if (reg > 0xff)
return -EINVAL;
ret = i2c_smbus_read_byte_data(i2c, reg);
if (ret < 0)
return ret;
*val = ret;
return 0;
}
static int regmap_smbus_byte_reg_write(void *context, unsigned int reg,
unsigned int val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
if (val > 0xff || reg > 0xff)
return -EINVAL;
return i2c_smbus_write_byte_data(i2c, reg, val);
}
static const struct regmap_bus regmap_smbus_byte = {
.reg_write = regmap_smbus_byte_reg_write,
.reg_read = regmap_smbus_byte_reg_read,
};
static int regmap_smbus_word_reg_read(void *context, unsigned int reg,
unsigned int *val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
int ret;
if (reg > 0xff)
return -EINVAL;
ret = i2c_smbus_read_word_data(i2c, reg);
if (ret < 0)
return ret;
*val = ret;
return 0;
}
static int regmap_smbus_word_reg_write(void *context, unsigned int reg,
unsigned int val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
if (val > 0xffff || reg > 0xff)
return -EINVAL;
return i2c_smbus_write_word_data(i2c, reg, val);
}
static const struct regmap_bus regmap_smbus_word = {
.reg_write = regmap_smbus_word_reg_write,
.reg_read = regmap_smbus_word_reg_read,
};
static int regmap_smbus_word_read_swapped(void *context, unsigned int reg,
unsigned int *val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
int ret;
if (reg > 0xff)
return -EINVAL;
ret = i2c_smbus_read_word_swapped(i2c, reg);
if (ret < 0)
return ret;
*val = ret;
return 0;
}
static int regmap_smbus_word_write_swapped(void *context, unsigned int reg,
unsigned int val)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
if (val > 0xffff || reg > 0xff)
return -EINVAL;
return i2c_smbus_write_word_swapped(i2c, reg, val);
}
static const struct regmap_bus regmap_smbus_word_swapped = {
.reg_write = regmap_smbus_word_write_swapped,
.reg_read = regmap_smbus_word_read_swapped,
};
static int regmap_i2c_write(void *context, const void *data, size_t count)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
int ret;
ret = i2c_master_send(i2c, data, count);
if (ret == count)
return 0;
else if (ret < 0)
return ret;
else
return -EIO;
}
static int regmap_i2c_gather_write(void *context,
const void *reg, size_t reg_size,
const void *val, size_t val_size)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
struct i2c_msg xfer[2];
int ret;
/* If the I2C controller can't do a gather tell the core, it
* will substitute in a linear write for us.
*/
if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART))
return -ENOTSUPP;
xfer[0].addr = i2c->addr;
xfer[0].flags = 0;
xfer[0].len = reg_size;
xfer[0].buf = (void *)reg;
xfer[1].addr = i2c->addr;
xfer[1].flags = I2C_M_NOSTART;
xfer[1].len = val_size;
xfer[1].buf = (void *)val;
ret = i2c_transfer(i2c->adapter, xfer, 2);
if (ret == 2)
return 0;
if (ret < 0)
return ret;
else
return -EIO;
}
static int regmap_i2c_read(void *context,
const void *reg, size_t reg_size,
void *val, size_t val_size)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
struct i2c_msg xfer[2];
int ret;
xfer[0].addr = i2c->addr;
xfer[0].flags = 0;
xfer[0].len = reg_size;
xfer[0].buf = (void *)reg;
xfer[1].addr = i2c->addr;
xfer[1].flags = I2C_M_RD;
xfer[1].len = val_size;
xfer[1].buf = val;
ret = i2c_transfer(i2c->adapter, xfer, 2);
if (ret == 2)
return 0;
else if (ret < 0)
return ret;
else
return -EIO;
}
static const struct regmap_bus regmap_i2c = {
.write = regmap_i2c_write,
.gather_write = regmap_i2c_gather_write,
.read = regmap_i2c_read,
.reg_format_endian_default = REGMAP_ENDIAN_BIG,
.val_format_endian_default = REGMAP_ENDIAN_BIG,
};
static int regmap_i2c_smbus_i2c_write(void *context, const void *data,
size_t count)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
if (count < 1)
return -EINVAL;
--count;
return i2c_smbus_write_i2c_block_data(i2c, ((u8 *)data)[0], count,
((u8 *)data + 1));
}
static int regmap_i2c_smbus_i2c_read(void *context, const void *reg,
size_t reg_size, void *val,
size_t val_size)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
int ret;
if (reg_size != 1 || val_size < 1)
return -EINVAL;
ret = i2c_smbus_read_i2c_block_data(i2c, ((u8 *)reg)[0], val_size, val);
if (ret == val_size)
return 0;
else if (ret < 0)
return ret;
else
return -EIO;
}
static const struct regmap_bus regmap_i2c_smbus_i2c_block = {
.write = regmap_i2c_smbus_i2c_write,
.read = regmap_i2c_smbus_i2c_read,
.max_raw_read = I2C_SMBUS_BLOCK_MAX,
.max_raw_write = I2C_SMBUS_BLOCK_MAX,
};
static int regmap_i2c_smbus_i2c_write_reg16(void *context, const void *data,
size_t count)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
if (count < 2)
return -EINVAL;
count--;
return i2c_smbus_write_i2c_block_data(i2c, ((u8 *)data)[0], count,
(u8 *)data + 1);
}
static int regmap_i2c_smbus_i2c_read_reg16(void *context, const void *reg,
size_t reg_size, void *val,
size_t val_size)
{
struct device *dev = context;
struct i2c_client *i2c = to_i2c_client(dev);
int ret, count, len = val_size;
if (reg_size != 2)
return -EINVAL;
ret = i2c_smbus_write_byte_data(i2c, ((u16 *)reg)[0] & 0xff,
((u16 *)reg)[0] >> 8);
if (ret < 0)
return ret;
count = 0;
do {
/* Current Address Read */
ret = i2c_smbus_read_byte(i2c);
if (ret < 0)
break;
*((u8 *)val++) = ret;
count++;
len--;
} while (len > 0);
if (count == val_size)
return 0;
else if (ret < 0)
return ret;
else
return -EIO;
}
static const struct regmap_bus regmap_i2c_smbus_i2c_block_reg16 = {
.write = regmap_i2c_smbus_i2c_write_reg16,
.read = regmap_i2c_smbus_i2c_read_reg16,
.max_raw_read = I2C_SMBUS_BLOCK_MAX,
.max_raw_write = I2C_SMBUS_BLOCK_MAX,
};
static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
const struct regmap_config *config)
{
if (i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C))
return &regmap_i2c;
else if (config->val_bits == 8 && config->reg_bits == 8 &&
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_I2C_BLOCK))
return &regmap_i2c_smbus_i2c_block;
else if (config->val_bits == 8 && config->reg_bits == 16 &&
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_I2C_BLOCK))
return &regmap_i2c_smbus_i2c_block_reg16;
else if (config->val_bits == 16 && config->reg_bits == 8 &&
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_WORD_DATA))
switch (regmap_get_val_endian(&i2c->dev, NULL, config)) {
case REGMAP_ENDIAN_LITTLE:
return &regmap_smbus_word;
case REGMAP_ENDIAN_BIG:
return &regmap_smbus_word_swapped;
default: /* everything else is not supported */
break;
}
else if (config->val_bits == 8 && config->reg_bits == 8 &&
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_BYTE_DATA))
return &regmap_smbus_byte;
return ERR_PTR(-ENOTSUPP);
}
struct regmap *__regmap_init_i2c(struct i2c_client *i2c,
const struct regmap_config *config,
struct lock_class_key *lock_key,
const char *lock_name)
{
const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
if (IS_ERR(bus))
return ERR_CAST(bus);
return __regmap_init(&i2c->dev, bus, &i2c->dev, config,
lock_key, lock_name);
}
EXPORT_SYMBOL_GPL(__regmap_init_i2c);
struct regmap *__devm_regmap_init_i2c(struct i2c_client *i2c,
const struct regmap_config *config,
struct lock_class_key *lock_key,
const char *lock_name)
{
const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
if (IS_ERR(bus))
return ERR_CAST(bus);
return __devm_regmap_init(&i2c->dev, bus, &i2c->dev, config,
lock_key, lock_name);
}
EXPORT_SYMBOL_GPL(__devm_regmap_init_i2c);
MODULE_LICENSE("GPL");
Reference in New Issue View Git Blame Copy Permalink