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linux/drivers/base/regmap/regmap-i2c.c
Jim Wylder 611b7eb19d
regmap-i2c: Subtract reg size from max_write 
Currently, when an adapter defines a max_write_len quirk,
the data will be chunked into data sizes equal to the
max_write_len quirk value.  But the payload will be increased by
the size of the register address before transmission.  The
resulting value always ends up larger than the limit set
by the quirk.

Avoid this error by setting regmap's max_write to the quirk's
max_write_len minus the number of bytes for the register and
padding.  This allows the chunking to work correctly for this
limited case without impacting other use-cases.

Signed-off-by: Jim Wylder <jwylder@google.com>
Link: https://msgid.link/r/20240523211437.2839942-1-jwylder@google.com
Signed-off-by: Mark Brown <broonie@kernel.org>
2024-05-27 01:30:33 +01:00

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// 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 - 1,
.max_raw_write = I2C_SMBUS_BLOCK_MAX - 1,
};
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 - 2,
.max_raw_write = I2C_SMBUS_BLOCK_MAX - 2,
};
static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
const struct regmap_config *config)
{
const struct i2c_adapter_quirks *quirks;
const struct regmap_bus *bus = NULL;
struct regmap_bus *ret_bus;
u16 max_read = 0, max_write = 0;
if (i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C))
bus = &regmap_i2c;
else if (config->val_bits == 8 && config->reg_bits == 8 &&
i2c_check_functionality(i2c->adapter,
I2C_FUNC_SMBUS_I2C_BLOCK))
bus = &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))
bus = &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:
bus = &regmap_smbus_word;
break;
case REGMAP_ENDIAN_BIG:
bus = &regmap_smbus_word_swapped;
break;
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))
bus = &regmap_smbus_byte;
if (!bus)
return ERR_PTR(-ENOTSUPP);
quirks = i2c->adapter->quirks;
if (quirks) {
if (quirks->max_read_len &&
(bus->max_raw_read == 0 || bus->max_raw_read > quirks->max_read_len))
max_read = quirks->max_read_len;
if (quirks->max_write_len &&
(bus->max_raw_write == 0 || bus->max_raw_write > quirks->max_write_len))
max_write = quirks->max_write_len -
(config->reg_bits + config->pad_bits) / BITS_PER_BYTE;
if (max_read || max_write) {
ret_bus = kmemdup(bus, sizeof(*bus), GFP_KERNEL);
if (!ret_bus)
return ERR_PTR(-ENOMEM);
ret_bus->free_on_exit = true;
ret_bus->max_raw_read = max_read;
ret_bus->max_raw_write = max_write;
bus = ret_bus;
}
}
return bus;
}
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");
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