mirror of
https://github.com/torvalds/linux
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0c9d2eb5e9
The SMBus I2C buses have limits on the size of transfers they can do but do not factor in the register length meaning we may try to do a transfer longer than our length limit, the core will not take care of this. Future changes will factor this out into the core but there are a number of users that assume current behaviour so let's just do something conservative here. This does not take account padding bits but practically speaking these are very rarely if ever used on I2C buses given that they generally run slowly enough to mean there's no issue. Cc: stable@kernel.org Signed-off-by: Mark Brown <broonie@kernel.org> Reviewed-by: Xu Yilun <yilun.xu@intel.com> Link: https://lore.kernel.org/r/20230712-regmap-max-transfer-v1-2-80e2aed22e83@kernel.org Signed-off-by: Mark Brown <broonie@kernel.org>
400 lines
9.2 KiB
C
400 lines
9.2 KiB
C
// SPDX-License-Identifier: GPL-2.0
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//
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// Register map access API - I2C support
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//
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// Copyright 2011 Wolfson Microelectronics plc
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//
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// Author: Mark Brown <broonie@opensource.wolfsonmicro.com>
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#include <linux/regmap.h>
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#include <linux/i2c.h>
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#include <linux/module.h>
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#include "internal.h"
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static int regmap_smbus_byte_reg_read(void *context, unsigned int reg,
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unsigned int *val)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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int ret;
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if (reg > 0xff)
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return -EINVAL;
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ret = i2c_smbus_read_byte_data(i2c, reg);
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if (ret < 0)
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return ret;
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*val = ret;
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return 0;
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}
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static int regmap_smbus_byte_reg_write(void *context, unsigned int reg,
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unsigned int val)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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if (val > 0xff || reg > 0xff)
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return -EINVAL;
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return i2c_smbus_write_byte_data(i2c, reg, val);
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}
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static const struct regmap_bus regmap_smbus_byte = {
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.reg_write = regmap_smbus_byte_reg_write,
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.reg_read = regmap_smbus_byte_reg_read,
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};
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static int regmap_smbus_word_reg_read(void *context, unsigned int reg,
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unsigned int *val)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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int ret;
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if (reg > 0xff)
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return -EINVAL;
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ret = i2c_smbus_read_word_data(i2c, reg);
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if (ret < 0)
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return ret;
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*val = ret;
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return 0;
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}
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static int regmap_smbus_word_reg_write(void *context, unsigned int reg,
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unsigned int val)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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if (val > 0xffff || reg > 0xff)
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return -EINVAL;
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return i2c_smbus_write_word_data(i2c, reg, val);
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}
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static const struct regmap_bus regmap_smbus_word = {
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.reg_write = regmap_smbus_word_reg_write,
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.reg_read = regmap_smbus_word_reg_read,
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};
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static int regmap_smbus_word_read_swapped(void *context, unsigned int reg,
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unsigned int *val)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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int ret;
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if (reg > 0xff)
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return -EINVAL;
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ret = i2c_smbus_read_word_swapped(i2c, reg);
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if (ret < 0)
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return ret;
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*val = ret;
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return 0;
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}
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static int regmap_smbus_word_write_swapped(void *context, unsigned int reg,
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unsigned int val)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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if (val > 0xffff || reg > 0xff)
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return -EINVAL;
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return i2c_smbus_write_word_swapped(i2c, reg, val);
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}
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static const struct regmap_bus regmap_smbus_word_swapped = {
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.reg_write = regmap_smbus_word_write_swapped,
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.reg_read = regmap_smbus_word_read_swapped,
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};
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static int regmap_i2c_write(void *context, const void *data, size_t count)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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int ret;
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ret = i2c_master_send(i2c, data, count);
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if (ret == count)
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return 0;
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else if (ret < 0)
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return ret;
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else
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return -EIO;
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}
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static int regmap_i2c_gather_write(void *context,
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const void *reg, size_t reg_size,
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const void *val, size_t val_size)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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struct i2c_msg xfer[2];
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int ret;
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/* If the I2C controller can't do a gather tell the core, it
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* will substitute in a linear write for us.
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*/
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if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_NOSTART))
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return -ENOTSUPP;
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xfer[0].addr = i2c->addr;
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xfer[0].flags = 0;
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xfer[0].len = reg_size;
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xfer[0].buf = (void *)reg;
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xfer[1].addr = i2c->addr;
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xfer[1].flags = I2C_M_NOSTART;
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xfer[1].len = val_size;
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xfer[1].buf = (void *)val;
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ret = i2c_transfer(i2c->adapter, xfer, 2);
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if (ret == 2)
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return 0;
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if (ret < 0)
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return ret;
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else
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return -EIO;
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}
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static int regmap_i2c_read(void *context,
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const void *reg, size_t reg_size,
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void *val, size_t val_size)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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struct i2c_msg xfer[2];
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int ret;
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xfer[0].addr = i2c->addr;
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xfer[0].flags = 0;
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xfer[0].len = reg_size;
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xfer[0].buf = (void *)reg;
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xfer[1].addr = i2c->addr;
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xfer[1].flags = I2C_M_RD;
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xfer[1].len = val_size;
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xfer[1].buf = val;
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ret = i2c_transfer(i2c->adapter, xfer, 2);
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if (ret == 2)
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return 0;
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else if (ret < 0)
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return ret;
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else
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return -EIO;
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}
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static const struct regmap_bus regmap_i2c = {
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.write = regmap_i2c_write,
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.gather_write = regmap_i2c_gather_write,
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.read = regmap_i2c_read,
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.reg_format_endian_default = REGMAP_ENDIAN_BIG,
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.val_format_endian_default = REGMAP_ENDIAN_BIG,
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};
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static int regmap_i2c_smbus_i2c_write(void *context, const void *data,
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size_t count)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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if (count < 1)
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return -EINVAL;
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--count;
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return i2c_smbus_write_i2c_block_data(i2c, ((u8 *)data)[0], count,
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((u8 *)data + 1));
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}
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static int regmap_i2c_smbus_i2c_read(void *context, const void *reg,
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size_t reg_size, void *val,
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size_t val_size)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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int ret;
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if (reg_size != 1 || val_size < 1)
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return -EINVAL;
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ret = i2c_smbus_read_i2c_block_data(i2c, ((u8 *)reg)[0], val_size, val);
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if (ret == val_size)
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return 0;
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else if (ret < 0)
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return ret;
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else
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return -EIO;
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}
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static const struct regmap_bus regmap_i2c_smbus_i2c_block = {
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.write = regmap_i2c_smbus_i2c_write,
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.read = regmap_i2c_smbus_i2c_read,
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.max_raw_read = I2C_SMBUS_BLOCK_MAX - 1,
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.max_raw_write = I2C_SMBUS_BLOCK_MAX - 1,
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};
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static int regmap_i2c_smbus_i2c_write_reg16(void *context, const void *data,
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size_t count)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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if (count < 2)
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return -EINVAL;
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count--;
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return i2c_smbus_write_i2c_block_data(i2c, ((u8 *)data)[0], count,
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(u8 *)data + 1);
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}
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static int regmap_i2c_smbus_i2c_read_reg16(void *context, const void *reg,
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size_t reg_size, void *val,
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size_t val_size)
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{
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struct device *dev = context;
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struct i2c_client *i2c = to_i2c_client(dev);
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int ret, count, len = val_size;
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if (reg_size != 2)
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return -EINVAL;
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ret = i2c_smbus_write_byte_data(i2c, ((u16 *)reg)[0] & 0xff,
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((u16 *)reg)[0] >> 8);
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if (ret < 0)
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return ret;
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count = 0;
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do {
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/* Current Address Read */
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ret = i2c_smbus_read_byte(i2c);
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if (ret < 0)
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break;
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*((u8 *)val++) = ret;
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count++;
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len--;
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} while (len > 0);
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if (count == val_size)
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return 0;
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else if (ret < 0)
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return ret;
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else
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return -EIO;
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}
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static const struct regmap_bus regmap_i2c_smbus_i2c_block_reg16 = {
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.write = regmap_i2c_smbus_i2c_write_reg16,
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.read = regmap_i2c_smbus_i2c_read_reg16,
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.max_raw_read = I2C_SMBUS_BLOCK_MAX - 2,
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.max_raw_write = I2C_SMBUS_BLOCK_MAX - 2,
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};
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static const struct regmap_bus *regmap_get_i2c_bus(struct i2c_client *i2c,
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const struct regmap_config *config)
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{
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const struct i2c_adapter_quirks *quirks;
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const struct regmap_bus *bus = NULL;
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struct regmap_bus *ret_bus;
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u16 max_read = 0, max_write = 0;
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if (i2c_check_functionality(i2c->adapter, I2C_FUNC_I2C))
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bus = ®map_i2c;
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else if (config->val_bits == 8 && config->reg_bits == 8 &&
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i2c_check_functionality(i2c->adapter,
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I2C_FUNC_SMBUS_I2C_BLOCK))
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bus = ®map_i2c_smbus_i2c_block;
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else if (config->val_bits == 8 && config->reg_bits == 16 &&
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i2c_check_functionality(i2c->adapter,
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I2C_FUNC_SMBUS_I2C_BLOCK))
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bus = ®map_i2c_smbus_i2c_block_reg16;
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else if (config->val_bits == 16 && config->reg_bits == 8 &&
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i2c_check_functionality(i2c->adapter,
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I2C_FUNC_SMBUS_WORD_DATA))
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switch (regmap_get_val_endian(&i2c->dev, NULL, config)) {
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case REGMAP_ENDIAN_LITTLE:
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bus = ®map_smbus_word;
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break;
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case REGMAP_ENDIAN_BIG:
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bus = ®map_smbus_word_swapped;
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break;
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default: /* everything else is not supported */
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break;
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}
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else if (config->val_bits == 8 && config->reg_bits == 8 &&
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i2c_check_functionality(i2c->adapter,
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I2C_FUNC_SMBUS_BYTE_DATA))
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bus = ®map_smbus_byte;
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if (!bus)
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return ERR_PTR(-ENOTSUPP);
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quirks = i2c->adapter->quirks;
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if (quirks) {
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if (quirks->max_read_len &&
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(bus->max_raw_read == 0 || bus->max_raw_read > quirks->max_read_len))
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max_read = quirks->max_read_len;
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if (quirks->max_write_len &&
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(bus->max_raw_write == 0 || bus->max_raw_write > quirks->max_write_len))
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max_write = quirks->max_write_len;
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if (max_read || max_write) {
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ret_bus = kmemdup(bus, sizeof(*bus), GFP_KERNEL);
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if (!ret_bus)
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return ERR_PTR(-ENOMEM);
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ret_bus->free_on_exit = true;
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ret_bus->max_raw_read = max_read;
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ret_bus->max_raw_write = max_write;
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bus = ret_bus;
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}
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}
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return bus;
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}
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struct regmap *__regmap_init_i2c(struct i2c_client *i2c,
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const struct regmap_config *config,
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struct lock_class_key *lock_key,
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const char *lock_name)
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{
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const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
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if (IS_ERR(bus))
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return ERR_CAST(bus);
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return __regmap_init(&i2c->dev, bus, &i2c->dev, config,
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lock_key, lock_name);
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}
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EXPORT_SYMBOL_GPL(__regmap_init_i2c);
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struct regmap *__devm_regmap_init_i2c(struct i2c_client *i2c,
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const struct regmap_config *config,
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struct lock_class_key *lock_key,
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const char *lock_name)
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{
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const struct regmap_bus *bus = regmap_get_i2c_bus(i2c, config);
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if (IS_ERR(bus))
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return ERR_CAST(bus);
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return __devm_regmap_init(&i2c->dev, bus, &i2c->dev, config,
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lock_key, lock_name);
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}
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EXPORT_SYMBOL_GPL(__devm_regmap_init_i2c);
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MODULE_LICENSE("GPL");
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