// SPDX-License-Identifier: GPL-2.0
/*
* I2C driver for Bosch BMI323 6-Axis IMU.
*
* Copyright (C) 2023, Jagath Jog J <[email protected]>
*/
#include <linux/i2c.h>
#include <linux/mod_devicetable.h>
#include <linux/module.h>
#include <linux/regmap.h>
#include "bmi323.h"
struct bmi323_i2c_priv {
struct i2c_client *i2c;
u8 i2c_rx_buffer[BMI323_FIFO_LENGTH_IN_BYTES + BMI323_I2C_DUMMY];
};
/*
* From BMI323 datasheet section 4: Notes on the Serial Interface Support.
* Each I2C register read operation requires to read two dummy bytes before
* the actual payload.
*/
static int bmi323_regmap_i2c_read(void *context, const void *reg_buf,
size_t reg_size, void *val_buf,
size_t val_size)
{
struct bmi323_i2c_priv *priv = context;
struct i2c_msg msgs[2];
int ret;
msgs[0].addr = priv->i2c->addr;
msgs[0].flags = priv->i2c->flags;
msgs[0].len = reg_size;
msgs[0].buf = (u8 *)reg_buf;
msgs[1].addr = priv->i2c->addr;
msgs[1].len = val_size + BMI323_I2C_DUMMY;
msgs[1].buf = priv->i2c_rx_buffer;
msgs[1].flags = priv->i2c->flags | I2C_M_RD;
ret = i2c_transfer(priv->i2c->adapter, msgs, ARRAY_SIZE(msgs));
if (ret < 0)
return -EIO;
memcpy(val_buf, priv->i2c_rx_buffer + BMI323_I2C_DUMMY, val_size);
return 0;
}
static int bmi323_regmap_i2c_write(void *context, const void *data,
size_t count)
{
struct bmi323_i2c_priv *priv = context;
u8 reg;
reg = *(u8 *)data;
return i2c_smbus_write_i2c_block_data(priv->i2c, reg,
count - sizeof(u8),
data + sizeof(u8));
}
static const struct regmap_bus bmi323_regmap_bus = {
.read = bmi323_regmap_i2c_read,
.write = bmi323_regmap_i2c_write,
};
static const struct regmap_config bmi323_i2c_regmap_config = {
.reg_bits = 8,
.val_bits = 16,
.max_register = BMI323_CFG_RES_REG,
.val_format_endian = REGMAP_ENDIAN_LITTLE,
};
static int bmi323_i2c_probe(struct i2c_client *i2c)
{
struct device *dev = &i2c->dev;
struct bmi323_i2c_priv *priv;
struct regmap *regmap;
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
priv->i2c = i2c;
regmap = devm_regmap_init(dev, &bmi323_regmap_bus, priv,
&bmi323_i2c_regmap_config);
if (IS_ERR(regmap))
return dev_err_probe(dev, PTR_ERR(regmap),
"Failed to initialize I2C Regmap\n");
return bmi323_core_probe(dev);
}
static const struct acpi_device_id bmi323_acpi_match[] = {
/*
* The "BOSC0200" identifier used here is not unique to bmi323 devices.
* The same "BOSC0200" identifier is found in the ACPI tables of devices
* using the bmc150 chip. This creates a conflict with duplicate ACPI
* identifiers which multiple drivers want to use. If a non-bmi323
* device starts to load with this "BOSC0200" ACPI match here, then the
* chip ID check portion should fail because the chip IDs received (via
* i2c) are unique between bmc150 and bmi323 and the driver should
* relinquish the device. If and when a different driver (such as
* bmc150) starts to load with the "BOSC0200" ACPI match, a short reset
* should ensure that the device is not in a bad state during that
* driver initialization. This device reset does occur in both the
* bmi323 and bmc150 init sequences.
*/
{ "BOSC0200" },
{ }
};
MODULE_DEVICE_TABLE(acpi, bmi323_acpi_match);
static const struct i2c_device_id bmi323_i2c_ids[] = {
{ "bmi323" },
{ }
};
MODULE_DEVICE_TABLE(i2c, bmi323_i2c_ids);
static const struct of_device_id bmi323_of_i2c_match[] = {
{ .compatible = "bosch,bmi323" },
{ }
};
MODULE_DEVICE_TABLE(of, bmi323_of_i2c_match);
static struct i2c_driver bmi323_i2c_driver = {
.driver = {
.name = "bmi323",
.pm = pm_ptr(&bmi323_core_pm_ops),
.of_match_table = bmi323_of_i2c_match,
.acpi_match_table = bmi323_acpi_match,
},
.probe = bmi323_i2c_probe,
.id_table = bmi323_i2c_ids,
};
module_i2c_driver(bmi323_i2c_driver);
MODULE_DESCRIPTION("Bosch BMI323 IMU driver");
MODULE_AUTHOR("Jagath Jog J <[email protected]>");
MODULE_LICENSE("GPL");
MODULE_IMPORT_NS(IIO_BMI323);
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