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1// SPDX-License-Identifier: GPL-2.02/*3 * I2C driver for Bosch BMI323 6-Axis IMU.4 *5 * Copyright (C) 2023, Jagath Jog J <jagathjog1996@gmail.com>6 */7 8#include <linux/i2c.h>9#include <linux/mod_devicetable.h>10#include <linux/module.h>11#include <linux/regmap.h>12 13#include "bmi323.h"14 15struct bmi323_i2c_priv {16 struct i2c_client *i2c;17 u8 i2c_rx_buffer[BMI323_FIFO_LENGTH_IN_BYTES + BMI323_I2C_DUMMY];18};19 20/*21 * From BMI323 datasheet section 4: Notes on the Serial Interface Support.22 * Each I2C register read operation requires to read two dummy bytes before23 * the actual payload.24 */25static int bmi323_regmap_i2c_read(void *context, const void *reg_buf,26 size_t reg_size, void *val_buf,27 size_t val_size)28{29 struct bmi323_i2c_priv *priv = context;30 struct i2c_msg msgs[2];31 int ret;32 33 msgs[0].addr = priv->i2c->addr;34 msgs[0].flags = priv->i2c->flags;35 msgs[0].len = reg_size;36 msgs[0].buf = (u8 *)reg_buf;37 38 msgs[1].addr = priv->i2c->addr;39 msgs[1].len = val_size + BMI323_I2C_DUMMY;40 msgs[1].buf = priv->i2c_rx_buffer;41 msgs[1].flags = priv->i2c->flags | I2C_M_RD;42 43 ret = i2c_transfer(priv->i2c->adapter, msgs, ARRAY_SIZE(msgs));44 if (ret < 0)45 return -EIO;46 47 memcpy(val_buf, priv->i2c_rx_buffer + BMI323_I2C_DUMMY, val_size);48 49 return 0;50}51 52static int bmi323_regmap_i2c_write(void *context, const void *data,53 size_t count)54{55 struct bmi323_i2c_priv *priv = context;56 u8 reg;57 58 reg = *(u8 *)data;59 return i2c_smbus_write_i2c_block_data(priv->i2c, reg,60 count - sizeof(u8),61 data + sizeof(u8));62}63 64static const struct regmap_bus bmi323_regmap_bus = {65 .read = bmi323_regmap_i2c_read,66 .write = bmi323_regmap_i2c_write,67};68 69static const struct regmap_config bmi323_i2c_regmap_config = {70 .reg_bits = 8,71 .val_bits = 16,72 .max_register = BMI323_CFG_RES_REG,73 .val_format_endian = REGMAP_ENDIAN_LITTLE,74};75 76static int bmi323_i2c_probe(struct i2c_client *i2c)77{78 struct device *dev = &i2c->dev;79 struct bmi323_i2c_priv *priv;80 struct regmap *regmap;81 82 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);83 if (!priv)84 return -ENOMEM;85 86 priv->i2c = i2c;87 regmap = devm_regmap_init(dev, &bmi323_regmap_bus, priv,88 &bmi323_i2c_regmap_config);89 if (IS_ERR(regmap))90 return dev_err_probe(dev, PTR_ERR(regmap),91 "Failed to initialize I2C Regmap\n");92 93 return bmi323_core_probe(dev);94}95 96static const struct acpi_device_id bmi323_acpi_match[] = {97 /*98 * The "BOSC0200" identifier used here is not unique to bmi323 devices.99 * The same "BOSC0200" identifier is found in the ACPI tables of devices100 * using the bmc150 chip. This creates a conflict with duplicate ACPI101 * identifiers which multiple drivers want to use. If a non-bmi323102 * device starts to load with this "BOSC0200" ACPI match here, then the103 * chip ID check portion should fail because the chip IDs received (via104 * i2c) are unique between bmc150 and bmi323 and the driver should105 * relinquish the device. If and when a different driver (such as106 * bmc150) starts to load with the "BOSC0200" ACPI match, a short reset107 * should ensure that the device is not in a bad state during that108 * driver initialization. This device reset does occur in both the109 * bmi323 and bmc150 init sequences.110 */111 { "BOSC0200" },112 { }113};114MODULE_DEVICE_TABLE(acpi, bmi323_acpi_match);115 116static const struct i2c_device_id bmi323_i2c_ids[] = {117 { "bmi323" },118 { }119};120MODULE_DEVICE_TABLE(i2c, bmi323_i2c_ids);121 122static const struct of_device_id bmi323_of_i2c_match[] = {123 { .compatible = "bosch,bmi323" },124 { }125};126MODULE_DEVICE_TABLE(of, bmi323_of_i2c_match);127 128static struct i2c_driver bmi323_i2c_driver = {129 .driver = {130 .name = "bmi323",131 .pm = pm_ptr(&bmi323_core_pm_ops),132 .of_match_table = bmi323_of_i2c_match,133 .acpi_match_table = bmi323_acpi_match,134 },135 .probe = bmi323_i2c_probe,136 .id_table = bmi323_i2c_ids,137};138module_i2c_driver(bmi323_i2c_driver);139 140MODULE_DESCRIPTION("Bosch BMI323 IMU driver");141MODULE_AUTHOR("Jagath Jog J <jagathjog1996@gmail.com>");142MODULE_LICENSE("GPL");143MODULE_IMPORT_NS(IIO_BMI323);144