1 // SPDX-License-Identifier: GPL-2.0
2 /*
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
15 struct 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 before
23 * the actual payload.
24 */
bmi323_regmap_i2c_read(void * context,const void * reg_buf,size_t reg_size,void * val_buf,size_t val_size)25 static 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
bmi323_regmap_i2c_write(void * context,const void * data,size_t count)52 static 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
64 static const struct regmap_bus bmi323_regmap_bus = {
65 .read = bmi323_regmap_i2c_read,
66 .write = bmi323_regmap_i2c_write,
67 };
68
69 static 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
bmi323_i2c_probe(struct i2c_client * i2c)76 static 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
96 static 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 devices
100 * using the bmc150 chip. This creates a conflict with duplicate ACPI
101 * identifiers which multiple drivers want to use. If a non-bmi323
102 * device starts to load with this "BOSC0200" ACPI match here, then the
103 * chip ID check portion should fail because the chip IDs received (via
104 * i2c) are unique between bmc150 and bmi323 and the driver should
105 * relinquish the device. If and when a different driver (such as
106 * bmc150) starts to load with the "BOSC0200" ACPI match, a short reset
107 * should ensure that the device is not in a bad state during that
108 * driver initialization. This device reset does occur in both the
109 * bmi323 and bmc150 init sequences.
110 */
111 { "BOSC0200" },
112 { }
113 };
114 MODULE_DEVICE_TABLE(acpi, bmi323_acpi_match);
115
116 static const struct i2c_device_id bmi323_i2c_ids[] = {
117 { "bmi323" },
118 { }
119 };
120 MODULE_DEVICE_TABLE(i2c, bmi323_i2c_ids);
121
122 static const struct of_device_id bmi323_of_i2c_match[] = {
123 { .compatible = "bosch,bmi323" },
124 { }
125 };
126 MODULE_DEVICE_TABLE(of, bmi323_of_i2c_match);
127
128 static 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 };
138 module_i2c_driver(bmi323_i2c_driver);
139
140 MODULE_DESCRIPTION("Bosch BMI323 IMU driver");
141 MODULE_AUTHOR("Jagath Jog J <jagathjog1996@gmail.com>");
142 MODULE_LICENSE("GPL");
143 MODULE_IMPORT_NS("IIO_BMI323");
144