1 /*
2 * Copyright (c) 2016 Intel Corporation
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #define DT_DRV_COMPAT asahi_kasei_ak8975
8
9 #include <zephyr/device.h>
10 #include <zephyr/drivers/i2c.h>
11 #include <zephyr/kernel.h>
12 #include <zephyr/drivers/sensor.h>
13 #include <zephyr/sys/__assert.h>
14 #include <zephyr/sys/byteorder.h>
15 #include <zephyr/sys/util.h>
16 #include <zephyr/logging/log.h>
17
18 #include "ak8975.h"
19
20 LOG_MODULE_REGISTER(AK8975, CONFIG_SENSOR_LOG_LEVEL);
21
ak8975_sample_fetch(const struct device * dev,enum sensor_channel chan)22 static int ak8975_sample_fetch(const struct device *dev,
23 enum sensor_channel chan)
24 {
25 struct ak8975_data *drv_data = dev->data;
26 const struct ak8975_config *drv_config = dev->config;
27 uint8_t buf[6];
28
29 __ASSERT_NO_MSG(chan == SENSOR_CHAN_ALL);
30
31 if (i2c_reg_write_byte_dt(&drv_config->i2c, AK8975_REG_CNTL, AK8975_MODE_MEASURE) < 0) {
32 LOG_ERR("Failed to start measurement.");
33 return -EIO;
34 }
35
36 k_busy_wait(AK8975_MEASURE_TIME_US);
37
38 if (i2c_burst_read_dt(&drv_config->i2c, AK8975_REG_DATA_START, buf, 6) < 0) {
39 LOG_ERR("Failed to read sample data.");
40 return -EIO;
41 }
42
43 drv_data->x_sample = sys_le16_to_cpu(buf[0] | (buf[1] << 8));
44 drv_data->y_sample = sys_le16_to_cpu(buf[2] | (buf[3] << 8));
45 drv_data->z_sample = sys_le16_to_cpu(buf[4] | (buf[5] << 8));
46
47 return 0;
48 }
49
ak8975_convert(struct sensor_value * val,int16_t sample,uint8_t adjustment)50 static void ak8975_convert(struct sensor_value *val, int16_t sample,
51 uint8_t adjustment)
52 {
53 int32_t conv_val;
54
55 conv_val = sample * AK8975_MICRO_GAUSS_PER_BIT *
56 ((uint16_t)adjustment + 128) / 256;
57 val->val1 = conv_val / 1000000;
58 val->val2 = conv_val % 1000000;
59 }
60
ak8975_channel_get(const struct device * dev,enum sensor_channel chan,struct sensor_value * val)61 static int ak8975_channel_get(const struct device *dev,
62 enum sensor_channel chan,
63 struct sensor_value *val)
64 {
65 struct ak8975_data *drv_data = dev->data;
66
67 __ASSERT_NO_MSG(chan == SENSOR_CHAN_MAGN_XYZ ||
68 chan == SENSOR_CHAN_MAGN_X ||
69 chan == SENSOR_CHAN_MAGN_Y ||
70 chan == SENSOR_CHAN_MAGN_Z);
71
72 if (chan == SENSOR_CHAN_MAGN_XYZ) {
73 ak8975_convert(val, drv_data->x_sample, drv_data->x_adj);
74 ak8975_convert(val + 1, drv_data->y_sample, drv_data->y_adj);
75 ak8975_convert(val + 2, drv_data->z_sample, drv_data->z_adj);
76 } else if (chan == SENSOR_CHAN_MAGN_X) {
77 ak8975_convert(val, drv_data->x_sample, drv_data->x_adj);
78 } else if (chan == SENSOR_CHAN_MAGN_Y) {
79 ak8975_convert(val, drv_data->y_sample, drv_data->y_adj);
80 } else if (chan == SENSOR_CHAN_MAGN_Z) {
81 ak8975_convert(val, drv_data->z_sample, drv_data->z_adj);
82 } else {
83 return -ENOTSUP;
84 }
85
86 return 0;
87 }
88
89 static DEVICE_API(sensor, ak8975_driver_api) = {
90 .sample_fetch = ak8975_sample_fetch,
91 .channel_get = ak8975_channel_get,
92 };
93
ak8975_read_adjustment_data(const struct device * dev)94 static int ak8975_read_adjustment_data(const struct device *dev)
95 {
96 struct ak8975_data *drv_data = dev->data;
97 const struct ak8975_config *drv_config = dev->config;
98 uint8_t buf[3];
99
100 if (i2c_reg_write_byte_dt(&drv_config->i2c, AK8975_REG_CNTL, AK8975_MODE_FUSE_ACCESS) < 0) {
101 LOG_ERR("Failed to set chip in fuse access mode.");
102 return -EIO;
103 }
104
105 if (i2c_burst_read_dt(&drv_config->i2c, AK8975_REG_ADJ_DATA_START, buf, 3) < 0) {
106 LOG_ERR("Failed to read adjustment data.");
107 return -EIO;
108 }
109
110 drv_data->x_adj = buf[0];
111 drv_data->y_adj = buf[1];
112 drv_data->z_adj = buf[2];
113
114 return 0;
115 }
116
ak8975_init(const struct device * dev)117 int ak8975_init(const struct device *dev)
118 {
119 const struct ak8975_config *drv_config = dev->config;
120 uint8_t id;
121
122 if (!device_is_ready(drv_config->i2c.bus)) {
123 LOG_ERR("I2C bus device not ready");
124 return -ENODEV;
125 }
126
127 /* check chip ID */
128 if (i2c_reg_read_byte_dt(&drv_config->i2c, AK8975_REG_CHIP_ID, &id) < 0) {
129 LOG_ERR("Failed to read chip ID.");
130 return -EIO;
131 }
132
133 if (id != AK8975_CHIP_ID) {
134 LOG_ERR("Invalid chip ID.");
135 return -EINVAL;
136 }
137
138 if (ak8975_read_adjustment_data(dev) < 0) {
139 return -EIO;
140 }
141
142 return 0;
143 }
144
145 #define AK8975_DEFINE(inst) \
146 static struct ak8975_data ak8975_data_##inst; \
147 \
148 static const struct ak8975_config ak8975_config_##inst = { \
149 .i2c = I2C_DT_SPEC_INST_GET(inst), \
150 }; \
151 \
152 SENSOR_DEVICE_DT_INST_DEFINE(inst, ak8975_init, NULL, \
153 &ak8975_data_##inst, &ak8975_config_##inst, \
154 POST_KERNEL, CONFIG_SENSOR_INIT_PRIORITY, \
155 &ak8975_driver_api); \
156
157 DT_INST_FOREACH_STATUS_OKAY(AK8975_DEFINE)
158
