1 /*
2 * Copyright (c) 2022, Maxmillion McLaughlin
3 * Copyright (c) 2020, SER Consulting LLC / Steven Riedl
4 *
5 * SPDX-License-Identifier: Apache-2.0
6 */
7
8 #define DT_DRV_COMPAT microchip_mcp9600
9
10 #include <zephyr/device.h>
11 #include <zephyr/drivers/i2c.h>
12 #include <zephyr/drivers/sensor.h>
13 #include <zephyr/kernel.h>
14 #include <zephyr/logging/log.h>
15
16 LOG_MODULE_REGISTER(MCP9600, CONFIG_SENSOR_LOG_LEVEL);
17
18 #define MCP9600_REG_TEMP_HOT 0x00
19
20 #define MCP9600_REG_TEMP_DIFF 0x01
21 #define MCP9600_REG_TEMP_COLD 0x02
22 #define MCP9600_REG_RAW_ADC 0x03
23
24 #define MCP9600_REG_STATUS 0x04
25
26 #define MCP9600_REG_TC_CONFIG 0x05
27 #define MCP9600_REG_DEV_CONFIG 0x06
28
29 #define MCP9600_REG_A1_CONFIG 0x08
30 #define MCP9600_REG_A2_CONFIG 0x09
31 #define MCP9600_REG_A3_CONFIG 0x0A
32 #define MCP9600_REG_A4_CONFIG 0x0B
33
34 #define MCP9600_A1_HYST 0x0C
35 #define MCP9600_A2_HYST 0x0D
36 #define MCP9600_A3_HYST 0x0E
37 #define MCP9600_A4_HYST 0x0F
38
39 #define MCP9600_A1_LIMIT 0x10
40 #define MCP9600_A2_LIMIT 0x11
41 #define MCP9600_A3_LIMIT 0x12
42 #define MCP9600_A4_LIMIT 0x13
43
44 #define MCP9600_REG_ID_REVISION 0x20
45
46 struct mcp9600_data {
47 int32_t temp;
48 };
49
50 struct mcp9600_config {
51 const struct i2c_dt_spec bus;
52 };
53
mcp9600_reg_read(const struct device * dev,uint8_t start,uint8_t * buf,int size)54 static int mcp9600_reg_read(const struct device *dev, uint8_t start, uint8_t *buf, int size)
55 {
56 const struct mcp9600_config *cfg = dev->config;
57
58 return i2c_burst_read_dt(&cfg->bus, start, buf, size);
59 }
60
mcp9600_sample_fetch(const struct device * dev,enum sensor_channel chan)61 static int mcp9600_sample_fetch(const struct device *dev, enum sensor_channel chan)
62 {
63 struct mcp9600_data *data = dev->data;
64 uint8_t buf[2];
65 int ret;
66
67 if (chan != SENSOR_CHAN_ALL && chan != SENSOR_CHAN_AMBIENT_TEMP) {
68 LOG_ERR("Unsupported sensor channel");
69 return -ENOTSUP;
70 }
71
72 /* read signed 16 bit double-buffered register value */
73 ret = mcp9600_reg_read(dev, MCP9600_REG_TEMP_HOT, buf, sizeof(buf));
74 if (ret < 0) {
75 data->temp = 1;
76 return ret;
77 }
78
79 /* device's hot junction register is a signed int */
80 data->temp = (int32_t)(int16_t)(buf[0] << 8) | buf[1];
81
82 /* 0.0625C resolution per LSB */
83 data->temp *= 62500;
84
85 return 0;
86 }
87
mcp9600_channel_get(const struct device * dev,enum sensor_channel chan,struct sensor_value * val)88 static int mcp9600_channel_get(const struct device *dev, enum sensor_channel chan,
89 struct sensor_value *val)
90 {
91 struct mcp9600_data *data = dev->data;
92
93 if (chan != SENSOR_CHAN_AMBIENT_TEMP) {
94 return -ENOTSUP;
95 }
96
97 if (data->temp == 1) {
98 return -EINVAL;
99 }
100
101 val->val1 = data->temp / 1000000;
102 val->val2 = data->temp % 1000000;
103
104 return 0;
105 }
106
107 static DEVICE_API(sensor, mcp9600_api) = {
108 .sample_fetch = mcp9600_sample_fetch,
109 .channel_get = mcp9600_channel_get,
110 };
111
mcp9600_init(const struct device * dev)112 static int mcp9600_init(const struct device *dev)
113 {
114 const struct mcp9600_config *cfg = dev->config;
115 uint8_t buf[2];
116 int ret;
117
118 if (!i2c_is_ready_dt(&cfg->bus)) {
119 LOG_ERR("mcp9600 i2c bus %s not ready", cfg->bus.bus->name);
120 return -ENODEV;
121 }
122
123 ret = mcp9600_reg_read(dev, MCP9600_REG_ID_REVISION, buf, sizeof(buf));
124 LOG_DBG("id: 0x%02x version: 0x%02x", buf[0], buf[1]);
125
126 return ret;
127 }
128
129 #define MCP9600_DEFINE(id) \
130 static struct mcp9600_data mcp9600_data_##id; \
131 \
132 static const struct mcp9600_config mcp9600_config_##id = { \
133 .bus = I2C_DT_SPEC_INST_GET(id), \
134 }; \
135 \
136 SENSOR_DEVICE_DT_INST_DEFINE(id, mcp9600_init, NULL, &mcp9600_data_##id, \
137 &mcp9600_config_##id, POST_KERNEL, \
138 CONFIG_SENSOR_INIT_PRIORITY, &mcp9600_api);
139
140 DT_INST_FOREACH_STATUS_OKAY(MCP9600_DEFINE)
141
