1 /*
2 * Copyright (c) 2019 Peter Bigot Consulting, LLC
3 * Copyright (c) 2016 Intel Corporation
4 *
5 * SPDX-License-Identifier: Apache-2.0
6 */
7
8 #ifndef ZEPHYR_DRIVERS_SENSOR_MCP9808_MCP9808_H_
9 #define ZEPHYR_DRIVERS_SENSOR_MCP9808_MCP9808_H_
10
11 #include <errno.h>
12
13 #include <zephyr/types.h>
14 #include <zephyr/device.h>
15 #include <zephyr/drivers/sensor.h>
16 #include <zephyr/sys/util.h>
17 #include <zephyr/drivers/i2c.h>
18 #include <zephyr/drivers/gpio.h>
19
20 #define MCP9808_REG_CONFIG 0x01
21 #define MCP9808_REG_UPPER_LIMIT 0x02
22 #define MCP9808_REG_LOWER_LIMIT 0x03
23 #define MCP9808_REG_CRITICAL 0x04
24 #define MCP9808_REG_TEMP_AMB 0x05
25
26 /* 16 bits control configuration and state.
27 *
28 * * Bit 0 controls alert signal output mode
29 * * Bit 1 controls interrupt polarity
30 * * Bit 2 disables upper and lower threshold checking
31 * * Bit 3 enables alert signal output
32 * * Bit 4 records alert status
33 * * Bit 5 records interrupt status
34 * * Bit 6 locks the upper/lower window registers
35 * * Bit 7 locks the critical register
36 * * Bit 8 enters shutdown mode
37 * * Bits 9-10 control threshold hysteresis
38 */
39 #define MCP9808_CFG_ALERT_MODE_INT BIT(0)
40 #define MCP9808_CFG_ALERT_ENA BIT(3)
41 #define MCP9808_CFG_ALERT_STATE BIT(4)
42 #define MCP9808_CFG_INT_CLEAR BIT(5)
43
44 /* 16 bits are used for temperature and state encoding:
45 * * Bits 0..11 encode the temperature in a 2s complement signed value
46 * in Celsius with 1/16 Cel resolution
47 * * Bit 12 is set to indicate a negative temperature
48 * * Bit 13 is set to indicate a temperature below the lower threshold
49 * * Bit 14 is set to indicate a temperature above the upper threshold
50 * * Bit 15 is set to indicate a temperature above the critical threshold
51 */
52 #define MCP9808_TEMP_SCALE_CEL 16 /* signed */
53 #define MCP9808_TEMP_SIGN_BIT BIT(12)
54 #define MCP9808_TEMP_ABS_MASK ((uint16_t)(MCP9808_TEMP_SIGN_BIT - 1U))
55 #define MCP9808_TEMP_LWR_BIT BIT(13)
56 #define MCP9808_TEMP_UPR_BIT BIT(14)
57 #define MCP9808_TEMP_CRT_BIT BIT(15)
58
59 #define MCP9808_REG_RESOLUTION 0x08
60
61 struct mcp9808_data {
62 uint16_t reg_val;
63
64 #ifdef CONFIG_MCP9808_TRIGGER
65 struct gpio_callback alert_cb;
66
67 const struct device *dev;
68
69 const struct sensor_trigger *trig;
70 sensor_trigger_handler_t trigger_handler;
71 #endif
72
73 #ifdef CONFIG_MCP9808_TRIGGER_OWN_THREAD
74 struct k_sem sem;
75 #endif
76
77 #ifdef CONFIG_MCP9808_TRIGGER_GLOBAL_THREAD
78 struct k_work work;
79 #endif
80 };
81
82 struct mcp9808_config {
83 struct i2c_dt_spec i2c;
84 uint8_t resolution;
85 #ifdef CONFIG_MCP9808_TRIGGER
86 struct gpio_dt_spec int_gpio;
87 #endif /* CONFIG_MCP9808_TRIGGER */
88 };
89
90 int mcp9808_reg_read(const struct device *dev, uint8_t reg, uint16_t *val);
91 int mcp9808_reg_write_16bit(const struct device *dev, uint8_t reg,
92 uint16_t val);
93 int mcp9808_reg_write_8bit(const struct device *dev, uint8_t reg,
94 uint8_t val);
95
96 #ifdef CONFIG_MCP9808_TRIGGER
97 int mcp9808_attr_set(const struct device *dev, enum sensor_channel chan,
98 enum sensor_attribute attr,
99 const struct sensor_value *val);
100 int mcp9808_trigger_set(const struct device *dev,
101 const struct sensor_trigger *trig,
102 sensor_trigger_handler_t handler);
103 int mcp9808_setup_interrupt(const struct device *dev);
104 #endif /* CONFIG_MCP9808_TRIGGER */
105
106 /* Encode a signed temperature in scaled Celsius to the format used in
107 * register values.
108 */
mcp9808_temp_reg_from_signed(int temp)109 static inline uint16_t mcp9808_temp_reg_from_signed(int temp)
110 {
111 /* Get the 12-bit 2s complement value */
112 uint16_t rv = temp & MCP9808_TEMP_ABS_MASK;
113
114 if (temp < 0) {
115 rv |= MCP9808_TEMP_SIGN_BIT;
116 }
117 return rv;
118 }
119
120 /* Decode a register temperature value to a signed temperature in
121 * scaled Celsius.
122 */
mcp9808_temp_signed_from_reg(uint16_t reg)123 static inline int mcp9808_temp_signed_from_reg(uint16_t reg)
124 {
125 int rv = reg & MCP9808_TEMP_ABS_MASK;
126
127 if (reg & MCP9808_TEMP_SIGN_BIT) {
128 /* Convert 12-bit 2s complement to signed negative
129 * value.
130 */
131 rv = -(1U + (rv ^ MCP9808_TEMP_ABS_MASK));
132 }
133 return rv;
134 }
135
136 #endif /* ZEPHYR_DRIVERS_SENSOR_MCP9808_MCP9808_H_ */
137
