135 lines
3.6 KiB
C
135 lines
3.6 KiB
C
/*
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* Copyright (c) 2019 Peter Bigot Consulting, LLC
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* Copyright (c) 2016 Intel Corporation
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#ifndef ZEPHYR_DRIVERS_SENSOR_MCP9808_MCP9808_H_
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#define ZEPHYR_DRIVERS_SENSOR_MCP9808_MCP9808_H_
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#include <errno.h>
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#include <zephyr/types.h>
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#include <device.h>
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#include <drivers/sensor.h>
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#include <sys/util.h>
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#include <drivers/gpio.h>
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#define MCP9808_REG_CONFIG 0x01
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#define MCP9808_REG_UPPER_LIMIT 0x02
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#define MCP9808_REG_LOWER_LIMIT 0x03
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#define MCP9808_REG_CRITICAL 0x04
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#define MCP9808_REG_TEMP_AMB 0x05
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/* 16 bits control configuration and state.
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*
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* * Bit 0 controls alert signal output mode
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* * Bit 1 controls interrupt polarity
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* * Bit 2 disables upper and lower threshold checking
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* * Bit 3 enables alert signal output
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* * Bit 4 records alert status
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* * Bit 5 records interrupt status
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* * Bit 6 locks the upper/lower window registers
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* * Bit 7 locks the critical register
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* * Bit 8 enters shutdown mode
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* * Bits 9-10 control threshold hysteresis
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*/
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#define MCP9808_CFG_ALERT_MODE_INT BIT(0)
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#define MCP9808_CFG_ALERT_ENA BIT(3)
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#define MCP9808_CFG_ALERT_STATE BIT(4)
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#define MCP9808_CFG_INT_CLEAR BIT(5)
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/* 16 bits are used for temperature and state encoding:
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* * Bits 0..11 encode the temperature in a 2s complement signed value
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* in Celsius with 1/16 Cel resolution
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* * Bit 12 is set to indicate a negative temperature
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* * Bit 13 is set to indicate a temperature below the lower threshold
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* * Bit 14 is set to indicate a temperature above the upper threshold
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* * Bit 15 is set to indicate a temperature above the critical threshold
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*/
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#define MCP9808_TEMP_SCALE_CEL 16 /* signed */
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#define MCP9808_TEMP_SIGN_BIT BIT(12)
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#define MCP9808_TEMP_ABS_MASK ((uint16_t)(MCP9808_TEMP_SIGN_BIT - 1U))
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#define MCP9808_TEMP_LWR_BIT BIT(13)
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#define MCP9808_TEMP_UPR_BIT BIT(14)
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#define MCP9808_TEMP_CRT_BIT BIT(15)
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struct mcp9808_data {
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struct device *i2c_master;
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uint16_t reg_val;
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#ifdef CONFIG_MCP9808_TRIGGER
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struct device *alert_gpio;
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struct gpio_callback alert_cb;
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struct device *dev;
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struct sensor_trigger trig;
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sensor_trigger_handler_t trigger_handler;
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#endif
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#ifdef CONFIG_MCP9808_TRIGGER_OWN_THREAD
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struct k_sem sem;
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#endif
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#ifdef CONFIG_MCP9808_TRIGGER_GLOBAL_THREAD
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struct k_work work;
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#endif
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};
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struct mcp9808_config {
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const char *i2c_bus;
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uint16_t i2c_addr;
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#ifdef CONFIG_MCP9808_TRIGGER
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uint8_t alert_pin;
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uint8_t alert_flags;
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const char *alert_controller;
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#endif /* CONFIG_MCP9808_TRIGGER */
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};
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int mcp9808_reg_read(struct device *dev, uint8_t reg, uint16_t *val);
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#ifdef CONFIG_MCP9808_TRIGGER
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int mcp9808_attr_set(struct device *dev, enum sensor_channel chan,
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enum sensor_attribute attr,
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const struct sensor_value *val);
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int mcp9808_trigger_set(struct device *dev,
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const struct sensor_trigger *trig,
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sensor_trigger_handler_t handler);
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int mcp9808_setup_interrupt(struct device *dev);
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#endif /* CONFIG_MCP9808_TRIGGER */
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/* Encode a signed temperature in scaled Celsius to the format used in
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* register values.
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*/
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static inline uint16_t mcp9808_temp_reg_from_signed(int temp)
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{
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/* Get the 12-bit 2s complement value */
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uint16_t rv = temp & MCP9808_TEMP_ABS_MASK;
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if (temp < 0) {
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rv |= MCP9808_TEMP_SIGN_BIT;
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}
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return rv;
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}
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/* Decode a register temperature value to a signed temperature in
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* scaled Celsius.
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*/
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static inline int mcp9808_temp_signed_from_reg(uint16_t reg)
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{
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int rv = reg & MCP9808_TEMP_ABS_MASK;
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if (reg & MCP9808_TEMP_SIGN_BIT) {
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/* Convert 12-bit 2s complement to signed negative
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* value.
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*/
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rv = -(1U + (rv ^ MCP9808_TEMP_ABS_MASK));
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}
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return rv;
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}
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#endif /* ZEPHYR_DRIVERS_SENSOR_MCP9808_MCP9808_H_ */
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