Add support for LPS22 pressure sensor.

CMakeLists.txt

@@ -107,6 +107,7 @@ add_executable(fanpico
   src/i2c_bmp180.c
   src/i2c_bmp280.c
   src/i2c_dps310.c
+  src/i2c_lps22.c
   src/i2c_lps25.c
   src/i2c_mcp9808.c
   src/i2c_pct2075.c

commands.md

@@ -1134,7 +1134,8 @@ AS621x||AS621x series: AS6212 (0.2C), AC6214 (0.4C), AC6218 (0.8C)
 BMP180||16bit, 0.5C accuracy
 BMP280|0x76, 0x77|20bit, 0.5C accuracy
 DPS310|0x77, 0x76|24bit, 0.5C accuracy
-LPS25|0x5d|Temperature and Pressure sensor, 2C accuracy
+LPS22|0x5d, 0x5c|Temperature and Pressure sensor
+LPS25|0x5d, 0x5c|Temperature and Pressure sensor, 2C accuracy
 MCP9808||13bit, 0.25C accuracy
 PCT2075||11bit, 1C accuracy
 SHTC3|0x70|Temperature and Humidity sensor, 0.2C accuracy

src/i2c.c

@@ -63,6 +63,11 @@ void* dps310_init(i2c_inst_t *i2c, uint8_t addr);
 int dps310_start_measurement(void *ctx);
 int dps310_get_measurement(void *ctx, float *temp, float *pressure, float *humidity);
 
+/* i2c_lps22.c */
+void* lps22_init(i2c_inst_t *i2c, uint8_t addr);
+int lps22_start_measurement(void *ctx);
+int lps22_get_measurement(void *ctx, float *temp, float *pressure, float *humidity);
+
 /* i2c_lps25.c */
 void* lps25_init(i2c_inst_t *i2c, uint8_t addr);
 int lps25_start_measurement(void *ctx);
@@ -107,6 +112,7 @@ static const i2c_sensor_entry_t i2c_sensor_types[] = {
 	{ "BMP180", bmp180_init, bmp180_start_measurement, bmp180_get_measurement },
 	{ "BMP280", bmp280_init, bmp280_start_measurement, bmp280_get_measurement },
 	{ "DPS310", dps310_init, dps310_start_measurement, dps310_get_measurement },
+	{ "LPS22", lps22_init, lps22_start_measurement, lps22_get_measurement },
 	{ "LPS25", lps25_init, lps25_start_measurement, lps25_get_measurement },
 	{ "MCP9808", mcp9808_init, mcp9808_start_measurement, mcp9808_get_measurement },
 	{ "PCT2075", pct2075_init, pct2075_start_measurement, pct2075_get_measurement },

src/i2c.h

@@ -26,7 +26,7 @@
 
 
 
-#define I2C_DEBUG 1
+#define I2C_DEBUG 0
 
 
 #if I2C_DEBUG > 0

src/i2c_lps22.c

@@ -0,0 +1,168 @@
+/* i2c_lps22.c
+   Copyright (C) 2024 Timo Kokkonen <tjko@iki.fi>
+
+   SPDX-License-Identifier: GPL-3.0-or-later
+
+   This file is part of FanPico.
+
+   FanPico is free software: you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation, either version 3 of the License, or
+   (at your option) any later version.
+
+   FanPico is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with FanPico. If not, see <https://www.gnu.org/licenses/>.
+*/
+
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include "pico/stdlib.h"
+#include "hardware/gpio.h"
+#include "hardware/i2c.h"
+
+#include "i2c.h"
+
+/* LPS22 Registers */
+#define INTERRUPT_CFG    0x0b
+#define THS_P_L          0x0c
+#define THS_P_H          0x0d
+#define IF_CTRL          0x0e
+#define WHO_AM_I         0x0f
+#define CTRL_REG1        0x10
+#define CTRL_REG2        0x11
+#define CTRL_REG3        0x12
+#define FIFO_CTRL        0x13
+#define FIFO_WTM         0x14
+#define REF_P_L          0x15
+#define REF_P_H          0x16
+#define RPDS_L           0x18
+#define RPDS_H           0x19
+#define INT_SOURCE       0x24
+#define FIFO_STATUS1     0x25
+#define FIFO_STATUS2     0x26
+#define STATUS           0x27
+#define PRES_OUT_XL      0x28
+#define PRES_OUT_L       0x29
+#define PRES_OUT_H       0x2a
+#define TEMP_OUT_L       0x2b
+#define TEMP_OUT_H       0x2c
+#define FIFO_DATA_OUT_PRESS_XL 0x78
+#define FIFO_DATA_OUT_PRESS_L  0x79
+#define FIFO_DATA_OUT_PRESS_H  0x7a
+#define FIFO_DATA_OUT_TEMP_L   0x7b
+#define FIFO_DATA_OUT_TEMP_H   0x7c
+
+#define LPS22_DEVICE_ID      0xb1
+
+
+typedef struct lps22_context_t {
+	i2c_inst_t *i2c;
+	uint8_t addr;
+} lps22_context_t;
+
+
+void* lps22_init(i2c_inst_t *i2c, uint8_t addr)
+{
+	int res;
+	uint8_t val = 0;
+	lps22_context_t *ctx = calloc(1, sizeof(lps22_context_t));
+
+	if (!ctx)
+		return NULL;
+	ctx->i2c = i2c;
+	ctx->addr = addr;
+
+	/* Read and verify device ID */
+	res  = i2c_read_register_u8(i2c, addr, WHO_AM_I, &val);
+	if (res || val != LPS22_DEVICE_ID)
+		goto panic;
+
+	/* Reset Sensor */
+	res = i2c_write_register_u8(i2c, addr, CTRL_REG2, 0x04); // SWRESET
+	if (res)
+		goto panic;
+	sleep_us(5);
+	res = i2c_write_register_u8(i2c, addr, CTRL_REG2, 0x92); // BOOT
+	if (res)
+		goto panic;
+	sleep_us(2300);
+
+	/* Read configuration register */
+	res = i2c_read_register_u8(i2c, addr, CTRL_REG2, &val);
+	if (res)
+		goto panic;
+	/* Check that boot is complete */
+	if (val & 0x80)
+		goto panic;
+
+
+	/* Set continuous mode and output data rate (25Hz) */
+	res = i2c_write_register_u8(i2c, addr, CTRL_REG1, 0x3c);
+	if (res)
+		goto panic;
+
+	/* Set FIFO to Continuous mode */
+	res = i2c_write_register_u8(i2c, addr, FIFO_CTRL, 0x03);
+	if (res)
+		goto panic;
+
+	return ctx;
+
+panic:
+	free(ctx);
+	return NULL;
+}
+
+
+int lps22_start_measurement(void *ctx)
+{
+	/* Nothing to do, sensor is in continuous measurement mode... */
+
+	return 1000;  /* measurement should be available after 1s */
+}
+
+
+int lps22_get_measurement(void *ctx, float *temp, float *pressure, float *humidity)
+{
+	lps22_context_t *c = (lps22_context_t*)ctx;
+	int res;
+	uint8_t val;
+	uint8_t buf[5];
+	int32_t t_raw, p_raw;
+
+
+	/* Read status register */
+	res = i2c_read_register_u8(c->i2c, c->addr, STATUS, &val);
+	if (res)
+		return -1;
+
+	/* Check P_DA and T_DA (data available) bits */
+	if ((val & 0x03) != 0x03)
+		return 1;
+
+	/* Get Measurement */
+	res = i2c_read_register_block(c->i2c, c->addr, PRES_OUT_XL, buf, sizeof(buf));
+	if (res)
+		return -2;
+
+	p_raw = twos_complement((uint32_t)((buf[2] << 16) | (buf[1] << 8) | buf[0]), 24);
+	t_raw = twos_complement((uint32_t)(((buf[4] << 8) | buf[3])), 16);
+
+	DEBUG_PRINT("t_raw = %ld, p_raw = %ld\n", t_raw, p_raw);
+
+	*temp = t_raw / 100.0;
+	*pressure = p_raw / 4096.0;
+	*humidity = -1.0;
+
+	DEBUG_PRINT("temp = %0.1f C, pressure = %0.1f hPa\n", *temp, *pressure);
+
+	return 0;
+}
+
+