drivers: added LPS331AP pressure sensor driver

drivers/Makefile

@@ -49,5 +49,8 @@ endif
 ifneq (,$(filter mq3,$(USEMODULE)))
     DIRS += mq3
 endif
+ifneq (,$(filter lps331ap,$(USEMODULE)))
+    DIRS += lps331ap
+endif
 
 include $(RIOTBASE)/Makefile.base

drivers/Makefile.include

@@ -13,3 +13,6 @@ endif
 ifneq (,$(filter isl29020,$(USEMODULE)))
     USEMODULE_INCLUDES += $(RIOTBASE)/drivers/isl29020/include
 endif
+ifneq (,$(filter lps331ap,$(USEMODULE)))
+    USEMODULE_INCLUDES += $(RIOTBASE)/drivers/lps331ap/include
+endif

drivers/include/lps331ap.h

@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @defgroup    driver_lps331ap LPS331AP Pressure Sensor Driver
+ * @ingroup     drivers
+ * @brief       Device driver for the LPS331AP pressure sensor
+ * @{
+ *
+ * @file
+ * @brief       Device driver interface for the LPS331AP pressure sensor
+ *
+ * @note This driver uses the sensors I2C interface
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ */
+
+#ifndef __LPS331AP_H
+#define __LPS331AP_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stdint.h>
+#include "periph/i2c.h"
+
+ /**
+  * @name The sensors default I2C address
+  */
+#define LPS331AP_DEFAULT_ADDRESS        0x5c
+
+/**
+ * @brief Device descriptor for LPS331AP sensors
+ */
+typedef struct {
+    i2c_t i2c;                  /**< I2C device the sensor is connected to */
+    uint8_t address;            /**< I2C bus address of the sensor */
+} lps331ap_t;
+
+/**
+ * @brief Possible sampling rates for LPS331AP sensors
+ */
+typedef enum {
+    LPS331AP_RATE_1HZ = 1,      /**< sample with 1Hz */
+    LPS331AP_RATE_7HZ = 5,      /**< sample with 7Hz */
+    LPS331AP_RATE_12HZ5 = 6,    /**< sample with 12.5Hz */
+    LPS331AP_RATE_25HZ = 7      /**< sample with 25Hz */
+} lps331ap_rate_t;
+
+/**
+ * @brief Initialize a given LPS331AP pressure sensor
+ *
+ * @param[out] dev      device descriptor of the sensor
+ * @param[in]  i2c      I2C bus the sensor is connected to
+ * @param[in]  address  the sensor's address on the I2C bus
+ * @param[in]  rate     internal sampling rate of the sensor
+ *
+ * @return              0 on success
+ * @return              -1 on error
+ */
+int lps331ap_init(lps331ap_t *dev, i2c_t i2c, uint8_t address, lps331ap_rate_t rate);
+
+/**
+ * @brief Read a temperature value from the given sensor, returned in m°C
+ *
+ * @param[in] dev       device descriptor of sensor to read from
+ *
+ * @return              temperature value in m°C
+ */
+int lps331ap_read_temp(lps331ap_t *dev);
+
+/**
+ * @brief Read a pressure value from the given sensor, returned in mbar
+ *
+ * @param[in] dev       device descriptor of sensor to read from
+ *
+ * @return              pressure value in mbar
+ */
+int lps331ap_read_pres(lps331ap_t *dev);
+
+/**
+ * @brief Enable the given sensor
+ *
+ * @param[in] dev       device descriptor of sensor to enable
+ *
+ * @return              0 on success
+ * @return              -1 on error
+ */
+int lps331ap_enable(lps331ap_t *dev);
+
+/**
+ * @brief Disable the given sensor
+ *
+ * @param[in] dev       device descriptor of sensor to disable
+ *
+ * @return              0 on success
+ * @return              -1 on error
+ */
+int lps331ap_disable(lps331ap_t *dev);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LPS331AP_H */
+/** @} */

drivers/lps331ap/Makefile

@@ -0,0 +1,3 @@
+MODULE = lps331ap
+
+include $(RIOTBASE)/Makefile.base

drivers/lps331ap/include/lps331ap-internal.h

@@ -0,0 +1,70 @@
+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     driver_lps331ap
+ * @{
+ *
+ * @file
+ * @brief       Definitions for the LPS331AP pressure sensor
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ */
+
+#ifndef __LPS331AP_INTERNAL_H
+#define __LPS331AP_INTERNAL_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @name LPS331AP registers
+ * @{
+ */
+#define LPS331AP_AUTO_INC               0x80
+#define LPS331AP_REG_REF_P_XL           0x08
+#define LPS331AP_REG_REF_P_L            0x09
+#define LPS331AP_REG_REF_P_H            0x0a
+#define LPS331AP_REG_WHO_AM_I           0x0f
+#define LPS331AP_REG_RES_CONF           0x10
+#define LPS331AP_REG_CTRL_REG1          0x20
+#define LPS331AP_REG_CTRL_REG2          0x21
+#define LPS331AP_REG_CTRL_REG3          0x22
+#define LPS331AP_REG_INT_CFG_REG        0x23
+#define LPS331AP_REG_INT_SOURCE_REG     0x24
+#define LPS331AP_REG_THS_P_LOW_REG      0x25
+#define LPS331AP_REG_THS_P_HIGH_REG     0x26
+#define LPS331AP_REG_STATUS_REG         0x27
+#define LPS331AP_REG_PRESS_OUT_XL       0x28
+#define LPS331AP_REG_PRESS_OUT_L        0x29
+#define LPS331AP_REG_PRESS_OUT_H        0x2a
+#define LPS331AP_REG_TEMP_OUT_L         0x2b
+#define LPS331AP_REG_TEMP_OUT_H         0x2c
+#define LPS331AP_REG_AMP_CTRL           0x30
+/** @} */
+
+/**
+ * @name LPS331AP CTRL_REG1 bitfields
+ * @{
+ */
+#define LPS331AP_CTRL_REG1_PD           0x80
+#define LPS331AP_CTRL_REG1_ODR          0x70
+#define LPS331AP_CTRL_REG1_ODR_POS      4
+#define LPS331AP_CTRL_REG1_DIFF_EN      0x08
+#define LPS331AP_CTRL_REG1_DBDU         0x04
+#define LPS331AP_CTRL_REG1_DELTA_EN     0x02
+#define LPS331AP_CTRL_REG1_SIM          0x01
+/** @} */
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* __LPS331AP_INTERNAL_H */
+/** @} */

drivers/lps331ap/lps331ap.c

@@ -0,0 +1,131 @@
+/*
+ * Copyright (C) 2014 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup     driver_lps331ap
+ * @{
+ *
+ * @file
+ * @brief       Device driver implementation for the LPS331AP pressure sensor
+ *
+ * @note The current driver implementation is very basic and allows only for polling the
+ *       devices temperature and pressure values. Threshold values and interrupts are not
+ *       used.
+ *
+ * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include <stdint.h>
+
+#include "periph/i2c.h"
+#include "lps331ap.h"
+#include "lps331ap-internal.h"
+
+/**
+ * @brief default I2C bus speed for this sensor
+ */
+#define BUS_SPEED           I2C_SPEED_FAST
+
+/**
+ * @brief pressure divider for norming pressure output
+ */
+#define PRES_DIVIDER        (4096U)
+
+/**
+ * @brief temperature base value and divider for norming temperature output
+ */
+#define TEMP_BASE           (42.5f)
+#define TEMP_DIVIDER        (480U)
+
+
+int lps331ap_init(lps331ap_t *dev, i2c_t i2c, uint8_t address, lps331ap_rate_t rate)
+{
+    char tmp;
+
+    /* save device specifics */
+    dev->i2c = i2c;
+    dev->address = address;
+
+    /* initialize underlying I2C bus */
+    if (i2c_init_master(dev->i2c, BUS_SPEED) < 0) {
+        return -1;
+    }
+
+    /* configure device, for simple operation only CTRL_REG1 needs to be touched */
+    tmp = LPS331AP_CTRL_REG1_DBDU | LPS331AP_CTRL_REG1_PD |
+          (rate << LPS331AP_CTRL_REG1_ODR_POS);
+    if (i2c_write_reg(dev->i2c, dev->address, LPS331AP_REG_CTRL_REG1, tmp) != 1) {
+        return -1;
+    }
+
+    return 0;
+}
+
+int lps331ap_read_temp(lps331ap_t *dev)
+{
+    char tmp;
+    int16_t val = 0;
+    float res = TEMP_BASE;      /* reference value -> see datasheet */
+
+    i2c_read_reg(dev->i2c, dev->address, LPS331AP_REG_TEMP_OUT_L, &tmp);
+    val |= tmp;
+    i2c_read_reg(dev->i2c, dev->address, LPS331AP_REG_TEMP_OUT_H, &tmp);
+    val |= (tmp << 8);
+
+    /* compute actual temperature value in °C */
+    res += ((float)val) / TEMP_DIVIDER;
+
+    /* return temperature in m°C */
+    return (int)(res * 1000);
+}
+
+int lps331ap_read_pres(lps331ap_t *dev)
+{
+    char tmp;
+    int32_t val = 0;
+    float res;
+
+    i2c_read_reg(dev->i2c, dev->address, LPS331AP_REG_PRESS_OUT_XL, &tmp);
+    val |= tmp;
+    i2c_read_reg(dev->i2c, dev->address, LPS331AP_REG_PRESS_OUT_L, &tmp);
+    val |= (tmp << 8);
+    i2c_read_reg(dev->i2c, dev->address, LPS331AP_REG_PRESS_OUT_H, &tmp);
+    val |= (tmp << 16);
+    /* see if value is negative */
+    if (tmp & 0x80) {
+        val |= (0xff << 24);
+    }
+
+    /* compute actual pressure value in mbar */
+    res = ((float)val) / PRES_DIVIDER;
+
+    return (int)res;
+}
+
+
+int lps331ap_enable(lps331ap_t *dev)
+{
+    char tmp;
+    if (i2c_read_reg(dev->i2c, dev->address, LPS331AP_REG_CTRL_REG1, &tmp) != 1) {
+        return -1;
+    }
+    tmp |= (LPS331AP_CTRL_REG1_PD);
+    return i2c_write_reg(dev->i2c, dev->address, LPS331AP_REG_CTRL_REG1, tmp);
+}
+
+int lps331ap_disable(lps331ap_t *dev)
+{
+    char tmp;
+    if (i2c_read_reg(dev->i2c, dev->address, LPS331AP_REG_CTRL_REG1, &tmp) != 1) {
+        return -1;
+    }
+    tmp &= ~(LPS331AP_CTRL_REG1_PD);
+    return i2c_write_reg(dev->i2c, dev->address, LPS331AP_REG_CTRL_REG1, tmp);
+}