From a7d9547d5e266fe5683469eca301c82bc5aaee3a Mon Sep 17 00:00:00 2001
From: smlng <s@mlng.net>
Date: Sun, 2 Jul 2017 11:28:15 +0200
Subject: [PATCH] driver, lsm6dsl: fix temperature reading
---
drivers/include/lsm6dsl.h | 6 +++++-
drivers/lsm6dsl/include/lsm6dsl_internal.h | 5 +++++
drivers/lsm6dsl/lsm6dsl.c | 25 ++++++++++++----------
3 files changed, 24 insertions(+), 12 deletions(-)
diff --git a/drivers/include/lsm6dsl.h b/drivers/include/lsm6dsl.h
index 5feebd88ac..650875b37f 100644
--- a/drivers/include/lsm6dsl.h
+++ b/drivers/include/lsm6dsl.h
@@ -132,8 +132,12 @@ int lsm6dsl_read_gyro(const lsm6dsl_t *dev, lsm6dsl_3d_data_t *data);
/**
* @brief Read temperature data
*
+ * @note To avoid floating point data types but still provide high resolution
+ * for temperature readings, resulting values are scale by factor 100.
+ *
+ *
* @param[in] dev device to read
- * @param[out] data temperature value
+ * @param[out] data temperature value, in °C x 100
*
* @return 0 on success
* @return < 0 on error
diff --git a/drivers/lsm6dsl/include/lsm6dsl_internal.h b/drivers/lsm6dsl/include/lsm6dsl_internal.h
index 7d112db207..e241a86210 100644
--- a/drivers/lsm6dsl/include/lsm6dsl_internal.h
+++ b/drivers/lsm6dsl/include/lsm6dsl_internal.h
@@ -149,6 +149,11 @@ extern "C" {
#define LSM6DSL_FIFO_CTRL3_GYRO_DEC_SHIFT (3)
/** @} */
+/**
+ * @brief Offset for temperature calculation
+ */
+#define LSM6DSL_TEMP_OFFSET (0x1900)
+
#ifdef __cplusplus
}
#endif
diff --git a/drivers/lsm6dsl/lsm6dsl.c b/drivers/lsm6dsl/lsm6dsl.c
index a641ab7c94..ee3cb5a519 100644
--- a/drivers/lsm6dsl/lsm6dsl.c
+++ b/drivers/lsm6dsl/lsm6dsl.c
@@ -198,21 +198,24 @@ int lsm6dsl_read_gyro(const lsm6dsl_t *dev, lsm6dsl_3d_data_t *data)
int lsm6dsl_read_temp(const lsm6dsl_t *dev, int16_t *data)
{
- int res;
uint8_t tmp;
-
+ uint16_t traw;
+ /* read raw temperature */
i2c_acquire(dev->params.i2c);
- res = i2c_read_reg(dev->params.i2c, dev->params.addr, LSM6DSL_REG_OUT_TEMP_L, &tmp);
- *data = tmp;
-
- res += i2c_read_reg(dev->params.i2c, dev->params.addr, LSM6DSL_REG_OUT_TEMP_H, &tmp);
- *data |= tmp << 8;
-
- i2c_release(dev->params.i2c);
-
- if (res < 2) {
+ if (i2c_read_reg(dev->params.i2c, dev->params.addr, LSM6DSL_REG_OUT_TEMP_L, &tmp) != 1) {
+ i2c_release(dev->params.i2c);
return -1;
}
+ traw = tmp;
+ if (i2c_read_reg(dev->params.i2c, dev->params.addr, LSM6DSL_REG_OUT_TEMP_H, &tmp) != 1) {
+ i2c_release(dev->params.i2c);
+ return -1;
+ }
+ traw |= (uint16_t)tmp << 8;
+ i2c_release(dev->params.i2c);
+ /* convert temperature */
+ traw += LSM6DSL_TEMP_OFFSET;
+ *data = (int16_t)(((int32_t)traw * 100) / 256);
return 0;
}
--
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