fxos8700: Add support for temperature

The fxos8700 is primarily an accelerometer/magnetometer, but it does also include a temperature sensor. Note that the temperature sensor is uncalibrated and can only be used when the magnetometer is enabled (magnetometer-only mode or hybrid mode). Change-Id: I74c4ae68c30e0f9836caa70baed44ad8956b17ea Signed-off-by: Maureen Helm <[email protected]>
inakimalerba · Mar 23, 2017 · 4905e40 · 4905e40
1 parent 1a344ed
commit 4905e40
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diff --git a/drivers/sensor/fxos8700/Kconfig b/drivers/sensor/fxos8700/Kconfig
@@ -57,6 +57,15 @@ config FXOS8700_MODE_HYBRID
 
 endchoice
 
+config FXOS8700_TEMP
+	bool "Enable temperature"
+	depends on FXOS8700 && (FXOS8700_MODE_MAGN || FXOS8700_MODE_HYBRID)
+	default n
+	help
+	Enable the temperature sensor. Note that the temperature sensor is
+	uncalibrated and its output for a given temperature may vary from one
+	device to the next.
+
 choice
 	prompt "Range"
 	depends on FXOS8700

diff --git a/drivers/sensor/fxos8700/fxos8700.c b/drivers/sensor/fxos8700/fxos8700.c
@@ -54,6 +54,15 @@ static int fxos8700_sample_fetch(struct device *dev, enum sensor_channel chan)
 		*raw++ = (buffer[i] << 8) | (buffer[i+1]);
 	}
 
+#ifdef CONFIG_FXOS8700_TEMP
+	if (i2c_reg_read_byte(data->i2c, config->i2c_address, FXOS8700_REG_TEMP,
+			      &data->temp)) {
+		SYS_LOG_ERR("Could not fetch temperature");
+		ret = -EIO;
+		goto exit;
+	}
+#endif
+
 exit:
 	k_sem_give(&data->sem);
 
@@ -100,6 +109,21 @@ static void fxos8700_magn_convert(struct sensor_value *val, int16_t raw)
 	val->val2 = micro_g % 1000000;
 }
 
+#ifdef CONFIG_FXOS8700_TEMP
+static void fxos8700_temp_convert(struct sensor_value *val, int8_t raw)
+{
+	int32_t micro_c;
+
+	/* Convert units to micro Celsius. Raw temperature data always has a
+	 * resolution of 0.96 deg C/LSB.
+	 */
+	micro_c = raw * 960 * 1000;
+
+	val->val1 = micro_c / 1000000;
+	val->val2 = micro_c % 1000000;
+}
+#endif
+
 static int fxos8700_channel_get(struct device *dev, enum sensor_channel chan,
 				struct sensor_value *val)
 {
@@ -191,6 +215,12 @@ static int fxos8700_channel_get(struct device *dev, enum sensor_channel chan,
 		if (num_channels > 0) {
 			ret = 0;
 		}
+#ifdef CONFIG_FXOS8700_TEMP
+		if (chan == SENSOR_CHAN_TEMP) {
+			fxos8700_temp_convert(val, data->temp);
+			ret = 0;
+		}
+#endif
 	}
 
 	if (ret != 0) {

diff --git a/drivers/sensor/fxos8700/fxos8700.h b/drivers/sensor/fxos8700/fxos8700.h
@@ -31,6 +31,7 @@
 #define FXOS8700_REG_CTRLREG4			0x2d
 #define FXOS8700_REG_CTRLREG5			0x2e
 #define FXOS8700_REG_M_OUTXMSB			0x33
+#define FXOS8700_REG_TEMP			0x51
 #define FXOS8700_REG_M_CTRLREG1			0x5b
 #define FXOS8700_REG_M_CTRLREG2			0x5c
 
@@ -131,6 +132,9 @@ struct fxos8700_data {
 	struct device *dev;
 #endif
 	int16_t raw[FXOS8700_MAX_NUM_CHANNELS];
+#ifdef CONFIG_FXOS8700_TEMP
+	int8_t temp;
+#endif
 };
 
 int fxos8700_get_power(struct device *dev, enum fxos8700_power *power);