thermisor: move header to include dir

Move the "thermistor.h" header to the include/driver/temp_sensor
directory. It is used by the Zephyr shim, so the change is useful to
include the header.

BUG=b:180403276
BRANCH=none
TEST=make buildall

Signed-off-by: Dawid Niedzwiecki <dn@semihalf.com>
Change-Id: I0e83df97e50a3b324440b65ddb900ddf135f2439
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/ec/+/2843323
Reviewed-by: Keith Short <keithshort@chromium.org>
Commit-Queue: Keith Short <keithshort@chromium.org>

1 files changed, 150 insertions, 0 deletions

diff --git a/include/driver/temp_sensor/thermistor.h b/include/driver/temp_sensor/thermistor.h
new file mode 100644
index 0000000000..7ebe2b42ac
--- /dev/null
+++ b/include/driver/temp_sensor/thermistor.h
@@ -0,0 +1,150 @@
+/* Copyright 2015 The Chromium OS Authors. All rights reserved.
+ * Use of this source code is governed by a BSD-style license that can be
+ * found in the LICENSE file.
+ */
+
+/* Thermistor module for Chrome EC */
+
+#ifndef __CROS_EC_TEMP_SENSOR_THERMISTOR_H
+#define __CROS_EC_TEMP_SENSOR_THERMISTOR_H
+
+struct thermistor_data_pair {
+	uint8_t mv;	/* Scaled voltage level at ADC (in mV) */
+	uint8_t temp;	/* Temperature in Celsius */
+};
+
+struct thermistor_info {
+	uint8_t scaling_factor;	/* Scaling factor for voltage in data pair. */
+	uint8_t num_pairs;	/* Number of data pairs. */
+
+	/*
+	 * Values between given data pairs will be calculated as points on
+	 * a line. Pairs can be derived using the Steinhart-Hart equation.
+	 *
+	 * Guidelines for data sets:
+	 * - Must contain at least two pairs.
+	 * - First and last pairs are the max and min.
+	 * - Pairs must be sorted in descending order.
+	 * - 5 pairs should provide reasonable accuracy in most cases. Use
+	 *   points where the slope changes significantly or to recalibrate
+	 *   the algorithm if needed.
+	 */
+	const struct thermistor_data_pair *data;
+};
+
+/**
+ * Calculate temperature using linear interpolation of data points.
+ *
+ * Given a set of datapoints, the algorithm will calculate the "step" in
+ * between each one in order to interpolate missing entries.
+ *
+ * @param mv	Value read from ADC (in millivolts).
+ * @param info	Reference data set and info.
+ *
+ * @return	temperature in C
+ */
+int thermistor_linear_interpolate(uint16_t mv,
+				  const struct thermistor_info *info);
+
+#ifdef CONFIG_THERMISTOR_NCP15WB
+/**
+ * ncp15wb temperature conversion routine.
+ *
+ * @param adc	10bit raw data on adc.
+ *
+ * @return	temperature in C.
+ */
+int ncp15wb_calculate_temp(uint16_t adc);
+#endif /* CONFIG_THERMISTOR_NCP15WB */
+
+#ifdef CONFIG_STEINHART_HART_3V3_13K7_47K_4050B
+/**
+ * Reads the specified ADC channel and uses a lookup table and interpolation to
+ * return a temperature in degrees K.
+ *
+ * The lookup table is based off of a resistor divider circuit on 3.3V with a
+ * 13.7K resistor in series with a thermistor with nominal value of 47K (at 25C)
+ * and a B (25/100) value of 4050.
+ *
+ * @param idx_adc	The idx value from the temp_sensor_t struct, which is
+ *			the ADC channel to read and convert to degrees K
+ * @param temp_ptr	Destination for temperature (in degrees K)
+ *
+ * @return EC_SUCCESS, or non-zero if error.
+ */
+int get_temp_3v3_13k7_47k_4050b(int idx_adc, int *temp_ptr);
+#endif
+
+#ifdef CONFIG_STEINHART_HART_3V3_51K1_47K_4050B
+/**
+ * Reads the specified ADC channel and uses a lookup table and interpolation to
+ * return a temperature in degrees K.
+ *
+ * The lookup table is based off of a resistor divider circuit on 3.3V with a
+ * 51.1K resistor in series with a thermistor with nominal value of 47K (at 25C)
+ * and a B (25/100) value of 4050.
+ *
+ * @param idx_adc	The idx value from the temp_sensor_t struct, which is
+ *			the ADC channel to read and convert to degrees K
+ * @param temp_ptr	Destination for temperature (in degrees K)
+ *
+ * @return EC_SUCCESS, or non-zero if error.
+ */
+int get_temp_3v3_51k1_47k_4050b(int idx_adc, int *temp_ptr);
+#endif
+
+#ifdef CONFIG_STEINHART_HART_6V0_51K1_47K_4050B
+/**
+ * Reads the specified ADC channel and uses a lookup table and interpolation to
+ * return a temperature in degrees K.
+ *
+ * The lookup table is based off of a resistor divider circuit on 6.0V with a
+ * 51.1K resistor in series with a thermistor with nominal value of 47K (at 25C)
+ * and a B (25/100) value of 4050.
+ *
+ * @param idx_adc	The idx value from the temp_sensor_t struct, which is
+ *			the ADC channel to read and convert to degrees K
+ * @param temp_ptr	Destination for temperature (in degrees K)
+ *
+ * @return EC_SUCCESS, or non-zero if error.
+ */
+int get_temp_6v0_51k1_47k_4050b(int idx_adc, int *temp_ptr);
+#endif
+
+#ifdef CONFIG_STEINHART_HART_3V0_22K6_47K_4050B
+/**
+ * Reads the specified ADC channel and uses a lookup table and interpolation to
+ * return a temperature in degrees K.
+ *
+ * The lookup table is based off of a resistor divider circuit on 3V with a
+ * 22.6K resistor in series with a thermistor with nominal value of 47K (at 25C)
+ * and a B (25/100) value of 4050.
+ *
+ * @param idx_adc	The idx value from the temp_sensor_t struct, which is
+ *			the ADC channel to read and convert to degrees K
+ * @param temp_ptr	Destination for temperature (in degrees K)
+ *
+ * @return EC_SUCCESS, or non-zero if error.
+ */
+int get_temp_3v0_22k6_47k_4050b(int idx_adc, int *temp_ptr);
+#endif
+
+#ifdef CONFIG_STEINHART_HART_3V3_30K9_47K_4050B
+/**
+ * Reads the specified ADC channel and uses a lookup table and interpolation to
+ * return a temperature in degrees K.
+ *
+ * The lookup table is based off of a resistor divider circuit on 3.3V with a
+ * 30.9K resistor in series with a thermistor with nominal value of 47K (at 25C)
+ * and a B (25/100) value of 4050.
+ *
+ * @param idx_adc	The idx value from the temp_sensor_t struct, which is
+ *			the ADC channel to read and convert to degrees K
+ * @param temp_ptr	Destination for temperature (in degrees K)
+ *
+ * @return EC_SUCCESS, or non-zero if error.
+ */
+int get_temp_3v3_30k9_47k_4050b(int idx_adc, int *temp_ptr);
+#endif
+
+#endif  /* __CROS_EC_TEMP_SENSOR_THERMISTOR_NCP15WB_H */