/* SPDX-License-Identifier: GPL-2.0-only */ /* gain-time-scale conversion helpers for IIO light sensors * * Copyright (c) 2023 Matti Vaittinen <[email protected]> */ #ifndef __IIO_GTS_HELPER__ #define __IIO_GTS_HELPER__ #include <linux/types.h> struct device; /** * struct iio_gain_sel_pair - gain - selector values * * In many cases devices like light sensors allow setting signal amplification * (gain) using a register interface. This structure describes amplification * and corresponding selector (register value) * * @gain: Gain (multiplication) value. Gain must be positive, negative * values are reserved for error handling. * @sel: Selector (usually register value) used to indicate this gain. * NOTE: Only selectors >= 0 supported. */ struct iio_gain_sel_pair { … }; /** * struct iio_itime_sel_mul - integration time description * * In many cases devices like light sensors allow setting the duration of * collecting data. Typically this duration has also an impact to the magnitude * of measured values (gain). This structure describes the relation of * integration time and amplification as well as corresponding selector * (register value). * * An example could be a sensor allowing 50, 100, 200 and 400 mS times. The * respective multiplication values could be 50 mS => 1, 100 mS => 2, * 200 mS => 4 and 400 mS => 8 assuming the impact of integration time would be * linear in a way that when collecting data for 50 mS caused value X, doubling * the data collection time caused value 2X etc. * * @time_us: Integration time in microseconds. Time values must be positive, * negative values are reserved for error handling. * @sel: Selector (usually register value) used to indicate this time * NOTE: Only selectors >= 0 supported. * @mul: Multiplication to the values caused by this time. * NOTE: Only multipliers > 0 supported. */ struct iio_itime_sel_mul { … }; struct iio_gts { … }; #define GAIN_SCALE_GAIN(_gain, _sel) … #define GAIN_SCALE_ITIME_US(_itime, _sel, _mul) … static inline const struct iio_itime_sel_mul * iio_gts_find_itime_by_time(struct iio_gts *gts, int time) { … } static inline const struct iio_itime_sel_mul * iio_gts_find_itime_by_sel(struct iio_gts *gts, int sel) { … } int devm_iio_init_iio_gts(struct device *dev, int max_scale_int, int max_scale_nano, const struct iio_gain_sel_pair *gain_tbl, int num_gain, const struct iio_itime_sel_mul *tim_tbl, int num_times, struct iio_gts *gts); /** * iio_gts_find_int_time_by_sel - find integration time matching a selector * @gts: Gain time scale descriptor * @sel: selector for which matching integration time is searched for * * Return: integration time matching given selector or -EINVAL if * integration time was not found. */ static inline int iio_gts_find_int_time_by_sel(struct iio_gts *gts, int sel) { … } /** * iio_gts_find_sel_by_int_time - find selector matching integration time * @gts: Gain time scale descriptor * @time: Integration time for which matching selector is searched for * * Return: a selector matching given integration time or -EINVAL if * selector was not found. */ static inline int iio_gts_find_sel_by_int_time(struct iio_gts *gts, int time) { … } /** * iio_gts_valid_time - check if given integration time is valid * @gts: Gain time scale descriptor * @time_us: Integration time to check * * Return: True if given time is supported by device. False if not. */ static inline bool iio_gts_valid_time(struct iio_gts *gts, int time_us) { … } int iio_gts_find_sel_by_gain(struct iio_gts *gts, int gain); /** * iio_gts_valid_gain - check if given HW-gain is valid * @gts: Gain time scale descriptor * @gain: HW-gain to check * * Return: True if given time is supported by device. False if not. */ static inline bool iio_gts_valid_gain(struct iio_gts *gts, int gain) { … } int iio_find_closest_gain_low(struct iio_gts *gts, int gain, bool *in_range); int iio_gts_find_gain_by_sel(struct iio_gts *gts, int sel); int iio_gts_get_min_gain(struct iio_gts *gts); int iio_gts_find_int_time_by_sel(struct iio_gts *gts, int sel); int iio_gts_find_sel_by_int_time(struct iio_gts *gts, int time); int iio_gts_total_gain_to_scale(struct iio_gts *gts, int total_gain, int *scale_int, int *scale_nano); int iio_gts_find_gain_sel_for_scale_using_time(struct iio_gts *gts, int time_sel, int scale_int, int scale_nano, int *gain_sel); int iio_gts_get_scale(struct iio_gts *gts, int gain, int time, int *scale_int, int *scale_nano); int iio_gts_find_new_gain_sel_by_old_gain_time(struct iio_gts *gts, int old_gain, int old_time_sel, int new_time_sel, int *new_gain); int iio_gts_find_new_gain_by_old_gain_time(struct iio_gts *gts, int old_gain, int old_time, int new_time, int *new_gain); int iio_gts_avail_times(struct iio_gts *gts, const int **vals, int *type, int *length); int iio_gts_all_avail_scales(struct iio_gts *gts, const int **vals, int *type, int *length); int iio_gts_avail_scales_for_time(struct iio_gts *gts, int time, const int **vals, int *type, int *length); #endif
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