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/* SPDX-License-Identifier: GPL-2.0-only */
/* gain-time-scale conversion helpers for IIO light sensors
*
* Copyright (c) 2023 Matti Vaittinen <mazziesaccount@gmail.com>
*/
#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 {
int gain;
int sel;
};
/**
* 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 {
int time_us;
int sel;
int mul;
};
struct iio_gts {
u64 max_scale;
const struct iio_gain_sel_pair *hwgain_table;
int num_hwgain;
const struct iio_itime_sel_mul *itime_table;
int num_itime;
int **per_time_avail_scale_tables;
int *avail_all_scales_table;
int num_avail_all_scales;
int *avail_time_tables;
int num_avail_time_tables;
};
#define GAIN_SCALE_GAIN(_gain, _sel) \
{ \
.gain = (_gain), \
.sel = (_sel), \
}
#define GAIN_SCALE_ITIME_US(_itime, _sel, _mul) \
{ \
.time_us = (_itime), \
.sel = (_sel), \
.mul = (_mul), \
}
static inline const struct iio_itime_sel_mul *
iio_gts_find_itime_by_time(struct iio_gts *gts, int time)
{
int i;
if (!gts->num_itime)
return NULL;
for (i = 0; i < gts->num_itime; i++)
if (gts->itime_table[i].time_us == time)
return >s->itime_table[i];
return NULL;
}
static inline const struct iio_itime_sel_mul *
iio_gts_find_itime_by_sel(struct iio_gts *gts, int sel)
{
int i;
for (i = 0; i < gts->num_itime; i++)
if (gts->itime_table[i].sel == sel)
return >s->itime_table[i];
return NULL;
}
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)
{
const struct iio_itime_sel_mul *itime;
itime = iio_gts_find_itime_by_sel(gts, sel);
if (!itime)
return -EINVAL;
return itime->time_us;
}
/**
* 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)
{
const struct iio_itime_sel_mul *itime;
itime = iio_gts_find_itime_by_time(gts, time);
if (!itime)
return -EINVAL;
return itime->sel;
}
/**
* 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)
{
return iio_gts_find_itime_by_time(gts, time_us) != NULL;
}
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)
{
return iio_gts_find_sel_by_gain(gts, gain) >= 0;
}
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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