drivers/iio/industrialio-gts-helper.c

2 /* gain-time-scale conversion helpers for IIO light sensors
45  * gain_get_scale_fraction - get the gain or time based on scale and known one
50  * @scale:	Linearized scale to compute the gain/time for.
51  * @known:	Either integration time or gain depending on which one is known
52  * @unknown:	Pointer to variable where the computed gain/time is stored
55  * Compute either gain or time based on scale and either the gain or time
115  * @gts:	Gain time scale descriptor
121  * generated by HW-gain or integration time. It is up to caller to decide what
122  * part of the total gain is due to integration time and what due to HW-gain.
141  * @gts:	Gain time scale descriptor
198 	 * We assume all the gains for same integration time were unique.
199 	 * It is likely the first time table had greatest time multiplier as
261  * @gts:	Gain time scale descriptor
264  * originally given gain and time tables. When both time and gain tables are
267  *    integration time.
340  * @gts:	Gain time scale descriptor
385 		 * the given time table were not unique. Else we could just
402  * iio_gts_purge_avail_time_table - free-up the available integration time table
403  * @gts:	Gain time scale descriptor
418  * @gts:	Gain time scale descriptor
422  * given gain and given time tables.
424  * When both time and gain tables are
427  *    integration time.
458  * @gts:	Gain time scale descriptor
461  * integration time and scale tables.
477  * @gts:	Gain time scale descriptor
481  * given gain and given time tables.
483  * When both time and gain tables are given this results:
485  *    integration time.
583  * devm_iio_init_iio_gts - Initialize the gain-time-scale helper
591  *			the integration time table sorted so that the preferred
592  *			integration time is in the first array index. The search
595  *			from first provided time.
596  * @num_times:		number of times in the time table
599  * Initialize the gain-time-scale helper for use. Note, gains, times, selectors
601  * checking. The total gain (maximum gain * maximum time multiplier) must not
624  * @gts:	Gain time scale descriptor
646  * iio_gts_avail_scales_for_time - list scales for integration time
647  * @gts:	Gain time scale descriptor
648  * @time:	Integration time for which the scales are listed
653  * Drivers which do not allow scale setting to change integration time can
655  * time.
659 int iio_gts_avail_scales_for_time(struct iio_gts *gts, int time,
665 		if (gts->itime_table[i].time_us == time)
681  * @gts:	Gain time scale descriptor
704  * @gts:	Gain time scale descriptor
724  * @gts:	Gain time scale descriptor
744  * @gts:	Gain time scale descriptor
767  * @gts:	Gain time scale descriptor
829 	const struct iio_itime_sel_mul *time;
831 	time = iio_gts_find_itime_by_sel(gts, sel);
832 	if (!time)
835 	return time->mul;
839  * iio_gts_find_gain_for_scale_using_time - Find gain by time and scale
840  * @gts:	Gain time scale descriptor
841  * @time_sel:	Integration time selector corresponding to the time gain is
848  * corresponds given scale and integration time. Sensors which fill the
849  * gain and time tables may use this helper to retrieve the gain.
883  * @gts:	Gain time scale descriptor
884  * @time_sel:	Integration time selector corresponding to the time gain is
913 static int iio_gts_get_total_gain(struct iio_gts *gts, int gain, int time)
923 	itime = iio_gts_find_itime_by_time(gts, time);
930 static int iio_gts_get_scale_linear(struct iio_gts *gts, int gain, int time,
936 	total_gain = iio_gts_get_total_gain(gts, gain, time);
950  * iio_gts_get_scale - get scale based on integration time and HW-gain
951  * @gts:	Gain time scale descriptor
953  * @time:	Integration time for which the scale is computed
957  * Compute scale matching the integration time and HW-gain given as parameter.
961 int iio_gts_get_scale(struct iio_gts *gts, int gain, int time, int *scale_int,
967 	ret = iio_gts_get_scale_linear(gts, gain, time, &lin_scale);
976  * iio_gts_find_new_gain_sel_by_old_gain_time - compensate for time change
977  * @gts:		Gain time scale descriptor
979  * @old_time_sel:	Selector corresponding previously set time
980  * @new_time_sel:	Selector corresponding new time to be set
984  * time (for a light sensor) by also updating the (HW)gain. This helper computes
985  * new gain value to maintain the scale with new integration time.
1033  * iio_gts_find_new_gain_by_old_gain_time - compensate for time change
1034  * @gts:		Gain time scale descriptor
1036  * @old_time:		Selector corresponding previously set time
1037  * @new_time:		Selector corresponding new time to be set
1041  * time (for a light sensor) by also updating the (HW)gain. This helper computes
1042  * new gain value to maintain the scale with new integration time.
1086 MODULE_DESCRIPTION("IIO light sensor gain-time-scale helpers");