Re: [PATCH v6 4/6] iio: filter: admv8818: fix range calculation

From: Jonathan Cameron
Date: Sat Mar 08 2025 - 09:04:18 EST

On Fri, 7 Mar 2025 10:02:14 -0500
Sam Winchenbach <sam.winchenbach@xxxxxxxxxxxxxxxx> wrote:

> Search for the minimum error while ensuring that the LPF corner
> frequency is greater than the target, and the HPF corner frequency
> is lower than the target
>
> This fixes issues where the range calculations were suboptimal.
>
> Add two new DTS properties to set the margin between the input frequency
> and the calculated corner frequency
>

This is a bit fiddly so I'd like Antoniu or one of the other
ADI folk to take a look ideally. No more comments from me.

Jonathan

> Below is a generated table of the differences between the old algorithm
> and the new. This is a sweep from 0 to 20 GHz in 10 MHz steps.
> === HPF ===
> freq = 1750 MHz, 3db: bypass => 1750 MHz
> freq = 3400 MHz, 3db: 3310 => 3400 MHz
> freq = 3410 MHz, 3db: 3310 => 3400 MHz
> freq = 3420 MHz, 3db: 3310 => 3400 MHz
> freq = 3660 MHz, 3db: 3550 => 3656 MHz
> freq = 6600 MHz, 3db: 6479 => 6600 MHz
> freq = 6610 MHz, 3db: 6479 => 6600 MHz
> freq = 6620 MHz, 3db: 6479 => 6600 MHz
> freq = 6630 MHz, 3db: 6479 => 6600 MHz
> freq = 6640 MHz, 3db: 6479 => 6600 MHz
> freq = 6650 MHz, 3db: 6479 => 6600 MHz
> freq = 6660 MHz, 3db: 6479 => 6600 MHz
> freq = 6670 MHz, 3db: 6479 => 6600 MHz
> freq = 6680 MHz, 3db: 6479 => 6600 MHz
> freq = 6690 MHz, 3db: 6479 => 6600 MHz
> freq = 6700 MHz, 3db: 6479 => 6600 MHz
> freq = 6710 MHz, 3db: 6479 => 6600 MHz
> freq = 6720 MHz, 3db: 6479 => 6600 MHz
> freq = 6730 MHz, 3db: 6479 => 6600 MHz
> freq = 6960 MHz, 3db: 6736 => 6960 MHz
> freq = 6970 MHz, 3db: 6736 => 6960 MHz
> freq = 6980 MHz, 3db: 6736 => 6960 MHz
> freq = 6990 MHz, 3db: 6736 => 6960 MHz
> freq = 7320 MHz, 3db: 7249 => 7320 MHz
> freq = 7330 MHz, 3db: 7249 => 7320 MHz
> freq = 7340 MHz, 3db: 7249 => 7320 MHz
> freq = 7350 MHz, 3db: 7249 => 7320 MHz
> freq = 7360 MHz, 3db: 7249 => 7320 MHz
> freq = 7370 MHz, 3db: 7249 => 7320 MHz
> freq = 7380 MHz, 3db: 7249 => 7320 MHz
> freq = 7390 MHz, 3db: 7249 => 7320 MHz
> freq = 7400 MHz, 3db: 7249 => 7320 MHz
> freq = 7410 MHz, 3db: 7249 => 7320 MHz
> freq = 7420 MHz, 3db: 7249 => 7320 MHz
> freq = 7430 MHz, 3db: 7249 => 7320 MHz
> freq = 7440 MHz, 3db: 7249 => 7320 MHz
> freq = 7450 MHz, 3db: 7249 => 7320 MHz
> freq = 7460 MHz, 3db: 7249 => 7320 MHz
> freq = 7470 MHz, 3db: 7249 => 7320 MHz
> freq = 7480 MHz, 3db: 7249 => 7320 MHz
> freq = 7490 MHz, 3db: 7249 => 7320 MHz
> freq = 7500 MHz, 3db: 7249 => 7320 MHz
> freq = 12500 MHz, 3db: 12000 => 12500 MHz
>
> === LPF ===
> freq = 2050 MHz, 3db: bypass => 2050 MHz
> freq = 2170 MHz, 3db: 2290 => 2170 MHz
> freq = 2290 MHz, 3db: 2410 => 2290 MHz
> freq = 2410 MHz, 3db: 2530 => 2410 MHz
> freq = 2530 MHz, 3db: 2650 => 2530 MHz
> freq = 2650 MHz, 3db: 2770 => 2650 MHz
> freq = 2770 MHz, 3db: 2890 => 2770 MHz
> freq = 2890 MHz, 3db: 3010 => 2890 MHz
> freq = 3010 MHz, 3db: 3130 => 3010 MHz
> freq = 3130 MHz, 3db: 3250 => 3130 MHz
> freq = 3250 MHz, 3db: 3370 => 3250 MHz
> freq = 3260 MHz, 3db: 3370 => 3350 MHz
> freq = 3270 MHz, 3db: 3370 => 3350 MHz
> freq = 3280 MHz, 3db: 3370 => 3350 MHz
> freq = 3290 MHz, 3db: 3370 => 3350 MHz
> freq = 3300 MHz, 3db: 3370 => 3350 MHz
> freq = 3310 MHz, 3db: 3370 => 3350 MHz
> freq = 3320 MHz, 3db: 3370 => 3350 MHz
> freq = 3330 MHz, 3db: 3370 => 3350 MHz
> freq = 3340 MHz, 3db: 3370 => 3350 MHz
> freq = 3350 MHz, 3db: 3370 => 3350 MHz
> freq = 3370 MHz, 3db: 3490 => 3370 MHz
> freq = 3490 MHz, 3db: 3610 => 3490 MHz
> freq = 3610 MHz, 3db: 3730 => 3610 MHz
> freq = 3730 MHz, 3db: 3850 => 3730 MHz
> freq = 3850 MHz, 3db: 3870 => 3850 MHz
> freq = 3870 MHz, 3db: 4130 => 3870 MHz
> freq = 4130 MHz, 3db: 4390 => 4130 MHz
> freq = 4390 MHz, 3db: 4650 => 4390 MHz
> freq = 4650 MHz, 3db: 4910 => 4650 MHz
> freq = 4910 MHz, 3db: 5170 => 4910 MHz
> freq = 5170 MHz, 3db: 5430 => 5170 MHz
> freq = 5430 MHz, 3db: 5690 => 5430 MHz
> freq = 5690 MHz, 3db: 5950 => 5690 MHz
> freq = 5950 MHz, 3db: 6210 => 5950 MHz
> freq = 6210 MHz, 3db: 6470 => 6210 MHz
> freq = 6470 MHz, 3db: 6730 => 6470 MHz
> freq = 6730 MHz, 3db: 6990 => 6730 MHz
> freq = 6990 MHz, 3db: 7250 => 6990 MHz
> freq = 7000 MHz, 3db: 7250 => 7000 MHz
> freq = 7250 MHz, 3db: 7400 => 7250 MHz
> freq = 7400 MHz, 3db: 7800 => 7400 MHz
> freq = 7800 MHz, 3db: 8200 => 7800 MHz
> freq = 8200 MHz, 3db: 8600 => 8200 MHz
> freq = 8600 MHz, 3db: 9000 => 8600 MHz
> freq = 9000 MHz, 3db: 9400 => 9000 MHz
> freq = 9400 MHz, 3db: 9800 => 9400 MHz
> freq = 9800 MHz, 3db: 10200 => 9800 MHz
> freq = 10200 MHz, 3db: 10600 => 10200 MHz
> freq = 10600 MHz, 3db: 11000 => 10600 MHz
> freq = 11000 MHz, 3db: 11400 => 11000 MHz
> freq = 11400 MHz, 3db: 11800 => 11400 MHz
> freq = 11800 MHz, 3db: 12200 => 11800 MHz
> freq = 12200 MHz, 3db: 12600 => 12200 MHz
> freq = 12210 MHz, 3db: 12600 => 12550 MHz
> freq = 12220 MHz, 3db: 12600 => 12550 MHz
> freq = 12230 MHz, 3db: 12600 => 12550 MHz
> freq = 12240 MHz, 3db: 12600 => 12550 MHz
> freq = 12250 MHz, 3db: 12600 => 12550 MHz
> freq = 12260 MHz, 3db: 12600 => 12550 MHz
> freq = 12270 MHz, 3db: 12600 => 12550 MHz
> freq = 12280 MHz, 3db: 12600 => 12550 MHz
> freq = 12290 MHz, 3db: 12600 => 12550 MHz
> freq = 12300 MHz, 3db: 12600 => 12550 MHz
> freq = 12310 MHz, 3db: 12600 => 12550 MHz
> freq = 12320 MHz, 3db: 12600 => 12550 MHz
> freq = 12330 MHz, 3db: 12600 => 12550 MHz
> freq = 12340 MHz, 3db: 12600 => 12550 MHz
> freq = 12350 MHz, 3db: 12600 => 12550 MHz
> freq = 12360 MHz, 3db: 12600 => 12550 MHz
> freq = 12370 MHz, 3db: 12600 => 12550 MHz
> freq = 12380 MHz, 3db: 12600 => 12550 MHz
> freq = 12390 MHz, 3db: 12600 => 12550 MHz
> freq = 12400 MHz, 3db: 12600 => 12550 MHz
> freq = 12410 MHz, 3db: 12600 => 12550 MHz
> freq = 12420 MHz, 3db: 12600 => 12550 MHz
> freq = 12430 MHz, 3db: 12600 => 12550 MHz
> freq = 12440 MHz, 3db: 12600 => 12550 MHz
> freq = 12450 MHz, 3db: 12600 => 12550 MHz
> freq = 12460 MHz, 3db: 12600 => 12550 MHz
> freq = 12470 MHz, 3db: 12600 => 12550 MHz
> freq = 12480 MHz, 3db: 12600 => 12550 MHz
> freq = 12490 MHz, 3db: 12600 => 12550 MHz
> freq = 12500 MHz, 3db: 12600 => 12550 MHz
> freq = 12510 MHz, 3db: 12600 => 12550 MHz
> freq = 12520 MHz, 3db: 12600 => 12550 MHz
> freq = 12530 MHz, 3db: 12600 => 12550 MHz
> freq = 12540 MHz, 3db: 12600 => 12550 MHz
> freq = 12550 MHz, 3db: 12600 => 12550 MHz
> freq = 12600 MHz, 3db: 13000 => 12600 MHz
> freq = 12610 MHz, 3db: 13000 => 12970 MHz
> freq = 12620 MHz, 3db: 13000 => 12970 MHz
> freq = 12630 MHz, 3db: 13000 => 12970 MHz
> freq = 12640 MHz, 3db: 13000 => 12970 MHz
> freq = 12650 MHz, 3db: 13000 => 12970 MHz
> freq = 12660 MHz, 3db: 13000 => 12970 MHz
> freq = 12670 MHz, 3db: 13000 => 12970 MHz
> freq = 12680 MHz, 3db: 13000 => 12970 MHz
> freq = 12690 MHz, 3db: 13000 => 12970 MHz
> freq = 12700 MHz, 3db: 13000 => 12970 MHz
> freq = 12710 MHz, 3db: 13000 => 12970 MHz
> freq = 12720 MHz, 3db: 13000 => 12970 MHz
> freq = 12730 MHz, 3db: 13000 => 12970 MHz
> freq = 12740 MHz, 3db: 13000 => 12970 MHz
> freq = 12750 MHz, 3db: 13000 => 12970 MHz
> freq = 12760 MHz, 3db: 13000 => 12970 MHz
> freq = 12770 MHz, 3db: 13000 => 12970 MHz
> freq = 12780 MHz, 3db: 13000 => 12970 MHz
> freq = 12790 MHz, 3db: 13000 => 12970 MHz
> freq = 12800 MHz, 3db: 13000 => 12970 MHz
> freq = 12810 MHz, 3db: 13000 => 12970 MHz
> freq = 12820 MHz, 3db: 13000 => 12970 MHz
> freq = 12830 MHz, 3db: 13000 => 12970 MHz
> freq = 12840 MHz, 3db: 13000 => 12970 MHz
> freq = 12850 MHz, 3db: 13000 => 12970 MHz
> freq = 12860 MHz, 3db: 13000 => 12970 MHz
> freq = 12870 MHz, 3db: 13000 => 12970 MHz
> freq = 12880 MHz, 3db: 13000 => 12970 MHz
> freq = 12890 MHz, 3db: 13000 => 12970 MHz
> freq = 12900 MHz, 3db: 13000 => 12970 MHz
> freq = 12910 MHz, 3db: 13000 => 12970 MHz
> freq = 12920 MHz, 3db: 13000 => 12970 MHz
> freq = 12930 MHz, 3db: 13000 => 12970 MHz
> freq = 12940 MHz, 3db: 13000 => 12970 MHz
> freq = 12950 MHz, 3db: 13000 => 12970 MHz
> freq = 12960 MHz, 3db: 13000 => 12970 MHz
> freq = 12970 MHz, 3db: 13000 => 12970 MHz
> freq = 13000 MHz, 3db: 13390 => 13000 MHz
> freq = 13390 MHz, 3db: 13810 => 13390 MHz
> freq = 13810 MHz, 3db: 14230 => 13810 MHz
> freq = 14230 MHz, 3db: 14650 => 14230 MHz
> freq = 14650 MHz, 3db: 15070 => 14650 MHz
> freq = 15070 MHz, 3db: 15490 => 15070 MHz
> freq = 15490 MHz, 3db: 15910 => 15490 MHz
> freq = 15910 MHz, 3db: 16330 => 15910 MHz
> freq = 16330 MHz, 3db: 16750 => 16330 MHz
> freq = 16750 MHz, 3db: 17170 => 16750 MHz
> freq = 17170 MHz, 3db: 17590 => 17170 MHz
> freq = 17590 MHz, 3db: 18010 => 17590 MHz
> freq = 18010 MHz, 3db: 18430 => 18010 MHz
> freq = 18430 MHz, 3db: 18850 => 18430 MHz
> freq = 18850 MHz, 3db: bypass => 18850 MHz
>
> Fixes: f34fe888ad05 ("iio:filter:admv8818: add support for ADMV8818")
> Signed-off-by: Sam Winchenbach <sam.winchenbach@xxxxxxxxxxxxxxxx>
> ---
> drivers/iio/filter/admv8818.c | 205 +++++++++++++++++++++++++---------
> 1 file changed, 152 insertions(+), 53 deletions(-)
>
> diff --git a/drivers/iio/filter/admv8818.c b/drivers/iio/filter/admv8818.c
> index a059282e0251..e9602bfd4af7 100644
> --- a/drivers/iio/filter/admv8818.c
> +++ b/drivers/iio/filter/admv8818.c
> @@ -14,6 +14,7 @@
> #include <linux/mod_devicetable.h>
> #include <linux/mutex.h>
> #include <linux/notifier.h>
> +#include <linux/property.h>
> #include <linux/regmap.h>
> #include <linux/spi/spi.h>
> #include <linux/units.h>
> @@ -70,6 +71,16 @@
> #define ADMV8818_HPF_WR0_MSK GENMASK(7, 4)
> #define ADMV8818_LPF_WR0_MSK GENMASK(3, 0)
>
> +#define ADMV8818_BAND_BYPASS 0
> +#define ADMV8818_BAND_MIN 1
> +#define ADMV8818_BAND_MAX 4
> +#define ADMV8818_BAND_CORNER_LOW 0
> +#define ADMV8818_BAND_CORNER_HIGH 1
> +
> +#define ADMV8818_STATE_MIN 0
> +#define ADMV8818_STATE_MAX 15
> +#define ADMV8818_NUM_STATES 16
> +
> enum {
> ADMV8818_BW_FREQ,
> ADMV8818_CENTER_FREQ
> @@ -90,16 +101,20 @@ struct admv8818_state {
> struct mutex lock;
> unsigned int filter_mode;
> u64 cf_hz;
> + u64 lpf_margin_hz;
> + u64 hpf_margin_hz;
> };
>
> -static const unsigned long long freq_range_hpf[4][2] = {
> +static const unsigned long long freq_range_hpf[5][2] = {
> + {0ULL, 0ULL}, /* bypass */
> {1750000000ULL, 3550000000ULL},
> {3400000000ULL, 7250000000ULL},
> {6600000000, 12000000000},
> {12500000000, 19900000000}
> };
>
> -static const unsigned long long freq_range_lpf[4][2] = {
> +static const unsigned long long freq_range_lpf[5][2] = {
> + {U64_MAX, U64_MAX}, /* bypass */
> {2050000000ULL, 3850000000ULL},
> {3350000000ULL, 7250000000ULL},
> {7000000000, 13000000000},
> @@ -121,44 +136,59 @@ static const char * const admv8818_modes[] = {
>
> static int __admv8818_hpf_select(struct admv8818_state *st, u64 freq)
> {
> - unsigned int hpf_step = 0, hpf_band = 0, i, j;
> - u64 freq_step;
> - int ret;
> + int band, state, ret;
> + unsigned int hpf_state = ADMV8818_STATE_MIN, hpf_band = ADMV8818_BAND_BYPASS;
> + u64 freq_error, min_freq_error, freq_corner, freq_step;
>
> - if (freq < freq_range_hpf[0][0])
> + if (freq < freq_range_hpf[ADMV8818_BAND_MIN][ADMV8818_BAND_CORNER_LOW])
> goto hpf_write;
>
> - if (freq > freq_range_hpf[3][1]) {
> - hpf_step = 15;
> - hpf_band = 4;
> -
> + if (freq >= freq_range_hpf[ADMV8818_BAND_MAX][ADMV8818_BAND_CORNER_HIGH]) {
> + hpf_state = ADMV8818_STATE_MAX;
> + hpf_band = ADMV8818_BAND_MAX;
> goto hpf_write;
> }
>
> - for (i = 0; i < 4; i++) {
> - freq_step = div_u64((freq_range_hpf[i][1] -
> - freq_range_hpf[i][0]), 15);
> + /* Close HPF frequency gap between 12 and 12.5 GHz */
> + if (freq >= 12000ULL * HZ_PER_MHZ && freq < 12500ULL * HZ_PER_MHZ) {
> + hpf_state = ADMV8818_STATE_MAX;
> + hpf_band = 3;
> + goto hpf_write;
> + }
>
> - if (freq > freq_range_hpf[i][0] &&
> - (freq < freq_range_hpf[i][1] + freq_step)) {
> - hpf_band = i + 1;
> + min_freq_error = U64_MAX;
> + for (band = ADMV8818_BAND_MIN; band <= ADMV8818_BAND_MAX; band++) {
> + /*
> + * This (and therefore all other ranges) have a corner
> + * frequency higher than the target frequency.
> + */
> + if (freq_range_hpf[band][ADMV8818_BAND_CORNER_LOW] > freq)
> + break;
>
> - for (j = 1; j <= 16; j++) {
> - if (freq < (freq_range_hpf[i][0] + (freq_step * j))) {
> - hpf_step = j - 1;
> - break;
> - }
> + freq_step = freq_range_hpf[band][ADMV8818_BAND_CORNER_HIGH] -
> + freq_range_hpf[band][ADMV8818_BAND_CORNER_LOW];
> + freq_step = div_u64(freq_step, ADMV8818_NUM_STATES - 1);
> +
> + for (state = ADMV8818_STATE_MIN; state <= ADMV8818_STATE_MAX; state++) {
> + freq_corner = freq_range_hpf[band][ADMV8818_BAND_CORNER_LOW] +
> + freq_step * state;
> +
> + /*
> + * This (and therefore all other states) have a corner
> + * frequency higher than the target frequency.
> + */
> + if (freq_corner > freq)
> + break;
> +
> + freq_error = freq - freq_corner;
> + if (freq_error < min_freq_error) {
> + min_freq_error = freq_error;
> + hpf_state = state;
> + hpf_band = band;
> }
> - break;
> }
> }
>
> - /* Close HPF frequency gap between 12 and 12.5 GHz */
> - if (freq >= 12000ULL * HZ_PER_MHZ && freq < 12500ULL * HZ_PER_MHZ) {
> - hpf_band = 3;
> - hpf_step = 15;
> - }
> -
> hpf_write:
> ret = regmap_update_bits(st->regmap, ADMV8818_REG_WR0_SW,
> ADMV8818_SW_IN_SET_WR0_MSK |
> @@ -170,7 +200,7 @@ static int __admv8818_hpf_select(struct admv8818_state *st, u64 freq)
>
> return regmap_update_bits(st->regmap, ADMV8818_REG_WR0_FILTER,
> ADMV8818_HPF_WR0_MSK,
> - FIELD_PREP(ADMV8818_HPF_WR0_MSK, hpf_step));
> + FIELD_PREP(ADMV8818_HPF_WR0_MSK, hpf_state));
> }
>
> static int admv8818_hpf_select(struct admv8818_state *st, u64 freq)
> @@ -186,31 +216,52 @@ static int admv8818_hpf_select(struct admv8818_state *st, u64 freq)
>
> static int __admv8818_lpf_select(struct admv8818_state *st, u64 freq)
> {
> - unsigned int lpf_step = 0, lpf_band = 0, i, j;
> - u64 freq_step;
> - int ret;
> + int band, state, ret;
> + unsigned int lpf_state = ADMV8818_STATE_MIN, lpf_band = ADMV8818_BAND_BYPASS;
> + u64 freq_error, min_freq_error, freq_corner, freq_step;
>
> - if (freq > freq_range_lpf[3][1])
> + if (freq > freq_range_lpf[ADMV8818_BAND_MAX][ADMV8818_BAND_CORNER_HIGH])
> goto lpf_write;
>
> - if (freq < freq_range_lpf[0][0]) {
> - lpf_band = 1;
> -
> + if (freq < freq_range_lpf[ADMV8818_BAND_MIN][ADMV8818_BAND_CORNER_LOW]) {
> + lpf_state = ADMV8818_STATE_MIN;
> + lpf_band = ADMV8818_BAND_MIN;
> goto lpf_write;
> }
>
> - for (i = 0; i < 4; i++) {
> - if (freq > freq_range_lpf[i][0] && freq < freq_range_lpf[i][1]) {
> - lpf_band = i + 1;
> - freq_step = div_u64((freq_range_lpf[i][1] - freq_range_lpf[i][0]), 15);
> + min_freq_error = U64_MAX;
> + for (band = ADMV8818_BAND_MAX; band >= ADMV8818_BAND_MIN; --band) {
> + /*
> + * At this point the highest corner frequency of
> + * all remaining ranges is below the target.
> + * LPF corner should be >= the target.
> + */
> + if (freq > freq_range_lpf[band][ADMV8818_BAND_CORNER_HIGH])
> + break;
> +
> + freq_step = freq_range_lpf[band][ADMV8818_BAND_CORNER_HIGH] -
> + freq_range_lpf[band][ADMV8818_BAND_CORNER_LOW];
> + freq_step = div_u64(freq_step, ADMV8818_NUM_STATES - 1);
> +
> + for (state = ADMV8818_STATE_MAX; state >= ADMV8818_STATE_MIN; --state) {
>
> - for (j = 0; j <= 15; j++) {
> - if (freq < (freq_range_lpf[i][0] + (freq_step * j))) {
> - lpf_step = j;
> - break;
> - }
> + freq_corner = freq_range_lpf[band][ADMV8818_BAND_CORNER_LOW] +
> + state * freq_step;
> +
> + /*
> + * At this point all other states in range will
> + * place the corner frequency below the target
> + * LPF corner should >= the target.
> + */
> + if (freq > freq_corner)
> + break;
> +
> + freq_error = freq_corner - freq;
> + if (freq_error < min_freq_error) {
> + min_freq_error = freq_error;
> + lpf_state = state;
> + lpf_band = band;
> }
> - break;
> }
> }
>
> @@ -225,7 +276,7 @@ static int __admv8818_lpf_select(struct admv8818_state *st, u64 freq)
>
> return regmap_update_bits(st->regmap, ADMV8818_REG_WR0_FILTER,
> ADMV8818_LPF_WR0_MSK,
> - FIELD_PREP(ADMV8818_LPF_WR0_MSK, lpf_step));
> + FIELD_PREP(ADMV8818_LPF_WR0_MSK, lpf_state));
> }
>
> static int admv8818_lpf_select(struct admv8818_state *st, u64 freq)
> @@ -242,16 +293,28 @@ static int admv8818_lpf_select(struct admv8818_state *st, u64 freq)
> static int admv8818_rfin_band_select(struct admv8818_state *st)
> {
> int ret;
> + u64 hpf_corner_target, lpf_corner_target;
>
> st->cf_hz = clk_get_rate(st->clkin);
>
> + /* Check for underflow */
> + if (st->cf_hz > st->hpf_margin_hz)
> + hpf_corner_target = st->cf_hz - st->hpf_margin_hz;
> + else
> + hpf_corner_target = 0;
> +
> + /* Check for overflow */
> + lpf_corner_target = st->cf_hz + st->lpf_margin_hz;
> + if (lpf_corner_target < st->cf_hz)
> + lpf_corner_target = U64_MAX;
> +
> mutex_lock(&st->lock);
>
> - ret = __admv8818_hpf_select(st, st->cf_hz);
> + ret = __admv8818_hpf_select(st, hpf_corner_target);
> if (ret)
> goto exit;
>
> - ret = __admv8818_lpf_select(st, st->cf_hz);
> + ret = __admv8818_lpf_select(st, lpf_corner_target);
> exit:
> mutex_unlock(&st->lock);
> return ret;
> @@ -278,8 +341,11 @@ static int __admv8818_read_hpf_freq(struct admv8818_state *st, u64 *hpf_freq)
>
> hpf_state = FIELD_GET(ADMV8818_HPF_WR0_MSK, data);
>
> - *hpf_freq = div_u64(freq_range_hpf[hpf_band - 1][1] - freq_range_hpf[hpf_band - 1][0], 15);
> - *hpf_freq = freq_range_hpf[hpf_band - 1][0] + (*hpf_freq * hpf_state);
> + *hpf_freq = freq_range_hpf[hpf_band][ADMV8818_BAND_CORNER_HIGH] -
> + freq_range_hpf[hpf_band][ADMV8818_BAND_CORNER_LOW];
> + *hpf_freq = div_u64(*hpf_freq, ADMV8818_NUM_STATES - 1);
> + *hpf_freq = freq_range_hpf[hpf_band][ADMV8818_BAND_CORNER_LOW] +
> + (*hpf_freq * hpf_state);
>
> return ret;
> }
> @@ -316,8 +382,11 @@ static int __admv8818_read_lpf_freq(struct admv8818_state *st, u64 *lpf_freq)
>
> lpf_state = FIELD_GET(ADMV8818_LPF_WR0_MSK, data);
>
> - *lpf_freq = div_u64(freq_range_lpf[lpf_band - 1][1] - freq_range_lpf[lpf_band - 1][0], 15);
> - *lpf_freq = freq_range_lpf[lpf_band - 1][0] + (*lpf_freq * lpf_state);
> + *lpf_freq = freq_range_lpf[lpf_band][ADMV8818_BAND_CORNER_HIGH] -
> + freq_range_lpf[lpf_band][ADMV8818_BAND_CORNER_LOW];
> + *lpf_freq = div_u64(*lpf_freq, ADMV8818_NUM_STATES - 1);
> + *lpf_freq = freq_range_lpf[lpf_band][ADMV8818_BAND_CORNER_LOW] +
> + (*lpf_freq * lpf_state);
>
> return ret;
> }
> @@ -647,6 +716,32 @@ static int admv8818_clk_setup(struct admv8818_state *st)
> return devm_add_action_or_reset(&spi->dev, admv8818_clk_notifier_unreg, st);
> }
>
> +static int admv8818_read_properties(struct admv8818_state *st)
> +{
> + struct spi_device *spi = st->spi;
> + u32 mhz;
> + int ret;
> +
> + ret = device_property_read_u32(&spi->dev, "adi,lpf-margin-mhz", &mhz);
> + if (ret == 0)
> + st->lpf_margin_hz = (u64)mhz * HZ_PER_MHZ;
> + else if (ret == -EINVAL)
> + st->lpf_margin_hz = 0;
> + else
> + return ret;
> +
> +
> + ret = device_property_read_u32(&spi->dev, "adi,hpf-margin-mhz", &mhz);
> + if (ret == 0)
> + st->hpf_margin_hz = (u64)mhz * HZ_PER_MHZ;
> + else if (ret == -EINVAL)
> + st->hpf_margin_hz = 0;
> + else if (ret < 0)
> + return ret;
> +
> + return 0;
> +}
> +
> static int admv8818_probe(struct spi_device *spi)
> {
> struct iio_dev *indio_dev;
> @@ -678,6 +773,10 @@ static int admv8818_probe(struct spi_device *spi)
>
> mutex_init(&st->lock);
>
> + ret = admv8818_read_properties(st);
> + if (ret)
> + return ret;
> +
> ret = admv8818_init(st);
> if (ret)
> return ret;