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Message-ID: <20230930182502.106d2c78@jic23-huawei>
Date: Sat, 30 Sep 2023 18:25:02 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: alisadariana@...il.com
Cc: Alisa-Dariana Roman <alisa.roman@...log.com>,
Lars-Peter Clausen <lars@...afoo.de>,
Alexandru Tachici <alexandru.tachici@...log.com>,
Michael Hennerich <Michael.Hennerich@...log.com>,
linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v3 2/3] iio: adc: ad7192: Improve f_order computation
On Mon, 25 Sep 2023 00:51:47 +0300
alisadariana@...il.com wrote:
> From: Alisa-Dariana Roman <alisa.roman@...log.com>
>
> Instead of using the f_order member of ad7192_state, a function that
> computes the f_order coefficient makes more sense. This coefficient is a
> function of the sinc filter and chop filter states.
>
> Remove f_order member of ad7192_state structure. Instead use
> ad7192_compute_f_order function to compute the f_order coefficient
> according to the sinc filter and chop filter states passed as
> parameters.
>
> Add ad7192_get_f_order function that returns the current f_order
> coefficient of the device.
>
> Add ad7192_compute_f_adc function that computes the f_adc value
> according to the sinc filter and chop filter states passed as
> parameters.
>
> Add ad7192_get_f_adc function that returns the current f_adc value of
> the device.
>
> Signed-off-by: Alisa-Dariana Roman <alisa.roman@...log.com>
Applied to the togreg branch of iio.git and pushed out as testing
for 0-day to see if it can find anything we missed.
Thanks,
Jonathan
> ---
> drivers/iio/adc/ad7192.c | 62 +++++++++++++++++++++++++++++-----------
> 1 file changed, 46 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
> index d693f2ce8a20..0f9d33002d35 100644
> --- a/drivers/iio/adc/ad7192.c
> +++ b/drivers/iio/adc/ad7192.c
> @@ -179,7 +179,6 @@ struct ad7192_state {
> struct clk *mclk;
> u16 int_vref_mv;
> u32 fclk;
> - u32 f_order;
> u32 mode;
> u32 conf;
> u32 scale_avail[8][2];
> @@ -419,7 +418,6 @@ static int ad7192_setup(struct iio_dev *indio_dev, struct device_node *np)
> st->conf |= AD7192_CONF_REFSEL;
>
> st->conf &= ~AD7192_CONF_CHOP;
> - st->f_order = AD7192_NO_SYNC_FILTER;
>
> buf_en = of_property_read_bool(np, "adi,buffer-enable");
> if (buf_en)
> @@ -530,22 +528,60 @@ static ssize_t ad7192_set(struct device *dev,
> return ret ? ret : len;
> }
>
> +static int ad7192_compute_f_order(bool sinc3_en, bool chop_en)
> +{
> + if (!chop_en)
> + return 1;
> +
> + if (sinc3_en)
> + return AD7192_SYNC3_FILTER;
> +
> + return AD7192_SYNC4_FILTER;
> +}
> +
> +static int ad7192_get_f_order(struct ad7192_state *st)
> +{
> + bool sinc3_en, chop_en;
> +
> + sinc3_en = FIELD_GET(AD7192_MODE_SINC3, st->mode);
> + chop_en = FIELD_GET(AD7192_CONF_CHOP, st->conf);
> +
> + return ad7192_compute_f_order(sinc3_en, chop_en);
> +}
> +
> +static int ad7192_compute_f_adc(struct ad7192_state *st, bool sinc3_en,
> + bool chop_en)
> +{
> + unsigned int f_order = ad7192_compute_f_order(sinc3_en, chop_en);
> +
> + return DIV_ROUND_CLOSEST(st->fclk,
> + f_order * FIELD_GET(AD7192_MODE_RATE_MASK, st->mode));
> +}
> +
> +static int ad7192_get_f_adc(struct ad7192_state *st)
> +{
> + unsigned int f_order = ad7192_get_f_order(st);
> +
> + return DIV_ROUND_CLOSEST(st->fclk,
> + f_order * FIELD_GET(AD7192_MODE_RATE_MASK, st->mode));
> +}
> +
> static void ad7192_get_available_filter_freq(struct ad7192_state *st,
> int *freq)
> {
> unsigned int fadc;
>
> /* Formulas for filter at page 25 of the datasheet */
> - fadc = DIV_ROUND_CLOSEST(st->fclk,
> - AD7192_SYNC4_FILTER * FIELD_GET(AD7192_MODE_RATE_MASK, st->mode));
> + fadc = ad7192_compute_f_adc(st, false, true);
> freq[0] = DIV_ROUND_CLOSEST(fadc * 240, 1024);
>
> - fadc = DIV_ROUND_CLOSEST(st->fclk,
> - AD7192_SYNC3_FILTER * FIELD_GET(AD7192_MODE_RATE_MASK, st->mode));
> + fadc = ad7192_compute_f_adc(st, true, true);
> freq[1] = DIV_ROUND_CLOSEST(fadc * 240, 1024);
>
> - fadc = DIV_ROUND_CLOSEST(st->fclk, FIELD_GET(AD7192_MODE_RATE_MASK, st->mode));
> + fadc = ad7192_compute_f_adc(st, false, false);
> freq[2] = DIV_ROUND_CLOSEST(fadc * 230, 1024);
> +
> + fadc = ad7192_compute_f_adc(st, true, false);
> freq[3] = DIV_ROUND_CLOSEST(fadc * 272, 1024);
> }
>
> @@ -628,25 +664,21 @@ static int ad7192_set_3db_filter_freq(struct ad7192_state *st,
>
> switch (idx) {
> case 0:
> - st->f_order = AD7192_SYNC4_FILTER;
> st->mode &= ~AD7192_MODE_SINC3;
>
> st->conf |= AD7192_CONF_CHOP;
> break;
> case 1:
> - st->f_order = AD7192_SYNC3_FILTER;
> st->mode |= AD7192_MODE_SINC3;
>
> st->conf |= AD7192_CONF_CHOP;
> break;
> case 2:
> - st->f_order = AD7192_NO_SYNC_FILTER;
> st->mode &= ~AD7192_MODE_SINC3;
>
> st->conf &= ~AD7192_CONF_CHOP;
> break;
> case 3:
> - st->f_order = AD7192_NO_SYNC_FILTER;
> st->mode |= AD7192_MODE_SINC3;
>
> st->conf &= ~AD7192_CONF_CHOP;
> @@ -664,8 +696,7 @@ static int ad7192_get_3db_filter_freq(struct ad7192_state *st)
> {
> unsigned int fadc;
>
> - fadc = DIV_ROUND_CLOSEST(st->fclk,
> - st->f_order * FIELD_GET(AD7192_MODE_RATE_MASK, st->mode));
> + fadc = ad7192_get_f_adc(st);
>
> if (FIELD_GET(AD7192_CONF_CHOP, st->conf))
> return DIV_ROUND_CLOSEST(fadc * 240, 1024);
> @@ -713,8 +744,7 @@ static int ad7192_read_raw(struct iio_dev *indio_dev,
> *val -= 273 * ad7192_get_temp_scale(unipolar);
> return IIO_VAL_INT;
> case IIO_CHAN_INFO_SAMP_FREQ:
> - *val = st->fclk /
> - (st->f_order * 1024 * FIELD_GET(AD7192_MODE_RATE_MASK, st->mode));
> + *val = DIV_ROUND_CLOSEST(ad7192_get_f_adc(st), 1024);
> return IIO_VAL_INT;
> case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> *val = ad7192_get_3db_filter_freq(st);
> @@ -764,7 +794,7 @@ static int ad7192_write_raw(struct iio_dev *indio_dev,
> break;
> }
>
> - div = st->fclk / (val * st->f_order * 1024);
> + div = st->fclk / (val * ad7192_get_f_order(st) * 1024);
> if (div < 1 || div > 1023) {
> ret = -EINVAL;
> break;
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