linux-kernel - Re: [PATCH v5 5/5] iio: pressure: bmp280: Add more tunable config parameters for BMP380

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Date:   Mon, 8 Aug 2022 11:13:56 +0200
From:   Andy Shevchenko <andy.shevchenko@...il.com>
To:     Angel Iglesias <ang.iglesiasg@...il.com>
Cc:     linux-iio <linux-iio@...r.kernel.org>,
        Jonathan Cameron <jic23@...nel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        Paul Cercueil <paul@...pouillou.net>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@...el.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v5 5/5] iio: pressure: bmp280: Add more tunable config
 parameters for BMP380

On Sun, Aug 7, 2022 at 2:44 PM Angel Iglesias <ang.iglesiasg@...il.com> wrote:
>
> Allows sampling frequency and IIR filter coefficients configuration
> using sysfs ABI.
>
> The IIR filter coefficient is configurable using the sysfs attribute
> "filter_low_pass_3db_frequency".

...

> +static const int bmp380_odr_table[][2] = {

s32_fract ?

> +       [BMP380_ODR_200HZ]      = {200, 0},
> +       [BMP380_ODR_100HZ]      = {100, 0},
> +       [BMP380_ODR_50HZ]       = {50, 0},
> +       [BMP380_ODR_25HZ]       = {25, 0},
> +       [BMP380_ODR_12_5HZ]     = {12, 500000},
> +       [BMP380_ODR_6_25HZ]     = {6, 250000},
> +       [BMP380_ODR_3_125HZ]    = {3, 125000},
> +       [BMP380_ODR_1_5625HZ]   = {1, 562500},
> +       [BMP380_ODR_0_78HZ]     = {0, 781250},
> +       [BMP380_ODR_0_39HZ]     = {0, 390625},
> +       [BMP380_ODR_0_2HZ]      = {0, 195313},
> +       [BMP380_ODR_0_1HZ]      = {0, 97656},
> +       [BMP380_ODR_0_05HZ]     = {0, 48828},
> +       [BMP380_ODR_0_02HZ]     = {0, 24414},
> +       [BMP380_ODR_0_01HZ]     = {0, 12207},
> +       [BMP380_ODR_0_006HZ]    = {0, 6104},
> +       [BMP380_ODR_0_003HZ]    = {0, 3052},
> +       [BMP380_ODR_0_0015HZ]   = {0, 1526},
> +};

...

> +               ret = regmap_write_bits(data->regmap, BMP380_REG_POWER_CONTROL,
> +                                       BMP380_MODE_MASK,

> +                                       FIELD_PREP(BMP380_MODE_MASK,
> +                                                  BMP380_MODE_SLEEP));

One line?

...

> +               ret = regmap_write_bits(data->regmap, BMP380_REG_POWER_CONTROL,
> +                                       BMP380_MODE_MASK,

> +                                       FIELD_PREP(BMP380_MODE_MASK,
> +                                                  BMP380_MODE_NORMAL));

Ditto.

...

> +static const int bmp380_iir_filter_coeffs_avail[] = { 0, 1, 3, 7, 15, 31, 63, 127 };

This seems like a power of two - 1, can it be replaced by a formula in the code?

-- 
With Best Regards,
Andy Shevchenko