Re: [PATCH 3/3] iio: pressure: bmp280: Adds more tunable config parameters for BMP380

From: Jonathan Cameron
Date: Sun Jun 26 2022 - 10:29:44 EST

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In reply to: Angel Iglesias: "[PATCH 3/3] iio: pressure: bmp280: Adds more tunable config parameters for BMP380"
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On Sat, 25 Jun 2022 17:10:36 +0200
Angel Iglesias <ang.iglesiasg@xxxxxxxxx> wrote:

> Allows to configure the IIR filter coefficient and the sampling frequency
> The IIR filter coefficient is exposed using the sysfs attribute
> "filter_low_pass_3db_frequency"
>
> Signed-off-by: Angel Iglesias <ang.iglesiasg@xxxxxxxxx>
Hi Angel

A few comments inline,
> ---
> drivers/iio/pressure/bmp280-core.c | 168 ++++++++++++++++++++++++++++-
> drivers/iio/pressure/bmp280.h | 18 ----
> 2 files changed, 166 insertions(+), 20 deletions(-)
>
> diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
> index 3887475a9059..3d22fc844e87 100644
> --- a/drivers/iio/pressure/bmp280-core.c
> +++ b/drivers/iio/pressure/bmp280-core.c
> @@ -96,6 +96,27 @@ static const char *const bmp280_supply_names[] = {
> "vddd", "vdda"
> };
>
> +enum bmp380_odr {
> + BMP380_ODR_200HZ,
> + BMP380_ODR_100HZ,
> + BMP380_ODR_50HZ,
> + BMP380_ODR_25HZ,
> + BMP380_ODR_12_5HZ,
> + BMP380_ODR_6_25HZ,
> + BMP380_ODR_3_125HZ,
> + BMP380_ODR_1_5625HZ,
> + BMP380_ODR_0_78HZ,
> + BMP380_ODR_0_39HZ,
> + BMP380_ODR_0_2HZ,
> + BMP380_ODR_0_1HZ,
> + BMP380_ODR_0_05HZ,
> + BMP380_ODR_0_02HZ,
> + BMP380_ODR_0_01HZ,
> + BMP380_ODR_0_006HZ,
> + BMP380_ODR_0_003HZ,
> + BMP380_ODR_0_0015HZ
> +};
> +
> #define BMP280_NUM_SUPPLIES ARRAY_SIZE(bmp280_supply_names)
>
> struct bmp280_data {
> @@ -117,6 +138,16 @@ struct bmp280_data {
> u8 oversampling_press;
> u8 oversampling_temp;
> u8 oversampling_humid;
> + u8 iir_filter_coeff;
> +
> + /* BMP380 devices introduce sampling frequecy configuration. See
> + * datasheet sections 3.3.3. and 4.3.19.
> + *
> + * BMx280 devices allowed indirect configuration of sampling frequency
> + * changing the t_standby duration between measurements. See datasheet
> + * section 3.6.3
> + */
> + int sampling_freq;
>
> /*
> * Carryover value from temperature conversion, used in pressure
> @@ -135,6 +166,12 @@ struct bmp280_chip_info {
> const int *oversampling_humid_avail;
> int num_oversampling_humid_avail;
>
> + const int *iir_filter_coeffs_avail;
> + int num_iir_filter_coeffs_avail;
> +
> + const int (*sampling_freq_avail)[2];
> + int num_sampling_freq_avail;
> +
> int (*chip_config)(struct bmp280_data *);
> int (*read_temp)(struct bmp280_data *, int *);
> int (*read_press)(struct bmp280_data *, int *, int *);
> @@ -185,6 +222,30 @@ static const struct iio_chan_spec bmp280_channels[] = {
> },
> };
>
> +static const struct iio_chan_spec bmp380_channels[] = {
> + {
> + .type = IIO_PRESSURE,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
> + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ) |
> + BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
> + },
> + {
> + .type = IIO_TEMP,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
> + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ) |
> + BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
> + },
> + {
> + .type = IIO_HUMIDITYRELATIVE,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
> + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
> + .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ) |
> + BIT(IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY),
> + },
> +};
> +
> static int bmp280_read_calib(struct bmp280_data *data,
> struct bmp280_calib *calib,
> unsigned int chip)
> @@ -514,6 +575,15 @@ static int bmp280_read_raw(struct iio_dev *indio_dev,
> break;
> }
> break;
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + *val = data->chip_info->sampling_freq_avail[data->sampling_freq][0];
This is currently safe, but given sampling_freq_avail is only present for one device type,
I'd prefer a sanity check that it is not NULL.

> + *val2 = data->chip_info->sampling_freq_avail[data->sampling_freq][1];
> + ret = IIO_VAL_INT_PLUS_MICRO;
> + break;
> + case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> + *val = data->chip_info->iir_filter_coeffs_avail[data->iir_filter_coeff];
> + ret = IIO_VAL_INT;
> + break;
> default:
> ret = -EINVAL;
> break;
> @@ -577,6 +647,39 @@ static int bmp280_write_oversampling_ratio_press(struct bmp280_data *data,
> return -EINVAL;
> }
>
> +static int bmp280_write_sampling_frequency(struct bmp280_data *data,
> + int val, int val2)
> +{
> + int i;
> + const int (*avail)[2] = data->chip_info->sampling_freq_avail;
> + const int n = data->chip_info->num_sampling_freq_avail;
> +
> + for (i = 0; i < n; i++) {
> + if (avail[i][0] == val && avail[i][1] == val2) {
> + data->sampling_freq = i;
better to only set the cached value if the write succeeds.

e.g.
ret = data->chip_info->chip_config(data);
if (ret)
return ret;

data->sampling_freq = i;

return 0;
> +
> + return data->chip_info->chip_config(data);
> + }
> + }
> + return -EINVAL;
> +}
> +
> +static int bmp280_write_iir_filter_coeffs(struct bmp280_data *data, int val)
> +{
> + int i;
> + const int *avail = data->chip_info->iir_filter_coeffs_avail;
> + const int n = data->chip_info->num_iir_filter_coeffs_avail;
> +
> + for (i = 0; i < n; i++) {
> + if (avail[i] == val) {
> + data->iir_filter_coeff = i;
> +
As for previous function, set the cached value only after you know the write
succeeded.

> + return data->chip_info->chip_config(data);
> + }
> + }
> + return -EINVAL;
> +}
> +
> static int bmp280_write_raw(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan,
> int val, int val2, long mask)
> @@ -606,6 +709,22 @@ static int bmp280_write_raw(struct iio_dev *indio_dev,
> pm_runtime_mark_last_busy(data->dev);
> pm_runtime_put_autosuspend(data->dev);
> break;
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + pm_runtime_get_sync(data->dev);
> + mutex_lock(&data->lock);
> + ret = bmp280_write_sampling_frequency(data, val, val2);
> + mutex_unlock(&data->lock);
> + pm_runtime_mark_last_busy(data->dev);
> + pm_runtime_put_autosuspend(data->dev);
> + break;
> + case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> + pm_runtime_get_sync(data->dev);
> + mutex_lock(&data->lock);
> + ret = bmp280_write_iir_filter_coeffs(data, val);
> + mutex_unlock(&data->lock);
> + pm_runtime_mark_last_busy(data->dev);
> + pm_runtime_put_autosuspend(data->dev);
> + break;
> default:
> return -EINVAL;
> }
> @@ -636,6 +755,17 @@ static int bmp280_read_avail(struct iio_dev *indio_dev,
> }
> *type = IIO_VAL_INT;
> return IIO_AVAIL_LIST;
> + case IIO_CHAN_INFO_SAMP_FREQ:
> + *vals = (const int *)data->chip_info->sampling_freq_avail;
> + *type = IIO_VAL_INT_PLUS_MICRO;
> + /* Values are stored in a 2D matrix */
> + *length = data->chip_info->num_sampling_freq_avail;
> + return IIO_AVAIL_LIST;
> + case IIO_CHAN_INFO_LOW_PASS_FILTER_3DB_FREQUENCY:
> + *vals = data->chip_info->iir_filter_coeffs_avail;
> + *type = IIO_VAL_INT;
> + *length = data->chip_info->num_iir_filter_coeffs_avail;
> + return IIO_AVAIL_LIST;
> default:
> return -EINVAL;
> }
> @@ -749,7 +879,7 @@ static int bmp380_cmd(struct bmp280_data *data, u8 cmd)
> goto failure;
> }
> /* wait for 2ms for command to be proccessed */
> - usleep_range(2000, 2500);
> + usleep_range(data->start_up_time, data->start_up_time + 100);
> /* check for command processing error */
> ret = regmap_read(data->regmap, BMP380_REG_ERROR, &reg);
> if (ret) {
> @@ -943,6 +1073,27 @@ static int bmp380_read_calib(struct bmp280_data *data,
> return 0;
> }
>
> +static const int bmp380_odr_table[][2] = {
> + [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},
> +};
> +
> static int bmp380_chip_config(struct bmp280_data *data)
> {
> u8 osrs;
> @@ -976,7 +1127,7 @@ static int bmp380_chip_config(struct bmp280_data *data)
>
> /* configure output data rate */
> ret = regmap_write_bits(data->regmap, BMP380_REG_ODR,
> - BMP380_ODRS_MASK, BMP380_ODRS_50HZ);
> + BMP380_ODRS_MASK, data->sampling_freq);
> if (ret < 0) {
> dev_err(data->dev, "failed to write ODR selection register\n");
> return ret;
> @@ -990,6 +1141,9 @@ static int bmp380_chip_config(struct bmp280_data *data)
> return ret;
> }
>
> + /* startup time wait to verify config */
> + usleep_range(data->start_up_time, data->start_up_time + 100);
> +

Only necessary now? Or is this a fix for what was here before?

> /* check config error flag */
> ret = regmap_read(data->regmap, BMP380_REG_ERROR, &tmp);
> if (ret < 0) {
> @@ -1007,6 +1161,7 @@ static int bmp380_chip_config(struct bmp280_data *data)
> }
>
> static const int bmp380_oversampling_avail[] = { 1, 2, 4, 8, 16, 32 };
> +static const int bmp380_iir_filter_coeffs_avail[] = { 0, 1, 3, 7, 15, 31, 63, 127 };
>
> static const struct bmp280_chip_info bmp380_chip_info = {
> .oversampling_temp_avail = bmp380_oversampling_avail,
> @@ -1015,6 +1170,12 @@ static const struct bmp280_chip_info bmp380_chip_info = {
> .oversampling_press_avail = bmp380_oversampling_avail,
> .num_oversampling_press_avail = ARRAY_SIZE(bmp380_oversampling_avail),
>
> + .sampling_freq_avail = bmp380_odr_table,
> + .num_sampling_freq_avail = ARRAY_SIZE(bmp380_odr_table) * 2,
> +
> + .iir_filter_coeffs_avail = bmp380_iir_filter_coeffs_avail,
> + .num_iir_filter_coeffs_avail = ARRAY_SIZE(bmp380_iir_filter_coeffs_avail),
> +
> .chip_config = bmp380_chip_config,
> .read_temp = bmp380_read_temp,
> .read_press = bmp380_read_press,
> @@ -1369,9 +1530,12 @@ int bmp280_common_probe(struct device *dev,
> break;
> case BMP380_CHIP_ID:
> indio_dev->num_channels = 2;
> + indio_dev->channels = bmp380_channels;
> data->chip_info = &bmp380_chip_info;
> data->oversampling_press = ilog2(4);
> data->oversampling_temp = ilog2(1);
> + data->iir_filter_coeff = 2;
> + data->sampling_freq = BMP380_ODR_50HZ;
> data->start_up_time = 2000;
> break;
> default:
> diff --git a/drivers/iio/pressure/bmp280.h b/drivers/iio/pressure/bmp280.h
> index b4c122525ffe..f9e21546957e 100644
> --- a/drivers/iio/pressure/bmp280.h
> +++ b/drivers/iio/pressure/bmp280.h
> @@ -71,24 +71,6 @@
> #define BMP380_OSRS_PRESS_32X BMP380_OSRS_PRESS_X(5)
>
> #define BMP380_ODRS_MASK GENMASK(4, 0)
> -#define BMP380_ODRS_200HZ 0x00
> -#define BMP380_ODRS_100HZ 0x01
> -#define BMP380_ODRS_50HZ 0x02
> -#define BMP380_ODRS_25HZ 0x03
> -#define BMP380_ODRS_12_5HZ 0x04
> -#define BMP380_ODRS_6_25HZ 0x05
> -#define BMP380_ODRS_3_1HZ 0x06
> -#define BMP380_ODRS_1_5HZ 0x07
> -#define BMP380_ODRS_0_78HZ 0x08
> -#define BMP380_ODRS_0_39HZ 0x09
> -#define BMP380_ODRS_0_2HZ 0x0A
> -#define BMP380_ODRS_0_1HZ 0x0B
> -#define BMP380_ODRS_0_05HZ 0x0C
> -#define BMP380_ODRS_0_02HZ 0x0D
> -#define BMP380_ODRS_0_01HZ 0x0E
> -#define BMP380_ODRS_0_006HZ 0x0F
> -#define BMP380_ODRS_0_003HZ 0x10
> -#define BMP380_ODRS_0_0015HZ 0x11
>
> #define BMP380_CTRL_SENSORS_MASK GENMASK(1, 0)
> #define BMP380_CTRL_SENSORS_PRESS_EN BIT(0)

Next message: Zheng Zhi Yuan: "[PATCH] drivers: fix typo in firmware/efi/memmap.c"
Previous message: Lino Sanfilippo: "Re: [PATCH 4/8] serial: core: sanitize RS485 delays read from device tree"
In reply to: Angel Iglesias: "[PATCH 3/3] iio: pressure: bmp280: Adds more tunable config parameters for BMP380"
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