Hi Akinobu,
On Sat, Apr 16, 2016 at 02:53:47AM +0900, Akinobu Mita wrote:
> This adds ability to control the oversampling ratio of the temperature
> and pressure measurement for both bmp180 and bmp280.
> (bmp280 is untested for now)
Code looks good, but I found a pretty big issue when testing with the
actual device. Details inline.
>
> Signed-off-by: Akinobu Mita <akinobu.mita@xxxxxxxxx>
> Cc: Vlad Dogaru <vlad.dogaru@xxxxxxxxx>
> Cc: Christoph Mair <christoph.mair@xxxxxxxxx>
> Cc: Jonathan Cameron <jic23@xxxxxxxxxx>
> Cc: Hartmut Knaack <knaack.h@xxxxxx>
> Cc: Lars-Peter Clausen <lars@xxxxxxxxxx>
> Cc: Peter Meerwald <pmeerw@xxxxxxxxxx>
> ---
> drivers/iio/pressure/bmp280.c | 202 ++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 184 insertions(+), 18 deletions(-)
>
> diff --git a/drivers/iio/pressure/bmp280.c b/drivers/iio/pressure/bmp280.c
> index 28daa74..fd931c7 100644
> --- a/drivers/iio/pressure/bmp280.c
> +++ b/drivers/iio/pressure/bmp280.c
> @@ -50,19 +50,21 @@
>
> #define BMP280_OSRS_TEMP_MASK (BIT(7) | BIT(6) | BIT(5))
> #define BMP280_OSRS_TEMP_SKIP 0
> -#define BMP280_OSRS_TEMP_1X BIT(5)
> -#define BMP280_OSRS_TEMP_2X BIT(6)
> -#define BMP280_OSRS_TEMP_4X (BIT(6) | BIT(5))
> -#define BMP280_OSRS_TEMP_8X BIT(7)
> -#define BMP280_OSRS_TEMP_16X (BIT(7) | BIT(5))
> +#define BMP280_OSRS_TEMP_X(osrs_t) ((osrs_t) << 5)
> +#define BMP280_OSRS_TEMP_1X BMP280_OSRS_TEMP_X(1)
> +#define BMP280_OSRS_TEMP_2X BMP280_OSRS_TEMP_X(2)
> +#define BMP280_OSRS_TEMP_4X BMP280_OSRS_TEMP_X(3)
> +#define BMP280_OSRS_TEMP_8X BMP280_OSRS_TEMP_X(4)
> +#define BMP280_OSRS_TEMP_16X BMP280_OSRS_TEMP_X(5)
>
> #define BMP280_OSRS_PRESS_MASK (BIT(4) | BIT(3) | BIT(2))
> #define BMP280_OSRS_PRESS_SKIP 0
> -#define BMP280_OSRS_PRESS_1X BIT(2)
> -#define BMP280_OSRS_PRESS_2X BIT(3)
> -#define BMP280_OSRS_PRESS_4X (BIT(3) | BIT(2))
> -#define BMP280_OSRS_PRESS_8X BIT(4)
> -#define BMP280_OSRS_PRESS_16X (BIT(4) | BIT(2))
> +#define BMP280_OSRS_PRESS_X(osrs_p) ((osrs_p) << 2)
> +#define BMP280_OSRS_PRESS_1X BMP280_OSRS_PRESS_X(1)
> +#define BMP280_OSRS_PRESS_2X BMP280_OSRS_PRESS_X(2)
> +#define BMP280_OSRS_PRESS_4X BMP280_OSRS_PRESS_X(3)
> +#define BMP280_OSRS_PRESS_8X BMP280_OSRS_PRESS_X(4)
> +#define BMP280_OSRS_PRESS_16X BMP280_OSRS_PRESS_X(5)
>
> #define BMP280_MODE_MASK (BIT(1) | BIT(0))
> #define BMP280_MODE_SLEEP 0
> @@ -104,6 +106,9 @@ struct bmp280_data {
> struct regmap *regmap;
> const struct bmp280_chip_info *chip_info;
>
> + u8 oversampling_press;
> + u8 oversampling_temp;
> +
> /*
> * Carryover value from temperature conversion, used in pressure
> * calculation.
> @@ -114,6 +119,12 @@ struct bmp280_data {
> struct bmp280_chip_info {
> const struct regmap_config *regmap_config;
>
> + const int *oversampling_temp_avail;
> + int num_oversampling_temp_avail;
> +
> + const int *oversampling_press_avail;
> + int num_oversampling_press_avail;
> +
> int (*chip_config)(struct bmp280_data *);
> int (*read_temp)(struct bmp280_data *, int *);
> int (*read_press)(struct bmp280_data *, int *, int *);
> @@ -129,11 +140,13 @@ enum { P1, P2, P3, P4, P5, P6, P7, P8, P9 };
> static const struct iio_chan_spec bmp280_channels[] = {
> {
> .type = IIO_PRESSURE,
> - .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
> + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
> },
> {
> .type = IIO_TEMP,
> - .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED),
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
> + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
> },
> };
>
> @@ -339,6 +352,21 @@ static int bmp280_read_raw(struct iio_dev *indio_dev,
> break;
> }
> break;
> + case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> + switch (chan->type) {
> + case IIO_PRESSURE:
> + *val = 1 << data->oversampling_press;
> + ret = IIO_VAL_INT;
> + break;
> + case IIO_TEMP:
> + *val = 1 << data->oversampling_temp;
> + ret = IIO_VAL_INT;
> + break;
> + default:
> + ret = -EINVAL;
> + break;
> + }
> + break;
> default:
> ret = -EINVAL;
> break;
> @@ -349,22 +377,135 @@ static int bmp280_read_raw(struct iio_dev *indio_dev,
> return ret;
> }
>
> +static int bmp280_write_oversampling_ratio_temp(struct bmp280_data *data,
> + int val)
> +{
> + int i;
> + const int *avail = data->chip_info->oversampling_temp_avail;
> + const int n = data->chip_info->num_oversampling_temp_avail;
> +
> + for (i = 0; i < n; i++) {
> + if (avail[i] == val) {
> + data->oversampling_temp = ilog2(val);
This is incorrect. According to the datasheet, you should add 1 to the
return value of ilog2. Thus, if val is 16, ilog2 is 4 and the
oversampling factor should be set to 5. See Table 21 and Table 22 of
the BMP280 datasheet.
I wouldn't have noticed this but for the following bug: as the code
stands right now, setting an oversampling factor of 1 will result in
setting the bits in the register to 0, which corresponds to "skip
measurement" and a constant reading of 25.0C and ~77kPa.
> +
> + return data->chip_info->chip_config(data);
> + }
> + }
> + return -EINVAL;
> +}
> +
> +static int bmp280_write_oversampling_ratio_press(struct bmp280_data *data,
> + int val)
> +{
> + int i;
> + const int *avail = data->chip_info->oversampling_press_avail;
> + const int n = data->chip_info->num_oversampling_press_avail;
> +
> + for (i = 0; i < n; i++) {
> + if (avail[i] == val) {
> + data->oversampling_press = ilog2(val);
Same remark as above.
Thanks,
Vlad
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