On Tue, 25 Jul 2017 11:11:14 +0200
Andreas Klinger <ak@xxxxxxxxxxxxx> wrote:
> If the device is not initialized at least once it happens that the humidity
> reading is skipped, which means the special value 0x8000 is delivered.
>
> For omitting this case the oversampling of the humidity must be set before
> the oversampling of the temperature und pressure is set as written in the
> datasheet of the BME280.
>
> Furthermore proper error detection is added in case a skipped value is read
> from the device. This is done also for pressure and temperature reading.
> Especially it don't make sense to compensate this value and treat it as
> regular value.
>
> Signed-off-by: Andreas Klinger <ak@xxxxxxxxxxxxx>
Applied to the fixes togreg branch of iio.git.
Thanks,
Jonathan
> ---
> drivers/iio/pressure/bmp280-core.c | 27 ++++++++++++++++++++++++---
> drivers/iio/pressure/bmp280.h | 5 +++++
> 2 files changed, 29 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c
> index 4d18826ac63c..d434e2c23833 100644
> --- a/drivers/iio/pressure/bmp280-core.c
> +++ b/drivers/iio/pressure/bmp280-core.c
> @@ -281,6 +281,11 @@ static int bmp280_read_temp(struct bmp280_data *data,
> }
>
> adc_temp = be32_to_cpu(tmp) >> 12;
> + if (adc_temp == BMP280_TEMP_SKIPPED) {
> + /* reading was skipped */
> + dev_err(data->dev, "reading temperature skipped\n");
> + return -EIO;
> + }
> comp_temp = bmp280_compensate_temp(data, adc_temp);
>
> /*
> @@ -316,6 +321,11 @@ static int bmp280_read_press(struct bmp280_data *data,
> }
>
> adc_press = be32_to_cpu(tmp) >> 12;
> + if (adc_press == BMP280_PRESS_SKIPPED) {
> + /* reading was skipped */
> + dev_err(data->dev, "reading pressure skipped\n");
> + return -EIO;
> + }
> comp_press = bmp280_compensate_press(data, adc_press);
>
> *val = comp_press;
> @@ -344,6 +354,11 @@ static int bmp280_read_humid(struct bmp280_data *data, int *val, int *val2)
> }
>
> adc_humidity = be16_to_cpu(tmp);
> + if (adc_humidity == BMP280_HUMIDITY_SKIPPED) {
> + /* reading was skipped */
> + dev_err(data->dev, "reading humidity skipped\n");
> + return -EIO;
> + }
> comp_humidity = bmp280_compensate_humidity(data, adc_humidity);
>
> *val = comp_humidity;
> @@ -596,14 +611,20 @@ static const struct bmp280_chip_info bmp280_chip_info = {
>
> static int bme280_chip_config(struct bmp280_data *data)
> {
> - int ret = bmp280_chip_config(data);
> + int ret;
> u8 osrs = BMP280_OSRS_HUMIDITIY_X(data->oversampling_humid + 1);
>
> + /*
> + * Oversampling of humidity must be set before oversampling of
> + * temperature/pressure is set to become effective.
> + */
> + ret = regmap_update_bits(data->regmap, BMP280_REG_CTRL_HUMIDITY,
> + BMP280_OSRS_HUMIDITY_MASK, osrs);
> +
> if (ret < 0)
> return ret;
>
> - return regmap_update_bits(data->regmap, BMP280_REG_CTRL_HUMIDITY,
> - BMP280_OSRS_HUMIDITY_MASK, osrs);
> + return bmp280_chip_config(data);
> }
>
> static const struct bmp280_chip_info bme280_chip_info = {
> diff --git a/drivers/iio/pressure/bmp280.h b/drivers/iio/pressure/bmp280.h
> index 2c770e13be0e..61347438b779 100644
> --- a/drivers/iio/pressure/bmp280.h
> +++ b/drivers/iio/pressure/bmp280.h
> @@ -96,6 +96,11 @@
> #define BME280_CHIP_ID 0x60
> #define BMP280_SOFT_RESET_VAL 0xB6
>
> +/* BMP280 register skipped special values */
> +#define BMP280_TEMP_SKIPPED 0x80000
> +#define BMP280_PRESS_SKIPPED 0x80000
> +#define BMP280_HUMIDITY_SKIPPED 0x8000
> +
> /* Regmap configurations */
> extern const struct regmap_config bmp180_regmap_config;
> extern const struct regmap_config bmp280_regmap_config;
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