From: Matt Ranostay <mranostay@gmail.com>
To: Matt Ranostay <matt.ranostay@intel.com>,
Daniel Baluta <daniel.baluta@intel.com>
Cc: Jonathan Cameron <jic23@kernel.org>,
"linux-iio@vger.kernel.org" <linux-iio@vger.kernel.org>
Subject: Re: [PATCH v2] iio: pressure: bmp280: add humidity support
Date: Tue, 10 May 2016 19:18:45 -0700 [thread overview]
Message-ID: <CAKzfze9sqJEUgijJyd11wqc9Co2nu1UDsg-BcaAbe3EnwDVBXA@mail.gmail.com> (raw)
In-Reply-To: <1462427850-19749-1-git-send-email-matt.ranostay@intel.com>
Adding Daniel who I forgot to CC in the initial submission
On Wed, May 4, 2016 at 10:57 PM, Matt Ranostay <matt.ranostay@intel.com> wrote:
> Enable humidity support for the BME280 part
>
> Signed-off-by: Matt Ranostay <matt.ranostay@intel.com>
> ---
>
> changes from v1:
> * rework to use new multiple chip selection method
> * fix issue with humidity coefficients being off by one
> * fixed incorrect shifted coefficients
> * added oversampling configuration for humidity
>
> drivers/iio/pressure/bmp280.c | 200 +++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 198 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/pressure/bmp280.c b/drivers/iio/pressure/bmp280.c
> index 2f1498e..1876b50 100644
> --- a/drivers/iio/pressure/bmp280.c
> +++ b/drivers/iio/pressure/bmp280.c
> @@ -10,6 +10,7 @@
> * Datasheet:
> * https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BMP180-DS000-121.pdf
> * https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BMP280-DS001-12.pdf
> + * https://ae-bst.resource.bosch.com/media/_tech/media/datasheets/BST-BME280_DS001-11.pdf
> */
>
> #define pr_fmt(fmt) "bmp280: " fmt
> @@ -23,6 +24,8 @@
> #include <linux/iio/sysfs.h>
>
> /* BMP280 specific registers */
> +#define BMP280_REG_HUMIDITY_LSB 0xFE
> +#define BMP280_REG_HUMIDITY_MSB 0xFD
> #define BMP280_REG_TEMP_XLSB 0xFC
> #define BMP280_REG_TEMP_LSB 0xFB
> #define BMP280_REG_TEMP_MSB 0xFA
> @@ -31,7 +34,17 @@
> #define BMP280_REG_PRESS_MSB 0xF7
>
> #define BMP280_REG_CONFIG 0xF5
> +#define BMP280_REG_CTRL_MEAS 0xF4
> #define BMP280_REG_STATUS 0xF3
> +#define BMP280_REG_CTRL_HUMIDITY 0xF2
> +
> +/* Due to non linear mapping, and data sizes we can't do a bulk read */
> +#define BMP280_REG_COMP_H1 0xA1
> +#define BMP280_REG_COMP_H2 0xE1
> +#define BMP280_REG_COMP_H3 0xE3
> +#define BMP280_REG_COMP_H4 0xE4
> +#define BMP280_REG_COMP_H5 0xE5
> +#define BMP280_REG_COMP_H6 0xE7
>
> #define BMP280_REG_COMP_TEMP_START 0x88
> #define BMP280_COMP_TEMP_REG_COUNT 6
> @@ -46,6 +59,15 @@
> #define BMP280_FILTER_8X (BIT(3) | BIT(2))
> #define BMP280_FILTER_16X BIT(4)
>
> +#define BMP280_OSRS_HUMIDITY_MASK (BIT(2) | BIT(1) | BIT(0))
> +#define BMP280_OSRS_HUMIDITIY_X(osrs_h) ((osrs_h) << 0)
> +#define BMP280_OSRS_HUMIDITY_SKIP 0
> +#define BMP280_OSRS_HUMIDITY_1X BMP280_OSRS_HUMIDITIY_X(1)
> +#define BMP280_OSRS_HUMIDITY_2X BMP280_OSRS_HUMIDITIY_X(2)
> +#define BMP280_OSRS_HUMIDITY_4X BMP280_OSRS_HUMIDITIY_X(3)
> +#define BMP280_OSRS_HUMIDITY_8X BMP280_OSRS_HUMIDITIY_X(4)
> +#define BMP280_OSRS_HUMIDITY_16X BMP280_OSRS_HUMIDITIY_X(5)
> +
> #define BMP280_OSRS_TEMP_MASK (BIT(7) | BIT(6) | BIT(5))
> #define BMP280_OSRS_TEMP_SKIP 0
> #define BMP280_OSRS_TEMP_X(osrs_t) ((osrs_t) << 5)
> @@ -92,6 +114,7 @@
>
> #define BMP180_CHIP_ID 0x55
> #define BMP280_CHIP_ID 0x58
> +#define BME280_CHIP_ID 0x60
> #define BMP280_SOFT_RESET_VAL 0xB6
>
> struct bmp280_data {
> @@ -103,6 +126,7 @@ struct bmp280_data {
> /* log of base 2 of oversampling rate */
> u8 oversampling_press;
> u8 oversampling_temp;
> + u8 oversampling_humid;
>
> /*
> * Carryover value from temperature conversion, used in pressure
> @@ -120,9 +144,13 @@ struct bmp280_chip_info {
> const int *oversampling_press_avail;
> int num_oversampling_press_avail;
>
> + const int *oversampling_humid_avail;
> + int num_oversampling_humid_avail;
> +
> int (*chip_config)(struct bmp280_data *);
> int (*read_temp)(struct bmp280_data *, int *);
> int (*read_press)(struct bmp280_data *, int *, int *);
> + int (*read_humid)(struct bmp280_data *, int *, int *);
> };
>
> /*
> @@ -143,12 +171,18 @@ static const struct iio_chan_spec bmp280_channels[] = {
> .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
> BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
> },
> + {
> + .type = IIO_HUMIDITYRELATIVE,
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED) |
> + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
> + },
> };
>
> static bool bmp280_is_writeable_reg(struct device *dev, unsigned int reg)
> {
> switch (reg) {
> case BMP280_REG_CONFIG:
> + case BMP280_REG_CTRL_HUMIDITY:
> case BMP280_REG_CTRL_MEAS:
> case BMP280_REG_RESET:
> return true;
> @@ -160,6 +194,8 @@ static bool bmp280_is_writeable_reg(struct device *dev, unsigned int reg)
> static bool bmp280_is_volatile_reg(struct device *dev, unsigned int reg)
> {
> switch (reg) {
> + case BMP280_REG_HUMIDITY_LSB:
> + case BMP280_REG_HUMIDITY_MSB:
> case BMP280_REG_TEMP_XLSB:
> case BMP280_REG_TEMP_LSB:
> case BMP280_REG_TEMP_MSB:
> @@ -177,7 +213,7 @@ static const struct regmap_config bmp280_regmap_config = {
> .reg_bits = 8,
> .val_bits = 8,
>
> - .max_register = BMP280_REG_TEMP_XLSB,
> + .max_register = BMP280_REG_HUMIDITY_LSB,
> .cache_type = REGCACHE_RBTREE,
>
> .writeable_reg = bmp280_is_writeable_reg,
> @@ -185,6 +221,70 @@ static const struct regmap_config bmp280_regmap_config = {
> };
>
> /*
> + * Returns humidity in percent, resolution is 0.01 percent. Output value of
> + * "47445" represents 47445/1024 = 46.333 %RH.
> + *
> + * Taken from BME280 datasheet, Section 4.2.3, "Compensation formula".
> + */
> +
> +static u32 bmp280_compensate_humidity(struct bmp280_data *data,
> + s32 adc_humidity)
> +{
> + struct device *dev = &data->client->dev;
> + unsigned int H1, H3, tmp;
> + int H2, H4, H5, H6, ret, var;
> +
> + ret = regmap_read(data->regmap, BMP280_REG_COMP_H1, &H1);
> + if (ret < 0) {
> + dev_err(dev, "failed to read H1 comp value\n");
> + return ret;
> + }
> +
> + ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H2, &tmp, 2);
> + if (ret < 0) {
> + dev_err(dev, "failed to read H2 comp value\n");
> + return ret;
> + }
> + H2 = sign_extend32(le16_to_cpu(tmp), 15);
> +
> + ret = regmap_read(data->regmap, BMP280_REG_COMP_H3, &H3);
> + if (ret < 0) {
> + dev_err(dev, "failed to read H3 comp value\n");
> + return ret;
> + }
> +
> + ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H4, &tmp, 2);
> + if (ret < 0) {
> + dev_err(dev, "failed to read H4 comp value\n");
> + return ret;
> + }
> + H4 = sign_extend32(((be16_to_cpu(tmp) >> 4) & 0xff0) |
> + (be16_to_cpu(tmp) & 0xf), 11);
> +
> + ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_H5, &tmp, 2);
> + if (ret < 0) {
> + dev_err(dev, "failed to read H5 comp value\n");
> + return ret;
> + }
> + H5 = sign_extend32(((le16_to_cpu(tmp) >> 4) & 0xfff), 11);
> +
> + ret = regmap_read(data->regmap, BMP280_REG_COMP_H6, &tmp);
> + if (ret < 0) {
> + dev_err(dev, "failed to read H6 comp value\n");
> + return ret;
> + }
> + H6 = sign_extend32(tmp, 7);
> +
> + var = ((s32)data->t_fine) - 76800;
> + var = ((((adc_humidity << 14) - (H4 << 20) - (H5 * var)) + 16384) >> 15)
> + * (((((((var * H6) >> 10) * (((var * H3) >> 11) + 32768)) >> 10)
> + + 2097152) * H2 + 8192) >> 14);
> + var -= ((((var >> 15) * (var >> 15)) >> 7) * H1) >> 4;
> +
> + return var >> 12;
> +};
> +
> +/*
> * Returns temperature in DegC, resolution is 0.01 DegC. Output value of
> * "5123" equals 51.23 DegC. t_fine carries fine temperature as global
> * value.
> @@ -324,6 +424,34 @@ static int bmp280_read_press(struct bmp280_data *data,
> return IIO_VAL_FRACTIONAL;
> }
>
> +static int bmp280_read_humid(struct bmp280_data *data, int *val, int *val2)
> +{
> + int ret;
> + __be16 tmp = 0;
> + s32 adc_humidity;
> + u32 comp_humidity;
> +
> + /* Read and compensate temperature so we get a reading of t_fine. */
> + ret = bmp280_read_temp(data, NULL);
> + if (ret < 0)
> + return ret;
> +
> + ret = regmap_bulk_read(data->regmap, BMP280_REG_HUMIDITY_MSB,
> + (u8 *) &tmp, 2);
> + if (ret < 0) {
> + dev_err(&data->client->dev, "failed to read humidity\n");
> + return ret;
> + }
> +
> + adc_humidity = be16_to_cpu(tmp);
> + comp_humidity = bmp280_compensate_humidity(data, adc_humidity);
> +
> + *val = comp_humidity;
> + *val2 = 1024;
> +
> + return IIO_VAL_FRACTIONAL;
> +}
> +
> static int bmp280_read_raw(struct iio_dev *indio_dev,
> struct iio_chan_spec const *chan,
> int *val, int *val2, long mask)
> @@ -336,6 +464,9 @@ static int bmp280_read_raw(struct iio_dev *indio_dev,
> switch (mask) {
> case IIO_CHAN_INFO_PROCESSED:
> switch (chan->type) {
> + case IIO_HUMIDITYRELATIVE:
> + ret = data->chip_info->read_humid(data, val, val2);
> + break;
> case IIO_PRESSURE:
> ret = data->chip_info->read_press(data, val, val2);
> break;
> @@ -349,6 +480,10 @@ static int bmp280_read_raw(struct iio_dev *indio_dev,
> break;
> case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> switch (chan->type) {
> + case IIO_HUMIDITYRELATIVE:
> + *val = 1 << data->oversampling_humid;
> + ret = IIO_VAL_INT;
> + break;
> case IIO_PRESSURE:
> *val = 1 << data->oversampling_press;
> ret = IIO_VAL_INT;
> @@ -372,6 +507,23 @@ static int bmp280_read_raw(struct iio_dev *indio_dev,
> return ret;
> }
>
> +static int bmp280_write_oversampling_ratio_humid(struct bmp280_data *data,
> + int val)
> +{
> + int i;
> + const int *avail = data->chip_info->oversampling_humid_avail;
> + const int n = data->chip_info->num_oversampling_humid_avail;
> +
> + for (i = 0; i < n; i++) {
> + if (avail[i] == val) {
> + data->oversampling_humid = ilog2(val);
> +
> + return data->chip_info->chip_config(data);
> + }
> + }
> + return -EINVAL;
> +}
> +
> static int bmp280_write_oversampling_ratio_temp(struct bmp280_data *data,
> int val)
> {
> @@ -417,6 +569,9 @@ static int bmp280_write_raw(struct iio_dev *indio_dev,
> case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> mutex_lock(&data->lock);
> switch (chan->type) {
> + case IIO_HUMIDITYRELATIVE:
> + ret = bmp280_write_oversampling_ratio_humid(data, val);
> + break;
> case IIO_PRESSURE:
> ret = bmp280_write_oversampling_ratio_press(data, val);
> break;
> @@ -535,6 +690,37 @@ static const struct bmp280_chip_info bmp280_chip_info = {
> .read_press = bmp280_read_press,
> };
>
> +static int bme280_chip_config(struct bmp280_data *data)
> +{
> + int ret = bmp280_chip_config(data);
> + u8 osrs = BMP280_OSRS_HUMIDITIY_X(data->oversampling_humid + 1);
> +
> + if (ret < 0)
> + return ret;
> +
> + return regmap_update_bits(data->regmap, BMP280_REG_CTRL_HUMIDITY,
> + BMP280_OSRS_HUMIDITY_MASK, osrs);
> +}
> +
> +static const struct bmp280_chip_info bme280_chip_info = {
> + .regmap_config = &bmp280_regmap_config,
> +
> + .oversampling_temp_avail = bmp280_oversampling_avail,
> + .num_oversampling_temp_avail = ARRAY_SIZE(bmp280_oversampling_avail),
> +
> + .oversampling_press_avail = bmp280_oversampling_avail,
> + .num_oversampling_press_avail = ARRAY_SIZE(bmp280_oversampling_avail),
> +
> + .oversampling_humid_avail = bmp280_oversampling_avail,
> + .num_oversampling_humid_avail = ARRAY_SIZE(bmp280_oversampling_avail),
> +
> + .chip_config = bme280_chip_config,
> + .read_temp = bmp280_read_temp,
> + .read_press = bmp280_read_press,
> + .read_humid = bmp280_read_humid,
> +};
> +
> +
> static bool bmp180_is_writeable_reg(struct device *dev, unsigned int reg)
> {
> switch (reg) {
> @@ -849,21 +1035,29 @@ static int bmp280_probe(struct i2c_client *client,
> indio_dev->dev.parent = &client->dev;
> indio_dev->name = id->name;
> indio_dev->channels = bmp280_channels;
> - indio_dev->num_channels = ARRAY_SIZE(bmp280_channels);
> indio_dev->info = &bmp280_info;
> indio_dev->modes = INDIO_DIRECT_MODE;
>
> switch (id->driver_data) {
> case BMP180_CHIP_ID:
> + indio_dev->num_channels = 2;
> data->chip_info = &bmp180_chip_info;
> data->oversampling_press = ilog2(8);
> data->oversampling_temp = ilog2(1);
> break;
> case BMP280_CHIP_ID:
> + indio_dev->num_channels = 2;
> data->chip_info = &bmp280_chip_info;
> data->oversampling_press = ilog2(16);
> data->oversampling_temp = ilog2(2);
> break;
> + case BME280_CHIP_ID:
> + indio_dev->num_channels = 3;
> + data->chip_info = &bme280_chip_info;
> + data->oversampling_press = ilog2(16);
> + data->oversampling_humid = ilog2(16);
> + data->oversampling_temp = ilog2(2);
> + break;
> default:
> return -EINVAL;
> }
> @@ -895,6 +1089,7 @@ static const struct acpi_device_id bmp280_acpi_match[] = {
> {"BMP0280", BMP280_CHIP_ID },
> {"BMP0180", BMP180_CHIP_ID },
> {"BMP0085", BMP180_CHIP_ID },
> + {"BME0280", BME280_CHIP_ID },
> { },
> };
> MODULE_DEVICE_TABLE(acpi, bmp280_acpi_match);
> @@ -903,6 +1098,7 @@ static const struct i2c_device_id bmp280_id[] = {
> {"bmp280", BMP280_CHIP_ID },
> {"bmp180", BMP180_CHIP_ID },
> {"bmp085", BMP180_CHIP_ID },
> + {"bme280", BME280_CHIP_ID },
> { },
> };
> MODULE_DEVICE_TABLE(i2c, bmp280_id);
> --
> 2.7.4
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
next prev parent reply other threads:[~2016-05-11 2:18 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-05 5:57 [PATCH v2] iio: pressure: bmp280: add humidity support Matt Ranostay
2016-05-11 2:18 ` Matt Ranostay [this message]
2016-05-14 17:12 ` Jonathan Cameron
2016-05-17 7:30 ` Vlad Dogaru
2016-05-20 2:00 ` Matt Ranostay
2016-05-21 19:26 ` Jonathan Cameron
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