Adding Daniel who I forgot to CC in the initial submission On Wed, May 4, 2016 at 10:57 PM, Matt Ranostay <matt.ranostay@xxxxxxxxx> wrote: > Enable humidity support for the BME280 part > > Signed-off-by: Matt Ranostay <matt.ranostay@xxxxxxxxx> > --- > > 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@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html -- To unsubscribe from this list: send the line "unsubscribe linux-iio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
