* 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
#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
#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
#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)
#define BMP180_CHIP_ID 0x55
#define BMP280_CHIP_ID 0x58
+#define BME280_CHIP_ID 0x60
#define BMP280_SOFT_RESET_VAL 0xB6
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
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 *);
};
/*
.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;
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:
.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,
.volatile_reg = bmp280_is_volatile_reg,
};
+/*
+ * 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
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)
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;
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;
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)
{
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;
.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) {
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;
}
{"BMP0280", BMP280_CHIP_ID },
{"BMP0180", BMP180_CHIP_ID },
{"BMP0085", BMP180_CHIP_ID },
+ {"BME0280", BME280_CHIP_ID },
{ },
};
MODULE_DEVICE_TABLE(acpi, bmp280_acpi_match);
{"bmp280", BMP280_CHIP_ID },
{"bmp180", BMP180_CHIP_ID },
{"bmp085", BMP180_CHIP_ID },
+ {"bme280", BME280_CHIP_ID },
{ },
};
MODULE_DEVICE_TABLE(i2c, bmp280_id);
projects / cascardo / linux.git / blobdiff