diff options
Diffstat (limited to 'drivers/iio/pressure/bmp280-core.c')
| -rw-r--r-- | drivers/iio/pressure/bmp280-core.c | 203 |
1 files changed, 132 insertions, 71 deletions
diff --git a/drivers/iio/pressure/bmp280-core.c b/drivers/iio/pressure/bmp280-core.c index fd1da26a62e4..5ec3e41b65f2 100644 --- a/drivers/iio/pressure/bmp280-core.c +++ b/drivers/iio/pressure/bmp280-core.c @@ -55,6 +55,28 @@ struct bmp180_calib { s16 MD; }; +/* See datasheet Section 4.2.2. */ +struct bmp280_calib { + u16 T1; + s16 T2; + s16 T3; + u16 P1; + s16 P2; + s16 P3; + s16 P4; + s16 P5; + s16 P6; + s16 P7; + s16 P8; + s16 P9; + u8 H1; + s16 H2; + u8 H3; + s16 H4; + s16 H5; + s8 H6; +}; + struct bmp280_data { struct device *dev; struct mutex lock; @@ -62,7 +84,10 @@ struct bmp280_data { struct completion done; bool use_eoc; const struct bmp280_chip_info *chip_info; - struct bmp180_calib calib; + union { + struct bmp180_calib bmp180; + struct bmp280_calib bmp280; + } calib; struct regulator *vddd; struct regulator *vdda; unsigned int start_up_time; /* in microseconds */ @@ -120,67 +145,121 @@ static const struct iio_chan_spec bmp280_channels[] = { }, }; -/* - * 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) +static int bmp280_read_calib(struct bmp280_data *data, + struct bmp280_calib *calib, + unsigned int chip) { + int ret; + unsigned int tmp; struct device *dev = data->dev; - unsigned int H1, H3, tmp; - int H2, H4, H5, H6, ret, var; + __le16 t_buf[BMP280_COMP_TEMP_REG_COUNT / 2]; + __le16 p_buf[BMP280_COMP_PRESS_REG_COUNT / 2]; + + /* Read temperature calibration values. */ + ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START, + t_buf, BMP280_COMP_TEMP_REG_COUNT); + if (ret < 0) { + dev_err(data->dev, + "failed to read temperature calibration parameters\n"); + return ret; + } + + calib->T1 = le16_to_cpu(t_buf[T1]); + calib->T2 = le16_to_cpu(t_buf[T2]); + calib->T3 = le16_to_cpu(t_buf[T3]); - ret = regmap_read(data->regmap, BMP280_REG_COMP_H1, &H1); + /* Read pressure calibration values. */ + ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_PRESS_START, + p_buf, BMP280_COMP_PRESS_REG_COUNT); + if (ret < 0) { + dev_err(data->dev, + "failed to read pressure calibration parameters\n"); + return ret; + } + + calib->P1 = le16_to_cpu(p_buf[P1]); + calib->P2 = le16_to_cpu(p_buf[P2]); + calib->P3 = le16_to_cpu(p_buf[P3]); + calib->P4 = le16_to_cpu(p_buf[P4]); + calib->P5 = le16_to_cpu(p_buf[P5]); + calib->P6 = le16_to_cpu(p_buf[P6]); + calib->P7 = le16_to_cpu(p_buf[P7]); + calib->P8 = le16_to_cpu(p_buf[P8]); + calib->P9 = le16_to_cpu(p_buf[P9]); + + /* + * Read humidity calibration values. + * Due to some odd register addressing we cannot just + * do a big bulk read. Instead, we have to read each Hx + * value separately and sometimes do some bit shifting... + * Humidity data is only available on BME280. + */ + if (chip != BME280_CHIP_ID) + return 0; + + ret = regmap_read(data->regmap, BMP280_REG_COMP_H1, &tmp); if (ret < 0) { dev_err(dev, "failed to read H1 comp value\n"); return ret; } + calib->H1 = tmp; 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); + calib->H2 = sign_extend32(le16_to_cpu(tmp), 15); - ret = regmap_read(data->regmap, BMP280_REG_COMP_H3, &H3); + ret = regmap_read(data->regmap, BMP280_REG_COMP_H3, &tmp); if (ret < 0) { dev_err(dev, "failed to read H3 comp value\n"); return ret; } + calib->H3 = tmp; 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); + calib->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); + calib->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); + calib->H6 = sign_extend32(tmp, 7); + + return 0; +} +/* + * 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) +{ + s32 var; + struct bmp280_calib *calib = &data->calib.bmp280; var = ((s32)data->t_fine) - (s32)76800; - var = ((((adc_humidity << 14) - (H4 << 20) - (H5 * var)) - + (s32)16384) >> 15) * (((((((var * H6) >> 10) - * (((var * (s32)H3) >> 11) + (s32)32768)) >> 10) - + (s32)2097152) * H2 + 8192) >> 14); - var -= ((((var >> 15) * (var >> 15)) >> 7) * (s32)H1) >> 4; + var = ((((adc_humidity << 14) - (calib->H4 << 20) - (calib->H5 * var)) + + (s32)16384) >> 15) * (((((((var * calib->H6) >> 10) + * (((var * (s32)calib->H3) >> 11) + (s32)32768)) >> 10) + + (s32)2097152) * calib->H2 + 8192) >> 14); + var -= ((((var >> 15) * (var >> 15)) >> 7) * (s32)calib->H1) >> 4; return var >> 12; }; @@ -195,31 +274,14 @@ static u32 bmp280_compensate_humidity(struct bmp280_data *data, static s32 bmp280_compensate_temp(struct bmp280_data *data, s32 adc_temp) { - int ret; s32 var1, var2; - __le16 buf[BMP280_COMP_TEMP_REG_COUNT / 2]; + struct bmp280_calib *calib = &data->calib.bmp280; - ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START, - buf, BMP280_COMP_TEMP_REG_COUNT); - if (ret < 0) { - dev_err(data->dev, - "failed to read temperature calibration parameters\n"); - return ret; - } - - /* - * The double casts are necessary because le16_to_cpu returns an - * unsigned 16-bit value. Casting that value directly to a - * signed 32-bit will not do proper sign extension. - * - * Conversely, T1 and P1 are unsigned values, so they can be - * cast straight to the larger type. - */ - var1 = (((adc_temp >> 3) - ((s32)le16_to_cpu(buf[T1]) << 1)) * - ((s32)(s16)le16_to_cpu(buf[T2]))) >> 11; - var2 = (((((adc_temp >> 4) - ((s32)le16_to_cpu(buf[T1]))) * - ((adc_temp >> 4) - ((s32)le16_to_cpu(buf[T1])))) >> 12) * - ((s32)(s16)le16_to_cpu(buf[T3]))) >> 14; + var1 = (((adc_temp >> 3) - ((s32)calib->T1 << 1)) * + ((s32)calib->T2)) >> 11; + var2 = (((((adc_temp >> 4) - ((s32)calib->T1)) * + ((adc_temp >> 4) - ((s32)calib->T1))) >> 12) * + ((s32)calib->T3)) >> 14; data->t_fine = var1 + var2; return (data->t_fine * 5 + 128) >> 8; @@ -235,34 +297,25 @@ static s32 bmp280_compensate_temp(struct bmp280_data *data, static u32 bmp280_compensate_press(struct bmp280_data *data, s32 adc_press) { - int ret; s64 var1, var2, p; - __le16 buf[BMP280_COMP_PRESS_REG_COUNT / 2]; - - ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_PRESS_START, - buf, BMP280_COMP_PRESS_REG_COUNT); - if (ret < 0) { - dev_err(data->dev, - "failed to read pressure calibration parameters\n"); - return ret; - } + struct bmp280_calib *calib = &data->calib.bmp280; var1 = ((s64)data->t_fine) - 128000; - var2 = var1 * var1 * (s64)(s16)le16_to_cpu(buf[P6]); - var2 += (var1 * (s64)(s16)le16_to_cpu(buf[P5])) << 17; - var2 += ((s64)(s16)le16_to_cpu(buf[P4])) << 35; - var1 = ((var1 * var1 * (s64)(s16)le16_to_cpu(buf[P3])) >> 8) + - ((var1 * (s64)(s16)le16_to_cpu(buf[P2])) << 12); - var1 = ((((s64)1) << 47) + var1) * ((s64)le16_to_cpu(buf[P1])) >> 33; + var2 = var1 * var1 * (s64)calib->P6; + var2 += (var1 * (s64)calib->P5) << 17; + var2 += ((s64)calib->P4) << 35; + var1 = ((var1 * var1 * (s64)calib->P3) >> 8) + + ((var1 * (s64)calib->P2) << 12); + var1 = ((((s64)1) << 47) + var1) * ((s64)calib->P1) >> 33; if (var1 == 0) return 0; p = ((((s64)1048576 - adc_press) << 31) - var2) * 3125; p = div64_s64(p, var1); - var1 = (((s64)(s16)le16_to_cpu(buf[P9])) * (p >> 13) * (p >> 13)) >> 25; - var2 = (((s64)(s16)le16_to_cpu(buf[P8])) * p) >> 19; - p = ((p + var1 + var2) >> 8) + (((s64)(s16)le16_to_cpu(buf[P7])) << 4); + var1 = (((s64)calib->P9) * (p >> 13) * (p >> 13)) >> 25; + var2 = ((s64)(calib->P8) * p) >> 19; + p = ((p + var1 + var2) >> 8) + (((s64)calib->P7) << 4); return (u32)p; } @@ -752,7 +805,7 @@ static int bmp180_read_calib(struct bmp280_data *data, static s32 bmp180_compensate_temp(struct bmp280_data *data, s32 adc_temp) { s32 x1, x2; - struct bmp180_calib *calib = &data->calib; + struct bmp180_calib *calib = &data->calib.bmp180; x1 = ((adc_temp - calib->AC6) * calib->AC5) >> 15; x2 = (calib->MC << 11) / (x1 + calib->MD); @@ -814,7 +867,7 @@ static u32 bmp180_compensate_press(struct bmp280_data *data, s32 adc_press) s32 b3, b6; u32 b4, b7; s32 oss = data->oversampling_press; - struct bmp180_calib *calib = &data->calib; + struct bmp180_calib *calib = &data->calib.bmp180; b6 = data->t_fine - 4000; x1 = (calib->B2 * (b6 * b6 >> 12)) >> 11; @@ -1028,11 +1081,19 @@ int bmp280_common_probe(struct device *dev, dev_set_drvdata(dev, indio_dev); /* - * The BMP085 and BMP180 has calibration in an E2PROM, read it out - * at probe time. It will not change. + * Some chips have calibration parameters "programmed into the devices' + * non-volatile memory during production". Let's read them out at probe + * time once. They will not change. */ if (chip_id == BMP180_CHIP_ID) { - ret = bmp180_read_calib(data, &data->calib); + ret = bmp180_read_calib(data, &data->calib.bmp180); + if (ret < 0) { + dev_err(data->dev, + "failed to read calibration coefficients\n"); + goto out_disable_vdda; + } + } else if (chip_id == BMP280_CHIP_ID || chip_id == BME280_CHIP_ID) { + ret = bmp280_read_calib(data, &data->calib.bmp280, chip_id); if (ret < 0) { dev_err(data->dev, "failed to read calibration coefficients\n"); |