diff options
Diffstat (limited to 'drivers/iio/pressure/bmp280.c')
| -rw-r--r-- | drivers/iio/pressure/bmp280.c | 150 |
1 files changed, 55 insertions, 95 deletions
diff --git a/drivers/iio/pressure/bmp280.c b/drivers/iio/pressure/bmp280.c index 75038dacfff1..7c623e2bd633 100644 --- a/drivers/iio/pressure/bmp280.c +++ b/drivers/iio/pressure/bmp280.c @@ -80,16 +80,12 @@ struct bmp280_data { s32 t_fine; }; -/* Compensation parameters. */ -struct bmp280_comp_temp { - u16 dig_t1; - s16 dig_t2, dig_t3; -}; - -struct bmp280_comp_press { - u16 dig_p1; - s16 dig_p2, dig_p3, dig_p4, dig_p5, dig_p6, dig_p7, dig_p8, dig_p9; -}; +/* + * These enums are used for indexing into the array of compensation + * parameters. + */ +enum { T1, T2, T3 }; +enum { P1, P2, P3, P4, P5, P6, P7, P8, P9 }; static const struct iio_chan_spec bmp280_channels[] = { { @@ -141,54 +137,6 @@ static const struct regmap_config bmp280_regmap_config = { .volatile_reg = bmp280_is_volatile_reg, }; -static int bmp280_read_compensation_temp(struct bmp280_data *data, - struct bmp280_comp_temp *comp) -{ - int ret; - __le16 buf[BMP280_COMP_TEMP_REG_COUNT / 2]; - - ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START, - buf, BMP280_COMP_TEMP_REG_COUNT); - if (ret < 0) { - dev_err(&data->client->dev, - "failed to read temperature calibration parameters\n"); - return ret; - } - - comp->dig_t1 = (u16) le16_to_cpu(buf[0]); - comp->dig_t2 = (s16) le16_to_cpu(buf[1]); - comp->dig_t3 = (s16) le16_to_cpu(buf[2]); - - return 0; -} - -static int bmp280_read_compensation_press(struct bmp280_data *data, - struct bmp280_comp_press *comp) -{ - int ret; - __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->client->dev, - "failed to read pressure calibration parameters\n"); - return ret; - } - - comp->dig_p1 = (u16) le16_to_cpu(buf[0]); - comp->dig_p2 = (s16) le16_to_cpu(buf[1]); - comp->dig_p3 = (s16) le16_to_cpu(buf[2]); - comp->dig_p4 = (s16) le16_to_cpu(buf[3]); - comp->dig_p5 = (s16) le16_to_cpu(buf[4]); - comp->dig_p6 = (s16) le16_to_cpu(buf[5]); - comp->dig_p7 = (s16) le16_to_cpu(buf[6]); - comp->dig_p8 = (s16) le16_to_cpu(buf[7]); - comp->dig_p9 = (s16) le16_to_cpu(buf[8]); - - return 0; -} - /* * Returns temperature in DegC, resolution is 0.01 DegC. Output value of * "5123" equals 51.23 DegC. t_fine carries fine temperature as global @@ -197,21 +145,35 @@ static int bmp280_read_compensation_press(struct bmp280_data *data, * Taken from datasheet, Section 3.11.3, "Compensation formula". */ static s32 bmp280_compensate_temp(struct bmp280_data *data, - struct bmp280_comp_temp *comp, s32 adc_temp) { - s32 var1, var2, t; + int ret; + s32 var1, var2; + __le16 buf[BMP280_COMP_TEMP_REG_COUNT / 2]; - var1 = (((adc_temp >> 3) - ((s32) comp->dig_t1 << 1)) * - ((s32) comp->dig_t2)) >> 11; - var2 = (((((adc_temp >> 4) - ((s32) comp->dig_t1)) * - ((adc_temp >> 4) - ((s32) comp->dig_t1))) >> 12) * - ((s32) comp->dig_t3)) >> 14; + ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START, + buf, BMP280_COMP_TEMP_REG_COUNT); + if (ret < 0) { + dev_err(&data->client->dev, + "failed to read temperature calibration parameters\n"); + return ret; + } - data->t_fine = var1 + var2; - t = (data->t_fine * 5 + 128) >> 8; + /* + * 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; - return t; + return (data->t_fine * 5 + 128) >> 8; } /* @@ -222,29 +184,38 @@ static s32 bmp280_compensate_temp(struct bmp280_data *data, * Taken from datasheet, Section 3.11.3, "Compensation formula". */ static u32 bmp280_compensate_press(struct bmp280_data *data, - struct bmp280_comp_press *comp, 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->client->dev, + "failed to read pressure calibration parameters\n"); + return ret; + } - var1 = ((s64) data->t_fine) - 128000; - var2 = var1 * var1 * (s64) comp->dig_p6; - var2 = var2 + ((var1 * (s64) comp->dig_p5) << 17); - var2 = var2 + (((s64) comp->dig_p4) << 35); - var1 = ((var1 * var1 * (s64) comp->dig_p3) >> 8) + - ((var1 * (s64) comp->dig_p2) << 12); - var1 = (((((s64) 1) << 47) + var1)) * ((s64) comp->dig_p1) >> 33; + 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; if (var1 == 0) return 0; - p = ((((s64) 1048576 - adc_press) << 31) - var2) * 3125; + p = ((((s64)1048576 - adc_press) << 31) - var2) * 3125; p = div64_s64(p, var1); - var1 = (((s64) comp->dig_p9) * (p >> 13) * (p >> 13)) >> 25; - var2 = (((s64) comp->dig_p8) * p) >> 19; - p = ((p + var1 + var2) >> 8) + (((s64) comp->dig_p7) << 4); + 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); - return (u32) p; + return (u32)p; } static int bmp280_read_temp(struct bmp280_data *data, @@ -253,11 +224,6 @@ static int bmp280_read_temp(struct bmp280_data *data, int ret; __be32 tmp = 0; s32 adc_temp, comp_temp; - struct bmp280_comp_temp comp; - - ret = bmp280_read_compensation_temp(data, &comp); - if (ret < 0) - return ret; ret = regmap_bulk_read(data->regmap, BMP280_REG_TEMP_MSB, (u8 *) &tmp, 3); @@ -267,7 +233,7 @@ static int bmp280_read_temp(struct bmp280_data *data, } adc_temp = be32_to_cpu(tmp) >> 12; - comp_temp = bmp280_compensate_temp(data, &comp, adc_temp); + comp_temp = bmp280_compensate_temp(data, adc_temp); /* * val might be NULL if we're called by the read_press routine, @@ -288,11 +254,6 @@ static int bmp280_read_press(struct bmp280_data *data, __be32 tmp = 0; s32 adc_press; u32 comp_press; - struct bmp280_comp_press comp; - - ret = bmp280_read_compensation_press(data, &comp); - if (ret < 0) - return ret; /* Read and compensate temperature so we get a reading of t_fine. */ ret = bmp280_read_temp(data, NULL); @@ -307,7 +268,7 @@ static int bmp280_read_press(struct bmp280_data *data, } adc_press = be32_to_cpu(tmp) >> 12; - comp_press = bmp280_compensate_press(data, &comp, adc_press); + comp_press = bmp280_compensate_press(data, adc_press); *val = comp_press; *val2 = 256000; @@ -366,7 +327,7 @@ static int bmp280_chip_init(struct bmp280_data *data) BMP280_MODE_NORMAL); if (ret < 0) { dev_err(&data->client->dev, - "failed to write config register\n"); + "failed to write ctrl_meas register\n"); return ret; } @@ -394,7 +355,6 @@ static int bmp280_probe(struct i2c_client *client, if (!indio_dev) return -ENOMEM; - i2c_set_clientdata(client, indio_dev); data = iio_priv(indio_dev); mutex_init(&data->lock); data->client = client; |