On Fri, Oct 31, 2014 at 02:25:22AM +0100, Hartmut Knaack wrote: > Compensation data is hard coded into the sensors, so it is sufficient to just > read it once during device initialization. Therefor struct bmp280_comp should be > part of bmp280_data (since the elements of bmp280_comp_temp and > bmp280_comp_press have distinct names, they could be merged into bmp280_comp). My first version of the patch did this, but Jonathan suggested [1] that, since we're using regmap, we can rely on it for caching the calibration parameters. I have no preference for either approach. [1] http://www.spinics.net/lists/linux-iio/msg15099.html > Signed-off-by: Hartmut Knaack <knaack.h@xxxxxx> > --- > diff --git a/drivers/iio/pressure/bmp280.c b/drivers/iio/pressure/bmp280.c > index 4f6ae4d..36e425c 100644 > --- a/drivers/iio/pressure/bmp280.c > +++ b/drivers/iio/pressure/bmp280.c > @@ -68,10 +68,19 @@ > #define BMP280_CHIP_ID 0x58 > #define BMP280_SOFT_RESET_VAL 0xB6 > > +/* Compensation parameters. */ > +struct bmp280_comp { > + u16 dig_p1; > + s16 dig_p2, dig_p3, dig_p4, dig_p5, dig_p6, dig_p7, dig_p8, dig_p9; > + u16 dig_t1; > + s16 dig_t2, dig_t3; > +}; > + > struct bmp280_data { > struct i2c_client *client; > struct mutex lock; > struct regmap *regmap; > + struct bmp280_comp comp; > > /* > * Carryover value from temperature conversion, used in pressure > @@ -80,17 +89,6 @@ 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; > -}; > - > static const struct iio_chan_spec bmp280_channels[] = { > { > .type = IIO_PRESSURE, > @@ -141,11 +139,11 @@ 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) > +static int bmp280_read_compensation_temp(struct bmp280_data *data) > { > int ret; > __le16 buf[BMP280_COMP_TEMP_REG_COUNT / 2]; > + struct bmp280_comp *comp = &data->comp; > > ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START, > buf, BMP280_COMP_TEMP_REG_COUNT); > @@ -162,11 +160,11 @@ static int bmp280_read_compensation_temp(struct bmp280_data *data, > return 0; > } > > -static int bmp280_read_compensation_press(struct bmp280_data *data, > - struct bmp280_comp_press *comp) > +static int bmp280_read_compensation_press(struct bmp280_data *data) > { > int ret; > __le16 buf[BMP280_COMP_PRESS_REG_COUNT / 2]; > + struct bmp280_comp *comp = &data->comp; > > ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_PRESS_START, > buf, BMP280_COMP_PRESS_REG_COUNT); > @@ -196,11 +194,10 @@ 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) > +static s32 bmp280_compensate_temp(struct bmp280_data *data, s32 adc_temp) > { > s32 var1, var2; > + struct bmp280_comp *comp = &data->comp; > > var1 = (((adc_temp >> 3) - ((s32) comp->dig_t1 << 1)) * > ((s32) comp->dig_t2)) >> 11; > @@ -219,11 +216,10 @@ 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) > +static u32 bmp280_compensate_press(struct bmp280_data *data, s32 adc_press) > { > s64 var1, var2, p; > + struct bmp280_comp *comp = &data->comp; > > var1 = ((s64) data->t_fine) - 128000; > var2 = var1 * var1 * (s64) comp->dig_p6; > @@ -249,11 +245,6 @@ 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); > @@ -263,7 +254,7 @@ 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, > @@ -284,11 +275,6 @@ 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); > @@ -303,7 +289,7 @@ 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; > @@ -375,6 +361,14 @@ static int bmp280_chip_init(struct bmp280_data *data) > return ret; > } > > + ret = bmp280_read_compensation_temp(data); > + if (ret < 0) > + return ret; > + > + ret = bmp280_read_compensation_press(data); > + if (ret < 0) > + return ret; > + > return ret; > } > -- 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
