On Fri, Dec 19, 2014 at 11:59:25PM +0100, Hartmut Knaack wrote:
> The calculations for temperature and pressure compensation were already slightly
> optimized in comparison to the datasheet. So, it makes sense to optimize even a
> bit more, making proper use of C operators:
> - variable t in bmp280_compensate_temp() can be eliminated by directly
> returning the result of the relevant equation.
> - make use of the += operator and eliminate an unnecessary parenthesis level in
> bmp280_compensate_press().
> When the initialization of the ctrl_meas register fails, the error message will
> now mention the right register name.
> During probe, i2c_set_clientdata() is called, although it is not necessary. Drop
> it.
>
> Signed-off-by: Hartmut Knaack <knaack.h@xxxxxx>
Reviewed-by: Vlad Dogaru <vlad.dogaru@xxxxxxxxx>
Thanks for following up with this one, Hartmut.
> ---
> Changes in V2:
> Rebase after refactoring of compensation code.
>
> diff --git a/drivers/iio/pressure/bmp280.c b/drivers/iio/pressure/bmp280.c
> index 47dfd34..7c623e2 100644
> --- a/drivers/iio/pressure/bmp280.c
> +++ b/drivers/iio/pressure/bmp280.c
> @@ -148,7 +148,7 @@ static s32 bmp280_compensate_temp(struct bmp280_data *data,
> s32 adc_temp)
> {
> int ret;
> - s32 var1, var2, t;
> + s32 var1, var2;
> __le16 buf[BMP280_COMP_TEMP_REG_COUNT / 2];
>
> ret = regmap_bulk_read(data->regmap, BMP280_REG_COMP_TEMP_START,
> @@ -173,10 +173,7 @@ static s32 bmp280_compensate_temp(struct bmp280_data *data,
> ((adc_temp >> 4) - ((s32)le16_to_cpu(buf[T1])))) >> 12) *
> ((s32)(s16)le16_to_cpu(buf[T3]))) >> 14;
>
> - data->t_fine = var1 + var2;
> - t = (data->t_fine * 5 + 128) >> 8;
> -
> - return t;
> + return (data->t_fine * 5 + 128) >> 8;
> }
>
> /*
> @@ -203,8 +200,8 @@ static u32 bmp280_compensate_press(struct bmp280_data *data,
>
> var1 = ((s64)data->t_fine) - 128000;
> var2 = var1 * var1 * (s64)(s16)le16_to_cpu(buf[P6]);
> - var2 = var2 + ((var1 * (s64)(s16)le16_to_cpu(buf[P5])) << 17);
> - var2 = var2 + (((s64)(s16)le16_to_cpu(buf[P4])) << 35);
> + 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;
> @@ -218,7 +215,7 @@ static u32 bmp280_compensate_press(struct bmp280_data *data,
> 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,
> @@ -330,7 +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;
> }
>
> @@ -358,7 +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;
--
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