lkml.org 
[lkml]   [2013]   [Aug]   [4]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH 2/2] iio: add Bosch BMA180 acceleration sensor driver
On 07/29/2013 04:58 PM, Oleksandr Kravchenko wrote:
> From: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
>
> This patch adds IIO driver for Bosch BMA180 triaxial
> acceleration sensor.
> http://omapworld.com/BMA180_111_1002839.pdf
>
> Signed-off-by: Oleksandr Kravchenko <o.v.kravchenko@globallogic.com>
> ---
> .../devicetree/bindings/iio/accel/bma180.txt | 53 +++
> drivers/iio/accel/Kconfig | 10 +
> drivers/iio/accel/Makefile | 2 +
> drivers/iio/accel/bma180.c | 462 ++++++++++++++++++++
> 4 files changed, 527 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/iio/accel/bma180.txt
> create mode 100644 drivers/iio/accel/bma180.c
>
> diff --git a/Documentation/devicetree/bindings/iio/accel/bma180.txt b/Documentation/devicetree/bindings/iio/accel/bma180.txt
> new file mode 100644
> index 0000000..7c13c84
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/iio/accel/bma180.txt
> @@ -0,0 +1,53 @@
> +* Bosch BMA180 triaxial acceleration sensor
> +
> +http://omapworld.com/BMA180_111_1002839.pdf
> +
> +Required properties:
> +
> + - compatible : should be "bosch,bma180"
> + - reg : the I2C address of the sensor
> +
> +Optional properties:
> +
> + - interrupt-parent : should be the phandle for the interrupt controller
> +
> + - interrupts : interrupt mapping for GPIO IRQ, it shuld by configured with
> + flags IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_EDGE_RISING
> +
> + - range : select the full scale acceleration range
> + 0 : -1g..+1g
> + 1 : -1.5g..+1.5g
> + 2 : -2g..+2g
> + 3 : -3g..+3g
> + 4 : -4g..+4g
> + 5 : -8g..+8g
> + 6 : -16g..+16g
> +
> + - bw : select bandwidth bandwidth
> + 0 : 10Hz
> + 1 : 20Hz
> + 2 : 40Hz
> + 3 : 75Hz
> + 4 : 150Hz
> + 5 : 300Hz
> + Don't use bandwidth frequency more than 300Hz couse it
> + influences the frequency of generating new data interrupts
> + and i2c reading phase can be longer than pheriod of interrupt
> + generation.
> +
> + - mode_config : 0 - select low noise mode, 1 - select low power mode
> +
> + - fuzz : specifies fuzz value that is used to filter noise from the event stream
> +

All the four properties above are vendor specific, so they need a vendor
prefix. Also no underscores in property names and no abbreviations. Also I
wonder if some of them should rather be runtime configurable, like range and
bandwidth,

> +Example:
> +
> +bma180@40 {
> + compatible = "bosch,bma180";
> + reg = <0x40>;
> + interrupt-parent = <&gpio6>;
> + interrupts = <18 (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_EDGE_RISING)>;
> + range = <2>;
> + bw = <0>;
> + mode_config = <1>;
> + fuzz = <555>;
> +};
[...]
> +static int bma180_read_raw(struct iio_dev *indio_dev,
> + struct iio_chan_spec const *chan, int *val, int *val2,
> + long mask)
> +{
> + struct bma180_data *data = iio_priv(indio_dev);
> + long tmp = ((s16)data->acc_reg[chan->channel] >> 2)
> + * bma180_range_table[data->range].ratio;

> +
> + if (data->acc_reg[chan->channel] < 0)
> + return data->acc_reg[chan->channel];
> +
> + *val = tmp / 1000000;
> + *val2 = (tmp % 1000000);
> +

This doesn't look as if the device needs a special conversion formula. Just
expose the raw value and ratio as the scale.

> + return IIO_VAL_INT_PLUS_MICRO;
> +}
[...]


\
 
 \ /
  Last update: 2013-08-04 16:01    [W:0.069 / U:12.452 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site