Re: Use LIS3MDL with LSM6DSM sensor-hub

[Jimmy Assarsson <jimmyassarsson@gmail.com>]

On 2020-03-19 21:49, Lorenzo Bianconi wrote:
>> On 2020-03-19 18:40, Lorenzo Bianconi wrote:
>>>> On 2020-03-14 13:43, Lorenzo Bianconi wrote:
>>>>> On Mar 11, Jimmy Assarsson wrote:
>>>>>> Hi,
>>>>>>
> 
> [...]
> 
>>>>> Hi Jimmy,
>>>>>
>>>>> in order to set the full scale on LIS3MDL you can try the following patch (just
>>>>> compiled, not tested)
>>>>>
>>>>> Regards,
>>>>> Lorenzo
>>>>
>>>> Hi Lorenzo,
>>>>
>>>> Sorry for the late response and thanks for the patch!
>>>
>>> Hi Jimmy,
>>>
>>> ok, I will post the patch, thx for testing.
>>
>> Great, you can add
>> Tested-by: Jimmy Assarsson <jimmyassarsson@gmail.com>
>>
>>>> The patches seems to work.
>>>> Are there any specific tests that we should carry out?
>>>> Via the sysfs interface, we've tested reading raw values of each channel and
>>>> configuring ODR and full scale.
>>>
>>> you can try to enable batching in the hw FIFO doing something like:
>>>
>>> $echo 1 > /sys/bus/iio/devices/<iio-magn>/scan_elements/in_magn_x_en
>>> $echo 1 > /sys/bus/iio/devices/<iio-magn>/scan_elements/in_magn_y_en
>>> $echo 1 > /sys/bus/iio/devices/<iio-magn>/scan_elements/in_magn_z_en
>>> $echo 1 > /sys/bus/iio/devices/<iio-magn>/scan_elements/in_timestamp_en
>>>
>>> $watermark=64
>>> $echo $((2*watermark)) > /sys/bus/iio/devices/<iio-magn>/buffer/length
>>> $echo $watermark > /sys/bus/iio/devices/<iio-magn>/buffer/watermark
>>>
>>> $generic_buffer -gn lsm6dsm_magn -c <# of samples>
>>
>> Ok. I don't got any scan_elements nor buffer directory, for any of the devices.
>> I guess it is not possible to use the FIFO without configuring any interrupt?
>> We got the following dts:
>> &spi1 {
>> 	#address-cells = <1>;
>> 	#size-cells = <0>;
>> 	lsm6dsm@0 {
>> 		compatible = "st,lsm6dsm";
>> 		reg = <0x0>;
>>
>> 		spi-max-frequency = <500000>;
>> 		st,pullups = "true";
> 
> yes, you need to provide the interrupt line doing something like (this is from
> the dts on my rpi):
> 
> 	lsm6dsm@0 {
> 		...
> 		interrupt-parent = <&gpio>;
> 		interrupts = <21 0x4>;
> 		...
> 	};
> 
>> 	};
>> };
>>
>> I'll look into this tomorrow or in the beginning of next week, thanks for the help.

Now I've tested this. It looks fine, except for the very first sample:
$ ./iio_generic_buffer -gn lsm6dsm_magn -c 1
iio device number being used is 3
trigger-less mode selected
-3.250836 -2.796192 10.212408 1584976428879020199
1.893036 2.343738 -0.853224 1584976428917070199
1.888218 2.343300 -0.852786 1584976428955095199
1.888218 2.343300 -0.852786 1584976428993145199
1.889532 2.345490 -0.851472 1584976429031170199

Is this expected?

Regards,
jimmy