Re: Use LIS3MDL with LSM6DSM sensor-hub

[Lorenzo Bianconi <lorenzo@kernel.org>]

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> On 2020-03-14 13:43, Lorenzo Bianconi wrote:
> > On Mar 11, Jimmy Assarsson wrote:
> > > Hi,
> > > 
> > > We are working on a project where we want to connect LS6DSM (via SPI), and
> > > connect LIS3MDL via the sensor hub, as I2C slave device.
> > > 
> > > We would like to add settings/configuration for LIS3MDL, to the shub
> > > source, since currently only LIS2MDL is supported. We've made an attempt,
> > > see diff at end of this mail.
> > > 
> > > 1. LIS2MDL only got a single full scale setting, hence it is not possible
> > >     to change. While LIS3MDL got four possible settings. Is it enough to add
> > >     a corresponding function like st_lsm6dsx_shub_set_fs_val() and call it
> > >     from st_lsm6dsx_shub_write_raw(), when mask == IIO_CHAN_INFO_SCALE?
> > > 2. LIS3MDL got 8 possible ODR settings, however ST_LSM6DSX_ODR_LIST_SIZE is
> > >     defined to 6 (st_lsm6dsx.h). Is it fine to increase
> > >     ST_LSM6DSX_ODR_LIST_SIZE to 8? This will also affect odr_table in
> > >     struct st_lsm6dsx_settings.
> > > 3. In the patch, we've tried to copy the correct registers and values from
> > >     magnetometer/st_magn_core.c, does it look ok?
> > > 
> > > The IIO subsystem is new to use, we possibly miss fundamental knowledge.
> > > 
> > > Regards,
> > > jimmy
> > 
> > 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.

> 
> 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>

Regards,
Lorenzo

> 
> Regards,
> jimmy
> 
> > diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> > index 64ef07a30726..fec1dbd5f00d 100644
> > --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> > +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> > @@ -518,6 +518,36 @@ st_lsm6dsx_shub_read_raw(struct iio_dev *iio_dev,
> >   	return ret;
> >   }
> > +static int
> > +st_lsm6dsx_shub_set_full_scale(struct st_lsm6dsx_sensor *sensor,
> > +			       u32 gain)
> > +{
> > +	const struct st_lsm6dsx_fs_table_entry *fs_table;
> > +	int i, err;
> > +
> > +	fs_table = &sensor->ext_info.settings->fs_table;
> > +	if (!fs_table->reg.addr)
> > +		return -ENOTSUPP;
> > +
> > +	for (i = 0; i < fs_table->fs_len; i++) {
> > +		if (fs_table->fs_avl[i].gain == gain)
> > +			break;
> > +	}
> > +
> > +	if (i == fs_table->fs_len)
> > +		return -EINVAL;
> > +
> > +	err = st_lsm6dsx_shub_write_with_mask(sensor, fs_table->reg.addr,
> > +					      fs_table->reg.mask,
> > +					      fs_table->fs_avl[i].val);
> > +	if (err < 0)
> > +		return err;
> > +
> > +	sensor->gain = gain;
> > +
> > +	return 0;
> > +}
> > +
> >   static int
> >   st_lsm6dsx_shub_write_raw(struct iio_dev *iio_dev,
> >   			  struct iio_chan_spec const *chan,
> > @@ -552,6 +582,9 @@ st_lsm6dsx_shub_write_raw(struct iio_dev *iio_dev,
> >   		}
> >   		break;
> >   	}
> > +	case IIO_CHAN_INFO_SCALE:
> > +		err = st_lsm6dsx_shub_set_full_scale(sensor, val2);
> > +		break;
> >   	default:
> >   		err = -EINVAL;
> >   		break;
> > 
> > > 
> > > ---
> > > diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> > > index eea5556..8621dba 100644
> > > --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> > > +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> > > @@ -88,6 +88,69 @@ static const struct st_lsm6dsx_ext_dev_settings st_lsm6dsx_ext_dev_table[] = {
> > >   			.len = 6,
> > >   		},
> > >   	},
> > > +	/* LIS3MDL */
> > > +	{
> > > +		.i2c_addr = { 0x1e },
> > > +		.wai = {
> > > +			.addr = 0x0f,
> > > +			.val = 0x3d,
> > > +		},
> > > +		.id = ST_LSM6DSX_ID_MAGN,
> > > +		.odr_table = {
> > > +			.reg = {
> > > +				.addr = 0x20,
> > > +				.mask = GENMASK(4, 2),
> > > +			},
> > > +			.odr_avl[0] = {  1000, 0x0 },
> > > +			.odr_avl[1] = {  2000, 0x1 },
> > > +			.odr_avl[2] = {  3000, 0x2 },
> > > +			.odr_avl[3] = {  5000, 0x3 },
> > > +			.odr_avl[4] = { 10000, 0x4 },
> > > +			.odr_avl[5] = { 20000, 0x5 },
> > > +			.odr_avl[6] = { 40000, 0x6 },
> > > +			.odr_avl[7] = { 80000, 0x7 },
> > > +			.odr_len = 8,
> > > +		},
> > > +		.fs_table = {
> > > +			.reg = {
> > > +				.addr = 0x21,
> > > +				.mask = GENMASK(6, 5),
> > > +			},
> > > +			.fs_avl[0] = {
> > > +				.gain = 146,
> > > +				.val = 0x00,
> > > +			}, /* 4000 uG/LSB */
> > > +			.fs_avl[1] = {
> > > +				.gain = 292,
> > > +				.val = 0x01,
> > > +			}, /* 8000 uG/LSB */
> > > +			.fs_avl[2] = {
> > > +				.gain = 438,
> > > +				.val = 0x02,
> > > +			}, /* 12000 uG/LSB */
> > > +			.fs_avl[3] = {
> > > +				.gain = 584,
> > > +				.val = 0x03,
> > > +			}, /* 16000 uG/LSB */
> > > +			.fs_len = 4,
> > > +		},
> > > +		.pwr_table = {
> > > +			.reg = {
> > > +				.addr = 0x22,
> > > +				.mask = GENMASK(1, 0),
> > > +			},
> > > +			.off_val = 0x2,
> > > +			.on_val = 0x0,
> > > +		},
> > > +		.bdu = {
> > > +			.addr = 0x24,
> > > +			.mask = BIT(6),
> > > +		},
> > > +		.out = {
> > > +			.addr = 0x28,
> > > +			.len = 6,
> > > +		},
> > > +	},
> > >   };

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