Re: Use LIS3MDL with LSM6DSM sensor-hub

[Jimmy Assarsson <jimmyassarsson@gmail.com>]

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!

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.

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,
>> +		},
>> +	},
>>   };