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From: Jonathan Cameron <jic23@kernel.org>
To: Daniel Drake <drake@endlessm.com>
Cc: knaack.h@gmx.de, lars@metafoo.de, pmeerw@pmeerw.net,
	linux-iio@vger.kernel.org, linux@endlessm.com,
	lorenzo.bianconi83@gmail.com, denis.ciocca@st.com,
	hadess@hadess.net, hdegoede@redhat.com
Subject: Re: [PATCH 2/2] iio: st_accel: use ACPI orientation data
Date: Sat, 12 Jan 2019 19:13:05 +0000	[thread overview]
Message-ID: <20190112191305.103daa46@archlinux> (raw)
In-Reply-To: <20181222180914.6d3b5e5e@archlinux>

On Sat, 22 Dec 2018 18:09:14 +0000
Jonathan Cameron <jic23@kernel.org> wrote:

> On Thu, 20 Dec 2018 14:59:33 +0800
> Daniel Drake <drake@endlessm.com> wrote:
> 
> > Platform-specific ST accelerometer mount matrix information can be
> > provided by returning a package of 6 integers from the ACPI _ONT
> > method. This has been seen on Acer products such as Veriton Z4860G,
> > Z6860G and A890, which include a ST SMO8840 sensor. We have also
> > confirmed experimentally that the Windows driver uses such information.
> > 
> > The _ONT data format was explained by a ST vendor contact. However,
> > strangely enough, the _ONT transformations must be applied after first
> > applying another mount matrix which we determined experimentally. ST
> > have not commented on why this is the case, but we imagine that perhaps
> > earlier devices (before _ONT was introduced) required this translation
> > and hence it became 'standard.'
> > 
> > Interpret the _ONT data and export the equivalent mount matrix to
> > userspace.
> > 
> > If no _ONT data is present, no mount matrix is exported.
> > 
> > Signed-off-by: Daniel Drake <drake@endlessm.com>  
> A trivial point.  Please stick to the local (and most common in kernel)
> multiline comment syntax of
> /*
>  * asdfsdfs
>  * more...
>  */
> 
> Otherwise looks sensible.  However, I'd really like Dennis or someone
> else at ST to take a look before I take this.  We are early in the cycle
> (well it hasn't quite started yet) so plenty of time.  Give me a
> bump in a few weeks if nothing is happening...

Note  I'm still lookign for Denis or someone else to come back on this one!

Thanks,

Jonathan
> 
> Thanks,
> 
> Jonathan
> 
> 
> > ---
> >  drivers/iio/accel/st_accel_core.c     | 171 +++++++++++++++++++++++++-
> >  include/linux/iio/common/st_sensors.h |   1 +
> >  2 files changed, 171 insertions(+), 1 deletion(-)
> > 
> > diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c
> > index 3e6fd5a8ac5b..54cc1a0c6a1d 100644
> > --- a/drivers/iio/accel/st_accel_core.c
> > +++ b/drivers/iio/accel/st_accel_core.c
> > @@ -11,6 +11,7 @@
> >  #include <linux/kernel.h>
> >  #include <linux/module.h>
> >  #include <linux/slab.h>
> > +#include <linux/acpi.h>
> >  #include <linux/errno.h>
> >  #include <linux/types.h>
> >  #include <linux/mutex.h>
> > @@ -917,12 +918,167 @@ static const struct iio_trigger_ops st_accel_trigger_ops = {
> >  #define ST_ACCEL_TRIGGER_OPS NULL
> >  #endif
> >  
> > +static const struct iio_mount_matrix *
> > +get_mount_matrix(const struct iio_dev *indio_dev,
> > +		 const struct iio_chan_spec *chan)
> > +{
> > +	struct st_sensor_data *adata = iio_priv(indio_dev);
> > +
> > +	return adata->mount_matrix;
> > +}
> > +
> > +static const struct iio_chan_spec_ext_info mount_matrix_ext_info[] = {
> > +	IIO_MOUNT_MATRIX(IIO_SHARED_BY_ALL, get_mount_matrix),
> > +	{ },
> > +};
> > +
> > +/* Read ST-specific _ONT orientation data from ACPI and generate an
> > + * appropriate mount matrix.
> > + */
> > +static int apply_acpi_orientation(struct iio_dev *indio_dev,
> > +				  struct iio_chan_spec *channels)
> > +{
> > +#ifdef CONFIG_ACPI
> > +	struct st_sensor_data *adata = iio_priv(indio_dev);
> > +	struct acpi_buffer buffer = {ACPI_ALLOCATE_BUFFER, NULL};
> > +	struct acpi_device *adev;
> > +	union acpi_object *ont;
> > +	union acpi_object *elements;
> > +	acpi_status status;
> > +	int ret = -EINVAL;
> > +	unsigned int val;
> > +	int i, j;
> > +	int final_ont[3][3] = { 0 };
> > +
> > +	/* For some reason, ST's _ONT translation does not apply directly
> > +	 * to the data read from the sensor. Another translation must be
> > +	 * performed first, as described by the matrix below. Perhaps
> > +	 * ST required this specific translation for the first product
> > +	 * where the device was mounted?
> > +	 */
> > +	const int default_ont[3][3] = {
> > +		{  0,  1,  0 },
> > +		{ -1,  0,  0 },
> > +		{  0,  0, -1 },
> > +	};
> > +
> > +
> > +	adev = ACPI_COMPANION(adata->dev);
> > +	if (!adev)
> > +		return 0;
> > +
> > +	/* Read _ONT data, which should be a package of 6 integers. */
> > +	status = acpi_evaluate_object(adev->handle, "_ONT", NULL, &buffer);
> > +	if (status == AE_NOT_FOUND) {
> > +		return 0;
> > +	} else if (ACPI_FAILURE(status)) {
> > +		dev_warn(&indio_dev->dev, "failed to execute _ONT: %d\n",
> > +			 status);
> > +		return status;
> > +	}
> > +
> > +	ont = buffer.pointer;
> > +	if (ont->type != ACPI_TYPE_PACKAGE || ont->package.count != 6)
> > +		goto out;
> > +
> > +	/* The first 3 integers provide axis order information.
> > +	 * e.g. 0 1 2 would indicate normal X,Y,Z ordering.
> > +	 * e.g. 1 0 2 indicates that data arrives in order Y,X,Z.
> > +	 */
> > +	elements = ont->package.elements;
> > +	for (i = 0; i < 3; i++) {
> > +		if (elements[i].type != ACPI_TYPE_INTEGER)
> > +			goto out;
> > +
> > +		val = elements[i].integer.value;
> > +		if (val < 0 || val > 2)
> > +			goto out;
> > +
> > +		/* Avoiding full matrix multiplication, we simply reorder the
> > +		 * columns in the default_ont matrix according to the
> > +		 * ordering provided by _ONT.
> > +		 */
> > +		final_ont[0][i] = default_ont[0][val];
> > +		final_ont[1][i] = default_ont[1][val];
> > +		final_ont[2][i] = default_ont[2][val];
> > +	}
> > +
> > +	/* The final 3 integers provide sign flip information.
> > +	 * 0 means no change, 1 means flip.
> > +	 * e.g. 0 0 1 means that Z data should be sign-flipped.
> > +	 * This is applied after the axis reordering from above.
> > +	 */
> > +	elements += 3;
> > +	for (i = 0; i < 3; i++) {
> > +		if (elements[i].type != ACPI_TYPE_INTEGER)
> > +			goto out;
> > +
> > +		val = elements[i].integer.value;
> > +		if (val != 0 && val != 1)
> > +			goto out;
> > +		if (!val)
> > +			continue;
> > +
> > +		/* Flip the values in the indicated column */
> > +		final_ont[0][i] *= -1;
> > +		final_ont[1][i] *= -1;
> > +		final_ont[2][i] *= -1;
> > +	}
> > +
> > +	/* Convert our integer matrix to a string-based iio_mount_matrix */
> > +	adata->mount_matrix = devm_kmalloc(&indio_dev->dev,
> > +					   sizeof(*adata->mount_matrix),
> > +					   GFP_KERNEL);
> > +	if (!adata->mount_matrix) {
> > +		ret = -ENOMEM;
> > +		goto out;
> > +	}
> > +
> > +	for (i = 0; i < 3; i++) {
> > +		for (j = 0; j < 3; j++) {
> > +			int matrix_val = final_ont[i][j];
> > +			char *str_value;
> > +
> > +			switch (matrix_val) {
> > +			case -1:
> > +				str_value = "-1";
> > +				break;
> > +			case 0:
> > +				str_value = "0";
> > +				break;
> > +			case 1:
> > +				str_value = "1";
> > +				break;
> > +			default:
> > +				goto out;
> > +			}
> > +			adata->mount_matrix->rotation[i * 3 + j] = str_value;
> > +		}
> > +	}
> > +
> > +	/* Expose the mount matrix via ext_info */
> > +	for (i = 0; i < indio_dev->num_channels; i++)
> > +		channels[i].ext_info = mount_matrix_ext_info;
> > +
> > +	ret = 0;
> > +	dev_info(&indio_dev->dev, "computed mount matrix from ACPI\n");
> > +
> > +out:
> > +	kfree(buffer.pointer);
> > +	return ret;
> > +#else /* !CONFIG_ACPI */
> > +	return 0;
> > +#endif
> > +}
> > +
> >  int st_accel_common_probe(struct iio_dev *indio_dev)
> >  {
> >  	struct st_sensor_data *adata = iio_priv(indio_dev);
> >  	struct st_sensors_platform_data *pdata =
> >  		(struct st_sensors_platform_data *)adata->dev->platform_data;
> >  	int irq = adata->get_irq_data_ready(indio_dev);
> > +	struct iio_chan_spec *channels;
> > +	size_t channels_size;
> >  	int err;
> >  
> >  	indio_dev->modes = INDIO_DIRECT_MODE;
> > @@ -941,9 +1097,22 @@ int st_accel_common_probe(struct iio_dev *indio_dev)
> >  
> >  	adata->num_data_channels = ST_ACCEL_NUMBER_DATA_CHANNELS;
> >  	adata->multiread_bit = adata->sensor_settings->multi_read_bit;
> > -	indio_dev->channels = adata->sensor_settings->ch;
> >  	indio_dev->num_channels = ST_SENSORS_NUMBER_ALL_CHANNELS;
> >  
> > +	channels_size = indio_dev->num_channels * sizeof(struct iio_chan_spec);
> > +	channels = devm_kmemdup(&indio_dev->dev,
> > +				adata->sensor_settings->ch,
> > +				channels_size, GFP_KERNEL);
> > +	if (!channels) {
> > +		err = -ENOMEM;
> > +		goto st_accel_power_off;
> > +	}
> > +
> > +	if (apply_acpi_orientation(indio_dev, channels))
> > +		dev_warn(&indio_dev->dev,
> > +			 "failed to apply ACPI orientation data: %d\n", err);
> > +
> > +	indio_dev->channels = channels;
> >  	adata->current_fullscale = (struct st_sensor_fullscale_avl *)
> >  					&adata->sensor_settings->fs.fs_avl[0];
> >  	adata->odr = adata->sensor_settings->odr.odr_avl[0].hz;
> > diff --git a/include/linux/iio/common/st_sensors.h b/include/linux/iio/common/st_sensors.h
> > index f9bd6e8ab138..fe15694128ac 100644
> > --- a/include/linux/iio/common/st_sensors.h
> > +++ b/include/linux/iio/common/st_sensors.h
> > @@ -260,6 +260,7 @@ struct st_sensor_settings {
> >  struct st_sensor_data {
> >  	struct device *dev;
> >  	struct iio_trigger *trig;
> > +	struct iio_mount_matrix *mount_matrix;
> >  	struct st_sensor_settings *sensor_settings;
> >  	struct st_sensor_fullscale_avl *current_fullscale;
> >  	struct regulator *vdd;  
> 


  reply	other threads:[~2019-01-12 19:13 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-12-20  6:59 [PATCH 1/2] iio: drop const typing from iio_mount_matrix rotation Daniel Drake
2018-12-20  6:59 ` [PATCH 2/2] iio: st_accel: use ACPI orientation data Daniel Drake
2018-12-22 18:09   ` Jonathan Cameron
2019-01-12 19:13     ` Jonathan Cameron [this message]
2019-01-15  0:18       ` Denis CIOCCA
2019-01-15  3:09         ` Daniel Drake
2019-01-19 16:50           ` Jonathan Cameron
2019-01-26 17:27             ` Jonathan Cameron
2019-01-19 16:49 ` [PATCH 1/2] iio: drop const typing from iio_mount_matrix rotation Jonathan Cameron
2019-01-21  8:42   ` Daniel Drake

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