On Thu, 20 Dec 2018 14:59:33 +0800 Daniel Drake <drake@xxxxxxxxxxxx> 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@xxxxxxxxxxxx> 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... 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;