Jonathan Cameron wrote:
> If we want to support their ONT we'll need to do this first, then
> apply ONT on top of that by forming the relevant mount matrix and
> outputting that to userspace.
> If you fancy having a go it would be good to have this support!
Cool, I didn't realise that there was a way to export mount matrices.
It looks like iio-sensor-proxy doesn't read that attribute yet, I will
submit a patch for that.
For the kernel changes, here is my initial attempt, comments welcome.
I had to drop the const typing from iio_mount_matrix otherwise it's
difficult to dynamically construct it.
Also I'm not sure whether we should apply this "default_ont" like Windows
does even when _ONT is not present?
I would also love to hear from ST about how this situation happened and
if this is the right way forward.
Regarding other devices with _ONT, the only other device we found
is Asus P4540UQ, a system that we worked on 2 years ago and no longer
have access to. I don't think we tested the accelerometer. The ACPI data
indicates SMO8820, with Y and Z axis values requiring sign flip.
Thanks
Daniel
---
drivers/iio/accel/st_accel_core.c | 161 +++++++++++++++++++++++++-
include/linux/iio/common/st_sensors.h | 1 +
include/linux/iio/iio.h | 2 +-
3 files changed, 162 insertions(+), 2 deletions(-)
diff --git a/drivers/iio/accel/st_accel_core.c b/drivers/iio/accel/st_accel_core.c
index 3e6fd5a8ac5b..3eb4e4b55596 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 +918,157 @@ 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)
+{
+ 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 (ACPI_FAILURE(status)) {
+ ret = status;
+ goto out;
+ }
+
+ 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)
+ 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;
+
+out:
+ kfree(buffer.pointer);
+ return ret;
+}
+
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 +1087,22 @@ 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;
+ }
+
+ err = apply_acpi_orientation(indio_dev, channels);
+ if (err < 0)
+ goto st_accel_power_off;
+
+ 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;
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index a74cb177dc6f..d3094ffeb9da 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -125,7 +125,7 @@ ssize_t iio_enum_write(struct iio_dev *indio_dev,
* main hardware
*/
struct iio_mount_matrix {
- const char *rotation[9];
+ char *rotation[9];
};
ssize_t iio_show_mount_matrix(struct iio_dev *indio_dev, uintptr_t priv,
--
2.19.1
