Expose a rotation matrix to indicate userspace the chip orientation with
respect to the overall hardware system.
Signed-off-by: Gregor Boirie <gregor.boirie@xxxxxxxxxx>
---
.../bindings/iio/magnetometer/ak8975.txt | 10 ++++++
drivers/iio/magnetometer/ak8975.c | 40 ++++++++++++++++++++--
include/linux/iio/magnetometer/ak8975.h | 16 +++++++++
3 files changed, 64 insertions(+), 2 deletions(-)
create mode 100644 include/linux/iio/magnetometer/ak8975.h
diff --git a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
index 34a3206..e1e7dd32 100644
--- a/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
+++ b/Documentation/devicetree/bindings/iio/magnetometer/ak8975.txt
@@ -9,6 +9,7 @@ Optional properties:
- gpios : should be device tree identifier of the magnetometer DRDY pin
- vdd-supply: an optional regulator that needs to be on to provide VDD
+ - mount-matrix: an optional 3x3 mounting rotation matrix
Example:
@@ -17,4 +18,13 @@ ak8975@0c {
reg = <0x0c>;
gpios = <&gpj0 7 0>;
vdd-supply = <&ldo_3v3_gnss>;
+ mount-matrix = "-0.984807753012208", /* x0 */
+ "0", /* y0 */
+ "-0.173648177666930", /* z0 */
+ "0", /* x1 */
+ "-1", /* y1 */
+ "0", /* z1 */
+ "-0.173648177666930", /* x2 */
+ "0", /* y2 */
+ "0.984807753012208"; /* z2 */
};
diff --git a/drivers/iio/magnetometer/ak8975.c b/drivers/iio/magnetometer/ak8975.c
index 48d127a..ec3f27a 100644
--- a/drivers/iio/magnetometer/ak8975.c
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -36,6 +36,9 @@
#include <linux/iio/iio.h>
#include <linux/iio/sysfs.h>
+
+#include <linux/iio/magnetometer/ak8975.h>
+
/*
* Register definitions, as well as various shifts and masks to get at the
* individual fields of the registers.
@@ -370,6 +373,7 @@ struct ak8975_data {
wait_queue_head_t data_ready_queue;
unsigned long flags;
u8 cntl_cache;
+ struct iio_mount_matrix orientation;
struct regulator *vdd;
};
@@ -714,6 +718,27 @@ static int ak8975_read_raw(struct iio_dev *indio_dev,
return -EINVAL;
}
+static ssize_t ak8975_show_orientation(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ const struct ak8975_data *data = iio_priv(dev_to_iio_dev(dev));
+
+ return iio_show_mount_matrix(&data->orientation, buf);
+}
+
+static IIO_DEV_ATTR_MOUNT_MATRIX(in_magn_mount_matrix, ak8975_show_orientation,
+ -1);
+
+static struct attribute *ak8975_attrs[] = {
+ &iio_dev_attr_in_magn_mount_matrix.dev_attr.attr,
+ NULL
+};
+
+static const struct attribute_group ak8975_attrs_group = {
+ .attrs = ak8975_attrs,
+};
+
#define AK8975_CHANNEL(axis, index) \
{ \
.type = IIO_MAGN, \
@@ -730,6 +755,7 @@ static const struct iio_chan_spec ak8975_channels[] = {
static const struct iio_info ak8975_info = {
.read_raw = &ak8975_read_raw,
+ .attrs = &ak8975_attrs_group,
.driver_module = THIS_MODULE,
};
@@ -765,10 +791,11 @@ static int ak8975_probe(struct i2c_client *client,
int err;
const char *name = NULL;
enum asahi_compass_chipset chipset;
+ const struct ak8975_platform_data *pdata = client->dev.platform_data;
/* Grab and set up the supplied GPIO. */
- if (client->dev.platform_data)
- eoc_gpio = *(int *)(client->dev.platform_data);
+ if (pdata)
+ eoc_gpio = pdata->eoc_gpio;
else if (client->dev.of_node)
eoc_gpio = of_get_gpio(client->dev.of_node, 0);
else
@@ -802,6 +829,15 @@ static int ak8975_probe(struct i2c_client *client,
data->eoc_gpio = eoc_gpio;
data->eoc_irq = 0;
+ if (!pdata) {
+ err = of_iio_read_mount_matrix(&client->dev,
+ "mount-matrix",
+ &data->orientation);
+ if (err)
+ return err;
+ } else
+ data->orientation = pdata->orientation;
+
/* id will be NULL when enumerated via ACPI */
if (id) {
chipset = (enum asahi_compass_chipset)(id->driver_data);
diff --git a/include/linux/iio/magnetometer/ak8975.h b/include/linux/iio/magnetometer/ak8975.h
new file mode 100644
index 0000000..52947d7
--- /dev/null
+++ b/include/linux/iio/magnetometer/ak8975.h
@@ -0,0 +1,16 @@
+#ifndef __IIO_MAGNETOMETER_AK8975_H__
+#define __IIO_MAGNETOMETER_AK8975_H__
+
+#include <linux/iio/sysfs.h>
+
+/**
+ * struct ak8975_platform_data - AK8975 magnetometer driver platform data
+ * @eoc_gpio: data ready event gpio
+ * @orientation: mounting matrix relative to main hardware
+ */
+struct ak8975_platform_data {
+ int eoc_gpio;
+ struct iio_mount_matrix orientation;
+};
+
+#endif
--
2.1.4
--
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