Expose a rotation matrix to indicate userspace the chip orientation with
respect to the overall hardware system.
Matrix is retrieved from "in_mount_matrix". It is declared into ak8975 DTS
entry as a "mount-matrix" property.
Signed-off-by: Gregor Boirie <gregor.boirie@xxxxxxxxxx>
---
.../bindings/iio/magnetometer/ak8975.txt | 10 +++++++
drivers/iio/magnetometer/ak8975.c | 34 +++++++++++++++++++---
include/linux/iio/magnetometer/ak8975.h | 16 ++++++++++
3 files changed, 56 insertions(+), 4 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 a2aac50..dbf0661 100644
--- a/drivers/iio/magnetometer/ak8975.c
+++ b/drivers/iio/magnetometer/ak8975.c
@@ -40,7 +40,8 @@
#include <linux/iio/trigger.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
-#include <linux/regulator/consumer.h>
+
+#include <linux/iio/magnetometer/ak8975.h>
/*
* Register definitions, as well as various shifts and masks to get at the
@@ -376,6 +377,7 @@ struct ak8975_data {
wait_queue_head_t data_ready_queue;
unsigned long flags;
u8 cntl_cache;
+ struct iio_mount_matrix orientation;
struct regulator *vdd;
};
@@ -726,6 +728,18 @@ static int ak8975_read_raw(struct iio_dev *indio_dev,
return -EINVAL;
}
+static const struct iio_mount_matrix *
+ak8975_get_mount_matrix(const struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ return &((struct ak8975_data *)iio_priv(indio_dev))->orientation;
+}
+
+static const struct iio_chan_spec_ext_info ak8975_ext_info[] = {
+ IIO_MOUNT_MATRIX(IIO_SHARED_BY_DIR, ak8975_get_mount_matrix),
+ { },
+};
+
#define AK8975_CHANNEL(axis, index) \
{ \
.type = IIO_MAGN, \
@@ -740,7 +754,8 @@ static int ak8975_read_raw(struct iio_dev *indio_dev,
.realbits = 16, \
.storagebits = 16, \
.endianness = IIO_CPU \
- } \
+ }, \
+ .ext_info = ak8975_ext_info, \
}
static const struct iio_chan_spec ak8975_channels[] = {
@@ -837,10 +852,12 @@ 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 =
+ dev_get_platdata(&client->dev);
/* 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
@@ -874,6 +891,15 @@ 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..c840095
--- /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/iio.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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