Add a new attribute to activate the self test mode.
When self test is activated, an electrostatic actuation force is
applied to the sensor, simulating a small acceleration.
Signed-off-by: Martin Fuzzey <mfuzzey@xxxxxxxxxxx>
---
.../ABI/testing/sysfs-bus-iio-accel-mma8452 | 10 ++++
drivers/iio/accel/mma8452.c | 52 ++++++++++++++++++++
2 files changed, 62 insertions(+)
create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-accel-mma8452
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-accel-mma8452 b/Documentation/ABI/testing/sysfs-bus-iio-accel-mma8452
new file mode 100644
index 0000000..387ed38
--- /dev/null
+++ b/Documentation/ABI/testing/sysfs-bus-iio-accel-mma8452
@@ -0,0 +1,10 @@
+What: /sys/bus/iio/devices/iio:deviceX/self_test
+KernelVersion: 3.21
+Contact: linux-iio@xxxxxxxxxxxxxxx
+Description:
+ Allow self test mode to be controlled:
+ "0" = inactive
+ "1" = active
+ When self test is activated, an electrostatic actuation force is
+ applied to the sensor, simulating a small acceleration.
+
diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index 6277b5d..75dcc6e 100644
--- a/drivers/iio/accel/mma8452.c
+++ b/drivers/iio/accel/mma8452.c
@@ -49,6 +49,7 @@
#define MMA8452_CTRL_REG1 0x2a
#define MMA8452_CTRL_REG2 0x2b
#define MMA8452_CTRL_REG2_RST BIT(6)
+#define MMA8452_CTRL_REG2_SELFTEST BIT(7)
#define MMA8452_CTRL_REG4 0x2d
#define MMA8452_CTRL_REG5 0x2e
@@ -639,6 +640,56 @@ static int mma8452_reg_access_dbg(struct iio_dev *indio_dev,
return ret;
}
+static ssize_t mma8452_show_selftest(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct mma8452_data *data = iio_priv(indio_dev);
+ int ret;
+
+ ret = i2c_smbus_read_byte_data(data->client, MMA8452_CTRL_REG2);
+ if (ret < 0)
+ return ret;
+
+ return sprintf(buf, "%d\n", ret & MMA8452_CTRL_REG2_SELFTEST ? 1 : 0);
+}
+
+static ssize_t mma8452_store_selftest(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t len)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct mma8452_data *data = iio_priv(indio_dev);
+ bool state;
+ int ret;
+ u8 val;
+
+ ret = strtobool(buf, &state);
+ if (ret < 0)
+ return ret;
+
+ ret = i2c_smbus_read_byte_data(data->client, MMA8452_CTRL_REG2);
+ if (ret < 0)
+ return ret;
+
+ val = ret;
+ if (state)
+ val |= MMA8452_CTRL_REG2_SELFTEST;
+ else
+ val &= ~MMA8452_CTRL_REG2_SELFTEST;
+
+ ret = mma8452_change_config(data, MMA8452_CTRL_REG2, val);
+ if (ret)
+ return ret;
+
+ return len;
+}
+
+static IIO_DEVICE_ATTR(self_test,
+ S_IRUGO | S_IWUSR,
+ mma8452_show_selftest,
+ mma8452_store_selftest, 0);
+
static const struct iio_event_spec mma8452_transient_event[] = {
{
.type = IIO_EV_TYPE_THRESH,
@@ -698,6 +749,7 @@ static struct attribute *mma8452_attributes[] = {
&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
&iio_dev_attr_in_accel_scale_available.dev_attr.attr,
&iio_dev_attr_in_accel_filter_high_pass_3db_frequency_available.dev_attr.attr,
+ &iio_dev_attr_self_test.dev_attr.attr,
NULL
};
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