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Commit 28e34278 authored by Martin Fuzzey's avatar Martin Fuzzey Committed by Jonathan Cameron
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iio: mma8452: Basic support for transient events.



The event is triggered when the highpass filtered absolute acceleration
exceeds the threshold.

Signed-off-by: default avatarMartin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 4892688d
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+211 −1
Original line number Diff line number Diff line
@@ -9,7 +9,7 @@
 *
 * 7-bit I2C slave address 0x1c/0x1d (pin selectable)
 *
 * TODO: interrupt, thresholding, orientation / freefall events, autosleep
 * TODO: orientation / freefall events, autosleep
 */

#include <linux/module.h>
@@ -19,20 +19,33 @@
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/buffer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/iio/events.h>
#include <linux/delay.h>

#define MMA8452_STATUS 0x00
#define MMA8452_OUT_X 0x01 /* MSB first, 12-bit  */
#define MMA8452_OUT_Y 0x03
#define MMA8452_OUT_Z 0x05
#define MMA8452_INT_SRC 0x0c
#define MMA8452_WHO_AM_I 0x0d
#define MMA8452_DATA_CFG 0x0e
#define MMA8452_TRANSIENT_CFG 0x1d
#define MMA8452_TRANSIENT_CFG_ELE		BIT(4)
#define MMA8452_TRANSIENT_CFG_CHAN(chan)	BIT(chan + 1)
#define MMA8452_TRANSIENT_SRC 0x1e
#define MMA8452_TRANSIENT_SRC_XTRANSE		BIT(1)
#define MMA8452_TRANSIENT_SRC_YTRANSE		BIT(3)
#define MMA8452_TRANSIENT_SRC_ZTRANSE		BIT(5)
#define MMA8452_TRANSIENT_THS 0x1f
#define MMA8452_TRANSIENT_THS_MASK	0x7f
#define MMA8452_OFF_X 0x2f
#define MMA8452_OFF_Y 0x30
#define MMA8452_OFF_Z 0x31
#define MMA8452_CTRL_REG1 0x2a
#define MMA8452_CTRL_REG2 0x2b
#define MMA8452_CTRL_REG2_RST		BIT(6)
#define MMA8452_CTRL_REG4 0x2d
#define MMA8452_CTRL_REG5 0x2e

#define MMA8452_MAX_REG 0x31

@@ -48,6 +61,8 @@
#define MMA8452_DATA_CFG_FS_4G 1
#define MMA8452_DATA_CFG_FS_8G 2

#define MMA8452_INT_TRANS	BIT(5)

#define MMA8452_DEVICE_ID 0x2a

struct mma8452_data {
@@ -274,6 +289,126 @@ static int mma8452_write_raw(struct iio_dev *indio_dev,
	}
}

static int mma8452_read_thresh(struct iio_dev *indio_dev,
			       const struct iio_chan_spec *chan,
			       enum iio_event_type type,
			       enum iio_event_direction dir,
			       enum iio_event_info info,
			       int *val, int *val2)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	int ret;

	ret = i2c_smbus_read_byte_data(data->client, MMA8452_TRANSIENT_THS);
	if (ret < 0)
		return ret;

	*val = ret & MMA8452_TRANSIENT_THS_MASK;

	return IIO_VAL_INT;
}

static int mma8452_write_thresh(struct iio_dev *indio_dev,
				const struct iio_chan_spec *chan,
				enum iio_event_type type,
				enum iio_event_direction dir,
				enum iio_event_info info,
				int val, int val2)
{
	struct mma8452_data *data = iio_priv(indio_dev);

	return mma8452_change_config(data, MMA8452_TRANSIENT_THS,
				     val & MMA8452_TRANSIENT_THS_MASK);
}

static int mma8452_read_event_config(struct iio_dev *indio_dev,
				     const struct iio_chan_spec *chan,
				     enum iio_event_type type,
				     enum iio_event_direction dir)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	int ret;

	ret = i2c_smbus_read_byte_data(data->client, MMA8452_TRANSIENT_CFG);
	if (ret < 0)
		return ret;

	return ret & MMA8452_TRANSIENT_CFG_CHAN(chan->scan_index) ? 1 : 0;
}

static int mma8452_write_event_config(struct iio_dev *indio_dev,
				      const struct iio_chan_spec *chan,
				      enum iio_event_type type,
				      enum iio_event_direction dir,
				      int state)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	int val;

	val = i2c_smbus_read_byte_data(data->client, MMA8452_TRANSIENT_CFG);
	if (val < 0)
		return val;

	if (state)
		val |= MMA8452_TRANSIENT_CFG_CHAN(chan->scan_index);
	else
		val &= ~MMA8452_TRANSIENT_CFG_CHAN(chan->scan_index);

	val |= MMA8452_TRANSIENT_CFG_ELE;

	return mma8452_change_config(data, MMA8452_TRANSIENT_CFG, val);
}

static void mma8452_transient_interrupt(struct iio_dev *indio_dev)
{
	struct mma8452_data *data = iio_priv(indio_dev);
	s64 ts = iio_get_time_ns();
	int src;

	src = i2c_smbus_read_byte_data(data->client, MMA8452_TRANSIENT_SRC);
	if (src < 0)
		return;

	if (src & MMA8452_TRANSIENT_SRC_XTRANSE)
		iio_push_event(indio_dev,
			       IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, IIO_MOD_X,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_RISING),
			       ts);

	if (src & MMA8452_TRANSIENT_SRC_YTRANSE)
		iio_push_event(indio_dev,
			       IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, IIO_MOD_Y,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_RISING),
			       ts);

	if (src & MMA8452_TRANSIENT_SRC_ZTRANSE)
		iio_push_event(indio_dev,
			       IIO_MOD_EVENT_CODE(IIO_ACCEL, 0, IIO_MOD_Z,
						  IIO_EV_TYPE_THRESH,
						  IIO_EV_DIR_RISING),
			       ts);
}

static irqreturn_t mma8452_interrupt(int irq, void *p)
{
	struct iio_dev *indio_dev = p;
	struct mma8452_data *data = iio_priv(indio_dev);
	int src;

	src = i2c_smbus_read_byte_data(data->client, MMA8452_INT_SRC);
	if (src < 0)
		return IRQ_NONE;

	if (src & MMA8452_INT_TRANS) {
		mma8452_transient_interrupt(indio_dev);
		return IRQ_HANDLED;
	}

	return IRQ_NONE;
}

static irqreturn_t mma8452_trigger_handler(int irq, void *p)
{
	struct iio_poll_func *pf = p;
@@ -316,6 +451,31 @@ static int mma8452_reg_access_dbg(struct iio_dev *indio_dev,
	return 0;
}

static const struct iio_event_spec mma8452_transient_event[] = {
	{
		.type = IIO_EV_TYPE_THRESH,
		.dir = IIO_EV_DIR_RISING,
		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
		.mask_shared_by_type = BIT(IIO_EV_INFO_VALUE)
	},
};

/*
 * Threshold is configured in fixed 8G/127 steps regardless of
 * currently selected scale for measurement.
 */
static IIO_CONST_ATTR_NAMED(accel_transient_scale, in_accel_scale, "0.617742");

static struct attribute *mma8452_event_attributes[] = {
	&iio_const_attr_accel_transient_scale.dev_attr.attr,
	NULL,
};

static struct attribute_group mma8452_event_attribute_group = {
	.attrs = mma8452_event_attributes,
	.name = "events",
};

#define MMA8452_CHANNEL(axis, idx) { \
	.type = IIO_ACCEL, \
	.modified = 1, \
@@ -332,6 +492,8 @@ static int mma8452_reg_access_dbg(struct iio_dev *indio_dev,
		.shift = 4, \
		.endianness = IIO_BE, \
	}, \
	.event_spec = mma8452_transient_event, \
	.num_event_specs = ARRAY_SIZE(mma8452_transient_event), \
}

static const struct iio_chan_spec mma8452_channels[] = {
@@ -355,6 +517,11 @@ static const struct iio_info mma8452_info = {
	.attrs = &mma8452_group,
	.read_raw = &mma8452_read_raw,
	.write_raw = &mma8452_write_raw,
	.event_attrs = &mma8452_event_attribute_group,
	.read_event_value = &mma8452_read_thresh,
	.write_event_value = &mma8452_write_thresh,
	.read_event_config = &mma8452_read_event_config,
	.write_event_config = &mma8452_write_event_config,
	.debugfs_reg_access = &mma8452_reg_access_dbg,
	.driver_module = THIS_MODULE,
};
@@ -425,6 +592,38 @@ static int mma8452_probe(struct i2c_client *client,
	if (ret < 0)
		return ret;

	/*
	 * By default set transient threshold to max to avoid events if
	 * enabling without configuring threshold.
	 */
	ret = i2c_smbus_write_byte_data(client, MMA8452_TRANSIENT_THS,
					MMA8452_TRANSIENT_THS_MASK);
	if (ret < 0)
		return ret;

	if (client->irq) {
		/*
		 * Although we enable the transient interrupt source once and
		 * for all here the transient event detection itself is not
		 * enabled until userspace asks for it by
		 * mma8452_write_event_config()
		 */
		int supported_interrupts = MMA8452_INT_TRANS;

		/* Assume wired to INT1 pin */
		ret = i2c_smbus_write_byte_data(client,
						MMA8452_CTRL_REG5,
						supported_interrupts);
		if (ret < 0)
			return ret;

		ret = i2c_smbus_write_byte_data(client,
						MMA8452_CTRL_REG4,
						supported_interrupts);
		if (ret < 0)
			return ret;
	}

	data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
		(MMA8452_CTRL_DR_DEFAULT << MMA8452_CTRL_DR_SHIFT);
	ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG1,
@@ -437,9 +636,20 @@ static int mma8452_probe(struct i2c_client *client,
	if (ret < 0)
		return ret;

	if (client->irq) {
		ret = devm_request_threaded_irq(&client->dev,
						client->irq,
						NULL, mma8452_interrupt,
						IRQF_TRIGGER_LOW | IRQF_ONESHOT,
						client->name, indio_dev);
		if (ret)
			goto buffer_cleanup;
	}

	ret = iio_device_register(indio_dev);
	if (ret < 0)
		goto buffer_cleanup;

	return 0;

buffer_cleanup: