Commit 28e34278 authored by Martin Fuzzey's avatar Martin Fuzzey Committed by Jonathan Cameron
Browse files

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

drivers/iio/accel/mma8452.c

+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: