Merge branches 'fixes' and 'ioremap' into for-linus

1 files changed, 545 insertions, 10 deletions

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index 5b80657883bb..e8e2077c7244 100644
--- a/drivers/iio/accel/mma8452.c
+++ b/drivers/iio/accel/mma8452.c
@@ -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>
@@ -18,20 +18,42 @@
 #include <linux/iio/sysfs.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.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_HP_FILTER_CUTOFF 0x0f
+#define MMA8452_HP_FILTER_CUTOFF_SEL_MASK	(BIT(0) | BIT(1))
+#define MMA8452_TRANSIENT_CFG 0x1d
+#define MMA8452_TRANSIENT_CFG_ELE		BIT(4)
+#define MMA8452_TRANSIENT_CFG_CHAN(chan)	BIT(chan + 1)
+#define MMA8452_TRANSIENT_CFG_HPF_BYP		BIT(0)
+#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_TRANSIENT_COUNT 0x20
 #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
 
 #define MMA8452_STATUS_DRDY (BIT(2) | BIT(1) | BIT(0))
 
@@ -44,6 +66,10 @@
 #define MMA8452_DATA_CFG_FS_2G 0
 #define MMA8452_DATA_CFG_FS_4G 1
 #define MMA8452_DATA_CFG_FS_8G 2
+#define MMA8452_DATA_CFG_HPF_MASK BIT(4)
+
+#define MMA8452_INT_DRDY	BIT(0)
+#define MMA8452_INT_TRANS	BIT(5)
 
 #define MMA8452_DEVICE_ID 0x2a
 
@@ -106,6 +132,12 @@ static int mma8452_get_int_plus_micros_index(const int (*vals)[2], int n,
 	return -EINVAL;
 }
 
+static int mma8452_get_odr_index(struct mma8452_data *data)
+{
+	return (data->ctrl_reg1 & MMA8452_CTRL_DR_MASK) >>
+			MMA8452_CTRL_DR_SHIFT;
+}
+
 static const int mma8452_samp_freq[8][2] = {
 	{800, 0}, {400, 0}, {200, 0}, {100, 0}, {50, 0}, {12, 500000},
 	{6, 250000}, {1, 560000}
@@ -121,6 +153,30 @@ static const int mma8452_scales[3][2] = {
 	{0, 9577}, {0, 19154}, {0, 38307}
 };
 
+/* Datasheet table 35  (step time vs sample frequency) */
+static const int mma8452_transient_time_step_us[8] = {
+	1250,
+	2500,
+	5000,
+	10000,
+	20000,
+	20000,
+	20000,
+	20000
+};
+
+/* Datasheet table 18 (normal mode) */
+static const int mma8452_hp_filter_cutoff[8][4][2] = {
+	{ {16, 0}, {8, 0}, {4, 0}, {2, 0} },		/* 800 Hz sample */
+	{ {16, 0}, {8, 0}, {4, 0}, {2, 0} },		/* 400 Hz sample */
+	{ {8, 0}, {4, 0}, {2, 0}, {1, 0} },		/* 200 Hz sample */
+	{ {4, 0}, {2, 0}, {1, 0}, {0, 500000} },	/* 100 Hz sample */
+	{ {2, 0}, {1, 0}, {0, 500000}, {0, 250000} },	/* 50 Hz sample */
+	{ {2, 0}, {1, 0}, {0, 500000}, {0, 250000} },	/* 12.5 Hz sample */
+	{ {2, 0}, {1, 0}, {0, 500000}, {0, 250000} },	/* 6.25 Hz sample */
+	{ {2, 0}, {1, 0}, {0, 500000}, {0, 250000} }	/* 1.56 Hz sample */
+};
+
 static ssize_t mma8452_show_samp_freq_avail(struct device *dev,
 				struct device_attribute *attr, char *buf)
 {
@@ -135,9 +191,23 @@ static ssize_t mma8452_show_scale_avail(struct device *dev,
 		ARRAY_SIZE(mma8452_scales));
 }
 
+static ssize_t mma8452_show_hp_cutoff_avail(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 i = mma8452_get_odr_index(data);
+
+	return mma8452_show_int_plus_micros(buf, mma8452_hp_filter_cutoff[i],
+		ARRAY_SIZE(mma8452_hp_filter_cutoff[0]));
+}
+
 static IIO_DEV_ATTR_SAMP_FREQ_AVAIL(mma8452_show_samp_freq_avail);
 static IIO_DEVICE_ATTR(in_accel_scale_available, S_IRUGO,
 	mma8452_show_scale_avail, NULL, 0);
+static IIO_DEVICE_ATTR(in_accel_filter_high_pass_3db_frequency_available,
+			S_IRUGO, mma8452_show_hp_cutoff_avail, NULL, 0);
 
 static int mma8452_get_samp_freq_index(struct mma8452_data *data,
 	int val, int val2)
@@ -153,6 +223,31 @@ static int mma8452_get_scale_index(struct mma8452_data *data,
 		ARRAY_SIZE(mma8452_scales), val, val2);
 }
 
+static int mma8452_get_hp_filter_index(struct mma8452_data *data,
+				       int val, int val2)
+{
+	int i = mma8452_get_odr_index(data);
+
+	return mma8452_get_int_plus_micros_index(mma8452_hp_filter_cutoff[i],
+		ARRAY_SIZE(mma8452_scales[0]), val, val2);
+}
+
+static int mma8452_read_hp_filter(struct mma8452_data *data, int *hz, int *uHz)
+{
+	int i, ret;
+
+	ret = i2c_smbus_read_byte_data(data->client, MMA8452_HP_FILTER_CUTOFF);
+	if (ret < 0)
+		return ret;
+
+	i = mma8452_get_odr_index(data);
+	ret &= MMA8452_HP_FILTER_CUTOFF_SEL_MASK;
+	*hz = mma8452_hp_filter_cutoff[i][ret][0];
+	*uHz = mma8452_hp_filter_cutoff[i][ret][1];
+
+	return 0;
+}
+
 static int mma8452_read_raw(struct iio_dev *indio_dev,
 			    struct iio_chan_spec const *chan,
 			    int *val, int *val2, long mask)
@@ -180,8 +275,7 @@ static int mma8452_read_raw(struct iio_dev *indio_dev,
 		*val2 = mma8452_scales[i][1];
 		return IIO_VAL_INT_PLUS_MICRO;
 	case IIO_CHAN_INFO_SAMP_FREQ:
-		i = (data->ctrl_reg1 & MMA8452_CTRL_DR_MASK) >>
-			MMA8452_CTRL_DR_SHIFT;
+		i = mma8452_get_odr_index(data);
 		*val = mma8452_samp_freq[i][0];
 		*val2 = mma8452_samp_freq[i][1];
 		return IIO_VAL_INT_PLUS_MICRO;
@@ -192,6 +286,16 @@ static int mma8452_read_raw(struct iio_dev *indio_dev,
 			return ret;
 		*val = sign_extend32(ret, 7);
 		return IIO_VAL_INT;
+	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
+		if (data->data_cfg & MMA8452_DATA_CFG_HPF_MASK) {
+			ret = mma8452_read_hp_filter(data, val, val2);
+			if (ret < 0)
+				return ret;
+		} else {
+			*val = 0;
+			*val2 = 0;
+		}
+		return IIO_VAL_INT_PLUS_MICRO;
 	}
 	return -EINVAL;
 }
@@ -233,12 +337,31 @@ fail:
 	return ret;
 }
 
+static int mma8452_set_hp_filter_frequency(struct mma8452_data *data,
+					   int val, int val2)
+{
+	int i, reg;
+
+	i = mma8452_get_hp_filter_index(data, val, val2);
+	if (i < 0)
+		return -EINVAL;
+
+	reg = i2c_smbus_read_byte_data(data->client,
+				       MMA8452_HP_FILTER_CUTOFF);
+	if (reg < 0)
+		return reg;
+	reg &= ~MMA8452_HP_FILTER_CUTOFF_SEL_MASK;
+	reg |= i;
+
+	return mma8452_change_config(data, MMA8452_HP_FILTER_CUTOFF, reg);
+}
+
 static int mma8452_write_raw(struct iio_dev *indio_dev,
 			     struct iio_chan_spec const *chan,
 			     int val, int val2, long mask)
 {
 	struct mma8452_data *data = iio_priv(indio_dev);
-	int i;
+	int i, ret;
 
 	if (iio_buffer_enabled(indio_dev))
 		return -EBUSY;
@@ -266,11 +389,217 @@ static int mma8452_write_raw(struct iio_dev *indio_dev,
 			return -EINVAL;
 		return mma8452_change_config(data, MMA8452_OFF_X +
 			chan->scan_index, val);
+
+	case IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY:
+		if (val == 0 && val2 == 0) {
+			data->data_cfg &= ~MMA8452_DATA_CFG_HPF_MASK;
+		} else {
+			data->data_cfg |= MMA8452_DATA_CFG_HPF_MASK;
+			ret = mma8452_set_hp_filter_frequency(data, val, val2);
+			if (ret < 0)
+				return ret;
+		}
+		return mma8452_change_config(data, MMA8452_DATA_CFG,
+						data->data_cfg);
+
+	default:
+		return -EINVAL;
+	}
+}
+
+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, us;
+
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		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;
+
+	case IIO_EV_INFO_PERIOD:
+		ret = i2c_smbus_read_byte_data(data->client,
+					       MMA8452_TRANSIENT_COUNT);
+		if (ret < 0)
+			return ret;
+
+		us = ret * mma8452_transient_time_step_us[
+				mma8452_get_odr_index(data)];
+		*val = us / USEC_PER_SEC;
+		*val2 = us % USEC_PER_SEC;
+		return IIO_VAL_INT_PLUS_MICRO;
+
+	case IIO_EV_INFO_HIGH_PASS_FILTER_3DB:
+		ret = i2c_smbus_read_byte_data(data->client,
+					       MMA8452_TRANSIENT_CFG);
+		if (ret < 0)
+			return ret;
+
+		if (ret & MMA8452_TRANSIENT_CFG_HPF_BYP) {
+			*val = 0;
+			*val2 = 0;
+		} else {
+			ret = mma8452_read_hp_filter(data, val, val2);
+			if (ret < 0)
+				return ret;
+		}
+		return IIO_VAL_INT_PLUS_MICRO;
+
+	default:
+		return -EINVAL;
+	}
+}
+
+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);
+	int ret, reg, steps;
+
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		return mma8452_change_config(data, MMA8452_TRANSIENT_THS,
+					     val & MMA8452_TRANSIENT_THS_MASK);
+
+	case IIO_EV_INFO_PERIOD:
+		steps = (val * USEC_PER_SEC + val2) /
+				mma8452_transient_time_step_us[
+					mma8452_get_odr_index(data)];
+
+		if (steps > 0xff)
+			return -EINVAL;
+
+		return mma8452_change_config(data, MMA8452_TRANSIENT_COUNT,
+					     steps);
+	case IIO_EV_INFO_HIGH_PASS_FILTER_3DB:
+		reg = i2c_smbus_read_byte_data(data->client,
+					       MMA8452_TRANSIENT_CFG);
+		if (reg < 0)
+			return reg;
+
+		if (val == 0 && val2 == 0) {
+			reg |= MMA8452_TRANSIENT_CFG_HPF_BYP;
+		} else {
+			reg &= ~MMA8452_TRANSIENT_CFG_HPF_BYP;
+			ret = mma8452_set_hp_filter_frequency(data, val, val2);
+			if (ret < 0)
+				return ret;
+		}
+		return mma8452_change_config(data, MMA8452_TRANSIENT_CFG, reg);
+
 	default:
 		return -EINVAL;
 	}
 }
 
+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 ret = IRQ_NONE;
+	int src;
+
+	src = i2c_smbus_read_byte_data(data->client, MMA8452_INT_SRC);
+	if (src < 0)
+		return IRQ_NONE;
+
+	if (src & MMA8452_INT_DRDY) {
+		iio_trigger_poll_chained(indio_dev->trig);
+		ret = IRQ_HANDLED;
+	}
+
+	if (src & MMA8452_INT_TRANS) {
+		mma8452_transient_interrupt(indio_dev);
+		ret = IRQ_HANDLED;
+	}
+
+	return ret;
+}
+
 static irqreturn_t mma8452_trigger_handler(int irq, void *p)
 {
 	struct iio_poll_func *pf = p;
@@ -291,6 +620,55 @@ done:
 	return IRQ_HANDLED;
 }
 
+static int mma8452_reg_access_dbg(struct iio_dev *indio_dev,
+				  unsigned reg, unsigned writeval,
+				  unsigned *readval)
+{
+	int ret;
+	struct mma8452_data *data = iio_priv(indio_dev);
+
+	if (reg > MMA8452_MAX_REG)
+		return -EINVAL;
+
+	if (!readval)
+		return mma8452_change_config(data, reg, writeval);
+
+	ret = i2c_smbus_read_byte_data(data->client, reg);
+	if (ret < 0)
+		return ret;
+
+	*readval = ret;
+
+	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) |
+					BIT(IIO_EV_INFO_PERIOD) |
+					BIT(IIO_EV_INFO_HIGH_PASS_FILTER_3DB)
+	},
+};
+
+/*
+ * 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, \
@@ -298,7 +676,8 @@ done:
 	.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
 		BIT(IIO_CHAN_INFO_CALIBBIAS), \
 	.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
-		BIT(IIO_CHAN_INFO_SCALE), \
+		BIT(IIO_CHAN_INFO_SCALE) | \
+		BIT(IIO_CHAN_INFO_HIGH_PASS_FILTER_3DB_FREQUENCY), \
 	.scan_index = idx, \
 	.scan_type = { \
 		.sign = 's', \
@@ -307,6 +686,8 @@ done:
 		.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[] = {
@@ -319,6 +700,7 @@ static const struct iio_chan_spec mma8452_channels[] = {
 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,
 	NULL
 };
 
@@ -330,11 +712,107 @@ 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,
 };
 
 static const unsigned long mma8452_scan_masks[] = {0x7, 0};
 
+static int mma8452_data_rdy_trigger_set_state(struct iio_trigger *trig,
+					      bool state)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct mma8452_data *data = iio_priv(indio_dev);
+	int reg;
+
+	reg = i2c_smbus_read_byte_data(data->client, MMA8452_CTRL_REG4);
+	if (reg < 0)
+		return reg;
+
+	if (state)
+		reg |= MMA8452_INT_DRDY;
+	else
+		reg &= ~MMA8452_INT_DRDY;
+
+	return mma8452_change_config(data, MMA8452_CTRL_REG4, reg);
+}
+
+static int mma8452_validate_device(struct iio_trigger *trig,
+				   struct iio_dev *indio_dev)
+{
+	struct iio_dev *indio = iio_trigger_get_drvdata(trig);
+
+	if (indio != indio_dev)
+		return -EINVAL;
+
+	return 0;
+}
+
+static const struct iio_trigger_ops mma8452_trigger_ops = {
+	.set_trigger_state = mma8452_data_rdy_trigger_set_state,
+	.validate_device = mma8452_validate_device,
+	.owner = THIS_MODULE,
+};
+
+static int mma8452_trigger_setup(struct iio_dev *indio_dev)
+{
+	struct mma8452_data *data = iio_priv(indio_dev);
+	struct iio_trigger *trig;
+	int ret;
+
+	trig = devm_iio_trigger_alloc(&data->client->dev, "%s-dev%d",
+				      indio_dev->name,
+				      indio_dev->id);
+	if (!trig)
+		return -ENOMEM;
+
+	trig->dev.parent = &data->client->dev;
+	trig->ops = &mma8452_trigger_ops;
+	iio_trigger_set_drvdata(trig, indio_dev);
+
+	ret = iio_trigger_register(trig);
+	if (ret)
+		return ret;
+
+	indio_dev->trig = trig;
+	return 0;
+}
+
+static void mma8452_trigger_cleanup(struct iio_dev *indio_dev)
+{
+	if (indio_dev->trig)
+		iio_trigger_unregister(indio_dev->trig);
+}
+
+static int mma8452_reset(struct i2c_client *client)
+{
+	int i;
+	int ret;
+
+	ret = i2c_smbus_write_byte_data(client,	MMA8452_CTRL_REG2,
+					MMA8452_CTRL_REG2_RST);
+	if (ret < 0)
+		return ret;
+
+	for (i = 0; i < 10; i++) {
+		usleep_range(100, 200);
+		ret = i2c_smbus_read_byte_data(client, MMA8452_CTRL_REG2);
+		if (ret == -EIO)
+			continue; /* I2C comm reset */
+		if (ret < 0)
+			return ret;
+		if (!(ret & MMA8452_CTRL_REG2_RST))
+			return 0;
+	}
+
+	return -ETIMEDOUT;
+}
+
 static int mma8452_probe(struct i2c_client *client,
 			 const struct i2c_device_id *id)
 {
@@ -365,10 +843,7 @@ static int mma8452_probe(struct i2c_client *client,
 	indio_dev->num_channels = ARRAY_SIZE(mma8452_channels);
 	indio_dev->available_scan_masks = mma8452_scan_masks;
 
-	data->ctrl_reg1 = MMA8452_CTRL_ACTIVE |
-		(MMA8452_CTRL_DR_DEFAULT << MMA8452_CTRL_DR_SHIFT);
-	ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG1,
-		data->ctrl_reg1);
+	ret = mma8452_reset(client);
 	if (ret < 0)
 		return ret;
 
@@ -378,18 +853,77 @@ 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_DRDY | MMA8452_INT_TRANS;
+		int enabled_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,
+						enabled_interrupts);
+		if (ret < 0)
+			return ret;
+
+		ret = mma8452_trigger_setup(indio_dev);
+		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,
+					data->ctrl_reg1);
+	if (ret < 0)
+		goto trigger_cleanup;
+
 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
 		mma8452_trigger_handler, NULL);
 	if (ret < 0)
-		return ret;
+		goto trigger_cleanup;
+
+	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:
 	iio_triggered_buffer_cleanup(indio_dev);
+
+trigger_cleanup:
+	mma8452_trigger_cleanup(indio_dev);
+
 	return ret;
 }
 
@@ -399,6 +933,7 @@ static int mma8452_remove(struct i2c_client *client)
 
 	iio_device_unregister(indio_dev);
 	iio_triggered_buffer_cleanup(indio_dev);
+	mma8452_trigger_cleanup(indio_dev);
 	mma8452_standby(iio_priv(indio_dev));
 
 	return 0;