Re: [PATCH 4/9] iio: mma8452: Basic support for transient events.

[Jonathan Cameron <jic23@kernel.org>]

On 19/02/15 14:16, Martin Fuzzey wrote:
> The event is triggered when the highpass filtered absolute acceleration
> exceeds the threshold.
> 
> Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
you in_accel_transient_scale isn't documented.
Why do we need this naming at all?
Ah. It's not clear this is just the event rather than the underlying channel.
Perhaps, make it an event parameter instead... e.g. add scale to the ev_info
array like we do for hysteresis etc.

Otherwise, looks good to me.

Again, Peter's input would be good.

> ---
>  drivers/iio/accel/mma8452.c |  212 +++++++++++++++++++++++++++++++++++++++++++
>  1 file changed, 211 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
> index c46df4e..d44044f 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>
> @@ -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_MASK(chan)	(BIT(1) << chan)
> +#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_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
>  
> @@ -48,6 +61,13 @@
>  #define MMA8452_DATA_CFG_FS_4G 1
>  #define MMA8452_DATA_CFG_FS_8G 2
>  
> +#define MMA8452_INT_DRDY	BIT(0)
> +#define MMA8452_INT_FF_MT	BIT(2)
> +#define MMA8452_INT_PULSE	BIT(3)
> +#define MMA8452_INT_LNDPRT	BIT(4)
> +#define MMA8452_INT_TRANS	BIT(5)
> +#define MMA8452_INT_ASLP	BIT(7)
> +
>  #define MMA8452_DEVICE_ID 0x2a
>  
>  struct mma8452_data {
> @@ -274,6 +294,121 @@ 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 & 0x7f;
> +
> +	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 & 0x7f);
> +}
> +
> +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_MASK(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_MASK(chan->scan_index);
> +	else
> +		val &= ~MMA8452_TRANSIENT_CFG_CHAN_MASK(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 +451,32 @@ static int mma8452_reg_access_dbg(struct iio_dev *indio_dev,
>  	return ret;
>  }
>  
> +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_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, \
> @@ -332,6 +493,8 @@ 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 +518,11 @@ 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 +593,37 @@ 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, 0x7f);
> +	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:
>