Re: [RFC PATCH 1/8] iio: dummy: Introduce virtual registers for dummy device

[Jonathan Cameron <jic23@kernel.org>]

On 02/10/14 14:43, Daniel Baluta wrote:
> We need a way to store events generated by iio_dummy_evgen module,
> in order to correctly process IRQs in iio_simple_dummy_events.
>
> For the moment, we add two registers:
>
> * id_reg  - ID register, stores the source of the event
> * id_data - DATA register, stores the type of the event
>
> e.g echo 4 > /sys/bus/iio/devices/iio_evgen/poke2
>
> id_reg 0x02, id_data 0x04
>
> This means, event of type 4 was generated by fake device 2.
>
> We currently use a hardcoded mapping of virtual events to IIO events.
>
> Signed-off-by: Daniel Baluta <daniel.baluta@intel.com>
> Signed-off-by: Irina Tirdea <irina.tirdea@intel.com>
Does the job and will look enough like a normal interrupt that
it allows the dummy driver to act as example code.

> ---
>  drivers/staging/iio/iio_dummy_evgen.c         | 16 ++++++++++++++++
>  drivers/staging/iio/iio_dummy_evgen.h         |  7 +++++++
>  drivers/staging/iio/iio_simple_dummy.h        |  2 ++
>  drivers/staging/iio/iio_simple_dummy_events.c | 23 ++++++++++++++++++-----
>  4 files changed, 43 insertions(+), 5 deletions(-)
>
> diff --git a/drivers/staging/iio/iio_dummy_evgen.c b/drivers/staging/iio/iio_dummy_evgen.c
> index 5a804f1..d44f138 100644
> --- a/drivers/staging/iio/iio_dummy_evgen.c
> +++ b/drivers/staging/iio/iio_dummy_evgen.c
> @@ -33,6 +33,7 @@
>   * @base: base of irq range
>   * @enabled: mask of which irqs are enabled
>   * @inuse: mask of which irqs are connected
> + * @regs: irq regs we are faking
>   * @lock: protect the evgen state
>   */
>  struct iio_dummy_eventgen {
> @@ -40,6 +41,7 @@ struct iio_dummy_eventgen {
>  	int base;
>  	bool enabled[IIO_EVENTGEN_NO];
>  	bool inuse[IIO_EVENTGEN_NO];
> +	struct iio_dummy_regs regs[IIO_EVENTGEN_NO];
>  	struct mutex lock;
>  };
>
> @@ -136,6 +138,12 @@ int iio_dummy_evgen_release_irq(int irq)
>  }
>  EXPORT_SYMBOL_GPL(iio_dummy_evgen_release_irq);
>
> +struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq)
> +{
> +	return &iio_evgen->regs[irq - iio_evgen->base];
> +}
> +EXPORT_SYMBOL_GPL(iio_dummy_evgen_get_regs);
> +
>  static void iio_dummy_evgen_free(void)
>  {
>  	irq_free_descs(iio_evgen->base, IIO_EVENTGEN_NO);
> @@ -153,6 +161,14 @@ static ssize_t iio_evgen_poke(struct device *dev,
>  			      size_t len)
>  {
>  	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
> +	unsigned long event, ret;
> +
> +	ret = kstrtoul(buf, 10, &event);
> +	if (ret)
> +		return ret;
> +
> +	iio_evgen->regs[this_attr->address].reg_id   = this_attr->address;
> +	iio_evgen->regs[this_attr->address].reg_data = event;
>
>  	if (iio_evgen->enabled[this_attr->address])
>  		handle_nested_irq(iio_evgen->base + this_attr->address);
> diff --git a/drivers/staging/iio/iio_dummy_evgen.h b/drivers/staging/iio/iio_dummy_evgen.h
> index d8845e2..5273478 100644
> --- a/drivers/staging/iio/iio_dummy_evgen.h
> +++ b/drivers/staging/iio/iio_dummy_evgen.h
> @@ -1,2 +1,9 @@
> +struct iio_dummy_regs {
> +	u32 reg_id;
> +	u32 reg_data;
> +};
> +
> +struct iio_dummy_regs *iio_dummy_evgen_get_regs(int irq);
>  int iio_dummy_evgen_get_irq(void);
>  int iio_dummy_evgen_release_irq(int irq);
> +
> diff --git a/drivers/staging/iio/iio_simple_dummy.h b/drivers/staging/iio/iio_simple_dummy.h
> index b126196..1a74e26 100644
> --- a/drivers/staging/iio/iio_simple_dummy.h
> +++ b/drivers/staging/iio/iio_simple_dummy.h
> @@ -11,6 +11,7 @@
>  #include <linux/kernel.h>
>
>  struct iio_dummy_accel_calibscale;
> +struct iio_dummy_regs;
>
>  /**
>   * struct iio_dummy_state - device instance specific state.
> @@ -33,6 +34,7 @@ struct iio_dummy_state {
>  	int accel_calibbias;
>  	const struct iio_dummy_accel_calibscale *accel_calibscale;
>  	struct mutex lock;
> +	struct iio_dummy_regs *regs;
>  #ifdef CONFIG_IIO_SIMPLE_DUMMY_EVENTS
>  	int event_irq;
>  	int event_val;
> diff --git a/drivers/staging/iio/iio_simple_dummy_events.c b/drivers/staging/iio/iio_simple_dummy_events.c
> index 64b45b0..719dfa5 100644
> --- a/drivers/staging/iio/iio_simple_dummy_events.c
> +++ b/drivers/staging/iio/iio_simple_dummy_events.c
> @@ -148,12 +148,23 @@ int iio_simple_dummy_write_event_value(struct iio_dev *indio_dev,
>  static irqreturn_t iio_simple_dummy_event_handler(int irq, void *private)
>  {
>  	struct iio_dev *indio_dev = private;
> +	struct iio_dummy_state *st = iio_priv(indio_dev);
> +
> +	dev_dbg(&indio_dev->dev, "id %x event %x\n",
> +		st->regs->reg_id, st->regs->reg_data);
> +
> +	switch (st->regs->reg_data) {
> +	case 0:
> +		iio_push_event(indio_dev,
> +			       IIO_EVENT_CODE(IIO_VOLTAGE, 0, 0,
> +					      IIO_EV_DIR_RISING,
> +					      IIO_EV_TYPE_THRESH, 0, 0, 0),
> +			       iio_get_time_ns());
> +		break;
> +	default:
> +		break;
> +	}
>
> -	iio_push_event(indio_dev,
> -		       IIO_EVENT_CODE(IIO_VOLTAGE, 0, 0,
> -				      IIO_EV_DIR_RISING,
> -				      IIO_EV_TYPE_THRESH, 0, 0, 0),
> -		       iio_get_time_ns());
>  	return IRQ_HANDLED;
>  }
>
> @@ -179,6 +190,8 @@ int iio_simple_dummy_events_register(struct iio_dev *indio_dev)
>  		ret = st->event_irq;
>  		goto error_ret;
>  	}
> +	st->regs = iio_dummy_evgen_get_regs(st->event_irq);
> +
>  	ret = request_threaded_irq(st->event_irq,
>  				   NULL,
>  				   &iio_simple_dummy_event_handler,
>