On 02/24/11 19:09, michael.hennerich@xxxxxxxxxx wrote:
> From: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
>
> Add timestamp attributes.
> Revise timestamp handling accordingly.
> Preset timestamp generation.
As an aside:
An alternative would be to define an always on version of IIO_SCAN_EL_TIMESTAMP.
That would lead to smaller changes. This way means we can turn it off though, which
on simple devices like this one means a big saving in 'ring_buffer' usage.
Patch is good, thanks. Technically this fixes a bug (by conforming to the abi)
as you pointed out the other day so could go to stable. Up to you...
>
> Signed-off-by: Michael Hennerich <michael.hennerich@xxxxxxxxxx>
Acked-by: Jonathan Cameron <jic23@xxxxxxxxx>
> ---
> drivers/staging/iio/adc/ad7476.h | 1 +
> drivers/staging/iio/adc/ad7476_ring.c | 37 +++++++++++++++++++-------------
> 2 files changed, 23 insertions(+), 15 deletions(-)
>
> diff --git a/drivers/staging/iio/adc/ad7476.h b/drivers/staging/iio/adc/ad7476.h
> index b51b49e..f917e9c 100644
> --- a/drivers/staging/iio/adc/ad7476.h
> +++ b/drivers/staging/iio/adc/ad7476.h
> @@ -33,6 +33,7 @@ struct ad7476_state {
> struct regulator *reg;
> struct work_struct poll_work;
> atomic_t protect_ring;
> + size_t d_size;
> u16 int_vref_mv;
> struct spi_transfer xfer;
> struct spi_message msg;
> diff --git a/drivers/staging/iio/adc/ad7476_ring.c b/drivers/staging/iio/adc/ad7476_ring.c
> index 85de142..1d654c8 100644
> --- a/drivers/staging/iio/adc/ad7476_ring.c
> +++ b/drivers/staging/iio/adc/ad7476_ring.c
> @@ -26,6 +26,8 @@
> #include "ad7476.h"
>
> static IIO_SCAN_EL_C(in0, 0, 0, NULL);
> +static IIO_SCAN_EL_TIMESTAMP(1);
> +static IIO_CONST_ATTR_SCAN_EL_TYPE(timestamp, s, 64, 64);
>
> static ssize_t ad7476_show_type(struct device *dev,
> struct device_attribute *attr,
> @@ -44,6 +46,9 @@ static IIO_DEVICE_ATTR(in_type, S_IRUGO, ad7476_show_type, NULL, 0);
> static struct attribute *ad7476_scan_el_attrs[] = {
> &iio_scan_el_in0.dev_attr.attr,
> &iio_const_attr_in0_index.dev_attr.attr,
> + &iio_const_attr_timestamp_index.dev_attr.attr,
> + &iio_scan_el_timestamp.dev_attr.attr,
> + &iio_const_attr_timestamp_type.dev_attr.attr,
> &iio_dev_attr_in_type.dev_attr.attr,
> NULL,
> };
> @@ -86,16 +91,21 @@ error_ret:
> static int ad7476_ring_preenable(struct iio_dev *indio_dev)
> {
> struct ad7476_state *st = indio_dev->dev_data;
> - size_t d_size;
> + struct iio_ring_buffer *ring = indio_dev->ring;
>
> - if (indio_dev->ring->access.set_bytes_per_datum) {
> - d_size = st->chip_info->storagebits / 8 + sizeof(s64);
> - if (d_size % 8)
> - d_size += 8 - (d_size % 8);
> - indio_dev->ring->access.set_bytes_per_datum(indio_dev->ring,
> - d_size);
> + st->d_size = ring->scan_count * st->chip_info->storagebits / 8;
> +
> + if (ring->scan_timestamp) {
> + st->d_size += sizeof(s64);
> +
> + if (st->d_size % sizeof(s64))
> + st->d_size += sizeof(s64) - (st->d_size % sizeof(s64));
> }
>
> + if (indio_dev->ring->access.set_bytes_per_datum)
> + indio_dev->ring->access.set_bytes_per_datum(indio_dev->ring,
> + st->d_size);
> +
> return 0;
> }
>
> @@ -131,18 +141,12 @@ static void ad7476_poll_bh_to_ring(struct work_struct *work_s)
> s64 time_ns;
> __u8 *rxbuf;
> int b_sent;
> - size_t d_size;
> -
> - /* Ensure the timestamp is 8 byte aligned */
> - d_size = st->chip_info->storagebits / 8 + sizeof(s64);
> - if (d_size % sizeof(s64))
> - d_size += sizeof(s64) - (d_size % sizeof(s64));
>
> /* Ensure only one copy of this function running at a time */
> if (atomic_inc_return(&st->protect_ring) > 1)
> return;
>
> - rxbuf = kzalloc(d_size, GFP_KERNEL);
> + rxbuf = kzalloc(st->d_size, GFP_KERNEL);
> if (rxbuf == NULL)
> return;
>
> @@ -152,7 +156,9 @@ static void ad7476_poll_bh_to_ring(struct work_struct *work_s)
>
> time_ns = iio_get_time_ns();
>
> - memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
> + if (indio_dev->ring->scan_timestamp)
> + memcpy(rxbuf + st->d_size - sizeof(s64),
> + &time_ns, sizeof(time_ns));
>
> indio_dev->ring->access.store_to(&sw_ring->buf, rxbuf, time_ns);
> done:
> @@ -182,6 +188,7 @@ int ad7476_register_ring_funcs_and_init(struct iio_dev *indio_dev)
> indio_dev->ring->postenable = &iio_triggered_ring_postenable;
> indio_dev->ring->predisable = &iio_triggered_ring_predisable;
> indio_dev->ring->scan_el_attrs = &ad7476_scan_el_group;
> + indio_dev->ring->scan_timestamp = true;
>
> INIT_WORK(&st->poll_work, &ad7476_poll_bh_to_ring);
>
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