IIO: ADC: AD7887: Update timestamp handling

Add timestamp attributes.
Revise timestamp handling accordingly.
Preset timestamp generation.

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 22 insertions, 15 deletions

diff --git a/drivers/staging/iio/adc/ad7887.h b/drivers/staging/iio/adc/ad7887.h
index 8c2a218c949..439c802b38f 100644
--- a/drivers/staging/iio/adc/ad7887.h
+++ b/drivers/staging/iio/adc/ad7887.h
@@ -63,6 +63,7 @@ struct ad7887_state {
         struct regulator                *reg;
         struct work_struct              poll_work;
         atomic_t                        protect_ring;
+        size_t                          d_size;
         u16                             int_vref_mv;
         bool                            en_dual;
         struct spi_transfer             xfer[4];
diff --git a/drivers/staging/iio/adc/ad7887_ring.c b/drivers/staging/iio/adc/ad7887_ring.c
index 6b9cb1f95a1..2d7fe65049d 100644
--- a/drivers/staging/iio/adc/ad7887_ring.c
+++ b/drivers/staging/iio/adc/ad7887_ring.c
@@ -27,6 +27,8 @@
 
 static IIO_SCAN_EL_C(in0, 0, 0, NULL);
 static IIO_SCAN_EL_C(in1, 1, 0, NULL);
+static IIO_SCAN_EL_TIMESTAMP(2);
+static IIO_CONST_ATTR_SCAN_EL_TYPE(timestamp, s, 64, 64);
 
 static ssize_t ad7887_show_type(struct device *dev,
                                 struct device_attribute *attr,
@@ -47,6 +49,9 @@ static struct attribute *ad7887_scan_el_attrs[] = {
         &iio_const_attr_in0_index.dev_attr.attr,
         &iio_scan_el_in1.dev_attr.attr,
         &iio_const_attr_in1_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,
 };
@@ -118,16 +123,20 @@ static int ad7887_ring_preenable(struct iio_dev *indio_dev)
 {
         struct ad7887_state *st = indio_dev->dev_data;
         struct iio_ring_buffer *ring = indio_dev->ring;
-        size_t d_size;
 
-        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);
+
         switch (ring->scan_mask) {
         case (1 << 0):
                 st->ring_msg = &st->msg[AD7887_CH0];
@@ -186,20 +195,14 @@ static void ad7887_poll_bh_to_ring(struct work_struct *work_s)
         s64 time_ns;
         __u8 *buf;
         int b_sent;
-        size_t d_size;
 
         unsigned int bytes = ring->scan_count * st->chip_info->storagebits / 8;
 
-        /* Ensure the timestamp is 8 byte aligned */
-        d_size = bytes + 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;
 
-        buf = kzalloc(d_size, GFP_KERNEL);
+        buf = kzalloc(st->d_size, GFP_KERNEL);
         if (buf == NULL)
                 return;
 
@@ -210,7 +213,9 @@ static void ad7887_poll_bh_to_ring(struct work_struct *work_s)
         time_ns = iio_get_time_ns();
 
         memcpy(buf, st->data, bytes);
-        memcpy(buf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
+        if (ring->scan_timestamp)
+                memcpy(buf + st->d_size - sizeof(s64),
+                        &time_ns, sizeof(time_ns));
 
         indio_dev->ring->access.store_to(&sw_ring->buf, buf, time_ns);
 done:
@@ -241,6 +246,7 @@ int ad7887_register_ring_funcs_and_init(struct iio_dev *indio_dev)
         indio_dev->ring->predisable = &iio_triggered_ring_predisable;
         indio_dev->ring->postdisable = &ad7887_ring_postdisable;
         indio_dev->ring->scan_el_attrs = &ad7887_scan_el_group;
+        indio_dev->ring->scan_timestamp = true;
 
         INIT_WORK(&st->poll_work, &ad7887_poll_bh_to_ring);