IIO: ADC: AD799x: 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>

3 files changed, 29 insertions, 27 deletions

diff --git a/drivers/staging/iio/adc/ad799x.h b/drivers/staging/iio/adc/ad799x.h
index 81a20d524b7..a421362c77f 100644
--- a/drivers/staging/iio/adc/ad799x.h
+++ b/drivers/staging/iio/adc/ad799x.h
@@ -116,6 +116,7 @@ struct ad799x_state {
         struct work_struct              poll_work;
         struct work_struct              work_thresh;
         atomic_t                        protect_ring;
+        size_t                          d_size;
         struct iio_trigger              *trig;
         struct regulator                *reg;
         s64                             last_timestamp;
diff --git a/drivers/staging/iio/adc/ad799x_core.c b/drivers/staging/iio/adc/ad799x_core.c
index 89ccf375a18..e50841b3ac6 100644
--- a/drivers/staging/iio/adc/ad799x_core.c
+++ b/drivers/staging/iio/adc/ad799x_core.c
@@ -123,6 +123,9 @@ static AD799X_SCAN_EL(5);
 static AD799X_SCAN_EL(6);
 static AD799X_SCAN_EL(7);
 
+static IIO_SCAN_EL_TIMESTAMP(8);
+static IIO_CONST_ATTR_SCAN_EL_TYPE(timestamp, s, 64, 64)
+
 static ssize_t ad799x_show_type(struct device *dev,
                                 struct device_attribute *attr,
                                 char *buf)
@@ -471,6 +474,9 @@ static struct attribute *ad7991_5_9_3_4_scan_el_attrs[] = {
         &iio_const_attr_in2_index.dev_attr.attr,
         &iio_scan_el_in3.dev_attr.attr,
         &iio_const_attr_in3_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,
 };
@@ -497,6 +503,9 @@ static struct attribute *ad7992_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,
 };
@@ -541,6 +550,9 @@ static struct attribute *ad7997_8_scan_el_attrs[] = {
         &iio_const_attr_in6_index.dev_attr.attr,
         &iio_scan_el_in7.dev_attr.attr,
         &iio_const_attr_in7_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,
 };
diff --git a/drivers/staging/iio/adc/ad799x_ring.c b/drivers/staging/iio/adc/ad799x_ring.c
index 975cdcbf083..56abc395f17 100644
--- a/drivers/staging/iio/adc/ad799x_ring.c
+++ b/drivers/staging/iio/adc/ad799x_ring.c
@@ -73,8 +73,6 @@ static int ad799x_ring_preenable(struct iio_dev *indio_dev)
 {
         struct iio_ring_buffer *ring = indio_dev->ring;
         struct ad799x_state *st = indio_dev->dev_data;
-        size_t d_size;
-        unsigned long numvals;
 
         /*
          * Need to figure out the current mode based upon the requested
@@ -84,15 +82,19 @@ static int ad799x_ring_preenable(struct iio_dev *indio_dev)
         if (st->id == ad7997 || st->id == ad7998)
                 ad799x_set_scan_mode(st, ring->scan_mask);
 
-        numvals = ring->scan_count;
+        st->d_size = ring->scan_count * 2;
 
-        if (ring->access.set_bytes_per_datum) {
-                d_size = numvals*2 + sizeof(s64);
-                if (d_size % 8)
-                        d_size += 8 - (d_size % 8);
-                ring->access.set_bytes_per_datum(ring, d_size);
+        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;
 }
 
@@ -130,29 +132,13 @@ static void ad799x_poll_bh_to_ring(struct work_struct *work_s)
         s64 time_ns;
         __u8 *rxbuf;
         int b_sent;
-        size_t d_size;
         u8 cmd;
 
-        unsigned long numvals = ring->scan_count;
-
-        /* Ensure the timestamp is 8 byte aligned */
-        d_size = numvals*2 + 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;
 
-        /* Monitor mode prevents reading. Whilst not currently implemented
-         * might as well have this test in here in the meantime as it does
-         * no harm.
-         */
-        if (numvals == 0)
-                return;
-
-        rxbuf = kmalloc(d_size, GFP_KERNEL);
+        rxbuf = kmalloc(st->d_size, GFP_KERNEL);
         if (rxbuf == NULL)
                 return;
 
@@ -177,13 +163,15 @@ static void ad799x_poll_bh_to_ring(struct work_struct *work_s)
         }
 
         b_sent = i2c_smbus_read_i2c_block_data(st->client,
-                        cmd, numvals*2, rxbuf);
+                        cmd, ring->scan_count * 2, rxbuf);
         if (b_sent < 0)
                 goto done;
 
         time_ns = iio_get_time_ns();
 
-        memcpy(rxbuf + d_size - sizeof(s64), &time_ns, sizeof(time_ns));
+        if (ring->scan_timestamp)
+                memcpy(rxbuf + st->d_size - sizeof(s64),
+                        &time_ns, sizeof(time_ns));
 
         ring->access.store_to(&ring_sw->buf, rxbuf, time_ns);
 done:
@@ -213,6 +201,7 @@ int ad799x_register_ring_funcs_and_init(struct iio_dev *indio_dev)
         indio_dev->ring->preenable = &ad799x_ring_preenable;
         indio_dev->ring->postenable = &iio_triggered_ring_postenable;
         indio_dev->ring->predisable = &iio_triggered_ring_predisable;
+        indio_dev->ring->scan_timestamp = true;
 
         INIT_WORK(&st->poll_work, &ad799x_poll_bh_to_ring);