[PATCH 1/3] iio: Implement counter channel specification and IIO_SIGNAL constant

From: William Breathitt Gray
Date: Mon Jul 31 2017 - 12:03:25 EST


Counters are IIO devices that are exposed via a generic counter
interface consisting of one or more counter signals (IIO_SIGNAL) linked
to one or more counter values (IIO_COUNT).

This patch introduces the IIO_SIGNAL constant which represents a counter
device signal line. Additionally, a new "counter" member is added to
struct iio_chan_spec, with relevant support, to indicate that a channel
is part of a counter.

Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx>
---
drivers/iio/industrialio-core.c | 14 +++++++++++++-
include/linux/iio/iio.h | 2 ++
include/uapi/linux/iio/types.h | 1 +
3 files changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/industrialio-core.c b/drivers/iio/industrialio-core.c
index 17ec4cee51dc..70347ee7416d 100644
--- a/drivers/iio/industrialio-core.c
+++ b/drivers/iio/industrialio-core.c
@@ -85,6 +85,7 @@ static const char * const iio_chan_type_name_spec[] = {
[IIO_COUNT] = "count",
[IIO_INDEX] = "index",
[IIO_GRAVITY] = "gravity",
+ [IIO_SIGNAL] = "signal",
};

static const char * const iio_modifier_names[] = {
@@ -989,7 +990,18 @@ int __iio_device_attr_init(struct device_attribute *dev_attr,
break;

case IIO_SEPARATE:
- if (chan->indexed)
+ if (chan->counter) {
+ if (!chan->indexed) {
+ WARN(1, "Counter channels must be indexed\n");
+ ret = -EINVAL;
+ goto error_free_full_postfix;
+ }
+ name = kasprintf(GFP_KERNEL, "%s%d-%d_%s",
+ iio_chan_type_name_spec[chan->type],
+ chan->channel,
+ chan->channel2,
+ full_postfix);
+ } else if (chan->indexed)
name = kasprintf(GFP_KERNEL, "%s_%s%d_%s",
iio_direction[chan->output],
iio_chan_type_name_spec[chan->type],
diff --git a/include/linux/iio/iio.h b/include/linux/iio/iio.h
index d68bec297a45..6acce1016625 100644
--- a/include/linux/iio/iio.h
+++ b/include/linux/iio/iio.h
@@ -263,6 +263,7 @@ struct iio_event_spec {
* attributes but not for event codes.
* @output: Channel is output.
* @differential: Channel is differential.
+ * @counter: Channel is part of a counter.
*/
struct iio_chan_spec {
enum iio_chan_type type;
@@ -295,6 +296,7 @@ struct iio_chan_spec {
unsigned indexed:1;
unsigned output:1;
unsigned differential:1;
+ unsigned counter:1;
};


diff --git a/include/uapi/linux/iio/types.h b/include/uapi/linux/iio/types.h
index ffafd6c25a48..313899652ca7 100644
--- a/include/uapi/linux/iio/types.h
+++ b/include/uapi/linux/iio/types.h
@@ -43,6 +43,7 @@ enum iio_chan_type {
IIO_COUNT,
IIO_INDEX,
IIO_GRAVITY,
+ IIO_SIGNAL,
};

enum iio_modifier {
--
2.13.3