The Signal polarity component represents the active level of a
respective Signal. There are two possible states: positive (rising edge)
and negative (falling edge); enum counter_signal_polarity represents
these states. A convenience macro COUNTER_COMP_POLARITY() is provided
for driver authors to declare a Signal polarity component.
Cc: Julien Panis <jpanis@xxxxxxxxxxxx>
Signed-off-by: William Breathitt Gray <william.gray@xxxxxxxxxx>
---
Documentation/ABI/testing/sysfs-bus-counter | 13 +++++++++++++
drivers/counter/counter-chrdev.c | 1 +
drivers/counter/counter-sysfs.c | 12 ++++++++++++
include/linux/counter.h | 10 ++++++++++
include/uapi/linux/counter.h | 6 ++++++
5 files changed, 42 insertions(+)
diff --git a/Documentation/ABI/testing/sysfs-bus-counter b/Documentation/ABI/testing/sysfs-bus-counter
index 06c2b3e27e0b..a234022f9add 100644
--- a/Documentation/ABI/testing/sysfs-bus-counter
+++ b/Documentation/ABI/testing/sysfs-bus-counter
@@ -303,6 +303,19 @@ Description:
Discrete set of available values for the respective Signal Y
configuration are listed in this file.
+What: /sys/bus/counter/devices/counterX/signalY/polarity
+KernelVersion: 6.1
+Contact: linux-iio@xxxxxxxxxxxxxxx
+Description:
+ Active level of Signal Y. The following polarity values are
+ available:
+
+ positive:
+ Signal high state considered active level (rising edge).
+
+ negative:
+ Signal low state considered active level (falling edge).
+
What: /sys/bus/counter/devices/counterX/signalY/name
KernelVersion: 5.2
Contact: linux-iio@xxxxxxxxxxxxxxx
diff --git a/drivers/counter/counter-chrdev.c b/drivers/counter/counter-chrdev.c
index 4e71a19d7e6a..120879ee2e87 100644
--- a/drivers/counter/counter-chrdev.c
+++ b/drivers/counter/counter-chrdev.c
@@ -487,6 +487,7 @@ static int counter_get_data(struct counter_device *const counter,
case COUNTER_COMP_ENUM:
case COUNTER_COMP_COUNT_DIRECTION:
case COUNTER_COMP_COUNT_MODE:
+ case COUNTER_COMP_SIGNAL_POLARITY:
switch (comp_node->component.scope) {
case COUNTER_SCOPE_DEVICE:
ret = comp->device_u32_read(counter, &value_u32);
diff --git a/drivers/counter/counter-sysfs.c b/drivers/counter/counter-sysfs.c
index 04eac41dad33..e5dd36e1a45f 100644
--- a/drivers/counter/counter-sysfs.c
+++ b/drivers/counter/counter-sysfs.c
@@ -91,6 +91,11 @@ static const char *const counter_count_mode_str[] = {
[COUNTER_COUNT_MODE_MODULO_N] = "modulo-n"
};
+static const char *const counter_signal_polarity_str[] = {
+ [COUNTER_SIGNAL_POLARITY_POSITIVE] = "positive",
+ [COUNTER_SIGNAL_POLARITY_NEGATIVE] = "negative"
+};
+
static ssize_t counter_comp_u8_show(struct device *dev,
struct device_attribute *attr, char *buf)
{
@@ -201,6 +206,8 @@ static ssize_t counter_comp_u32_show(struct device *dev,
return sysfs_emit(buf, "%s\n", counter_count_direction_str[data]);
case COUNTER_COMP_COUNT_MODE:
return sysfs_emit(buf, "%s\n", counter_count_mode_str[data]);
+ case COUNTER_COMP_SIGNAL_POLARITY:
+ return sysfs_emit(buf, "%s\n", counter_signal_polarity_str[data]);
default:
return sysfs_emit(buf, "%u\n", (unsigned int)data);
}
@@ -252,6 +259,10 @@ static ssize_t counter_comp_u32_store(struct device *dev,
err = counter_find_enum(&data, avail->enums, avail->num_items,
buf, counter_count_mode_str);
break;
+ case COUNTER_COMP_SIGNAL_POLARITY:
+ err = counter_find_enum(&data, avail->enums, avail->num_items,
+ buf, counter_signal_polarity_str);
+ break;
default:
err = kstrtou32(buf, 0, &data);
break;
@@ -469,6 +480,7 @@ static int counter_attr_create(struct device *const dev,
case COUNTER_COMP_ENUM:
case COUNTER_COMP_COUNT_DIRECTION:
case COUNTER_COMP_COUNT_MODE:
+ case COUNTER_COMP_SIGNAL_POLARITY:
if (comp->device_u32_read) {
dev_attr->attr.mode |= 0444;
dev_attr->show = counter_comp_u32_show;
diff --git a/include/linux/counter.h b/include/linux/counter.h
index 1fe17f5adb09..d508b260aaca 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -31,6 +31,7 @@ enum counter_comp_type {
COUNTER_COMP_ENUM,
COUNTER_COMP_COUNT_DIRECTION,
COUNTER_COMP_COUNT_MODE,
+ COUNTER_COMP_SIGNAL_POLARITY,
};
/**
@@ -483,4 +484,13 @@ struct counter_available {
#define COUNTER_COMP_PRESET_ENABLE(_read, _write) \
COUNTER_COMP_COUNT_BOOL("preset_enable", _read, _write)
+#define COUNTER_COMP_POLARITY(_read, _write, _available) \
+{ \
+ .type = COUNTER_COMP_SIGNAL_POLARITY, \
+ .name = "polarity", \
+ .signal_u32_read = (_read), \
+ .signal_u32_write = (_write), \
+ .priv = &(_available), \
+}
+
#endif /* _COUNTER_H_ */
diff --git a/include/uapi/linux/counter.h b/include/uapi/linux/counter.h
index 96c5ffd368ad..e9610e1944dc 100644
--- a/include/uapi/linux/counter.h
+++ b/include/uapi/linux/counter.h
@@ -153,4 +153,10 @@ enum counter_synapse_action {
COUNTER_SYNAPSE_ACTION_BOTH_EDGES,
};
+/* Signal polarity values */
+enum counter_signal_polarity {
+ COUNTER_SIGNAL_POLARITY_POSITIVE,
+ COUNTER_SIGNAL_POLARITY_NEGATIVE,
+};
+
#endif /* _UAPI_COUNTER_H_ */
--
2.37.3
