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counter: Introduce the Signal polarity component

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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@baylibre.com>
Link: https://lore.kernel.org/r/8f47d6e1db71a11bb1e2666f8e2a6e9d256d4131.1664204990.git.william.gray@linaro.org/
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/b6e53438badcb6318997d13dd2fc052f97d808ac.1664318353.git.william.gray@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
William Breathitt Gray 2022-09-27 18:53:38 -04:00 committed by Greg Kroah-Hartman
parent 7bbf842cdc
commit 650ae67bbf
5 changed files with 43 additions and 0 deletions
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14
Documentation/ABI/testing/sysfs-bus-counter
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@ -217,6 +217,7 @@ What: /sys/bus/counter/devices/counterX/signalY/cable_fault_component_id
What: /sys/bus/counter/devices/counterX/signalY/cable_fault_enable_component_id
What: /sys/bus/counter/devices/counterX/signalY/filter_clock_prescaler_component_id
What: /sys/bus/counter/devices/counterX/signalY/index_polarity_component_id
What: /sys/bus/counter/devices/counterX/signalY/polarity_component_id
What: /sys/bus/counter/devices/counterX/signalY/synchronous_mode_component_id
KernelVersion: 5.16
Contact: linux-iio@vger.kernel.org
@ -303,6 +304,19 @@ 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@vger.kernel.org
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@vger.kernel.org

1
drivers/counter/counter-chrdev.c
View File

@ -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);

12
drivers/counter/counter-sysfs.c
View File

@ -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;

10
include/linux/counter.h
View File

@ -31,6 +31,7 @@ enum counter_comp_type {
COUNTER_COMP_ENUM,
COUNTER_COMP_COUNT_DIRECTION,
COUNTER_COMP_COUNT_MODE,
COUNTER_COMP_SIGNAL_POLARITY,
};
/**
@ -477,6 +478,15 @@ struct counter_available {
#define COUNTER_COMP_FLOOR(_read, _write) \
COUNTER_COMP_COUNT_U64("floor", _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), \
}
#define COUNTER_COMP_PRESET(_read, _write) \
COUNTER_COMP_COUNT_U64("preset", _read, _write)

6
include/uapi/linux/counter.h
View File

@ -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_ */