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Implement support for Counter array components

PATCH Superseded William Breathitt Gray 1 participant 5 messages Sep 18, 2022

Subsystems (3)

v3 of 6 Superseded Latest is v6 →

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#0 lore raw

v3 cover Implement support for Counter array components

Changes in v3:
- Fix array length overwrite by allocating space for each array element
- Add support for counter array component reads from Counter chrdev

The COUNTER_COMP_ARRAY Counter component type is introduced to enable support for Counter array components. With Counter array components, exposure for buffers on counter devices can be defined via new Counter array component macros. This should simplify code for driver authors who would otherwise need to define individual Counter components for each array element.

Driver authors can handle reads/writes for an array component by receiving an element index via the idx parameter and processing the respective value via the val parameter.

For example, suppose a driver wants to expose a Count's read-only capture buffer of four elements using a callback foobar_capture_read()::

        DEFINE_COUNTER_ARRAY(foobar_capture_array, COUNTER_COMP_U64,
                             NULL, 4)
        COUNTER_COMP_COUNT_ARRAY_U64("capture", foobar_capture_read,
                                     NULL, foobar_capture_array)

Respective sysfs attributes for each array element would appear for the respective Count:

* /sys/bus/counter/devices/counterX/countY/capture0
* /sys/bus/counter/devices/counterX/countY/capture1
* /sys/bus/counter/devices/counterX/countY/capture2
* /sys/bus/counter/devices/counterX/countY/capture3

If a user tries to read _capture2_ for example, idx will be 2 when passed to the foobar_capture_read() callback, and thus the driver knows which array element to handle.

In addition, this patchset introduces the Signal polarity component, which represents the active level of a respective Signal. There are two possible states: positive (rising edge) and negative (falling edge). The 104-quad-8 driver is updated to expose its index_polarity functionality via this new polarity component.

A macro COUNTER_COMP_ARRAY_POLARITY() is provided for driver authors to support Counter arrays of Signal polarity component type; DEFINE_COUNTER_AVAILABLE may be used to define the polarity modes that are passed to DEFINE_COUNTER_ARRAY. The only component types supported for Counter arrays currently are COUNTER_COMP_U64 and COUNTER_COMP_SIGNAL_POLARITY.

William Breathitt Gray (4):
counter: Introduce the Signal polarity component
counter: 104-quad-8: Add Signal polarity component
counter: Consolidate Counter extension sysfs attribute creation
counter: Introduce the COUNTER_COMP_ARRAY component type

 Documentation/ABI/testing/sysfs-bus-counter |  13 +
 drivers/counter/104-quad-8.c                |  35 +++
 drivers/counter/counter-chrdev.c            |  47 ++-
 drivers/counter/counter-sysfs.c             | 303 ++++++++++++++++----
 include/linux/counter.h                     | 131 +++++++++
 include/uapi/linux/counter.h                |   6 +
 6 files changed, 483 insertions(+), 52 deletions(-)

base-commit: a12224997bec72d231a8dd642876e6364decdc45

Signature · 1 line
2.37.3
#1 lore raw

PATCH v3 1/4 counter: Introduce the Signal polarity component

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.

---
 Documentation/ABI/testing/sysfs-bus-counter | 13 +++++++++++++
 drivers/counter/counter-sysfs.c             | 11 +++++++++++
 include/linux/counter.h                     | 10 ++++++++++
 include/uapi/linux/counter.h                |  6 ++++++
 4 files changed, 40 insertions(+)
Documentation/ABI/testing/sysfs-bus-counter +13 -0
index 06c2b3e27e0b..a234022f9add 100644
@@ -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:	[email protected]
+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:	[email protected]
drivers/counter/counter-sysfs.c +11 -0
index 04eac41dad33..92d3d4f549cb 100644
@@ -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;
include/linux/counter.h +10 -0
index 1fe17f5adb09..d508b260aaca 100644
@@ -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_ */
include/uapi/linux/counter.h +6 -0
index 96c5ffd368ad..e9610e1944dc 100644
@@ -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_ */
Signature · 1 line
2.37.3
#2 lore raw

PATCH v3 2/4 counter: 104-quad-8: Add Signal polarity component

In reply to William Breathitt Gray

The 104-quad-8 driver provides support for Index signal polarity modes via the "index_polarity" Signal component. This patch exposes the same functionality through the more standard "polarity" Signal component.

---
 drivers/counter/104-quad-8.c | 35 +++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
drivers/counter/104-quad-8.c +35 -0
index 1323edfbe40c..2a9d8259ed4b 100644
@@ -549,6 +549,32 @@ static int quad8_index_polarity_set(struct counter_device *counter,
 	return 0;
 }
 
+static int quad8_polarity_read(struct counter_device *counter,
+			       struct counter_signal *signal,
+			       enum counter_signal_polarity *polarity)
+{
+	int err;
+	u32 index_polarity;
+
+	err = quad8_index_polarity_get(counter, signal, &index_polarity);
+	if (err)
+		return err;
+
+	*polarity = (index_polarity) ? COUNTER_SIGNAL_POLARITY_POSITIVE :
+		COUNTER_SIGNAL_POLARITY_NEGATIVE;
+
+	return 0;
+}
+
+static int quad8_polarity_write(struct counter_device *counter,
+				struct counter_signal *signal,
+				enum counter_signal_polarity polarity)
+{
+	const u32 pol = (polarity == COUNTER_SIGNAL_POLARITY_POSITIVE) ? 1 : 0;
+
+	return quad8_index_polarity_set(counter, signal, pol);
+}
+
 static const char *const quad8_synchronous_modes[] = {
 	"non-synchronous",
 	"synchronous"
@@ -977,6 +1003,13 @@ static struct counter_comp quad8_signal_ext[] = {
 			       quad8_signal_fck_prescaler_write)
 };
 
+static const enum counter_signal_polarity quad8_polarities[] = {
+	COUNTER_SIGNAL_POLARITY_POSITIVE,
+	COUNTER_SIGNAL_POLARITY_NEGATIVE,
+};
+
+static DEFINE_COUNTER_AVAILABLE(quad8_polarity_available, quad8_polarities);
+
 static DEFINE_COUNTER_ENUM(quad8_index_pol_enum, quad8_index_polarity_modes);
 static DEFINE_COUNTER_ENUM(quad8_synch_mode_enum, quad8_synchronous_modes);
 
@@ -984,6 +1017,8 @@ static struct counter_comp quad8_index_ext[] = {
 	COUNTER_COMP_SIGNAL_ENUM("index_polarity", quad8_index_polarity_get,
 				 quad8_index_polarity_set,
 				 quad8_index_pol_enum),
+	COUNTER_COMP_POLARITY(quad8_polarity_read, quad8_polarity_write,
+			      quad8_polarity_available),
 	COUNTER_COMP_SIGNAL_ENUM("synchronous_mode", quad8_synchronous_mode_get,
 				 quad8_synchronous_mode_set,
 				 quad8_synch_mode_enum),
Signature · 1 line
2.37.3
#3 lore raw

PATCH v3 3/4 counter: Consolidate Counter extension sysfs attribute creation

In reply to William Breathitt Gray

Counter extensions are handled for the Device, Counts, and Signals. The code loops through each Counter extension and creates the expected sysfs attributes. This patch consolidates that code into functions to reduce redundancy and make the intention of the code clearer.

---
 drivers/counter/counter-sysfs.c | 98 ++++++++++++++++-----------------
 1 file changed, 49 insertions(+), 49 deletions(-)
drivers/counter/counter-sysfs.c +49 -49
index 92d3d4f549cb..7ce7c51395da 100644
@@ -591,6 +591,46 @@ static int counter_comp_id_attr_create(struct device *const dev,
 	return 0;
 }
 
+static int counter_ext_attrs_create(struct device *const dev,
+				    struct counter_attribute_group *const group,
+				    const struct counter_comp *const ext,
+				    const enum counter_scope scope,
+				    void *const parent, const size_t id)
+{
+	int err;
+
+	/* Create main extension attribute */
+	err = counter_attr_create(dev, group, ext, scope, parent);
+	if (err < 0)
+		return err;
+
+	/* Create extension id attribute */
+	return counter_comp_id_attr_create(dev, group, ext->name, id);
+}
+
+static int counter_sysfs_exts_add(struct device *const dev,
+				  struct counter_attribute_group *const group,
+				  const struct counter_comp *const exts,
+				  const size_t num_ext,
+				  const enum counter_scope scope,
+				  void *const parent)
+{
+	size_t i;
+	const struct counter_comp *ext;
+	int err;
+
+	/* Create attributes for each extension */
+	for (i = 0; i < num_ext; i++) {
+		ext = &exts[i];
+		err = counter_ext_attrs_create(dev, group, ext, scope, parent,
+					       i);
+		if (err < 0)
+			return err;
+	}
+
+	return 0;
+}
+
 static struct counter_comp counter_signal_comp = {
 	.type = COUNTER_COMP_SIGNAL_LEVEL,
 	.name = "signal",
@@ -604,8 +644,6 @@ static int counter_signal_attrs_create(struct counter_device *const counter,
 	struct device *const dev = &counter->dev;
 	int err;
 	struct counter_comp comp;
-	size_t i;
-	struct counter_comp *ext;
 
 	/* Create main Signal attribute */
 	comp = counter_signal_comp;
@@ -619,21 +657,9 @@ static int counter_signal_attrs_create(struct counter_device *const counter,
 	if (err < 0)
 		return err;
 
-	/* Create an attribute for each extension */
-	for (i = 0; i < signal->num_ext; i++) {
-		ext = &signal->ext[i];
-
-		err = counter_attr_create(dev, cattr_group, ext, scope, signal);
-		if (err < 0)
-			return err;
-
-		err = counter_comp_id_attr_create(dev, cattr_group, ext->name,
-						  i);
-		if (err < 0)
-			return err;
-	}
-
-	return 0;
+	/* Add Signal extensions */
+	return counter_sysfs_exts_add(dev, cattr_group, signal->ext,
+				      signal->num_ext, scope, signal);
 }
 
 static int counter_sysfs_signals_add(struct counter_device *const counter,
@@ -718,8 +744,6 @@ static int counter_count_attrs_create(struct counter_device *const counter,
 	struct device *const dev = &counter->dev;
 	int err;
 	struct counter_comp comp;
-	size_t i;
-	struct counter_comp *ext;
 
 	/* Create main Count attribute */
 	comp = counter_count_comp;
@@ -742,21 +766,9 @@ static int counter_count_attrs_create(struct counter_device *const counter,
 	if (err < 0)
 		return err;
 
-	/* Create an attribute for each extension */
-	for (i = 0; i < count->num_ext; i++) {
-		ext = &count->ext[i];
-
-		err = counter_attr_create(dev, cattr_group, ext, scope, count);
-		if (err < 0)
-			return err;
-
-		err = counter_comp_id_attr_create(dev, cattr_group, ext->name,
-						  i);
-		if (err < 0)
-			return err;
-	}
-
-	return 0;
+	/* Add Count extensions */
+	return counter_sysfs_exts_add(dev, cattr_group, count->ext,
+				      count->num_ext, scope, count);
 }
 
 static int counter_sysfs_counts_add(struct counter_device *const counter,
@@ -849,8 +861,6 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
 	const enum counter_scope scope = COUNTER_SCOPE_DEVICE;
 	struct device *const dev = &counter->dev;
 	int err;
-	size_t i;
-	struct counter_comp *ext;
 
 	/* Add Signals sysfs attributes */
 	err = counter_sysfs_signals_add(counter, cattr_group);
@@ -887,19 +897,9 @@ static int counter_sysfs_attr_add(struct counter_device *const counter,
 	if (err < 0)
 		return err;
 
-	/* Create an attribute for each extension */
-	for (i = 0; i < counter->num_ext; i++) {
-		ext = &counter->ext[i];
-
-		err = counter_attr_create(dev, cattr_group, ext, scope, NULL);
-		if (err < 0)
-			return err;
-
-		err = counter_comp_id_attr_create(dev, cattr_group, ext->name,
-						  i);
-		if (err < 0)
-			return err;
-	}
+	/* Add device extensions */
+	return counter_sysfs_exts_add(dev, cattr_group, counter->ext,
+				      counter->num_ext, scope, NULL);
 
 	return 0;
 }
Signature · 1 line
2.37.3
#4 lore raw

PATCH v3 4/4 counter: Introduce the COUNTER_COMP_ARRAY component type

In reply to William Breathitt Gray

The COUNTER_COMP_ARRAY Counter component type is introduced to enable support for Counter array components. With Counter array components, exposure for buffers on counter devices can be defined via new Counter array component macros. This should simplify code for driver authors who would otherwise need to define individual Counter components for each array element.

Five Counter array component macros are introduced::

        DEFINE_COUNTER_ARRAY(_name, _type, _available, _length)
        COUNTER_COMP_DEVICE_ARRAY_U64(_name, _read, _write, _array)
        COUNTER_COMP_COUNT_ARRAY_U64(_name, _read, _write, _array)
        COUNTER_COMP_SIGNAL_ARRAY_U64(_name, _read, _write, _array)
        COUNTER_COMP_ARRAY_POLARITY(_read, _write, _array)

Eight Counter array callbacks are introduced as well::

int (*signal_array_u32_read)(struct counter_device *counter,
struct counter_signal *signal, size_t idx, u32 *val);
int (*signal_array_u32_write)(struct counter_device *counter,
struct counter_signal *signal, size_t idx, u32 val);
int (*device_array_u64_read)(struct counter_device *counter,
size_t idx, u64 *val);
int (*count_array_u64_read)(struct counter_device *counter,
struct counter_count *count, size_t idx, u64 *val);
int (*signal_array_u64_read)(struct counter_device *counter,
struct counter_signal *signal, size_t idx, u64 *val);
int (*device_array_u64_write)(struct counter_device *counter,
size_t idx, u64 val);
int (*count_array_u64_write)(struct counter_device *counter,
struct counter_count *count, size_t idx, u64 val);
int (*signal_array_u64_write)(struct counter_device *counter,
struct counter_signal *signal, size_t idx, u64 val);

Driver authors can handle reads/writes for an array component by receiving an element index via the idx parameter and processing the respective value via the val parameter.

For example, suppose a driver wants to expose a Count's read-only capture buffer of four elements using a callback foobar_capture_read()::

        DEFINE_COUNTER_ARRAY(foobar_capture_array, COUNTER_COMP_U64,
                             NULL, 4)
        COUNTER_COMP_COUNT_ARRAY_U64("capture", foobar_capture_read,
                                     NULL, foobar_capture_array)

Respective sysfs attributes for each array element would appear for the respective Count:

* /sys/bus/counter/devices/counterX/countY/capture0
* /sys/bus/counter/devices/counterX/countY/capture1
* /sys/bus/counter/devices/counterX/countY/capture2
* /sys/bus/counter/devices/counterX/countY/capture3

If a user tries to read _capture2_ for example, idx will be 2 when passed to the foobar_capture_read() callback, and thus the driver knows which array element to handle.

---
 drivers/counter/counter-chrdev.c |  47 +++++++-
 drivers/counter/counter-sysfs.c  | 198 ++++++++++++++++++++++++++++++-
 include/linux/counter.h          | 121 +++++++++++++++++++
 3 files changed, 361 insertions(+), 5 deletions(-)
drivers/counter/counter-chrdev.c +44 -3
index 4e71a19d7e6a..8df0360b0277 100644
@@ -451,11 +451,49 @@ void counter_chrdev_remove(struct counter_device *const counter)
 	kfifo_free(&counter->events);
 }
 
+static int counter_get_array_data(struct counter_device *const counter,
+				  const enum counter_scope scope,
+				  void *const parent,
+				  const struct counter_comp *const comp,
+				  u64 *const value)
+{
+	const struct counter_array *const element = comp->priv;
+	u32 value_u32 = 0;
+	int ret;
+
+	switch (element->type) {
+	case COUNTER_COMP_SIGNAL_POLARITY:
+		if (scope != COUNTER_SCOPE_SIGNAL)
+			return -EINVAL;
+		ret = comp->signal_array_u32_read(counter, parent, element->idx,
+						  &value_u32);
+		*value = value_u32;
+		return ret;
+	case COUNTER_COMP_U64:
+		switch (scope) {
+		case COUNTER_SCOPE_DEVICE:
+			return comp->device_array_u64_read(counter,
+							   element->idx, value);
+		case COUNTER_SCOPE_SIGNAL:
+			return comp->signal_array_u64_read(counter, parent,
+							   element->idx, value);
+		case COUNTER_SCOPE_COUNT:
+			return comp->count_array_u64_read(counter, parent,
+							  element->idx, value);
+		default:
+			return -EINVAL;
+		}
+	default:
+		return -EINVAL;
+	}
+}
+
 static int counter_get_data(struct counter_device *const counter,
 			    const struct counter_comp_node *const comp_node,
 			    u64 *const value)
 {
 	const struct counter_comp *const comp = &comp_node->comp;
+	const enum counter_scope scope = comp_node->component.scope;
 	void *const parent = comp_node->parent;
 	u8 value_u8 = 0;
 	u32 value_u32 = 0;
@@ -467,7 +505,7 @@ static int counter_get_data(struct counter_device *const counter,
 	switch (comp->type) {
 	case COUNTER_COMP_U8:
 	case COUNTER_COMP_BOOL:
-		switch (comp_node->component.scope) {
+		switch (scope) {
 		case COUNTER_SCOPE_DEVICE:
 			ret = comp->device_u8_read(counter, &value_u8);
 			break;
@@ -487,7 +525,7 @@ static int counter_get_data(struct counter_device *const counter,
 	case COUNTER_COMP_ENUM:
 	case COUNTER_COMP_COUNT_DIRECTION:
 	case COUNTER_COMP_COUNT_MODE:
-		switch (comp_node->component.scope) {
+		switch (scope) {
 		case COUNTER_SCOPE_DEVICE:
 			ret = comp->device_u32_read(counter, &value_u32);
 			break;
@@ -504,7 +542,7 @@ static int counter_get_data(struct counter_device *const counter,
 		*value = value_u32;
 		return ret;
 	case COUNTER_COMP_U64:
-		switch (comp_node->component.scope) {
+		switch (scope) {
 		case COUNTER_SCOPE_DEVICE:
 			return comp->device_u64_read(counter, value);
 		case COUNTER_SCOPE_SIGNAL:
@@ -519,6 +557,9 @@ static int counter_get_data(struct counter_device *const counter,
 					&value_u32);
 		*value = value_u32;
 		return ret;
+	case COUNTER_COMP_ARRAY:
+		return counter_get_array_data(counter, scope, parent, comp,
+					      value);
 	default:
 		return -EINVAL;
 	}
drivers/counter/counter-sysfs.c +196 -2

232 lines not on this page · raw message

include/linux/counter.h +121 -0

161 lines not on this page · raw message

Signature · 1 line
2.37.3