counter: Introduce the COUNTER_COMP_ARRAY component type

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.

Eight Counter array component macros are introduced::

        DEFINE_COUNTER_ARRAY_U64(_name, _length)
        DEFINE_COUNTER_ARRAY_CAPTURE(_name, _length)
        DEFINE_COUNTER_ARRAY_POLARITY(_name, _enums, _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_CAPTURE(_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_CAPTURE(foobar_capture_array, 4);
        COUNTER_COMP_ARRAY_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.

Counter arrays for polarity elements can be defined in a similar
manner as u64 elements::

        const enum counter_signal_polarity foobar_polarity_states[] = {
                COUNTER_SIGNAL_POLARITY_POSITIVE,
                COUNTER_SIGNAL_POLARITY_NEGATIVE,
        };
        DEFINE_COUNTER_ARRAY_POLARITY(foobar_polarity_array,
                                      foobar_polarity_states, 4);
        COUNTER_COMP_ARRAY_POLARITY(foobar_polarity_read,
                                    foobar_polarity_write,
                                    foobar_polarity_array)

Tested-by: Julien Panis <jpanis@baylibre.com>
Link: https://lore.kernel.org/r/5310c22520aeae65b1b74952419f49ac4c8e1ec1.1664204990.git.william.gray@linaro.org/
Signed-off-by: William Breathitt Gray <william.gray@linaro.org>
Link: https://lore.kernel.org/r/a51fd608704bdfc5a0efa503fc5481df34241e0a.1664318353.git.william.gray@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 134 insertions, 0 deletions

diff --git a/include/linux/counter.h b/include/linux/counter.h
index e160197971dd..c41fa602ed28 100644
--- a/include/linux/counter.h
+++ b/include/linux/counter.h
@@ -32,6 +32,7 @@ enum counter_comp_type {
 	COUNTER_COMP_COUNT_DIRECTION,
 	COUNTER_COMP_COUNT_MODE,
 	COUNTER_COMP_SIGNAL_POLARITY,
+	COUNTER_COMP_ARRAY,
 };
 
 /**
@@ -69,6 +70,30 @@ enum counter_comp_type {
  * @signal_u64_read:	Signal u64 component read callback. The read value of
  *			the respective Signal u64 component should be passed
  *			back via the val parameter.
+ * @signal_array_u32_read:	Signal u32 array component read callback. The
+ *				index of the respective Count u32 array
+ *				component element is passed via the idx
+ *				parameter. The read value of the respective
+ *				Count u32 array component element should be
+ *				passed back via the val parameter.
+ * @device_array_u64_read:	Device u64 array component read callback. The
+ *				index of the respective Device u64 array
+ *				component element is passed via the idx
+ *				parameter. The read value of the respective
+ *				Device u64 array component element should be
+ *				passed back via the val parameter.
+ * @count_array_u64_read:	Count u64 array component read callback. The
+ *				index of the respective Count u64 array
+ *				component element is passed via the idx
+ *				parameter. The read value of the respective
+ *				Count u64 array component element should be
+ *				passed back via the val parameter.
+ * @signal_array_u64_read:	Signal u64 array component read callback. The
+ *				index of the respective Count u64 array
+ *				component element is passed via the idx
+ *				parameter. The read value of the respective
+ *				Count u64 array component element should be
+ *				passed back via the val parameter.
  * @action_write:	Synapse action mode write callback. The write value of
  *			the respective Synapse action mode is passed via the
  *			action parameter.
@@ -99,6 +124,30 @@ enum counter_comp_type {
  * @signal_u64_write:	Signal u64 component write callback. The write value of
  *			the respective Signal u64 component is passed via the
  *			val parameter.
+ * @signal_array_u32_write:	Signal u32 array component write callback. The
+ *				index of the respective Signal u32 array
+ *				component element is passed via the idx
+ *				parameter. The write value of the respective
+ *				Signal u32 array component element is passed via
+ *				the val parameter.
+ * @device_array_u64_write:	Device u64 array component write callback. The
+ *				index of the respective Device u64 array
+ *				component element is passed via the idx
+ *				parameter. The write value of the respective
+ *				Device u64 array component element is passed via
+ *				the val parameter.
+ * @count_array_u64_write:	Count u64 array component write callback. The
+ *				index of the respective Count u64 array
+ *				component element is passed via the idx
+ *				parameter. The write value of the respective
+ *				Count u64 array component element is passed via
+ *				the val parameter.
+ * @signal_array_u64_write:	Signal u64 array component write callback. The
+ *				index of the respective Signal u64 array
+ *				component element is passed via the idx
+ *				parameter. The write value of the respective
+ *				Signal u64 array component element is passed via
+ *				the val parameter.
  */
 struct counter_comp {
 	enum counter_comp_type type;
@@ -126,6 +175,17 @@ struct counter_comp {
 				      struct counter_count *count, u64 *val);
 		int (*signal_u64_read)(struct counter_device *counter,
 				       struct counter_signal *signal, u64 *val);
+		int (*signal_array_u32_read)(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);
 	};
 	union {
 		int (*action_write)(struct counter_device *counter,
@@ -149,6 +209,17 @@ struct counter_comp {
 				       struct counter_count *count, u64 val);
 		int (*signal_u64_write)(struct counter_device *counter,
 					struct counter_signal *signal, u64 val);
+		int (*signal_array_u32_write)(struct counter_device *counter,
+					      struct counter_signal *signal,
+					      size_t idx, u32 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);
 	};
 };
 
@@ -453,6 +524,57 @@ struct counter_available {
 	.priv = &(_available), \
 }
 
+struct counter_array {
+	enum counter_comp_type type;
+	const struct counter_available *avail;
+	union {
+		size_t length;
+		size_t idx;
+	};
+};
+
+#define DEFINE_COUNTER_ARRAY_U64(_name, _length) \
+	struct counter_array _name = { \
+		.type = COUNTER_COMP_U64, \
+		.length = (_length), \
+	}
+
+#define DEFINE_COUNTER_ARRAY_CAPTURE(_name, _length) \
+	DEFINE_COUNTER_ARRAY_U64(_name, _length)
+
+#define DEFINE_COUNTER_ARRAY_POLARITY(_name, _enums, _length) \
+	DEFINE_COUNTER_AVAILABLE(_name##_available, _enums); \
+	struct counter_array _name = { \
+		.type = COUNTER_COMP_SIGNAL_POLARITY, \
+		.avail = &(_name##_available), \
+		.length = (_length), \
+	}
+
+#define COUNTER_COMP_DEVICE_ARRAY_U64(_name, _read, _write, _array) \
+{ \
+	.type = COUNTER_COMP_ARRAY, \
+	.name = (_name), \
+	.device_array_u64_read = (_read), \
+	.device_array_u64_write = (_write), \
+	.priv = &(_array), \
+}
+#define COUNTER_COMP_COUNT_ARRAY_U64(_name, _read, _write, _array) \
+{ \
+	.type = COUNTER_COMP_ARRAY, \
+	.name = (_name), \
+	.count_array_u64_read = (_read), \
+	.count_array_u64_write = (_write), \
+	.priv = &(_array), \
+}
+#define COUNTER_COMP_SIGNAL_ARRAY_U64(_name, _read, _write, _array) \
+{ \
+	.type = COUNTER_COMP_ARRAY, \
+	.name = (_name), \
+	.signal_array_u64_read = (_read), \
+	.signal_array_u64_write = (_write), \
+	.priv = &(_array), \
+}
+
 #define COUNTER_COMP_CAPTURE(_read, _write) \
 	COUNTER_COMP_COUNT_U64("capture", _read, _write)
 
@@ -496,4 +618,16 @@ struct counter_available {
 #define COUNTER_COMP_PRESET_ENABLE(_read, _write) \
 	COUNTER_COMP_COUNT_BOOL("preset_enable", _read, _write)
 
+#define COUNTER_COMP_ARRAY_CAPTURE(_read, _write, _array) \
+	COUNTER_COMP_COUNT_ARRAY_U64("capture", _read, _write, _array)
+
+#define COUNTER_COMP_ARRAY_POLARITY(_read, _write, _array) \
+{ \
+	.type = COUNTER_COMP_ARRAY, \
+	.name = "polarity", \
+	.signal_array_u32_read = (_read), \
+	.signal_array_u32_write = (_write), \
+	.priv = &(_array), \
+}
+
 #endif /* _COUNTER_H_ */