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review.trustedfirmware.org / hafnium / third_party / linux / 0f672f6c0b52b7b0700b0915c72b540721af4465 / . / Documentation / ABI / testing / sysfs-bus-counter
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David Brazdil0f672f62019-12-10 10:32:29 +0000[diff] [blame^]1What: /sys/bus/counter/devices/counterX/countY/count
2KernelVersion: 5.2
3Contact: linux-iio@vger.kernel.org
4Description:
5 Count data of Count Y represented as a string.
6
7What: /sys/bus/counter/devices/counterX/countY/ceiling
8KernelVersion: 5.2
9Contact: linux-iio@vger.kernel.org
10Description:
11 Count value ceiling for Count Y. This is the upper limit for the
12 respective counter.
13
14What: /sys/bus/counter/devices/counterX/countY/floor
15KernelVersion: 5.2
16Contact: linux-iio@vger.kernel.org
17Description:
18 Count value floor for Count Y. This is the lower limit for the
19 respective counter.
20
21What: /sys/bus/counter/devices/counterX/countY/count_mode
22KernelVersion: 5.2
23Contact: linux-iio@vger.kernel.org
24Description:
25 Count mode for channel Y. The ceiling and floor values for
26 Count Y are used by the count mode where required. The following
27 count modes are available:
28
29 normal:
30 Counting is continuous in either direction.
31
32 range limit:
33 An upper or lower limit is set, mimicking limit switches
34 in the mechanical counterpart. The upper limit is set to
35 the Count Y ceiling value, while the lower limit is set
36 to the Count Y floor value. The counter freezes at
37 count = ceiling when counting up, and at count = floor
38 when counting down. At either of these limits, the
39 counting is resumed only when the count direction is
40 reversed.
41
42 non-recycle:
43 The counter is disabled whenever a counter overflow or
44 underflow takes place. The counter is re-enabled when a
45 new count value is loaded to the counter via a preset
46 operation or direct write.
47
48 modulo-n:
49 A count value boundary is set between the Count Y floor
50 value and the Count Y ceiling value. The counter is
51 reset to the Count Y floor value at count = ceiling when
52 counting up, while the counter is set to the Count Y
53 ceiling value at count = floor when counting down; the
54 counter does not freeze at the boundary points, but
55 counts continuously throughout.
56
57What: /sys/bus/counter/devices/counterX/countY/count_mode_available
58What: /sys/bus/counter/devices/counterX/countY/error_noise_available
59What: /sys/bus/counter/devices/counterX/countY/function_available
60What: /sys/bus/counter/devices/counterX/countY/signalZ_action_available
61KernelVersion: 5.2
62Contact: linux-iio@vger.kernel.org
63Description:
64 Discrete set of available values for the respective Count Y
65 configuration are listed in this file. Values are delimited by
66 newline characters.
67
68What: /sys/bus/counter/devices/counterX/countY/direction
69KernelVersion: 5.2
70Contact: linux-iio@vger.kernel.org
71Description:
72 Read-only attribute that indicates the count direction of Count
73 Y. Two count directions are available: forward and backward.
74
75 Some counter devices are able to determine the direction of
76 their counting. For example, quadrature encoding counters can
77 determine the direction of movement by evaluating the leading
78 phase of the respective A and B quadrature encoding signals.
79 This attribute exposes such count directions.
80
81What: /sys/bus/counter/devices/counterX/countY/enable
82KernelVersion: 5.2
83Contact: linux-iio@vger.kernel.org
84Description:
85 Whether channel Y counter is enabled. Valid attribute values are
86 boolean.
87
88 This attribute is intended to serve as a pause/unpause mechanism
89 for Count Y. Suppose a counter device is used to count the total
90 movement of a conveyor belt: this attribute allows an operator
91 to temporarily pause the counter, service the conveyor belt,
92 and then finally unpause the counter to continue where it had
93 left off.
94
95What: /sys/bus/counter/devices/counterX/countY/error_noise
96KernelVersion: 5.2
97Contact: linux-iio@vger.kernel.org
98Description:
99 Read-only attribute that indicates whether excessive noise is
100 present at the channel Y counter inputs.
101
102What: /sys/bus/counter/devices/counterX/countY/function
103KernelVersion: 5.2
104Contact: linux-iio@vger.kernel.org
105Description:
106 Count function mode of Count Y; count function evaluation is
107 triggered by conditions specified by the Count Y signalZ_action
108 attributes. The following count functions are available:
109
110 increase:
111 Accumulated count is incremented.
112
113 decrease:
114 Accumulated count is decremented.
115
116 pulse-direction:
117 Rising edges on signal A updates the respective count.
118 The input level of signal B determines direction.
119
120 quadrature x1 a:
121 If direction is forward, rising edges on quadrature pair
122 signal A updates the respective count; if the direction
123 is backward, falling edges on quadrature pair signal A
124 updates the respective count. Quadrature encoding
125 determines the direction.
126
127 quadrature x1 b:
128 If direction is forward, rising edges on quadrature pair
129 signal B updates the respective count; if the direction
130 is backward, falling edges on quadrature pair signal B
131 updates the respective count. Quadrature encoding
132 determines the direction.
133
134 quadrature x2 a:
135 Any state transition on quadrature pair signal A updates
136 the respective count. Quadrature encoding determines the
137 direction.
138
139 quadrature x2 b:
140 Any state transition on quadrature pair signal B updates
141 the respective count. Quadrature encoding determines the
142 direction.
143
144 quadrature x4:
145 Any state transition on either quadrature pair signals
146 updates the respective count. Quadrature encoding
147 determines the direction.
148
149What: /sys/bus/counter/devices/counterX/countY/name
150KernelVersion: 5.2
151Contact: linux-iio@vger.kernel.org
152Description:
153 Read-only attribute that indicates the device-specific name of
154 Count Y. If possible, this should match the name of the
155 respective channel as it appears in the device datasheet.
156
157What: /sys/bus/counter/devices/counterX/countY/preset
158KernelVersion: 5.2
159Contact: linux-iio@vger.kernel.org
160Description:
161 If the counter device supports preset registers -- registers
162 used to load counter channels to a set count upon device-defined
163 preset operation trigger events -- the preset count for channel
164 Y is provided by this attribute.
165
166What: /sys/bus/counter/devices/counterX/countY/preset_enable
167KernelVersion: 5.2
168Contact: linux-iio@vger.kernel.org
169Description:
170 Whether channel Y counter preset operation is enabled. Valid
171 attribute values are boolean.
172
173What: /sys/bus/counter/devices/counterX/countY/signalZ_action
174KernelVersion: 5.2
175Contact: linux-iio@vger.kernel.org
176Description:
177 Action mode of Count Y for Signal Z. This attribute indicates
178 the condition of Signal Z that triggers the count function
179 evaluation for Count Y. The following action modes are
180 available:
181
182 none:
183 Signal does not trigger the count function. In
184 Pulse-Direction count function mode, this Signal is
185 evaluated as Direction.
186
187 rising edge:
188 Low state transitions to high state.
189
190 falling edge:
191 High state transitions to low state.
192
193 both edges:
194 Any state transition.
195
196What: /sys/bus/counter/devices/counterX/name
197KernelVersion: 5.2
198Contact: linux-iio@vger.kernel.org
199Description:
200 Read-only attribute that indicates the device-specific name of
201 the Counter. This should match the name of the device as it
202 appears in its respective datasheet.
203
204What: /sys/bus/counter/devices/counterX/num_counts
205KernelVersion: 5.2
206Contact: linux-iio@vger.kernel.org
207Description:
208 Read-only attribute that indicates the total number of Counts
209 belonging to the Counter.
210
211What: /sys/bus/counter/devices/counterX/num_signals
212KernelVersion: 5.2
213Contact: linux-iio@vger.kernel.org
214Description:
215 Read-only attribute that indicates the total number of Signals
216 belonging to the Counter.
217
218What: /sys/bus/counter/devices/counterX/signalY/signal
219KernelVersion: 5.2
220Contact: linux-iio@vger.kernel.org
221Description:
222 Signal data of Signal Y represented as a string.
223
224What: /sys/bus/counter/devices/counterX/signalY/name
225KernelVersion: 5.2
226Contact: linux-iio@vger.kernel.org
227Description:
228 Read-only attribute that indicates the device-specific name of
229 Signal Y. If possible, this should match the name of the
230 respective signal as it appears in the device datasheet.