add gpio led uart

hc

2024-05-10 748e4f3d702def1a4bff191e0cf93b6a05340f01

 kernel/Documentation/ABI/testing/sysfs-bus-iio-adc-envelope-detector
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@@ -5,7 +5,8 @@
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 Description:
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 		The DAC is used to find the peak level of an alternating
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 		voltage input signal by a binary search using the output
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-		of a comparator wired to an interrupt pin. Like so:
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+		of a comparator wired to an interrupt pin. Like so::
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+
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 		                           _
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 		                          | \
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 		     input +------>-------|+ \
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@@ -19,10 +20,12 @@
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 		            |    irq|------<-------'
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 		            |       |
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 		            '-------'
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+
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 		The boolean invert attribute (0/1) should be set when the
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 		input signal is centered around the maximum value of the
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 		dac instead of zero. The envelope detector will search
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 		from below in this case and will also invert the result.
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+
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 		The edge/level of the interrupt is also switched to its
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 		opposite value.
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