diff options
| author | Peter Rosin <peda@axentia.se> | 2016-11-08 12:58:58 +0100 |
|---|---|---|
| committer | Jonathan Cameron <jic23@kernel.org> | 2016-11-13 14:07:17 +0100 |
| commit | b475f80b354a1915fda1b34070d712b825b60543 (patch) | |
| tree | 02777a8c1349ace429f1dfa3e58e15661fed1eb5 /Documentation/ABI | |
| parent | dt-bindings: iio: document envelope-detector bindings (diff) | |
| download | linux-b475f80b354a1915fda1b34070d712b825b60543.tar.xz linux-b475f80b354a1915fda1b34070d712b825b60543.zip | |
iio: envelope-detector: ADC driver based on a DAC and a comparator
The DAC is used to find the peak level of an alternating voltage input
signal by a binary search using the output of a comparator wired to
an interrupt pin. Like so:
_
| \
input +------>-------|+ \
| \
.-------. | }---.
| | | / |
| dac|-->--|- / |
| | |_/ |
| | |
| | |
| irq|------<-------'
| |
'-------'
Signed-off-by: Peter Rosin <peda@axentia.se>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-iio-adc-envelope-detector | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-adc-envelope-detector b/Documentation/ABI/testing/sysfs-bus-iio-adc-envelope-detector new file mode 100644 index 000000000000..2071f9bcfaa5 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-iio-adc-envelope-detector @@ -0,0 +1,36 @@ +What: /sys/bus/iio/devices/iio:deviceX/in_altvoltageY_invert +Date: October 2016 +KernelVersion: 4.9 +Contact: Peter Rosin <peda@axentia.se> +Description: + The DAC is used to find the peak level of an alternating + voltage input signal by a binary search using the output + of a comparator wired to an interrupt pin. Like so: + _ + | \ + input +------>-------|+ \ + | \ + .-------. | }---. + | | | / | + | dac|-->--|- / | + | | |_/ | + | | | + | | | + | irq|------<-------' + | | + '-------' + The boolean invert attribute (0/1) should be set when the + input signal is centered around the maximum value of the + dac instead of zero. The envelope detector will search + from below in this case and will also invert the result. + The edge/level of the interrupt is also switched to its + opposite value. + +What: /sys/bus/iio/devices/iio:deviceX/in_altvoltageY_compare_interval +Date: October 2016 +KernelVersion: 4.9 +Contact: Peter Rosin <peda@axentia.se> +Description: + Number of milliseconds to wait for the comparator in each + step of the binary search for the input peak level. Needs + to relate to the frequency of the input signal. |