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| author | Fabrice Gasnier <fabrice.gasnier@st.com> | 2017-08-28 12:04:13 +0200 |
|---|---|---|
| committer | Lee Jones <lee.jones@linaro.org> | 2017-09-04 14:49:30 +0100 |
| commit | d8958824cf0714cc4ddcf320cf12028277ad55c4 (patch) | |
| tree | bd94b7676d3f8c63b310ea90ca2c03a1e539fedb /Documentation/ABI | |
| parent | 717e6922de754c3aa5da5a1e417683cc899efe1c (diff) | |
| download | lwn-d8958824cf0714cc4ddcf320cf12028277ad55c4.tar.gz lwn-d8958824cf0714cc4ddcf320cf12028277ad55c4.zip | |
iio: counter: Add support for STM32 LPTimer
Add support for STM32 Low-Power Timer, that can be used as counter
or quadrature encoder.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Signed-off-by: Lee Jones <lee.jones@linaro.org>
Diffstat (limited to 'Documentation/ABI')
| -rw-r--r-- | Documentation/ABI/testing/sysfs-bus-iio-lptimer-stm32 | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/sysfs-bus-iio-lptimer-stm32 b/Documentation/ABI/testing/sysfs-bus-iio-lptimer-stm32 new file mode 100644 index 000000000000..ad2cc63e4bf8 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-bus-iio-lptimer-stm32 @@ -0,0 +1,57 @@ +What: /sys/bus/iio/devices/iio:deviceX/in_count0_preset +KernelVersion: 4.13 +Contact: fabrice.gasnier@st.com +Description: + Reading returns the current preset value. Writing sets the + preset value. Encoder counts continuously from 0 to preset + value, depending on direction (up/down). + +What: /sys/bus/iio/devices/iio:deviceX/in_count_quadrature_mode_available +KernelVersion: 4.13 +Contact: fabrice.gasnier@st.com +Description: + Reading returns the list possible quadrature modes. + +What: /sys/bus/iio/devices/iio:deviceX/in_count0_quadrature_mode +KernelVersion: 4.13 +Contact: fabrice.gasnier@st.com +Description: + Configure the device counter quadrature modes: + - non-quadrature: + Encoder IN1 input servers as the count input (up + direction). + - quadrature: + Encoder IN1 and IN2 inputs are mixed to get direction + and count. + +What: /sys/bus/iio/devices/iio:deviceX/in_count_polarity_available +KernelVersion: 4.13 +Contact: fabrice.gasnier@st.com +Description: + Reading returns the list possible active edges. + +What: /sys/bus/iio/devices/iio:deviceX/in_count0_polarity +KernelVersion: 4.13 +Contact: fabrice.gasnier@st.com +Description: + Configure the device encoder/counter active edge: + - rising-edge + - falling-edge + - both-edges + + In non-quadrature mode, device counts up on active edge. + In quadrature mode, encoder counting scenarios are as follows: + ---------------------------------------------------------------- + | Active | Level on | IN1 signal | IN2 signal | + | edge | opposite |------------------------------------------ + | | signal | Rising | Falling | Rising | Falling | + ---------------------------------------------------------------- + | Rising | High -> | Down | - | Up | - | + | edge | Low -> | Up | - | Down | - | + ---------------------------------------------------------------- + | Falling | High -> | - | Up | - | Down | + | edge | Low -> | - | Down | - | Up | + ---------------------------------------------------------------- + | Both | High -> | Down | Up | Up | Down | + | edges | Low -> | Up | Down | Down | Up | + ---------------------------------------------------------------- |