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d8958824cf
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>
57 lines
2.3 KiB
Text
57 lines
2.3 KiB
Text
What: /sys/bus/iio/devices/iio:deviceX/in_count0_preset
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KernelVersion: 4.13
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Contact: fabrice.gasnier@st.com
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Description:
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Reading returns the current preset value. Writing sets the
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preset value. Encoder counts continuously from 0 to preset
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value, depending on direction (up/down).
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What: /sys/bus/iio/devices/iio:deviceX/in_count_quadrature_mode_available
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KernelVersion: 4.13
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Contact: fabrice.gasnier@st.com
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Description:
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Reading returns the list possible quadrature modes.
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What: /sys/bus/iio/devices/iio:deviceX/in_count0_quadrature_mode
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KernelVersion: 4.13
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Contact: fabrice.gasnier@st.com
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Description:
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Configure the device counter quadrature modes:
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- non-quadrature:
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Encoder IN1 input servers as the count input (up
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direction).
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- quadrature:
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Encoder IN1 and IN2 inputs are mixed to get direction
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and count.
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What: /sys/bus/iio/devices/iio:deviceX/in_count_polarity_available
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KernelVersion: 4.13
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Contact: fabrice.gasnier@st.com
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Description:
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Reading returns the list possible active edges.
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What: /sys/bus/iio/devices/iio:deviceX/in_count0_polarity
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KernelVersion: 4.13
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Contact: fabrice.gasnier@st.com
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Description:
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Configure the device encoder/counter active edge:
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- rising-edge
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- falling-edge
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- both-edges
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In non-quadrature mode, device counts up on active edge.
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In quadrature mode, encoder counting scenarios are as follows:
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----------------------------------------------------------------
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| Active | Level on | IN1 signal | IN2 signal |
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| edge | opposite |------------------------------------------
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| | signal | Rising | Falling | Rising | Falling |
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----------------------------------------------------------------
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| Rising | High -> | Down | - | Up | - |
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| edge | Low -> | Up | - | Down | - |
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----------------------------------------------------------------
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| Falling | High -> | - | Up | - | Down |
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| edge | Low -> | - | Down | - | Up |
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----------------------------------------------------------------
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| Both | High -> | Down | Up | Up | Down |
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| edges | Low -> | Up | Down | Down | Up |
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----------------------------------------------------------------
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