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authorFabrice Gasnier <fabrice.gasnier@st.com>2017-08-28 13:04:13 +0300
committerLee Jones <lee.jones@linaro.org>2017-09-04 16:49:30 +0300
commitd8958824cf0714cc4ddcf320cf12028277ad55c4 (patch)
treebd94b7676d3f8c63b310ea90ca2c03a1e539fedb /Documentation/ABI
parent717e6922de754c3aa5da5a1e417683cc899efe1c (diff)
downloadlinux-d8958824cf0714cc4ddcf320cf12028277ad55c4.tar.xz
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-stm3257
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
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index 000000000000..ad2cc63e4bf8
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+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 |
+ ----------------------------------------------------------------