summaryrefslogtreecommitdiffstats
path: root/Documentation
diff options
context:
space:
mode:
authorEugen Hristev <eugen.hristev@microchip.com>2019-09-11 08:24:20 +0000
committerWolfram Sang <wsa@the-dreams.de>2019-10-24 20:23:24 +0200
commitb644257f0ec210a668f6cb24b675cb010a4ab542 (patch)
tree905175031e34a4166f1837810530968cc43b523a /Documentation
parent2034e3f4c9a5c74a6869de7f378d1a9022777ee8 (diff)
downloadlinux-stable-b644257f0ec210a668f6cb24b675cb010a4ab542.tar.gz
linux-stable-b644257f0ec210a668f6cb24b675cb010a4ab542.tar.bz2
linux-stable-b644257f0ec210a668f6cb24b675cb010a4ab542.zip
dt-bindings: i2c: add bindings for i2c analog and digital filter
Some i2c controllers have a built-in digital or analog filter. This is specifically required depending on the hardware PCB/board. Some controllers also allow specifying the maximum width of the spikes that can be filtered for digital filter. The width length can be specified in nanoseconds. Analog filters can be configured to have a cutoff frequency (low-pass filter). This frequency can be specified in Hz. Added an optional property for such types of analog filters. Signed-off-by: Eugen Hristev <eugen.hristev@microchip.com> Reviewed-by: Rob Herring <robh@kernel.org> Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com> Reviewed-by: Peter Rosin <peda@axentia.se> Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/devicetree/bindings/i2c/i2c.txt18
1 files changed, 18 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
index 44efafdfd7f5..9a53df4243c6 100644
--- a/Documentation/devicetree/bindings/i2c/i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c.txt
@@ -55,6 +55,24 @@ wants to support one of the below features, it should adapt the bindings below.
Number of nanoseconds the SDA signal takes to fall; t(f) in the I2C
specification.
+- i2c-analog-filter
+ Enable analog filter for i2c lines.
+
+- i2c-digital-filter
+ Enable digital filter for i2c lines.
+
+- i2c-digital-filter-width-ns
+ Width of spikes which can be filtered by digital filter
+ (i2c-digital-filter). This width is specified in nanoseconds.
+
+- i2c-analog-filter-cutoff-frequency
+ Frequency that the analog filter (i2c-analog-filter) uses to distinguish
+ which signal to filter. Signal with higher frequency than specified will
+ be filtered out. Only lower frequency will pass (this is applicable to
+ a low-pass analog filter). Typical value should be above the normal
+ i2c bus clock frequency (clock-frequency).
+ Specified in Hz.
+
- interrupts
interrupts used by the device.