On 02.09.2019 13:49, Peter Rosin wrote:

On 2019-09-02 12:12, Eugen.Hristev@microchip.com wrote:

quoted

From: Eugen Hristev <redacted>

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. The width length can be specified in nanoseconds.

Signed-off-by: Eugen Hristev <redacted>
---
  Documentation/devicetree/bindings/i2c/i2c.txt | 11 +++++++++++
  1 file changed, 11 insertions(+)

diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt
index 44efafd..8dbff67 100644
--- a/Documentation/devicetree/bindings/i2c/i2c.txt
+++ b/Documentation/devicetree/bindings/i2c/i2c.txt

@@ -55,6 +55,17 @@ 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-filter-width-ns
+	Width of spikes which can be filtered by either digital or analog
+	filters (i2c-analog-filtr or i2c-digital-filtr). This width is specified

filtr -> filter (two instances)

What if you want/need to have different bandwidth for the digital and analog
filters? After all, this is a generic binding...

Hi Peter,

For our needs, this is enough: the purpose of the filters is to avoid 
noise on the lines, the noise is as big as it is for the digital and for 
the analog filters, since we use an absolute measurement for them. So I 
do not know how useful it would be to make a difference.

Wolfram, what do you think ?

Eugen

Cheers,
Peter

quoted

+	in nanoseconds.
+
  - interrupts
  	interrupts used by the device.
  

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