From: <Eugen.Hristev@microchip.com>
To: peda@axentia.se, wsa@the-dreams.de, mark.rutland@arm.com,
Ludovic.Desroches@microchip.com, linux-i2c@vger.kernel.org,
devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
linux-kernel@vger.kernel.org, pierre-yves.mordret@st.com,
alexandre.belloni@bootlin.com, robh+dt@kernel.org
Subject: Re: [PATCH v4 2/9] dt-bindings: i2c: add bindings for i2c analog and digital filter
Date: Mon, 2 Sep 2019 14:15:14 +0000 [thread overview]
Message-ID: <b6528812-65d3-6561-38e7-c0545af900d8@microchip.com> (raw)
In-Reply-To: <9a9c209c-2fb8-0a4c-4e0a-b04fefda3360@axentia.se>
On 02.09.2019 13:49, Peter Rosin wrote:
> On 2019-09-02 12:12, Eugen.Hristev@microchip.com wrote:
>> From: Eugen Hristev <eugen.hristev@microchip.com>
>>
>> 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 <eugen.hristev@microchip.com>
>> ---
>> 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
>
>> + in nanoseconds.
>> +
>> - interrupts
>> interrupts used by the device.
>>
>>
>
> _______________________________________________
> linux-arm-kernel mailing list
> linux-arm-kernel@lists.infradead.org
> http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
>
>
next prev parent reply other threads:[~2019-09-02 14:15 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-02 10:11 [PATCH v4 0/9] i2c: add support for filters Eugen.Hristev
2019-09-02 10:11 ` [PATCH v4 1/9] dt-bindings: i2c: at91: add new compatible Eugen.Hristev
2019-09-02 10:44 ` Peter Rosin
2019-09-02 14:12 ` Eugen.Hristev
2019-09-02 10:12 ` [PATCH v4 2/9] dt-bindings: i2c: add bindings for i2c analog and digital filter Eugen.Hristev
2019-09-02 10:49 ` Peter Rosin
2019-09-02 14:15 ` Eugen.Hristev [this message]
2019-09-02 14:22 ` Alexandre Belloni
2019-09-02 14:40 ` Peter Rosin
2019-09-02 15:47 ` Wolfram Sang
2019-09-02 10:12 ` [PATCH v4 3/9] i2c: add support for filter-width-ns optional property Eugen.Hristev
2019-09-02 10:12 ` [PATCH v4 4/9] i2c: at91: add new platform support for sam9x60 Eugen.Hristev
2019-09-02 10:12 ` [PATCH v4 5/9] i2c: at91: add support for digital filtering Eugen.Hristev
2019-09-02 10:12 ` [PATCH v4 6/9] i2c: at91: add support for advanced " Eugen.Hristev
2019-09-02 10:12 ` [PATCH v4 7/9] i2c: at91: add support for analog filtering Eugen.Hristev
2019-09-02 10:12 ` [PATCH v4 8/9] ARM: dts: at91: sama5d2_xplained: add analog and digital filter for i2c Eugen.Hristev
2019-09-02 10:12 ` [PATCH v4 9/9] ARM: dts: at91: sama5d4_xplained: add " Eugen.Hristev
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