Messages in this thread |  | | Date | Thu, 15 Dec 2022 12:49:18 -0800 | From | Bjorn Andersson <> | Subject | Re: [PATCH v2 2/4] dt-bindings: pinctrl: qcom,tlmm-common: document i2c pull property |
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On Tue, Nov 29, 2022 at 09:15:02AM +0100, Neil Armstrong wrote: > Hi Linus, > > On 26/11/2022 22:53, Linus Walleij wrote: > > On Fri, Nov 25, 2022 at 1:40 PM <neil.armstrong@linaro.org> wrote: > > > > > As I understood, it enables an "I2C resistor" on the pin, removing the need > > > of an external pull-up resistor on the line. > > > > > > I assume the classical pull-up bias is not strong enough to replace an actual > > > resistor on the PCB.
That is correct.
> > > > In that case I think this should be an argument to bias-pull-up like: > > > > bias-pull-up = <360000>; > > > > Nominally the pull up is in ohms: > > > > bias-pull-up: > > oneOf: > > - type: boolean > > - $ref: /schemas/types.yaml#/definitions/uint32 > > description: pull up the pin. Takes as optional argument on hardware > > supporting it the pull strength in Ohm. > > > > Then the driver can choose to shunt in this extra I2C resistance > > from the resistance passed as argument. So no special property > > is needed, provided you can get an idea about the resistance > > provided here. > > I like this alternative, I'll try to figure out if we can find a value > to match against. >
The typical value for this resistor is 2.2kOhm.
Regards, Bjorn
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