On Tue, Apr 12, 2022 at 10:50:45AM +0200, Vincent Whitchurch wrote: > When drivers with ->detect callbacks are loaded, the I2C core does a > bunch of transactions to try to probe for these devices, regardless of > whether they are specified in the devicetree or not. (This only happens > on I2C controllers whose drivers enable the I2C_CLASS* flags, but this > is the case for generic drivers like i2c-gpio.) > > These kinds of transactions are unnecessary on systems where the > devicetree specifies all the devices on the I2C bus, so add a property > to indicate that the devicetree description of the hardware is complete > and thus allow this discovery to be disabled. > > Signed-off-by: Vincent Whitchurch <vincent.whitchurch@xxxxxxxx> > --- > > Notes: > v2: > - Change subject prefix > - Reword description of property > > Documentation/devicetree/bindings/i2c/i2c.txt | 4 ++++ > 1 file changed, 4 insertions(+) > > diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt > index fc3dd7ec0445..960d1d5c9362 100644 > --- a/Documentation/devicetree/bindings/i2c/i2c.txt > +++ b/Documentation/devicetree/bindings/i2c/i2c.txt > @@ -72,6 +72,10 @@ wants to support one of the below features, it should adapt these bindings. > this information to adapt power management to keep the arbitration awake > all the time, for example. Can not be combined with 'single-master'. > > +- no-detect > + states that no other devices are present on this bus other than the > + ones listed in the devicetree. This belongs in the schema instead: https://github.com/devicetree-org/dt-schema/blob/main/dtschema/schemas/i2c/i2c-controller.yaml Rob
