On Mon, Aug 15, 2016 at 03:40:23PM +0200, Peter Rosin wrote: > Hi! > > The nxp pca9541 chip does not have any devicetree bindings. > When trying to write such bindings matching the implementation, > I stumbled upon something which I did not like. I had to > give the node holding the i2c child bus a 'reg' property that > is left unused and is really odd to explain from a devicetree > point of view. It really is a leftover from the fact that linux > implements i2c arbitrators (and i2c gates) using the i2c mux > code. See this thread for history [1]. > > This series resolves the issues, and maintains backwards compat > with old device trees (well, one could, in theory, create a > device tree that would break with these changes, but my guess > is that the odds for that happening inadvertedly are high...) > > This should also help Crestez Dan Leonard with the mpu6050 > series containing the changes for its auxiliary i2c master [2], > especially if you also consider the recent (very similar) changes > from Jon Hunter that adds an optional 'i2c-bus' subnode [3]. > > If this is ok, I will follow up with patches for other drivers > so that they inform the i2c mux core if they are muxes, arbs or > gates. As stated, they will continue to work with these changes, > so there is no huge rush. > > The mux core does not really need to differentiate between > arbitrators and gates. Should they be folded? What to call them > in that case? > > Changes since v1: > > - Fixes and additions suggested by Rob Herring (3/8 still needs an ack). > - Inserted patch 6/8 so that the two arb drivers support the new more > compact dt syntax. > > Cheers, > Peter > > [1] https://lkml.org/lkml/2016/6/27/203 > [2] https://lkml.org/lkml/2016/5/18/355 > [3] https://patchwork.ozlabs.org/patch/641934/ > > Peter Rosin (8): > dt-bindings: i2c: add support for 'i2c-mux' subnode > dt-bindings: i2c: add support for 'i2c-arb' subnode > dt-bindings: i2c: add support for 'i2c-gate' subnode > dt-bindings: i2c: add bindings for nxp,pca9541 > i2c: mux: add support for 'i2c-mux', 'i2c-arb' and 'i2c-gate' DT > subnodes > i2c: mux: inform the i2c mux core about how it is used > i2c: pca9541: add device tree binding > i2c: pca954x: add device tree binding Applied to for-next, thanks!
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