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 .../bindings/i2c/i2c-arb-gpio-challenge.txt | 8 +--- Documentation/devicetree/bindings/i2c/i2c-arb.txt | 35 ++++++++++++++++ Documentation/devicetree/bindings/i2c/i2c-gate.txt | 41 +++++++++++++++++++ Documentation/devicetree/bindings/i2c/i2c-mux.txt | 23 ++++++++--- .../devicetree/bindings/i2c/nxp,pca9541.txt | 29 ++++++++++++++ MAINTAINERS | 2 + drivers/i2c/i2c-mux.c | 44 +++++++++++++++++---- drivers/i2c/muxes/i2c-arb-gpio-challenge.c | 2 +- drivers/i2c/muxes/i2c-mux-pca9541.c | 11 +++++- drivers/i2c/muxes/i2c-mux-pca954x.c | 46 ++++++++++++++++------ include/linux/i2c-mux.h | 8 +++- 11 files changed, 214 insertions(+), 35 deletions(-) create mode 100644 Documentation/devicetree/bindings/i2c/i2c-arb.txt create mode 100644 Documentation/devicetree/bindings/i2c/i2c-gate.txt create mode 100644 Documentation/devicetree/bindings/i2c/nxp,pca9541.txt -- 2.1.4 -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
