Messages in this thread | | | Date | Mon, 23 Apr 2012 10:11:33 -0700 | From | David Daney <> | Subject | Re: [PATCH 1/2] i2c: mux: add device tree support |
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On 04/23/2012 09:13 AM, Stephen Warren wrote: > On 04/23/2012 05:15 AM, Wolfram Sang wrote: >> On Tue, Apr 17, 2012 at 12:49:04PM -0600, Stephen Warren wrote: >>> From: Stephen Warren<swarren@nvidia.com> >>> >>> * Define core portions of the DT binding for I2C bus muxes. >>> * Enhance i2c_add_mux_adapter(): >>> ** Add parameters required for DT support. Update all callers. >>> ** Set the appropriate adap->dev.of_node for the child bus. >>> ** Call of_i2c_register_devices() for the child bus. >>> >>> Signed-off-by: Stephen Warren<swarren@nvidia.com> >> >> David Daney (CCed) posted another variant [1]. Just looking at the >> patches (and not really using them), I tend to like the approach using >> <reg> better. But I am open for discussion, so I'd appreciate your >> feedback. >> >> Regards, >> >> Wolfram >> >> [1] http://lkml.org/lkml/2012/4/12/423 > > Ah, that does look like a reasonable binding. >
It was arrived at by iterating through several versions with Grant and Rob.
You make at least the third person (after me and Lars-Peter Clausen) wanting to use the device tree to configure the I2C muxes. So at a minimum, it shows a need for this.
David Daney.
> I had meant to call out to reviewers the potentially unusual use of > explicitly named sub-nodes, rather than using the usual reg-based matching. > > The main reason I chose named sub-nodes for the busses was so the > sub-nodes would match the pinctrl named states. However, I think we can > make the pinctrl numbering match rather than the pinctrl naming instead. > The only issue is the "idle" state; if we allow it to exist anywhere in > the pinctrl-names list, it'll make the pinctrl numbering mismatch the > sub-node numbering. I think we can solve this by forcing the idle state > to be listed last in pinctrl-names (if it's listed at all). I'll update > my patches based on that David's patch.
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