Messages in this thread | | | Date | Tue, 22 May 2012 08:52:08 -0500 | From | Rob Herring <> | Subject | Re: [GIT PULL] DT clk binding support |
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On 05/21/2012 11:17 PM, Stephen Boyd wrote: > On 05/21/12 19:15, Shawn Guo wrote: >> On Mon, May 21, 2012 at 06:52:37PM -0500, Rob Herring wrote: >>> As Grant states: "This proposed binding is only about one thing: >>> attaching clock providers to clock consumers." This means you have to >>> have at least a single provider and a single consumer defined in the DT. >>> >> I just read through Grant's comments over again. I agree with the >> statement which implicitly requires the clk provider defined in DT. >> However, for some case, this provider in DT is just a skeleton which >> is backed by clock driver where the provider is actually defined. >> >> Looking at Grant's comment below, the second option is also to match >> the clock in driver just using name. The only difference to my >> proposal is the name here is given by the argument of phandle pointing >> to that skeleton provider node. >> >> I'm fine with that. So go ahead with your bindings. >> > > Can we do what the regulator framework has done and have a common > binding of <connection_name>-clk = <&phandle>? Something like: > > core-clk = <&uart3_clk> > > and then have clk_get() use the of node of the device passed in to find > a property named %s-clk and find the clock with the matching phandle.
Sigh... That is what we had in previous versions from over a year ago and we moved away from that approach. The current binding has been reviewed multiple times in the last 6 months...
The current approach is aligned with how interrupts are handled (with the addition of a phandle). I think not having per clock property names is easier to parse and easier to document.
> This looks like it's trying to cover both the end consumers (uart uses > uart3_clk) and the internal clock tree consumers (a crystal oscillator > connects to a PLL or a mux has multiple parents). We can certainly use > these bindings for muxes and internal parent-child relationships but I > would prefer we use different bindings for consumer bindings that match > what regulators do today.
The binding supports either defining every last internal clock or just the leaf clocks. I took the former route on highbank since I don't have a lot of clocks. If I was doing imx or omap for example, I'd probably just define all the clock controller outputs.
Rob
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