Messages in this thread | | | Date | Sun, 11 Dec 2011 11:34:01 -0800 | From | Tony Lindgren <> | Subject | Re: [PATCH] [RFC] pinctrl: add a driver for Energy Micro's efm32 SoCs |
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* Stephen Warren <swarren@nvidia.com> [111209 15:42]: > Tony Lindgren wrote at Friday, December 09, 2011 10:53 AM: > > * Tony Lindgren <tony@atomide.com> [111209 08:53]: > ... > > > For letting a device do it's pingroup in DT, I've played with the > > > following: > > > > > > /* mux func phandle mux func name hw initial flags */ > > > pins = <&uart3_rx_irrx>, "uart3_rx_irrx", <0xdeadbeef>, > > > <&uart3_tx_irtx>, "uart3_tx_irtx", <0xdeadbeef>; > > > > > > But it seems that doing mixed-property arrays gets nasty as any > ... > > > So I've pretty much come to the conclusion that we would have to > > > use something like this instead: > > > > > > /* phandle f hw specific initial flags */ > > > pins = <&uart3_rx_irrx 0 0xdeadbeef > > > &uart3_tx_irtx 0 0xdeadbeef>; > > > > > > This however has a problem for cases where we may not have a phandle > > > in DT for the mux function. For example, let's assume that we'll have > > > tens of thousands of lines of mux data for omaps (we already have > > > over 6k LOC) and just want to load that from /lib/firmware to avoid > > > bloating the kernel. In that case we won't have the phandle for the > > > mux function in DT. > ... > > Oh forgot to mention of course what Benoit came up which is reg-names. > > That of course is doable with both phandles and pin names: > > > > So optionally either > > > > pins = <&uart3_rx_irrx &uart3_tx_irtx>; > > or > > > > pin-names = "uart3_rx_irrx", "uart3_tx_irtx"; > > Tony, > > It sounds like you've already started working on some DT bindings for > pin muxing. Are you just at the thinking stage as above, or do you have > any concrete code? I'd obviously be interested in looking at any early > bindings to see if I can port the Tegra pinctrl driver to use them.
Yeah I have some code but it still needs a bit more work.. The DT bindings part I have only briefly played with so far. Mostly to verify that trying to use the mixed-property arrays will get messy.
For parsing the pins as phandles, drivers/of/gpio.c is a nice example.
After still thinking more about it, I think the cleanest and most flexible option is using both the pins phandle array or pin-names string array, combined with a separate pin-flags initial value array. That way we can use the DT generated maps also for non-dt pinmux drivers where we don't have phandles around.
Regards,
Tony
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