Hi,
I would like to start a discussion about pinmuxing and device tree bindings.
I am currently writing a new pinmuxing driver using the generic pinconf.
My main concern is about defining functions and which pins belong to a
group.
At the moment, it seems that most drivers using the generic pinconf
define this stuff in a static way. The pinctrl-at91 driver covers many
devices, the new one should do the same for new Atmel devices. Having
the group and function definitions in the driver could involve a huge
file...
I am not sure it is a good thing to embed all these information into a
single zImage...
How can we achieved this? I was thinking about something like this:
pinctrl@fc06a000 {
[...]
pinctrl_defs {
mci0 {
mci0_ioset0_1bit_grp {
at91,pins = <68 69 70>;
at91,mux = <2>;
};
mci0_ioset0_4bit_grp {
at91,pins = <68 69 70 71 72 73>;
at91,mux = <2>;
};
mci0_ioset0_8bit_grp {
at91,pins = <68 69 70 71 72 73 74 75 76 77>;
at91,mux = <2>;
};
};
};
pinctrl_mci0_default: mci0_default {
mux {
function = "mci0";
groups = &mci0_ioset0_8bit_grp;
};
conf {
groups = &mci0_ioset0_8bit_grp;
bias-pullup;
};
};
};
- A subnode for these definitions in order to not parse the whole
pinctrl node to retrieve groups and functions.
- Using node names as function and group names.
- Can we get generic properties to define the groups? Of course a 'pins'
property is mandatory. In my case I will need an extra one to tell the
controller how to mux the pins (a same pin can have up to 7 muxing
possibilities).
Thanks for your advices.
Ludovic
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