[RESEND PATCH 2/2] pinctrl: introduce complex pin description
swarren at wwwdotorg.org
Mon Jun 15 09:01:29 PDT 2015
On 06/10/2015 09:04 AM, Ludovic Desroches wrote:
> Using a string to describe a pin in the device tree can be not enough.
> Some controllers may need extra information to fully describe a pin. It
> concerns mainly controllers which have a per pin muxing approach which
> don't fit well the notions of groups and functions.
> Instead of using a pin name, a 32 bit value is used. The 16 least
> significant bits are used for the pin number. Other 16 bits can be used to
> store extra parameters.
The driver for the pin controller is supposed to provide this
information in a table. The whole point of having a driver, rather than
a table/list of raw register values in the DT, is so the driver can
provide this information at a semantic level. This information is fixed
per SoC and so make sense to put into a driver, while the board-specific
configuration varies wildly, and hence makes sense to put into DT.
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