Most of the gpio controller cannot configure or get the configuration
of the pin muxing as it's usually handled in the pinctrl driver.
But they can know what is the pinmuxing driver either because they are
child of it or via the gpio-range property.
Add some new methods to fdt_pinctrl that a pin controller can implement.
Some methods are :
fdt_pinctrl_is_gpio: Use to know if the pin in the gpio mode
fdt_pinctrl_set_flags: Set the flags of the pin (pullup/pulldown etc ...)
fdt_pinctrl_get_flags: Get the flags of the pin (pullup/pulldown etc ...)
The defaults method returns EOPNOTSUPP.
Reviewed by: ian, bcr (manpages)
MFC after: 1 month
Differential Revision: https://reviews.freebsd.org/D23093
r332341 introduced OF_getencprop_alloc_multi that should be used
instead of OF_getencprop_alloc to get multi-cell properties.
Fix example to reflect this change.
- Add fdt_pinctrl(4) with general information for the driver
- Add fdt_pinctrl(9) with fdt_pinctrl KPI description
Reviewed by: ian, manu, wblock
MFC after: 2 weeks
Differential Revision: https://reviews.freebsd.org/D14235
