The sunxi pinctrl hardware has bias and drive control. Add driver
support for configuring those options.
Reviewed-by: Simon Glass <sjg@chromium.org>
Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Implement the operations to get pin and function names, and to set the
mux for a pin. The pin count and pin names are calculated as if each
bank has the maximum number of pins. Function names are simply the index
into a list of { function name, mux value } pairs.
We assume all pins associated with a function use the same mux value for
that function. This is generally true within a group of pins on a single
port, but generally false when some peripheral can be muxed to multiple
ports. For example, A64 UART3 uses mux 3 on port D, and mux 2 on port H.
But all of the port D pins use the same mux value, and so do all of the
port H pins. This applies even when the pins for some function are not
contiguous, and when the lower-numbered mux values are unused. A good
example of both of these cases is SPI0 on most SoCs.
This strategy saves a lot of space (which is especially important for
SPL), but where the mux value for a certain function differs across
ports, it forces us to choose a single port for that function at build
time. Since almost all boards use the default (i.e. reference design)
pin muxes[1], this is unlikely to be a problem.
[1]: See commit dda9fa734f ("sunxi: Simplify MMC pinmux selection")
Signed-off-by: Samuel Holland <samuel@sholland.org>
[Andre: add comment summarising the commit message]
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
Create a do-nothing driver for each sunxi pin controller variant.
Since only one driver can automatically bind to a DT node, since the
GPIO driver already requires a manual binding process, and since the
pinctrl driver needs access to some of the same information, refactor
the GPIO driver to be bound by the pinctrl driver. This commit should
cause no functional change.
Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Andre Przywara <andre.przywara@arm.com>
