pinctrl: Add core support for Aspeed SoCs

The Aspeed SoCs typically provide more than 200 pins for GPIO and other
functions. The signal enabled on a pin is determined on a priority
basis, where a given pin can provide a number of different signal types.

In addition to the priority levels, the Aspeed pin controllers describe
the signal active on a pin by compound logical expressions involving
multiple operators, registers and bits. Some difficulty arises as a
pin's function bit masks for each priority level are frequently not the
same (i.e. we cannot just flip a bit to change from a high to low
priority signal), or even in the same register(s). Some configuration
bits affect multiple pins, while in other cases the signals for a bus
must each be enabled individually.

Together, these features give rise to some complexity in the
implementation. A more complete description of the complexities is
provided in the associated header file.

The patch doesn't implement pinctrl/pinmux/pinconf for any particular
Aspeed SoC, rather it adds the framework for defining pinmux
configurations.

Signed-off-by: Andrew Jeffery <andrew@aj.id.au>
Reviewed-by: Joel Stanley <joel@jms.id.au>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/drivers/pinctrl/aspeed/Kconfig b/drivers/pinctrl/aspeed/Kconfig
new file mode 100644
index 000000000000..757002f9be30
--- /dev/null
+++ b/drivers/pinctrl/aspeed/Kconfig
@@ -0,0 +1,8 @@
+config PINCTRL_ASPEED
+	bool
+	depends on (ARCH_ASPEED || COMPILE_TEST) && OF
+	depends on MFD_SYSCON
+	select PINMUX
+	select PINCONF
+	select GENERIC_PINCONF
+	select REGMAP_MMIO