pinctrl: add pin control uclass support

This creates a new framework for handling of pin control devices,
i.e. devices that control different aspects of package pins.

This uclass handles pinmuxing and pin configuration; pinmuxing
controls switching among silicon blocks that share certain physical
pins, pin configuration handles electronic properties such as pin-
biasing, load capacitance etc.

This framework can support the same device tree bindings, but if you
do not need full interface support, you can disable some features to
reduce memory foot print.  Typically around 1.5KB is necessary to
include full-featured uclass support on ARM board (CONFIG_PINCTRL +
CONFIG_PINCTRL_FULL + CONFIG_PINCTRL_GENERIC + CONFIG_PINCTRL_PINMUX),
for example.

We are often limited on code size for SPL.  Besides, we still have
many boards that do not support device tree configuration.  The full
pinctrl, which requires OF_CONTROL, does not make sense for those
boards.  So, this framework also has a Do-It-Yourself (let's say
simple pinctrl) interface.  With CONFIG_PINCTRL_FULL disabled, the
uclass itself provides no systematic mechanism for identifying the
peripheral device, applying pinctrl settings, etc.  They must be
done in each low-level driver.  In return, you can save much memory
footprint and it might be useful especially for SPL.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Acked-by: Simon Glass <sjg@chromium.org>

1 files changed, 101 insertions, 0 deletions

diff --git a/drivers/pinctrl/Kconfig b/drivers/pinctrl/Kconfig
new file mode 100644
index 0000000000..6ac56ebe7d
--- /dev/null
+++ b/drivers/pinctrl/Kconfig
@@ -0,0 +1,101 @@
+#
+# PINCTRL infrastructure and drivers
+#
+
+menu "Pin controllers"
+
+config PINCTRL
+	bool "Support pin controllers"
+	depends on DM
+	help
+	  This enables the basic support for pinctrl framework.  You may want
+	  to enable some more options depending on what you want to do.
+
+config PINCTRL_FULL
+	bool "Support full pin controllers"
+	depends on PINCTRL && OF_CONTROL
+	default y
+	help
+	  This provides Linux-compatible device tree interface for the pinctrl
+	  subsystem.  This feature depends on device tree configuration because
+	  it parses a device tree to look for the pinctrl device which the
+	  peripheral device is associated with.
+
+	  If this option is disabled (it is the only possible choice for non-DT
+	  boards), the pinctrl core provides no systematic mechanism for
+	  identifying peripheral devices, applying needed pinctrl settings.
+	  It is totally up to the implementation of each low-level driver.
+	  You can save memory footprint in return for some limitations.
+
+config PINCTRL_GENERIC
+	bool "Support generic pin controllers"
+	depends on PINCTRL_FULL
+	default y
+	help
+	  Say Y here if you want to use the pinctrl subsystem through the
+	  generic DT interface.  If enabled, some functions become available
+	  to parse common properties such as "pins", "groups", "functions" and
+	  some pin configuration parameters.  It would be easier if you only
+	  need the generic DT interface for pin muxing and pin configuration.
+	  If you need to handle vendor-specific DT properties, you can disable
+	  this option and implement your own set_state callback in the pinctrl
+	  operations.
+
+config PINMUX
+	bool "Support pin multiplexing controllers"
+	depends on PINCTRL_GENERIC
+	default y
+	help
+	  This option enables pin multiplexing through the generic pinctrl
+	  framework.
+
+config PINCONF
+	bool "Support pin configuration controllers"
+	depends on PINCTRL_GENERIC
+	help
+	  This option enables pin configuration through the generic pinctrl
+	  framework.
+
+config SPL_PINCTRL
+	bool "Support pin controlloers in SPL"
+	depends on SPL && SPL_DM
+	help
+	  This option is an SPL-variant of the PINCTRL option.
+	  See the help of PINCTRL for details.
+
+config SPL_PINCTRL_FULL
+	bool "Support full pin controllers in SPL"
+	depends on SPL_PINCTRL && SPL_OF_CONTROL
+	default y
+	help
+	  This option is an SPL-variant of the PINCTRL_FULL option.
+	  See the help of PINCTRL_FULL for details.
+
+config SPL_PINCTRL_GENERIC
+	bool "Support generic pin controllers in SPL"
+	depends on SPL_PINCTRL_FULL
+	default y
+	help
+	  This option is an SPL-variant of the PINCTRL_GENERIC option.
+	  See the help of PINCTRL_GENERIC for details.
+
+config SPL_PINMUX
+	bool "Support pin multiplexing controllers in SPL"
+	depends on SPL_PINCTRL_GENERIC
+	default y
+	help
+	  This option is an SPL-variant of the PINMUX option.
+	  See the help of PINMUX for details.
+
+config SPL_PINCONF
+	bool "Support pin configuration controllers in SPL"
+	depends on SPL_PINCTRL_GENERIC
+	help
+	  This option is an SPL-variant of the PINCONF option.
+	  See the help of PINCONF for details.
+
+if PINCTRL || SPL_PINCTRL
+
+endif
+
+endmenu