ARM: at91: add pinctrl support

This is also include the gpio controller as the IP share both.
Each soc will have to describe the SoC limitation and pin configuration via
DT.

This will allow to do not need to touch the C code when adding new SoC if the
IP version is supported.

Signed-off-by: Jean-Christophe PLAGNIOL-VILLARD <plagnioj@jcrosoft.com>

1 files changed, 136 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt b/Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt
new file mode 100644
index 00000000000..20a987e55a2
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+++ b/Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt
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+* Atmel AT91 Pinmux Controller
+
+The AT91 Pinmux Controler, enables the IC
+to share one PAD to several functional blocks. The sharing is done by
+multiplexing the PAD input/output signals. For each PAD there are up to
+8 muxing options (called periph modes). Since different modules require
+different PAD settings (like pull up, keeper, etc) the contoller controls
+also the PAD settings parameters.
+
+Please refer to pinctrl-bindings.txt in this directory for details of the
+common pinctrl bindings used by client devices, including the meaning of the
+phrase "pin configuration node".
+
+Atmel AT91 pin configuration node is a node of a group of pins which can be
+used for a specific device or function. This node represents both mux and config
+of the pins in that group. The 'pins' selects the function mode(also named pin
+mode) this pin can work on and the 'config' configures various pad settings
+such as pull-up, multi drive, etc.
+
+Required properties for iomux controller:
+- compatible: "atmel,at91rm9200-pinctrl"
+- atmel,mux-mask: array of mask (periph per bank) to describe if a pin can be
+  configured in this periph mode. All the periph and bank need to be describe.
+
+How to create such array:
+
+Each column will represent the possible peripheral of the pinctrl
+Each line will represent a pio bank
+
+Take an example on the 9260
+Peripheral: 2 ( A and B)
+Bank: 3 (A, B and C)
+=>
+
+  /*    A         B     */
+  0xffffffff 0xffc00c3b  /* pioA */
+  0xffffffff 0x7fff3ccf  /* pioB */
+  0xffffffff 0x007fffff  /* pioC */
+
+For each peripheral/bank we will descibe in a u32 if a pin can can be
+configured in it by putting 1 to the pin bit (1 << pin)
+
+Let's take the pioA on peripheral B
+From the datasheet Table 10-2.
+Peripheral B
+PA0	MCDB0
+PA1	MCCDB
+PA2
+PA3	MCDB3
+PA4	MCDB2
+PA5	MCDB1
+PA6
+PA7
+PA8
+PA9
+PA10	ETX2
+PA11	ETX3
+PA12
+PA13
+PA14
+PA15
+PA16
+PA17
+PA18
+PA19
+PA20
+PA21
+PA22	ETXER
+PA23	ETX2
+PA24	ETX3
+PA25	ERX2
+PA26	ERX3
+PA27	ERXCK
+PA28	ECRS
+PA29	ECOL
+PA30	RXD4
+PA31	TXD4
+
+=> 0xffc00c3b
+
+Required properties for pin configuration node:
+- atmel,pins: 4 integers array, represents a group of pins mux and config
+  setting. The format is atmel,pins = <PIN_BANK PIN_BANK_NUM PERIPH CONFIG>.
+  The PERIPH 0 means gpio.
+
+Bits used for CONFIG:
+PULL_UP(1 << 0): indicate this pin need a pull up.
+MULTIDRIVE(1 << 1): indicate this pin need to be configured as multidrive.
+
+NOTE:
+Some requirements for using atmel,at91rm9200-pinctrl binding:
+1. We have pin function node defined under at91 controller node to represent
+   what pinmux functions this SoC supports.
+2. The driver can use the function node's name and pin configuration node's
+   name describe the pin function and group hierarchy.
+   For example, Linux at91 pinctrl driver takes the function node's name
+   as the function name and pin configuration node's name as group name to
+   create the map table.
+3. Each pin configuration node should have a phandle, devices can set pins
+   configurations by referring to the phandle of that pin configuration node.
+4. The gpio controller must be describe in the pinctrl simple-bus.
+
+Examples:
+
+pinctrl@fffff400 {
+	#address-cells = <1>;
+	#size-cells = <1>;
+	ranges;
+	compatible = "atmel,at91rm9200-pinctrl", "simple-bus";
+	reg = <0xfffff400 0x600>;
+
+	atmel,mux-mask = <
+	      /*    A         B     */
+	       0xffffffff 0xffc00c3b  /* pioA */
+	       0xffffffff 0x7fff3ccf  /* pioB */
+	       0xffffffff 0x007fffff  /* pioC */
+	      >;
+
+	/* shared pinctrl settings */
+	dbgu {
+		pinctrl_dbgu: dbgu-0 {
+			atmel,pins =
+				<1 14 0x1 0x0	/* PB14 periph A */
+				 1 15 0x1 0x1>;	/* PB15 periph with pullup */
+		};
+	};
+};
+
+dbgu: serial@fffff200 {
+	compatible = "atmel,at91sam9260-usart";
+	reg = <0xfffff200 0x200>;
+	interrupts = <1 4 7>;
+	pinctrl-names = "default";
+	pinctrl-0 = <&pinctrl_dbgu>;
+	status = "disabled";
+};