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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 0000000..20a987e --- /dev/null +++ b/Documentation/devicetree/bindings/pinctrl/atmel,at91-pinctrl.txt @@ -0,0 +1,136 @@ +* 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"; +}; |