152 lines
4.5 KiB
Plaintext
Executable file
152 lines
4.5 KiB
Plaintext
Executable file
* Atmel AT91 Pinmux Controller
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The AT91 Pinmux Controller, enables the IC
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to share one PAD to several functional blocks. The sharing is done by
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multiplexing the PAD input/output signals. For each PAD there are up to
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8 muxing options (called periph modes). Since different modules require
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different PAD settings (like pull up, keeper, etc) the controller controls
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also the PAD settings parameters.
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Please refer to pinctrl-bindings.txt in this directory for details of the
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common pinctrl bindings used by client devices, including the meaning of the
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phrase "pin configuration node".
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Atmel AT91 pin configuration node is a node of a group of pins which can be
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used for a specific device or function. This node represents both mux and config
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of the pins in that group. The 'pins' selects the function mode(also named pin
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mode) this pin can work on and the 'config' configures various pad settings
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such as pull-up, multi drive, etc.
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Required properties for iomux controller:
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- compatible: "atmel,at91rm9200-pinctrl" or "atmel,at91sam9x5-pinctrl"
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or "atmel,sama5d3-pinctrl"
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- atmel,mux-mask: array of mask (periph per bank) to describe if a pin can be
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configured in this periph mode. All the periph and bank need to be describe.
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How to create such array:
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Each column will represent the possible peripheral of the pinctrl
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Each line will represent a pio bank
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Take an example on the 9260
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Peripheral: 2 ( A and B)
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Bank: 3 (A, B and C)
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=>
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/* A B */
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0xffffffff 0xffc00c3b /* pioA */
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0xffffffff 0x7fff3ccf /* pioB */
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0xffffffff 0x007fffff /* pioC */
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For each peripheral/bank we will descibe in a u32 if a pin can be
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configured in it by putting 1 to the pin bit (1 << pin)
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Let's take the pioA on peripheral B
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From the datasheet Table 10-2.
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Peripheral B
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PA0 MCDB0
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PA1 MCCDB
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PA2
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PA3 MCDB3
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PA4 MCDB2
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PA5 MCDB1
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PA6
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PA7
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PA8
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PA9
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PA10 ETX2
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PA11 ETX3
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PA12
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PA13
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PA14
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PA15
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PA16
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PA17
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PA18
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PA19
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PA20
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PA21
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PA22 ETXER
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PA23 ETX2
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PA24 ETX3
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PA25 ERX2
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PA26 ERX3
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PA27 ERXCK
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PA28 ECRS
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PA29 ECOL
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PA30 RXD4
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PA31 TXD4
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=> 0xffc00c3b
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Required properties for pin configuration node:
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- atmel,pins: 4 integers array, represents a group of pins mux and config
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setting. The format is atmel,pins = <PIN_BANK PIN_BANK_NUM PERIPH CONFIG>.
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The PERIPH 0 means gpio, PERIPH 1 is periph A, PERIPH 2 is periph B...
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PIN_BANK 0 is pioA, PIN_BANK 1 is pioB...
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Bits used for CONFIG:
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PULL_UP (1 << 0): indicate this pin needs a pull up.
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MULTIDRIVE (1 << 1): indicate this pin needs to be configured as multi-drive.
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Multi-drive is equivalent to open-drain type output.
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DEGLITCH (1 << 2): indicate this pin needs deglitch.
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PULL_DOWN (1 << 3): indicate this pin needs a pull down.
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DIS_SCHMIT (1 << 4): indicate this pin needs to the disable schmitt trigger.
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DRIVE_STRENGTH (3 << 5): indicate the drive strength of the pin using the
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following values:
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00 - No change (reset state value kept)
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01 - Low
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10 - Medium
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11 - High
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OUTPUT (1 << 7): indicate this pin need to be configured as an output.
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OUTPUT_VAL (1 << 8): output val (1 = high, 0 = low)
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DEBOUNCE (1 << 16): indicate this pin needs debounce.
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DEBOUNCE_VAL (0x3fff << 17): debounce value.
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NOTE:
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Some requirements for using atmel,at91rm9200-pinctrl binding:
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1. We have pin function node defined under at91 controller node to represent
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what pinmux functions this SoC supports.
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2. The driver can use the function node's name and pin configuration node's
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name describe the pin function and group hierarchy.
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For example, Linux at91 pinctrl driver takes the function node's name
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as the function name and pin configuration node's name as group name to
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create the map table.
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3. Each pin configuration node should have a phandle, devices can set pins
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configurations by referring to the phandle of that pin configuration node.
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4. The gpio controller must be describe in the pinctrl simple-bus.
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Examples:
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pinctrl@fffff400 {
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#address-cells = <1>;
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#size-cells = <1>;
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ranges;
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compatible = "atmel,at91rm9200-pinctrl", "simple-bus";
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reg = <0xfffff400 0x600>;
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atmel,mux-mask = <
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/* A B */
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0xffffffff 0xffc00c3b /* pioA */
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0xffffffff 0x7fff3ccf /* pioB */
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0xffffffff 0x007fffff /* pioC */
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>;
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/* shared pinctrl settings */
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dbgu {
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pinctrl_dbgu: dbgu-0 {
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atmel,pins =
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<1 14 0x1 0x0 /* PB14 periph A */
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1 15 0x1 0x1>; /* PB15 periph A with pullup */
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};
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};
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};
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dbgu: serial@fffff200 {
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compatible = "atmel,at91sam9260-usart";
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reg = <0xfffff200 0x200>;
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interrupts = <1 4 7>;
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pinctrl-names = "default";
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pinctrl-0 = <&pinctrl_dbgu>;
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};
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