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| -rw-r--r-- | Documentation/devicetree/bindings/pinctrl/pinctrl-st.txt | 174 |
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diff --git a/Documentation/devicetree/bindings/pinctrl/pinctrl-st.txt b/Documentation/devicetree/bindings/pinctrl/pinctrl-st.txt new file mode 100644 index 000000000..48b9be48a --- /dev/null +++ b/Documentation/devicetree/bindings/pinctrl/pinctrl-st.txt @@ -0,0 +1,174 @@ +*ST pin controller. + +Each multi-function pin is controlled, driven and routed through the +PIO multiplexing block. Each pin supports GPIO functionality (ALT0) +and multiple alternate functions(ALT1 - ALTx) that directly connect +the pin to different hardware blocks. + +When a pin is in GPIO mode, Output Enable (OE), Open Drain(OD), and +Pull Up (PU) are driven by the related PIO block. + +ST pinctrl driver controls PIO multiplexing block and also interacts with +gpio driver to configure a pin. + +GPIO bank can have one of the two possible types of interrupt-wirings. + +First type is via irqmux, single interrupt is used by multiple gpio banks. This +reduces number of overall interrupts numbers required. All these banks belong to +a single pincontroller. + _________ + | |----> [gpio-bank (n) ] + | |----> [gpio-bank (n + 1)] + [irqN]-- | irq-mux |----> [gpio-bank (n + 2)] + | |----> [gpio-bank (... )] + |_________|----> [gpio-bank (n + 7)] + +Second type has a dedicated interrupt per gpio bank. + + [irqN]----> [gpio-bank (n)] + + +Pin controller node: +Required properties: +- compatible : should be "st,stih407-<pio-block>-pinctrl" +- st,syscfg : Should be a phandle of the syscfg node. +- st,retime-pin-mask : Should be mask to specify which pins can be retimed. + If the property is not present, it is assumed that all the pins in the + bank are capable of retiming. Retiming is mainly used to improve the + IO timing margins of external synchronous interfaces. +- ranges : defines mapping between pin controller node (parent) to gpio-bank + node (children). + +Optional properties: +- interrupts : Interrupt number of the irqmux. If the interrupt is shared + with other gpio banks via irqmux. + a irqline and gpio banks. +- reg : irqmux memory resource. If irqmux is present. +- reg-names : irqmux resource should be named as "irqmux". + +GPIO controller/bank node. +Required properties: +- gpio-controller : Indicates this device is a GPIO controller +- #gpio-cells : Must be two. + - First cell: specifies the pin number inside the controller + - Second cell: specifies whether the pin is logically inverted. + - 0 = active high + - 1 = active low +- st,bank-name : Should be a name string for this bank as specified in + datasheet. + +Optional properties: +- interrupts : Interrupt number for this gpio bank. If there is a dedicated + interrupt wired up for this gpio bank. + +- interrupt-controller : Indicates this device is a interrupt controller. GPIO + bank can be an interrupt controller iff one of the interrupt type either via +irqmux or a dedicated interrupt per bank is specified. + +- #interrupt-cells: the value of this property should be 2. + - First Cell: represents the external gpio interrupt number local to the + gpio interrupt space of the controller. + - Second Cell: flags to identify the type of the interrupt + - 1 = rising edge triggered + - 2 = falling edge triggered + - 3 = rising and falling edge triggered + - 4 = high level triggered + - 8 = low level triggered +for related macros look in: +include/dt-bindings/interrupt-controller/irq.h + +Example: + pin-controller-sbc { + #address-cells = <1>; + #size-cells = <1>; + compatible = "st,stih407-sbc-pinctrl"; + st,syscfg = <&syscfg_sbc>; + reg = <0x0961f080 0x4>; + reg-names = "irqmux"; + interrupts = <GIC_SPI 188 IRQ_TYPE_NONE>; + interrupt-names = "irqmux"; + ranges = <0 0x09610000 0x6000>; + + pio0: gpio@9610000 { + gpio-controller; + #gpio-cells = <2>; + interrupt-controller; + #interrupt-cells = <2>; + reg = <0x0 0x100>; + st,bank-name = "PIO0"; + }; + ... + pin-functions nodes follow... + }; + + +Contents of function subnode node: +---------------------- +Required properties for pin configuration node: +- st,pins : Child node with list of pins with configuration. + +Below is the format of how each pin conf should look like. + +<bank offset mux mode rt_type rt_delay rt_clk> + +Every PIO is represented with 4-7 parameters depending on retime configuration. +Each parameter is explained as below. + +-bank : Should be bank phandle to which this PIO belongs. +-offset : Offset in the PIO bank. +-mux : Should be alternate function number associated this pin. + Use same numbers from datasheet. +-mode :pin configuration is selected from one of the below values. + IN + IN_PU + OUT + BIDIR + BIDIR_PU + +-rt_type Retiming Configuration for the pin. + Possible retime configuration are: + + ------- ------------- + value args + ------- ------------- + NICLK <delay> <clk> + ICLK_IO <delay> <clk> + BYPASS <delay> + DE_IO <delay> <clk> + SE_ICLK_IO <delay> <clk> + SE_NICLK_IO <delay> <clk> + +- delay is retime delay in pico seconds as mentioned in data sheet. + +- rt_clk :clk to be use for retime. + Possible values are: + CLK_A + CLK_B + CLK_C + CLK_D + +Example of mmcclk pin which is a bi-direction pull pu with retime config +as non inverted clock retimed with CLK_B and delay of 0 pico seconds: + +pin-controller { + ... + mmc0 { + pinctrl_mmc: mmc { + st,pins { + mmcclk = <&PIO13 4 ALT4 BIDIR_PU NICLK 0 CLK_B>; + ... + }; + }; + ... + }; +}; + +sdhci0:sdhci@fe810000{ + ... + interrupt-parent = <&pio3>; + #interrupt-cells = <2>; + interrupts = <3 IRQ_TYPE_LEVEL_HIGH>; /* Interrupt line via PIO3-3 */ + interrupt-names = "card-detect"; + pinctrl-names = "default"; + pinctrl-0 = <&pinctrl_mmc>; +}; |