*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--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 = ; 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. 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 ICLK_IO BYPASS DE_IO SE_ICLK_IO SE_NICLK_IO - 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>; };