--- /dev/null
+*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,<SOC>-<pio-block>-pinctrl"
+ like st,stih415-sbc-pinctrl, st,stih415-front-pinctrl and so on.
+- 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 : Should be one. The first cell is the pin number.
+- 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,stih415-sbc-pinctrl";
+ st,syscfg = <&syscfg_sbc>;
+ reg = <0xfe61f080 0x4>;
+ reg-names = "irqmux";
+ interrupts = <GIC_SPI 180 IRQ_TYPE_LEVEL_HIGH>;
+ interrupt-names = "irqmux";
+ ranges = <0 0xfe610000 0x5000>;
+
+ PIO0: gpio@fe610000 {
+ gpio-controller;
+ #gpio-cells = <1>;
+ interrupt-controller;
+ #interrupt-cells = <2>;
+ reg = <0 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>;
+};
Code Review / kvmfornfv.git / blobdiff