| Samsung GPIO and Pin Mux/Config controller |
| |
| Samsung's ARM based SoC's integrates a GPIO and Pin mux/config hardware |
| controller. It controls the input/output settings on the available pads/pins |
| and also provides ability to multiplex and configure the output of various |
| on-chip controllers onto these pads. |
| |
| Required Properties: |
| - compatible: should be one of the following. |
| - "samsung,pinctrl-exynos4210": for Exynos4210 compatible pin-controller. |
| - "samsung,pinctrl-exynos5250": for Exynos5250 compatible pin-controller. |
| |
| - reg: Base address of the pin controller hardware module and length of |
| the address space it occupies. |
| |
| - Pin banks as child nodes: Pin banks of the controller are represented by child |
| nodes of the controller node. Bank name is taken from name of the node. Each |
| bank node must contain following properties: |
| |
| - gpio-controller: identifies the node as a gpio controller and pin bank. |
| - #gpio-cells: number of cells in GPIO specifier. Since the generic GPIO |
| binding is used, the amount of cells must be specified as 2. See generic |
| GPIO binding documentation for description of particular cells. |
| |
| - Pin mux/config groups as child nodes: The pin mux (selecting pin function |
| mode) and pin config (pull up/down, driver strength) settings are represented |
| as child nodes of the pin-controller node. There should be atleast one |
| child node and there is no limit on the count of these child nodes. |
| |
| The child node should contain a list of pin(s) on which a particular pin |
| function selection or pin configuration (or both) have to applied. This |
| list of pins is specified using the property name "samsung,pins". There |
| should be atleast one pin specfied for this property and there is no upper |
| limit on the count of pins that can be specified. The pins are specified |
| using pin names which are derived from the hardware manual of the SoC. As |
| an example, the pins in GPA0 bank of the pin controller can be represented |
| as "gpa0-0", "gpa0-1", "gpa0-2" and so on. The names should be in lower case. |
| The format of the pin names should be (as per the hardware manual) |
| "[pin bank name]-[pin number within the bank]". |
| |
| The pin function selection that should be applied on the pins listed in the |
| child node is specified using the "samsung,pin-function" property. The value |
| of this property that should be applied to each of the pins listed in the |
| "samsung,pins" property should be picked from the hardware manual of the SoC |
| for the specified pin group. This property is optional in the child node if |
| no specific function selection is desired for the pins listed in the child |
| node. The value of this property is used as-is to program the pin-controller |
| function selector register of the pin-bank. |
| |
| The child node can also optionally specify one or more of the pin |
| configuration that should be applied on all the pins listed in the |
| "samsung,pins" property of the child node. The following pin configuration |
| properties are supported. |
| |
| - samsung,pin-pud: Pull up/down configuration. |
| - samsung,pin-drv: Drive strength configuration. |
| - samsung,pin-pud-pdn: Pull up/down configuration in power down mode. |
| - samsung,pin-drv-pdn: Drive strength configuration in power down mode. |
| |
| The values specified by these config properties should be derived from the |
| hardware manual and these values are programmed as-is into the pin |
| pull up/down and driver strength register of the pin-controller. |
| |
| Note: A child should include atleast a pin function selection property or |
| pin configuration property (one or more) or both. |
| |
| The client nodes that require a particular pin function selection and/or |
| pin configuration should use the bindings listed in the "pinctrl-bindings.txt" |
| file. |
| |
| External GPIO and Wakeup Interrupts: |
| |
| The controller supports two types of external interrupts over gpio. The first |
| is the external gpio interrupt and second is the external wakeup interrupts. |
| The difference between the two is that the external wakeup interrupts can be |
| used as system wakeup events. |
| |
| A. External GPIO Interrupts: For supporting external gpio interrupts, the |
| following properties should be specified in the pin-controller device node. |
| |
| - interrupt-parent: phandle of the interrupt parent to which the external |
| GPIO interrupts are forwarded to. |
| - interrupts: interrupt specifier for the controller. The format and value of |
| the interrupt specifier depends on the interrupt parent for the controller. |
| |
| In addition, following properties must be present in node of every bank |
| of pins supporting GPIO interrupts: |
| |
| - interrupt-controller: identifies the controller node as interrupt-parent. |
| - #interrupt-cells: the value of this property should be 2. |
| - First Cell: represents the external gpio interrupt number local to the |
| external 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 |
| |
| B. External Wakeup Interrupts: For supporting external wakeup interrupts, a |
| child node representing the external wakeup interrupt controller should be |
| included in the pin-controller device node. This child node should include |
| the following properties. |
| |
| - compatible: identifies the type of the external wakeup interrupt controller |
| The possible values are: |
| - samsung,exynos4210-wakeup-eint: represents wakeup interrupt controller |
| found on Samsung Exynos4210 SoC. |
| - interrupt-parent: phandle of the interrupt parent to which the external |
| wakeup interrupts are forwarded to. |
| - interrupts: interrupt used by multiplexed wakeup interrupts. |
| |
| In addition, following properties must be present in node of every bank |
| of pins supporting wake-up interrupts: |
| |
| - interrupt-controller: identifies the node as interrupt-parent. |
| - #interrupt-cells: the value of this property should be 2 |
| - First Cell: represents the external wakeup interrupt number local to |
| the external wakeup 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 |
| |
| Node of every bank of pins supporting direct wake-up interrupts (without |
| multiplexing) must contain following properties: |
| |
| - interrupt-parent: phandle of the interrupt parent to which the external |
| wakeup interrupts are forwarded to. |
| - interrupts: interrupts of the interrupt parent which are used for external |
| wakeup interrupts from pins of the bank, must contain interrupts for all |
| pins of the bank. |
| |
| Aliases: |
| |
| All the pin controller nodes should be represented in the aliases node using |
| the following format 'pinctrl{n}' where n is a unique number for the alias. |
| |
| Example: A pin-controller node with pin banks: |
| |
| pinctrl_0: pinctrl@11400000 { |
| compatible = "samsung,pinctrl-exynos4210"; |
| reg = <0x11400000 0x1000>; |
| interrupts = <0 47 0>; |
| |
| /* ... */ |
| |
| /* Pin bank without external interrupts */ |
| gpy0: gpy0 { |
| gpio-controller; |
| #gpio-cells = <2>; |
| }; |
| |
| /* ... */ |
| |
| /* Pin bank with external GPIO or muxed wake-up interrupts */ |
| gpj0: gpj0 { |
| gpio-controller; |
| #gpio-cells = <2>; |
| |
| interrupt-controller; |
| #interrupt-cells = <2>; |
| }; |
| |
| /* ... */ |
| |
| /* Pin bank with external direct wake-up interrupts */ |
| gpx0: gpx0 { |
| gpio-controller; |
| #gpio-cells = <2>; |
| |
| interrupt-controller; |
| interrupt-parent = <&gic>; |
| interrupts = <0 16 0>, <0 17 0>, <0 18 0>, <0 19 0>, |
| <0 20 0>, <0 21 0>, <0 22 0>, <0 23 0>; |
| #interrupt-cells = <2>; |
| }; |
| |
| /* ... */ |
| }; |
| |
| Example 1: A pin-controller node with pin groups. |
| |
| pinctrl_0: pinctrl@11400000 { |
| compatible = "samsung,pinctrl-exynos4210"; |
| reg = <0x11400000 0x1000>; |
| interrupts = <0 47 0>; |
| |
| /* ... */ |
| |
| uart0_data: uart0-data { |
| samsung,pins = "gpa0-0", "gpa0-1"; |
| samsung,pin-function = <2>; |
| samsung,pin-pud = <0>; |
| samsung,pin-drv = <0>; |
| }; |
| |
| uart0_fctl: uart0-fctl { |
| samsung,pins = "gpa0-2", "gpa0-3"; |
| samsung,pin-function = <2>; |
| samsung,pin-pud = <0>; |
| samsung,pin-drv = <0>; |
| }; |
| |
| uart1_data: uart1-data { |
| samsung,pins = "gpa0-4", "gpa0-5"; |
| samsung,pin-function = <2>; |
| samsung,pin-pud = <0>; |
| samsung,pin-drv = <0>; |
| }; |
| |
| uart1_fctl: uart1-fctl { |
| samsung,pins = "gpa0-6", "gpa0-7"; |
| samsung,pin-function = <2>; |
| samsung,pin-pud = <0>; |
| samsung,pin-drv = <0>; |
| }; |
| |
| i2c2_bus: i2c2-bus { |
| samsung,pins = "gpa0-6", "gpa0-7"; |
| samsung,pin-function = <3>; |
| samsung,pin-pud = <3>; |
| samsung,pin-drv = <0>; |
| }; |
| }; |
| |
| Example 2: A pin-controller node with external wakeup interrupt controller node. |
| |
| pinctrl_1: pinctrl@11000000 { |
| compatible = "samsung,pinctrl-exynos4210"; |
| reg = <0x11000000 0x1000>; |
| interrupts = <0 46 0> |
| |
| /* ... */ |
| |
| wakeup-interrupt-controller { |
| compatible = "samsung,exynos4210-wakeup-eint"; |
| interrupt-parent = <&gic>; |
| interrupts = <0 32 0>; |
| }; |
| }; |
| |
| Example 3: A uart client node that supports 'default' and 'flow-control' states. |
| |
| uart@13800000 { |
| compatible = "samsung,exynos4210-uart"; |
| reg = <0x13800000 0x100>; |
| interrupts = <0 52 0>; |
| pinctrl-names = "default", "flow-control; |
| pinctrl-0 = <&uart0_data>; |
| pinctrl-1 = <&uart0_data &uart0_fctl>; |
| }; |
| |
| Example 4: Set up the default pin state for uart controller. |
| |
| static int s3c24xx_serial_probe(struct platform_device *pdev) { |
| struct pinctrl *pinctrl; |
| |
| /* ... */ |
| |
| pinctrl = devm_pinctrl_get_select_default(&pdev->dev); |
| } |