Overview

The aim of this document is to explain how to setup pins of SP7350 in device-tree source. SP7350 has 106 general purpose IO (GPIO) pins which are multiplexed with other special functions, like eMMC device, SPI-NOR flash, SPI-NAND flash, Ethernet PHY (RGMII or RMII interface), UART, I2C pins, and etc.

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SP7350 has 106 GPIO pins. ID is from 0 to 105. Name is in form of GPIO(id), like GPIO0, GPIO1, GPIO2, GPIO99, GPIO105, and etc. There are two kinds of GPIO pins. One is 1.8V GPIO pins, and the other is 1.8V/3.0V Dual Voltage IO (DVIO) pins. Beside configure 1.8V or 3.0V power to power supply of a DVIO group in your circuit boards (hardware), you need to setup MS control in device-tree source. Refer to groups of GPIO and DVIO in appendix GPIO Table below in details.

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We define a bunch of groups as listed in appendix Function-group Table below.

pinmux

1. Set a single pin to function "GPIO"

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Voltage Mode Select

For 1.8V/3.0V Dual Voltage IO (DVIO) pins，we offer several properties to select their voltage in pinctrl node in DTS file.

pinmux

1. Set a single pin to function "GPIO"

• set "GPIO0" to function"GPIO"

pinmux_example {
    function = "GPIO";
    pins = "GPIO0";
};

2. Set several pins to function "GPIO"

• set "GPIO0" and "GPIO1" to function"GPIO"

pinmux_example {
    function = "GPIO";
    pins = "GPIOGPIO0", "GPIO1";
};

3. Set a group of pins to a particular function

• set group "UART0_X1" to function "UART0"

pinmux_example {
    function = "UART0";
    pinsgroup = "GPIO0UART0_X1";
};

2. Set several pins to function "GPIO"

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pinconf

1. bias-disable

• description

Disable any pin bias on the pin.

• argument

The argument is ignored.

• usage

pinmuxpinconf_example {
	:
   function :
   = "GPIO" bias-disable;
    pins = "GPIO0", "GPIO1";
};

3. Set a group of pins to a particular function

• set group "UART0_X1" to function "UART0"

:
    :
};

2. bias-high-impedance

• description

The pin will be set to a high impedance mode, also know as "third-state" (tri-state) or "high-Z" or "floating".

• argument

The argument is ignored.

• usage

pinmuxpinconf_example {
	:
    :
  function = "UART0"; bias-high-impedance;
    :
group   = "UART0_X1"; :
};

pinconf

3. bias-pull-

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3. up

• description

Disable any pin bias on the pinThe pin will be pulled up.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    bias-pull-disableup;
    :
    :
};

4. bias-

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4. pull-

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4. down

• description

The pin will be set to a high impedance mode, also know as "third-state" (tri-state) or "high-Z" or "floating"pulled down.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    bias-highpull-impedancedown;
    :
    :
};

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5. drive-

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5. open-

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5. drain

• description

The pin will be driven with open drain (open collector) which means it is usually wired with other output ports which are then pulled up with an external resistor. Setting this config will enable open drain mode.

• argument

The argument is ignored.

...

pinconf_example {
	:
    :
    biasdrive-pullopen-updrain;
    :
    :
};

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6. drive-

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6. strength-

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6. microamp

• description

The pin will be pulled downsink or source at most the current passed as argument.

• argument

The argument is ignoredin uA.

See linux/kernel/include/dt-bindings/pinctrl/sppctl-config-sp7350.h for selectable argument.

• usage

pinconf_example {
	:
    :
    bias-pull-down;
    :/* source current 1100uA for GPIO*/
    :
};drive-

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• description

The pin will be driven with open drain (open collector) which means it is usually wired with other output ports which are then pulled up with an external resistor. Setting this config will enable open drain mode.

• argument

The argument is ignored.

• usage

strength-microamp = <SPPCTRL_GPIO_DRV_IOH_1100_IOL_1100UA>; 
    :
    :
};

pinconf_example {
	:
    :
    /* source current 5100uA for DVIO*/
    drive-open-drainstrength-microamp = <SPPCTRL_DVIO_DRV_IOH_5100_IOL_6200UA>;
    :
    :
};

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7. input-

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7. enable

• description

The pin will sink or source at most the current passed as argumentEnable the pin's input.

• argument

The argument is in uA.See linux/kernel/include/dt-bindings/pinctrl/sppctl-config-sp7350.h for selectable argumentargument is ignored.

• usage

pinconf_example {
	:
    :
    /* source current 1100uA for GPIO*/
    drive-strength-microamp = <SPPCTRL_GPIO_DRV_IOH_1100_IOL_1100UA>input-enable;
     :
    :
};

8. input-disable

• description

Disable the pin's input.

• argument

The argument is ignored.

• usage

pinconf_example {
	:
    :
    /* source current 5100uA for DVIO*/
    drive-strength-microamp = <SPPCTRL_DVIO_DRV_IOH_5100_IOL_6200UA>input-disable;
    :
    :
};

9. input-schmitt-enable

• description

...

This will configure an input pin to run in Schmitt-trigger mode.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    input-schmitt-enable;
    :
    :
};

10. input-schmitt-disable

• description

Disable This will disable the pin's inputSchmitt-trigger mode.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    input-schmitt-disable;
    :
    :
};

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11. output-enable

• description

This will configure an input pin to run in Schmitt-trigger modeenable the pin's output mode without driving a value there.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    inputoutput-schmitt-enable;
    :
    :
};

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12. output-disable

• description

This will disable the pin's Schmitt-trigger output mode.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    input-schmittoutput-disable;
    :
    :
};

13. output-

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13. high

• description

This will enable configure the pin 's output mode without driving a value thereas output and drive high level on the line.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    output-enablehigh;
    :
    :
};

14. output-

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14. low

• description

This will disable configure the pin 's output modeas output and drive low level on the line.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    output-disablelow;
    :
    :
};

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15. sunplus,input-invert-enable

• description

This will configure invert the pin as output and drive high level on the line's input value. High level as 0, Low level as 1.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    output-highsunplus,input-invert-enable;
    :
    :
};

16. sunplus,output-invert-

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16. enable

• description

This will configure invert the pin as output and drive low level on the line's output value. 1 as low level, 0 as high level.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    sunplus,output-lowinvert-enable;
    :
    :
};

17. sunplus,input-invert-

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17. disable

• description

This will invert normalize the pin's input value. High level as 01, Low level as 10.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    sunplus,input-invert-enabledisable;
    :
    :
};

18. sunplus,output-invert-

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18. disable

• description

This will invert normalize the pin's output value. 1 as low high level, 0 as high low level.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    sunplus,output-invert-enabledisable;
    :
    :
};

19. sunplus,

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19. bias-strong-

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19. pull-

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19. up

• description

This will normalize the pin's input value. High level as 1, Low level as 0The pin will be pulled up strongly.

• argument

The argument is ignored.

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pinconf_example {
	:
    :
    sunplus,inputbias-strong-invertpull-disableup;
    :
    :
};

18. sunplus,output-invert-disable

• description

This will normalize the pin's output value. 1 as high level, 0 as low level.

• argument

The argument is ignored.

• usage

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DTS

Device-tree source files of SP7350 are located in linux/kernel/arch/arm64/boot/dts/sunplus/.

Here lists all files for SP7350 boards:

Example

Voltage Mode

For 1.8V/3.0V Dual Voltage IO (DVIO) pins，we need to select their voltage in pinctrl top node in DTS file. As below:

pctl: pinctrl@f8800080 {
    compatible = "sunplus,sp7350-pctl";
    :
    :
    sunplus,outputms-dvio-invert-disablegroup-0 = "1V8";
    :
 sunplus,ms-dvio-group-1 = "1V8";
  :  };sunplus,

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ms-

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dvio-

...

• description

The pin will be pulled up strongly.

• argument

The argument is ignored.

• usage

pinconf_example {
	:
    :ao-group-0 = "1V8";
    sunplus,ms-dvio-ao-group-1 = "3V0";
    sunplus,biasms-dvio-strongao-pull-upgroup-2 = "3V0";
    :
    :
};

DTS

Device-tree source files of SP7350 are located in linux/kernel/arch/arm64/boot/dts/sunplus/.

Here lists all files for SP7350 boards:

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GPIO

SP7350 has 106 general purpose IO (GPIO) pins. Most of them are multiplexed with other special function pins. This section explains how to modify device-tree source file to set up GPIO pins as digital input or output pins.

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