linux_dsm_epyc7002/Documentation/devicetree/bindings/pinctrl/atmel,at91-pio4-pinctrl.txt
Ludovic Desroches ff10e353a4 pinctrl: at91-pio4: add support for drive strength
Add support for the drive strength configuration. Usually, this value is
expressed in mA. Since the numeric value depends on VDDIOP voltage, a
value we can't retrieve at runtime, the controller uses low, medium and
high to define the drive strength.

The PIO controller accepts two values for the low drive configuration: 0
and 1. Most of the time, we don't care about the drive strength. So we
keep the default value which is 0. The drive strength is advertised
through the sysfs only when it has been explicitly set in the device
tree i.e. if its value is different from 0.

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2018-07-16 14:46:11 +02:00

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* Atmel PIO4 Controller
The Atmel PIO4 controller is used to select the function of a pin and to
configure it.
Required properties:
- compatible: "atmel,sama5d2-pinctrl".
- reg: base address and length of the PIO controller.
- interrupts: interrupt outputs from the controller, one for each bank.
- interrupt-controller: mark the device node as an interrupt controller.
- #interrupt-cells: should be two.
- gpio-controller: mark the device node as a gpio controller.
- #gpio-cells: should be two.
Please refer to ../gpio/gpio.txt and ../interrupt-controller/interrupts.txt for
a general description of GPIO and interrupt bindings.
Please refer to pinctrl-bindings.txt in this directory for details of the
common pinctrl bindings used by client devices.
Subnode format
Each node (or subnode) will list the pins it needs and how to configured these
pins.
node {
pinmux = <PIN_NUMBER_PINMUX>;
GENERIC_PINCONFIG;
};
Required properties:
- pinmux: integer array. Each integer represents a pin number plus mux and
ioset settings. Use the macros from boot/dts/<soc>-pinfunc.h file to get the
right representation of the pin.
Optional properties:
- GENERIC_PINCONFIG: generic pinconfig options to use, bias-disable,
bias-pull-down, bias-pull-up, drive-open-drain, input-schmitt-enable,
input-debounce, output-low, output-high.
- atmel,drive-strength: 0 or 1 for low drive, 2 for medium drive and 3 for
high drive. The default value is low drive.
Example:
#include <sama5d2-pinfunc.h>
...
{
pioA: pinctrl@fc038000 {
compatible = "atmel,sama5d2-pinctrl";
reg = <0xfc038000 0x600>;
interrupts = <18 IRQ_TYPE_LEVEL_HIGH 7>,
<68 IRQ_TYPE_LEVEL_HIGH 7>,
<69 IRQ_TYPE_LEVEL_HIGH 7>,
<70 IRQ_TYPE_LEVEL_HIGH 7>;
interrupt-controller;
#interrupt-cells = <2>;
gpio-controller;
#gpio-cells = <2>;
clocks = <&pioA_clk>;
pinctrl_i2c0_default: i2c0_default {
pinmux = <PIN_PD21__TWD0>,
<PIN_PD22__TWCK0>;
bias-disable;
};
pinctrl_led_gpio_default: led_gpio_default {
pinmux = <PIN_PB0>,
<PIN_PB5>;
bias-pull-up;
atmel,drive-strength = <ATMEL_PIO_DRVSTR_ME>;
};
pinctrl_sdmmc1_default: sdmmc1_default {
cmd_data {
pinmux = <PIN_PA28__SDMMC1_CMD>,
<PIN_PA18__SDMMC1_DAT0>,
<PIN_PA19__SDMMC1_DAT1>,
<PIN_PA20__SDMMC1_DAT2>,
<PIN_PA21__SDMMC1_DAT3>;
bias-pull-up;
};
ck_cd {
pinmux = <PIN_PA22__SDMMC1_CK>,
<PIN_PA30__SDMMC1_CD>;
bias-disable;
};
};
...
};
};
...