CREG GPIO: add device tree bindings

Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Alexey Brodkin <abrodkin@synopsys.com>
This commit is contained in:
Eugeniy Paltsev 2018-06-08 17:58:24 +03:00 committed by Alexey Brodkin
parent fe3eb7a887
commit 7620ec4df6
2 changed files with 44 additions and 0 deletions

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@ -74,6 +74,7 @@ ARC HSDK CREG GPIO
M: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
S: Maintained
L: uboot-snps-arc@synopsys.com
F: doc/device-tree-bindings/gpio/snps,creg-gpio.txt
F: drivers/gpio/hsdk-creg-gpio.c
ARM

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@ -0,0 +1,43 @@
GPIO via CREG (control registers) driver
31 9 7 5 0 < bit number
| | | | |
[ not used | gpio-1 | gpio-0 | <-shift-> ] < 32 bit register
^ ^
| |
write 0x2 == set output to "1" (activate)
write 0x3 == set output to "0" (deactivate)
Required properties:
- compatible : "snps,creg-gpio"
- reg : Exactly one register range with length 0x4.
- #gpio-cells : Should be one - the pin number.
- gpio-controller : Marks the device node as a GPIO controller.
- gpio-count: Number of GPIO pins.
- gpio-bit-per-line: Number of bits per gpio line (see picture).
- gpio-first-shift: Shift (in bits) of the first GPIO field in register
(see picture).
- gpio-activate-val: Value should be set in corresponding field to set
output to "1" (see picture). Applied to all GPIO ports.
- gpio-deactivate-val: Value should be set in corresponding field to set
output to "0" (see picture). Applied to all GPIO ports.
Optional properties:
- gpio-bank-name: name of bank (as default driver name is used is used)
- gpio-default-val: array of default output values (must me 0 or 1)
Example (see picture):
gpio: gpio@f00014b0 {
compatible = "snps,creg-gpio";
reg = <0xf00014b0 0x4>;
gpio-controller;
#gpio-cells = <1>;
gpio-bank-name = "hsdk-spi-cs";
gpio-count = <2>;
gpio-first-shift = <5>;
gpio-bit-per-line = <2>;
gpio-activate-val = <2>;
gpio-deactivate-val = <3>;
gpio-default-val = <1 1>;
};