mirror of
https://github.com/brain-hackers/u-boot-brain
synced 2024-06-09 23:36:03 +09:00
2a48c15d2e
This add device tree binding documentation for the MSCC serial GPIO driver. Signed-off-by: Lars Povlsen <lars.povlsen@microsemi.com> Acked-by: Linus Walleij <linus.walleij@linaro.org>
46 lines
1.7 KiB
Plaintext
46 lines
1.7 KiB
Plaintext
Microsemi Corporation (MSCC) Serial GPIO driver
|
|
|
|
The MSCC serial GPIO extends the number or GPIO's on the system by
|
|
means of 4 dedicated pins: one input, one output, one clock and one
|
|
strobe pin. By attaching a number of (external) shift registers, the
|
|
effective GPIO count can be extended by up to 128 GPIO's per
|
|
controller.
|
|
|
|
Required properties:
|
|
- compatible : "mscc,luton-sgpio" or "mscc,ocelot-sgpio"
|
|
- clock: Reference clock used to generate clock divider setting. See
|
|
mscc,sgpio-frequency property.
|
|
- reg : Physical base address and length of the controller's registers.
|
|
- #gpio-cells : Should be two. The first cell is the pin number and the
|
|
second cell is used to specify optional parameters:
|
|
- bit 0 specifies polarity (0 for normal, 1 for inverted)
|
|
- gpio-controller : Marks the device node as a GPIO controller.
|
|
- gpio-ranges: Standard gpio range(s): phandle, gpio base, pinctrl base
|
|
and count.
|
|
|
|
Optional properties:
|
|
- ngpios: See gpio.txt
|
|
- mscc,sgpio-frequency: The frequency at which the serial bitstream is
|
|
generated and sampled. Default: 12500000 (Hz).
|
|
- mscc,sgpio-ports: A bitmask (32 bits) of which ports are enabled in
|
|
the serialized gpio stream. One 'port' will transport from 1 to 4
|
|
gpio bits. Default: 0xFFFFFFFF.
|
|
|
|
Typically the pinctrl-0 and pinctrl-names properties will also be
|
|
present to enable the use of the SIO CLK, LD, DI and DO for some
|
|
regular GPIO pins.
|
|
|
|
Example:
|
|
|
|
sgpio: gpio@10700f8 {
|
|
compatible = "mscc,ocelot-sgpio";
|
|
pinctrl-0 = <&sgpio_pins>;
|
|
pinctrl-names = "default";
|
|
reg = <0x10700f8 0x100>;
|
|
gpio-controller;
|
|
#gpio-cells = <2>;
|
|
gpio-ranges = <&sgpio 0 0 64>;
|
|
mscc,sgpio-frequency = <12500>;
|
|
mscc,sgpio-ports = <0x000FFFFF>;
|
|
};
|