Re: [PATCH 1/2] dt-binding: can: mcp2517fd: document device tree bindings

Hello Martin,


I didn't catch the whole discussion but you may want to check

include/dt-bindings/gpio/gpio.h

#define GPIO_OPEN_DRAIN (GPIO_SINGLE_ENDED | GPIO_ACTIVE_LOW)

This corresponds to

Documentation/devicetree/bindings/gpio/gpio.txt

Most controllers are however specifying a generic flag bitfield
in the last cell, so for these, use the macros defined in
include/dt-bindings/gpio/gpio.h whenever possible:

Example of a node using GPIOs:

    node {
        enable-gpios = <&qe_pio_e 18 GPIO_ACTIVE_HIGH>;
    };

GPIO_ACTIVE_HIGH is 0, so in this example gpio-specifier is "18 0" and
encodes
GPIO pin number, and GPIO flags as accepted by the "qe_pio_e"
gpio-controller.

Optional standard bitfield specifiers for the last cell:

- Bit 0: 0 means active high, 1 means active low
- Bit 1: 1 means single-ended wiring, see:
           https://en.wikipedia.org/wiki/Single-ended_triode
       When used with active-low, this means open drain/collector, see:
           https://en.wikipedia.org/wiki/Open_collector
       When used with active-high, this means open source/emitter

Regards,

Patrick



Am 29.11.2017 um 12:55 schrieb kernel-TqfNSX0MhmxHKSADF0wUEw@public.gmane.org:

Hi Rob!

Thanks for all the effort - I shall incorporate those changes into V2.

quoted

s/Microcip/Microchip/
s/_/-/

quoted

+					   0 = Start of Frame output
+					   default: 10
+ - microchip,clock_div = <1|2>: internal clock divider - default 1
+ - microchip,gpio_opendrain: gpio (int0,1) in open drain mode
+			     instead of default push/pull
+ - microchip,int_opendrain: int pin in open drain mode
+			    instead of default push/pull

IIRC, we have a standard property for this.

Would you know what that could be - I did a quick search for
standard properties, but could not find a definitive list…

The only thing I found in:
  Documentation/devicetree/bindings/w1/w1-gpio.txt
is:
  linux,open-drain

But there is also:  
  nvidia,open-drain
  open_drain
  open-drain
  drive-open-drain (pinctrl)
  st,irq-open-drain

Only the last is specific to the interrupt line and none to the other
GPIOs of the chip (txcan, GPIO) - and each can get set differently.

So how shall I implement that?

Thanks,
	Martin--
To unsubscribe from this list: send the line "unsubscribe linux-can" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html