Date: Thu, 6 Feb 2014 20:21:52 -0700 From: Warner Losh <imp@bsdimp.com> To: Luiz Otavio O Souza <loos.br@gmail.com> Cc: freebsd-arm@freebsd.org, freebsd-embedded@freebsd.org Subject: Re: FDT/OFW GPIO bus Message-ID: <C8E49E48-F575-466F-8036-8E57CC025ADE@bsdimp.com> In-Reply-To: <2D5F2707-FD55-46BB-A44F-8870B48E2BB1@gmail.com> References: <2D5F2707-FD55-46BB-A44F-8870B48E2BB1@gmail.com>
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On Feb 6, 2014, at 11:53 AM, Luiz Otavio O Souza wrote:
> Hello guys,
>=20
> Last call for alcohol^Wtest and reviews.
>=20
> I=92ve finally managed to test these changes on a some FDT and non FDT =
systems, so now it is all cleared to commit.
>=20
> I plan to commit these changes on the weekend unless someone objects.
This is cool.
> They add support to describe GPIO connections on the DTS files. It =
also add the support to the in tree GPIO devices (gpioiic(4), =
gpioled(4)).
>=20
> The last patch (005-bbb-gpioled.diff) sets the gpioled(4) for the 4 on =
board LEDs on BBB (beaglebone-black). The RPi led is already set and =
just need the first patch (001-ofw-gpiobus.diff) to work.
>=20
> The tests were done on RPi and BBB using I2C devices (two lm75 on the =
same bus), LEDs (for gpioled(4)) and even with some non committed =
ethernet over SPI. The I2C tests are conducted using the hardware I2C =
controller (when available) and also the software big bang controller - =
gpioiic(4).
>=20
> I used the RSPRO (MIPS/ar71xx) to check for regressions without any =
visible problem.
>=20
> gpioiic(4) devices can be described in DTS as follow:
>=20
> gpio {
>=20
> gpioiic {
> compatible =3D "gpioiic";
Linux uses 'i2c-gpio' here. Can we follow that standard rather than =
invent our own? Or at least support both?
> gpios =3D <&gpio 17 2 0
> &gpio 21 2 0>;
> scl =3D <0>;
> sda =3D <1>;
Linux doesn't have these at all, it seems, since they are implicit in =
the gpios property. It would be ideal if the scl and sda properties were =
optional...
In addition, you'll often see things like:
i2c-gpio,sda-open-drain;
i2c-gpio,scl-open-drain;
i2c-gpio,delay-us =3D <2>;
as well. These should be easy enough to add and shouldn't gate things.
There's also many DTS files that don't have this as a direct child of =
gpio... But that's not strictly required. I'll cope with adding support =
for that when I get the Atmel stuff working...
> lm750 {
> compatible =3D "lm75";
> i2c-address =3D <0x4b>;
> };
> lm751 {
> compatible =3D "lm75";
> i2c-address =3D <0x4f>;
> };
> };
> };
>=20
> gpioled(4) devices can be described in two ways:
>=20
> - directly under the GPIO controller node:
>=20
> gpio {
>=20
> led0 {
> compatible =3D "gpioled";
cool.
> gpios =3D <&gpio 16 2 0>;
> label =3D "ok";
> };
>=20
> led1 {
> compatible =3D "gpioled";
> gpios =3D <&gpio 17 2 0>;
> name =3D "user-led1";
> };
> };
>=20
> - Or under a single =93gpio-leds=94 node:
This follows Linux convention, which is cool...
> leds {
> compatible =3D "gpio-leds";
>=20
> led1 {
> gpios =3D <&GPIO 53 2 0>;
> name =3D "led1";
> };
>=20
> led2 {
> gpios =3D <&GPIO 54 2 0>;
> name =3D "led2";
> };
> };
>=20
>=20
> gpioiic(4) and gpioled(4) man pages were updated to cover FDT/OFW =
based systems.
Cool.
> =46rom the latest patchset (published on freebsd-arch@ and =
freebsd-arm@) i removed the check for disabled devices on DTS as this =
seems to indicate that the device needs special attention but should not =
be skipped at attach time.
>=20
> Please let me know if there are problems or concerns with the =
following changes.
I'll have to look at these in detail
> Thanks,
> Luiz
>=20
> =
<001-ofw-gpiobus.diff><002-iicbb-ofw-iicbus.diff><003-ofw-gpio-man.diff><0=
04-gpio-node.diff><005-bbb-gpioled.diff>__________________________________=
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