Date: Tue, 11 Feb 2014 17:10:05 -0200 From: Luiz Otavio O Souza <loos.br@gmail.com> To: Warner Losh <imp@bsdimp.com> Cc: freebsd-arm@freebsd.org, freebsd-embedded@freebsd.org Subject: Re: FDT/OFW GPIO bus Message-ID: <9090D088-8F3C-494F-8F41-AA8A16361CB2@gmail.com> In-Reply-To: <C8E49E48-F575-466F-8036-8E57CC025ADE@bsdimp.com> References: <2D5F2707-FD55-46BB-A44F-8870B48E2BB1@gmail.com> <C8E49E48-F575-466F-8036-8E57CC025ADE@bsdimp.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Feb 7, 2014, at 1:21 AM, Warner Losh wrote:
>=20
> On Feb 6, 2014, at 11:53 AM, Luiz Otavio O Souza wrote:
[=85]
>>=20
>> gpioiic(4) devices can be described in DTS as follow:
>>=20
>> gpio {
>>=20
>> gpioiic {
>> compatible =3D "gpioiic";
>=20
> Linux uses 'i2c-gpio' here. Can we follow that standard rather than =
invent our own? Or at least support both?
Sure, no problem.
>=20
>> gpios =3D <&gpio 17 2 0
>> &gpio 21 2 0>;
>> scl =3D <0>;
>> sda =3D <1>;
>=20
> 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=85
They are optional and only needed when you want to change the default =
setting (scl =3D 0 and sda =3D 1 - yes, in this example they are just a =
no op).
>=20
> In addition, you'll often see things like:
>=20
> i2c-gpio,sda-open-drain;
> i2c-gpio,scl-open-drain;
> i2c-gpio,delay-us =3D <2>;
>=20
> as well. These should be easy enough to add and shouldn't gate things.
Right, ATM gpioiic(4) is coded as an open collector/drain for both SCL =
and SDA as per standard. The delay option should be added.
>=20
> 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...
>=20
>> lm750 {
>> compatible =3D "lm75";
>> i2c-address =3D <0x4b>;
>> };
>> lm751 {
>> compatible =3D "lm75";
>> i2c-address =3D <0x4f>;
>> };
>> };
>> };
I see. I found a DTS from Atmel and i=92ll add support for that.
Thank you for point that out.
Luiz=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?9090D088-8F3C-494F-8F41-AA8A16361CB2>