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Date:      Thu, 19 Sep 2013 10:00:57 -0300
From:      Luiz Otavio O Souza <lists.br@gmail.com>
To:        fabiodive <fabiodive@gmail.com>
Cc:        "freebsd-arm@FreeBSD.org" <freebsd-arm@freebsd.org>
Subject:   Re: SPI device on Raspberry PI
Message-ID:  <CAB=2f8x=T7u_mgAUDbDx2z3t%2BoW6w2oyKLutaFUBrxVT6NQQ3g@mail.gmail.com>
In-Reply-To: <935B7003-F750-42E7-9100-C27028B6A111@gmail.com>
References:  <935B7003-F750-42E7-9100-C27028B6A111@gmail.com>

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On 17 September 2013 19:00, fabiodive <fabiodive@gmail.com> wrote:

> Hello Luiz,
>
> I was able to use your patches on Raspberry PI,
> I builded an image with crochet and this is my dmesg output:
>
>
> [...]
>
> Now.. I see the GPIO device and iic as well but what about SPI?
> Should I create the device or just use GPIO?
> Any ideas?
>
>
The devices you see for gpio and iic are used to control (or read and write
data) from userland and actually there is no such support for SPI.

I've plans to write an userland tool similar to i2c(8) for SPI together
with some other pending work i've for SPI.

But until it happens you need a kernel driver for the SPI device you want
to use:

spi0: <BCM2708/2835 SPI controller> mem 0x20204000-0x2020401f irq 62 on
simplebus0
spibus0: <OFW SPI bus> on spi0
mx25l0: <M25Pxx Flash Family> at cs 0 on spibus0
enc28j600: <enc28j60 Microchip SPI Ethernet controller> at cs 1 on spibus0

And the bindings also need to be described in the rpi dts file, i.e. in my
case:

                spi0 {
                        flash0 {
                                compatible = "flash,mx25l";
                                spi-chipselect = <0>;
                        };

                        enc28j600 {
                                compatible = "ethernet,enc28j60";
                                spi-chipselect = <1>;
                        };
                };

Thanks for your feedback.

Luiz



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