Re: How to I2C in RPi3B+ (also gpioiic) ?

["Dr. Nicola Mingotti" <nmingotti%gmail.com@localhost>]

I peeked into the code you linked, it is very clean.

Also extra info you provided is valuable.

thanks

n.


On Wed-10-Jul-2024 19:49, Michael van Elst wrote:
> nmingotti%gmail.com@localhost ("Dr. Nicola Mingotti") writes:
>
> > 1. Is anybody able to get some form of I2C to work ?
> yes.
>
> http://cdn.netbsd.org/pub/NetBSD/misc/mlelstv/antipasti2.jpg
>
> shows an RPI0W driving two I2C devices, a CO2 sensor from Sensirion
> and an OLED display.
>
> http://cdn.netbsd.org/pub/NetBSD/misc/mlelstv/scd30.tgz
>
> has the C source of the program running.
>
> > 2. Does it exist a command similar to i2cget in NetBSD to query
> > Â Â  directly a device via shell ? Otherwise, is there a code
> > Â Â  snipped around I can start from to get the same thing in C ?
> There is no such command in base.
>
> man 4 iic shows the device ioctls that are used to send or receive
> data.
>
> The standard DTB has 3 I2C controllers enabled, but only one
> (i2c@7e804000) is supposed to be used and configured on GPIO.
>
> When all 3 I2C controllers are enabled that "good" controller
> should be /dev/iic2.
>
>
> > 3. using gpioiic the widget was recognized and it seems
> > Â Â  the device dsrtc0 was created (I guess a driver was found) but
> > .. Where is it ? I don't see it in /dev/
> > .. How do I use that device dsrtc0 ?
> That device has no interface to userland, the driver attaches to
> the todr(9) routines to provide a time-of-day clock to the kernel.
> You can read it with gettimeofday() or set it with settimeofday().