Re: I cannot make i2c work in raspberry pi Zero W

[Ramiro Aceves <ea1abz%gmail.com@localhost>]

Hello Brad,

El 7/7/24 a las 20:40, Brad Spencer escribió:
> ...
>...
> All of the above is probably fine, assuming that the i2c bus is found.
> I am not familiar with using that particular dtparam line... and don't
> have a RPI0W.  I have never needed anything to enable i2c on the RPI.
> You will have to use an overlay to enable SPI..  Be aware that the Linux
> overlays (nearly every one of the found on the Internet) probably won't
> work with NetBSD.
>
> > But the result is the same. Am I missing something?
>
> Ya...  just load the driver ... i.e. put bmx280thp and bmx280thpi2c in
> /etc/modules.conf and do modules=YES in /etc/rc.conf and reboot (you can
> probably get away with bmx280thpi2c, as the main driver should be a
> dependent module and if you have auto loading enabled, it should
> load... but you can load it yourself too).  Or... compile up a custom
> kernel with the additional config lines you need.. See bmx280thp(4) for
> examples of that.

I greatly appreciate your email with the precise instructions to follow. 
NetBSD community help is marvelous. It is a pleasure to have many expert 
people ready to help the mediocre users!

Sensor is working fine following your guidelines!

netbsd-raspaZeroW$ cat /etc/modules.conf
bmx280thp
bmx280thpi2c


netbsd-raspaZeroW$ cat /etc/rc.conf |grep module
modules=YES


netbsd-raspaZeroW$ envstat
                 Current  CritMax  WarnMax  WarnMin  CritMin  Unit
[bmx280thp0]
  temperature:    28.260                                      degC
     pressure:   929.880                                       hPa
[vcmbox0]
  temperature:    47.078   85.000                             degC
netbsd-raspaZeroW$

Thank you very much for all!

Regards.
Ramiro.



> In the first case, simply loading the drivers, the driver will probe the
> i2c bus for something at i2c address 0x76 and 0x77 and see if it is a
> BMP280 or BME280.  If so, the driver will attach.  If your chip is at
> another address, you will have to use the second way and compile a
> kernel telling it what address the chip is at.  It would be unusual for
> your chip to NOT be at 0x76 or 0x77.
>
> You may also be able to speak to the chip using SPI if the breakout
> board you have brought out the SPI pins.  To do that, wire your board up
> as a SPI device and enable SPI for your RPI device.  This may require an
> device tree overlay.  Then compile a kernel with the needed config
> lines..  see bmx280thp(4) for examples of this.  There are no modules
> for SPI.
>
> The BM[PE]280 should work just fine on gpioiic (the bitbanger i2c bus
> using gpio pins) too...  just make sure you add pull up resisters to the
> SDA and SCL lines.  See gpioiic(4) and gpioctl(8) for examples of how to
> attach gpioiic to gpio pins.
>
> > Thanks so much.
> > Ramiro.
>
>
> I wrote the BM[PE]280 driver and use one all of the time on a RPI0 with
> NetBSD 10.x (and 9.x before that).