Re: ADS1256 SPI driver for Raspberry Pi

[Vladimir Toutain <vladimir.toutain@xxxxxxxxxxxxxxxxxxxxxxxxx>]

Thank you for your quick answer.

IIO drivers look like what I need to develop. 

However I still have some questions:

    I found this driver https://github.com/raspberrypi/linux/blob/rpi-3.18.y/drivers/iio/adc/ti-adc128s052.c and then tried to find the corresponding DT overlay without success.
    . Is it then loaded just like a module? How does the subsystem know which GPIO pins are used by this driver?
    . Is it correct to use
           line 37     "ret = spi_write(adc->spi, &adc->buffer, 2);"
      to send commands to the ADC by filling adc->buffer with these commands?

Thanks,


Vladimir TOUTAIN 

Promotion 2016 département IR 
Grenoble INP - Esisar

----- Mail original -----
De: "Martin Sperl" <kernel@xxxxxxxxxxxxxxxx>
À: "Vladimir Toutain" <vladimir.toutain@xxxxxxxxxxxxxxxxxxxxxxxxx>
Cc: linux-spi@xxxxxxxxxxxxxxx
Envoyé: Mercredi 27 Mai 2015 15:02:36
Objet: Re: ADS1256 SPI driver for Raspberry Pi

> Any help would be much appreciated !

You would probably want to look at the drivers in drivers/iio/adc 
(and the staging drivers in drivers/staging/iio/adc)
and take one as an example for your development - maybe on is even
sufficiently compatible to your ADS1256, so that you only need to
extend the compatibility list.

To activate it instead of the default spi-dev create a device-overlay
similar to this one:
https://github.com/raspberrypi/linux/blob/rpi-3.18.y/arch/arm/boot/dts/ads7846-overlay.dts
compile it and reference it in /boot/config.txt
(here some more info on the overlays: https://www.raspberrypi.org/documentation/configuration/device-tree.md)

As for how to use those drivers from user-space here an introduction
to the iio framework (kernel and user-space):
https://archive.fosdem.org/2012/schedule/event/693/127_iio-a-new-subsystem.pdf
--
To unsubscribe from this list: send the line "unsubscribe linux-spi" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html