On Wed, Oct 1, 2014 at 1:21 PM, robert.berger
<[email protected]> wrote:
> Hi,
>
> I made another attempt to read some analog values with the 3.14 RCN kernel.
>
> How am I supposed to read analog values?
>
> The only thing which gives something (strange) seems to be a hacked version
> of the generic_buffer test of the iio framwork. Does anyone know what I am
> doing wrong and/or how else to read A/D values? I am thinking about wiring
> via i2c an a/d converter and use this instead of those on board.
>
> root@beaglebone:~# cat /proc/version
> Linux version 3.14.0-custom-student4+ (student4@bh4) (gcc version 4.8.2
> (GCC) ) #1 SMP Tue Sep 30 20:09:53 EEST 2014
>
> + lsmod
> Module                  Size  Used by
> nfc                    56331  0
> bluetooth             232921  2
> 6lowpan_iphc            6182  1 bluetooth
> omap_aes               11951  0
> omap_sham              17071  0
> ti_am335x_adc           4743  0
> kfifo_buf               2517  1 ti_am335x_adc
> industrialio           46758  2 ti_am335x_adc,kfifo_buf
> ti_am335x_tsc           4715  0
> rtc_omap                5240  0
> uio_pdrv_genirq         3258  0
> uio                     8858  1 uio_pdrv_genirq
> gpio_keys               8038  0
> + modprobe iio-trig-sysfs
> + echo 1 > /sys/bus/iio/devices/iio_sysfs_trigger/add_trigger
> we should have a trigger0 folder now
> + ls /sys/bus/iio/devices/
> iio:device0  iio_sysfs_trigger  trigger0
> + cat /sys/bus/iio/devices/trigger0/name
> sysfstrig1
>
> + cat /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage4_en
> 0
> + cat /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage5_en
> 0
> + cat /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage6_en
> 0
> + echo 1 > /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage5_en
> + cat /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage4_en
> 0
> + cat /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage5_en
> 1
> + cat /sys/bus/iio/devices/iio:device0/scan_elements/in_voltage6_en
> 0
>
> ADC Value: 246484699
> ADC Value: 237047412
> ADC Value: 228527626
> ADC Value: 218828111
> ADC Value: 209587410
> ...
>
> I would expect 12 bits out of 16 bits.

How did you enable them in the dts?

I have one example here:

https://github.com/RobertCNelson/dtb-rebuilder/blob/3.14-ti/src/arm/am335x-bone-basic-proto-cape.dtsi

Regards,

-- 
Robert Nelson
http://www.rcn-ee.com/

-- 
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