Hi,
I’m just playing around with iio dummy drivers and couldn’t get it work with kernel 4.9 while everything was fine with
kernel 4.4.
Steps for kernel 4.4:
* edit Kconfig to create IIO_SIMPLE_DUMMY module
* build and install kernel
* edit /etc/modules to load iio_dummy
* after reboot there is an iio_dummy module loaded and the device appears in sysfs
Steps for kernel 4.9:
* edit Kconfig to create IIO_SW_DEVICE, IIO_SIMPLE_DUMMY, IIO_SIMPLE_DUMMY_BUFFER modules
* build and install kernel
* edit /etc/modules to load iio_dummy
* after reboot there is an iio_dummy module loaded but doesn’t appear in sysfs
Is there something wrong with the order, loading modules or do I miss some dependencies?
Thanks,
Franziska
Here are some more detailed information, as first kernel 4.4, then 4.9:
Linux raspberrypi-3 4.4.50-v7+ #1 SMP Fri Jun 2 00:19:42 CEST 2017 armv7l GNU/Linux
---
pi@raspberrypi-3:~/projects $ cat /etc/modules
# /etc/modules: kernel modules to load at boot time.
#
# This file contains the names of kernel modules that should be loaded
# at boot time, one per line. Lines beginning with "#" are ignored.
iio_dummy
---
pi@raspberrypi-3:~/projects/raspi-linux $ git diff drivers/staging/iio/Kconfig
diff --git a/drivers/staging/iio/Kconfig b/drivers/staging/iio/Kconfig
index 9d7f000..42d03a3 100644
--- a/drivers/staging/iio/Kconfig
+++ b/drivers/staging/iio/Kconfig
@@ -23,6 +23,7 @@ config IIO_DUMMY_EVGEN
config IIO_SIMPLE_DUMMY
tristate "An example driver with no hardware requirements"
+ default y
help
Driver intended mainly as documentation for how to write
a driver. May also be useful for testing userspace code
---
pi@raspberrypi-3:~/projects $ lsmod
Module Size Used by
bnep 10340 2
hci_uart 17943 1
btbcm 5929 1 hci_uart
bluetooth 326067 22 bnep,btbcm,hci_uart
brcmfmac 186282 0
brcmutil 5661 1 brcmfmac
cfg80211 428833 1 brcmfmac
rfkill 16018 4 cfg80211,bluetooth
snd_bcm2835 20447 0
snd_pcm 75890 1 snd_bcm2835
snd_timer 19288 1 snd_pcm
bcm2835_gpiomem 2976 0
snd 51908 3 snd_bcm2835,snd_timer,snd_pcm
bcm2835_wdt 3225 0
uio_pdrv_genirq 3164 0
uio 8000 1 uio_pdrv_genirq
iio_dummy 3072 0
industrialio 33826 1 iio_dummy
ipv6 347563 32
---
pi@raspberrypi-3:/sys/bus/iio/devices/iio:device0 $ ll
insgesamt 0
drwxr-xr-x 3 root root 0 Jun 4 13:42 .
drwxr-xr-x 10 root root 0 Jun 4 13:42 ..
-r--r--r-- 1 root root 4,0K Jun 4 13:42 dev
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_accel_x_calibbias
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_accel_x_calibscale
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_accel_x_raw
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_activity_running_input
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_activity_walking_input
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_sampling_frequency
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_steps_calibheight
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_steps_en
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_steps_input
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_voltage0_offset
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_voltage0_raw
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_voltage0_scale
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_voltage1-voltage2_raw
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_voltage3-voltage4_raw
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 in_voltage-voltage_scale
-r--r--r-- 1 root root 4,0K Jun 4 13:42 name
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 out_voltage0_raw
drwxr-xr-x 2 root root 0 Jun 4 13:42 power
lrwxrwxrwx 1 root root 0 Jun 4 13:42 subsystem -> ../../bus/iio
-rw-r--r-- 1 root root 4,0K Jun 4 13:42 uevent
-------------------------------------------------------------------------------------------------------------------------
Linux raspberrypi-3 4.9.30-v7+ #1 SMP Sun Jun 4 21:07:31 CEST 2017 armv7l GNU/Linux
---
/etc/modules -> is the same
---
pi@raspberrypi-3:~/projects/raspi-linux $ git diff drivers/iio/Kconfig
diff --git a/drivers/iio/Kconfig b/drivers/iio/Kconfig
index 6743b18..e804f63 100644
--- a/drivers/iio/Kconfig
+++ b/drivers/iio/Kconfig
@@ -49,6 +49,7 @@ config IIO_CONSUMERS_PER_TRIGGER
config IIO_SW_DEVICE
tristate "Enable software IIO device support"
select IIO_CONFIGFS
+ default y
help
Provides IIO core support for software devices. A software
device can be created via configfs or directly by a driver
---
pi@raspberrypi-3:~/projects/raspi-linux $ git diff drivers/iio/dummy/Kconfig
diff --git a/drivers/iio/dummy/Kconfig b/drivers/iio/dummy/Kconfig
index aa5824d..1eb7991 100644
--- a/drivers/iio/dummy/Kconfig
+++ b/drivers/iio/dummy/Kconfig
@@ -11,6 +11,7 @@ config IIO_DUMMY_EVGEN
config IIO_SIMPLE_DUMMY
tristate "An example driver with no hardware requirements"
depends on IIO_SW_DEVICE
+ default y
help
Driver intended mainly as documentation for how to write
a driver. May also be useful for testing userspace code
@@ -29,6 +30,7 @@ config IIO_SIMPLE_DUMMY_BUFFER
select IIO_BUFFER
select IIO_TRIGGER
select IIO_KFIFO_BUF
+ default y
help
Add buffered data capture to the simple dummy driver.
---
pi@raspberrypi-3:~/projects/raspi-linux $ lsmod
Module Size Used by
bnep 12051 2
hci_uart 20020 1
btbcm 7916 1 hci_uart
bluetooth 365473 22 hci_uart,bnep,btbcm
brcmfmac 222798 0
brcmutil 9092 1 brcmfmac
cfg80211 542989 1 brcmfmac
rfkill 20832 4 bluetooth,cfg80211
snd_bcm2835 24427 0
snd_pcm 98565 1 snd_bcm2835
snd_timer 23904 1 snd_pcm
bcm2835_gpiomem 3940 0
snd 70032 3 snd_timer,snd_bcm2835,snd_pcm
uio_pdrv_genirq 3923 0
fixed 3285 0
uio 10268 1 uio_pdrv_genirq
iio_dummy 4984 0
industrialio_sw_device 3691 1 iio_dummy
industrialio_configfs 1370 1 industrialio_sw_device
kfifo_buf 3668 1 iio_dummy
industrialio 62929 2 iio_dummy,kfifo_buf
ipv6 408530 32
---
pi@raspberrypi-3:/sys/bus/iio/devices $ ll
insgesamt 0
drwxr-xr-x 2 root root 0 Jun 5 15:33 .
drwxr-xr-x 4 root root 0 Jun 5 15:33 ..
--
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