Opened 7 years ago
Last modified 4 years ago
#9514 new defect
Device /dev/gpio not created
Reported by: | Nicolas Le Falher <n.lefalher@…> | Owned by: | developers |
---|---|---|---|
Priority: | normal | Milestone: | Barrier Breaker 14.07 |
Component: | packages | Version: | Trunk |
Keywords: | gpio_dev | Cc: | 27114 |
Description
On platform RDC/Bifferboard device /dev/gpio is not created.
root@OpenWrt:/# uname -a Linux OpenWrt 2.6.32.33 #1 Mon Jun 6 19:45:15 CEST 2011 i486 GNU/Linux root@OpenWrt:/# dmesg | grep gpio rdc321x-gpio rdc321x-gpio: registering 58 GPIOs root@OpenWrt:/# lsmod | grep gpio_dev gpio_dev 1012 0 root@OpenWrt:/# gpioctl set 1 Error whilst opening /dev/gpio root@OpenWrt:/# ls /dev/ | grep gpio root@OpenWrt:/#
Regards.
Attachments (0)
Change History (5)
comment:1 Changed 7 years ago by florian
comment:2 Changed 7 years ago by Nicolas Le Falher <n.lefalher@…>
It's just for know why it not work, and no rewrite some code to sysfs.
I read on a ticket gpio dev was three time faster than gpio sysfs.
But if now gpio_dev is deprecated, and the new standard is sysfs for manage gpio, I think I must switch on it.
comment:3 follow-up: ↓ 4 Changed 7 years ago by florian
In any case, if you need to quickly toggle some GPIOs, you will have to write a kernel module to do that, otherwise, the cost of the context switch and such will dramatically slown down the gpio toggling. gpioctl/kmod-gpio-dev are fast because the command is received from user-space and the toggling is done in kernel.
comment:4 in reply to: ↑ 3 Changed 6 years ago by anonymous
Replying to florian:
In any case, if you need to quickly toggle some GPIOs, you will have to write a kernel module to do that, otherwise, the cost of the context switch and such will dramatically slown down the gpio toggling. gpioctl/kmod-gpio-dev are fast because the command is received from user-space and the toggling is done in kernel.
Yes, I agree with you, sysfs would be slower than the gpioctl
comment:5 Changed 4 years ago by jow
- Milestone changed from Attitude Adjustment 12.09 to Barrier Breaker 14.07
Milestone Attitude Adjustment 12.09 deleted
ok, I see why this does not work, the platform_device is not created, what is wrong with using sysfs gpio like I proposed first? There is nothing it cannot do that gpioctl does, besides, gpio_dev is a non standard interface to driving gpios.