Messages in this thread | | | From | Linus Walleij <> | Date | Thu, 1 Jun 2023 19:11:10 +0200 | Subject | Re: [PATCH v2 4/5] hwmon: (gxp_fan_ctrl) Provide fan info via gpio |
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On Thu, Jun 1, 2023 at 5:48 PM Hawkins, Nick <nick.hawkins@hpe.com> wrote:
> Thank you for your valuable feedback with the solutions you have provided. > Before I proceed though I have a quick query about the fan driver. > If I were to let the user space "own" gpio pins, would it be permissible for > the userspace to feed a kernel driver data via sysfs? > > Ex: > GPIO Driver -> (OpenBMC) -> Fandriver (sysfs). > > Here the GPIO driver would provide fan presence information to OpenBMC > and then OpenBMC would provide fan presence info to the fan driver.
But why? Don't be so obsessed about userspace doing stuff using sysfs, usually it is a better idea to let the kernel handle hardware.
I think this is a simple thermal zone you can define in the device tree as indicated in my previous comment.
> If it were permissible to provide data to the driver via this method I could > apply it to the PSU driver as well. the PSU driver which requires presence > info to verify a PSU is inserted / removed.
It feels like you are looking for a way for two drivers to communicate with each other.
This can be done several ways, the most straight-forward is notifiers. include/linux/notifier.h
Yours, Linus Walleij
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