Re: [PATCH] pinctrl: baytrail: show output gpio state correctly on Intel Baytrail

David Cohen
2014-10-31T16:22:56Z

On Fri, Oct 31, 2014 at 08:20:05AM -0500, Felipe Balbi wrote:
> Hi,
>
> On Fri, Oct 31, 2014 at 09:12:16AM +0100, Linus Walleij wrote:
> > On Tue, Oct 28, 2014 at 3:42 PM, Felipe Balbi <balbi@ti.com> wrote:
> > > On Tue, Oct 28, 2014 at 11:15:20AM +0100, Linus Walleij wrote:
> > >> On Mon, Oct 13, 2014 at 9:36 PM, Felipe Balbi <balbi@ti.com> wrote:
> > >> > On Mon, Oct 13, 2014 at 02:26:32PM -0500, Felipe Balbi wrote:
> > >>
> > >> > I also noticed that this is missing:
> > >> >
> > >> > diff --git a/drivers/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c
> > >> > index e12e5b0..7db5ab9 100644
> > >> > --- a/drivers/pinctrl/pinctrl-baytrail.c
> > >> > +++ b/drivers/pinctrl/pinctrl-baytrail.c
> > >> > @@ -614,3 +614,9 @@ static int __init byt_gpio_init(void)
> > >> > }
> > >> >
> > >> > subsys_initcall(byt_gpio_init);
> > >> > +
> > >> > +static void __exit byt_gpio_exit(void)
> > >> > +{
> > >> > + platform_driver_unregister(&byt_gpio_driver);
> > >> > +}
> > >> > +module_exit(byt_gpio_exit);
> > >>
> > >> But the Baytrail driver is not a loadable module, it is bool:
> > >>
> > >> config PINCTRL_BAYTRAIL
> > >> bool "Intel Baytrail GPIO pin control"
> > >> depends on GPIOLIB && ACPI && X86
> > >>
> > >> (...)
> > >>
> > >> So I guess it won't need handling for removal, as it can only
> > >> be compiled-in.
> > >
> > > you can still unbind it through sysfs, right ? The thing also already
> > > provides a ->remove() method anyway.
> >
> > Yes you're right of course...
> >
> > But another way to get rid of the dilemma is to set
> > .suppress_bind_attrs = true on the .driver field of the
> > device driver. The one can't unbind it through sysfs anymore.
> >
> > .driver = {
> > .name = "foo",
> > .suppress_bind_attrs = true,
> > },
> >
> > So one of them need to be done.
> >
> > I suspect this is a kind of common problem...
>
> so instead of taking of taking a three-liner which just makes sure this
> can be used as "intended" you prefer to:
>
> diff --git a/drivers/pinctrl/pinctrl-baytrail.c b/drivers/pinctrl/pinctrl-baytrail.c
> index e12e5b0..254ba81 100644
> --- a/drivers/pinctrl/pinctrl-baytrail.c
> +++ b/drivers/pinctrl/pinctrl-baytrail.c
> @@ -587,16 +587,6 @@ static const struct acpi_device_id byt_gpio_acpi_match[] = {
> };
> MODULE_DEVICE_TABLE(acpi, byt_gpio_acpi_match);
>
> -static int byt_gpio_remove(struct platform_device *pdev)
> -{
> - struct byt_gpio *vg = platform_get_drvdata(pdev);
> -
> - pm_runtime_disable(&pdev->dev);
> - gpiochip_remove(&vg->chip);
> -
> - return 0;
> -}
> -
> static struct platform_driver byt_gpio_driver = {
> .probe = byt_gpio_probe,
> .remove = byt_gpio_remove,
> @@ -605,6 +595,7 @@ static struct platform_driver byt_gpio_driver = {
> .owner = THIS_MODULE,
> .pm = &byt_gpio_pm_ops,
> .acpi_match_table = ACPI_PTR(byt_gpio_acpi_match),
> + .suppress_bind_attrs = true,
> },
> };
>
>
> I don't quite care since this is not an architecture I work for, but I
> prefer drivers which can be unbound one way or another. Not to mention
> that there's already a ->remove callback on the platform_driver anyway.

I think adding the module exit + allowing this driver to be a module
would be a good approach. Then we don't need to force generic x86 kernel
binaries to always have this driver. Unless Mathias or Mika knows a
constraint to force this driver to be builtin only.

Br, David

>
> --
> balbi