Re: [PATCH 2/2] vfio: platform: Add generic DT reset support

From: Philipp Zabel
Date: Thu Feb 22 2018 - 04:36:20 EST


Hi Geert,

On Thu, 2018-02-22 at 09:50 +0100, Geert Uytterhoeven wrote:
[...]
> > > @@ -127,8 +134,15 @@ static int vfio_platform_get_reset(struct vfio_platform_device *vdev)
> > > vdev->of_reset = vfio_platform_lookup_reset(vdev->compat,
> > > &vdev->reset_module);
> > > }
> > > + if (vdev->of_reset)
> > > + return 0;
> > > +
> > > + vdev->reset_control = __of_reset_control_get(vdev->device->of_node,
> > > + NULL, 0, false, false);
> > > + if (!IS_ERR(vdev->reset_control))
> > > + return 0;
> >
> > if you assign to a local variable first here:
> >
> > struct reset_control *rstc;
> >
> > ...
> >
> > rstc = of_reset_control_get_exclusive(vdev->device->of_node, NULL);
> > if (!IS_ERR(rstc)) {
> > vdev->reset_control = rstc;
> > return 0;
> > }
> >
> > Also, please don't use __of_reset_control_get directly.
>
> OK, apparently I didn't read <linux/reset.h> beyond the first #else...

I don't blame you, this is missing some documentation.

> > > @@ -217,6 +233,9 @@ static int vfio_platform_call_reset(struct vfio_platform_device *vdev,
> > > } else if (vdev->of_reset) {
> > > dev_info(vdev->device, "reset\n");
> > > return vdev->of_reset(vdev);
> > > + } else if (!IS_ERR_OR_NULL(vdev->reset_control)) {
> > > + dev_info(vdev->device, "reset\n");
> > > + return reset_control_reset(vdev->reset_control);
> >
> > } else {
> > if (vdev->reset_control)
> > dev_info(vdev->device, "reset\n");
> > return reset_control_reset(vdev->reset_control);
> >
> > > }
>
> I'd like to keep the "else if", as that's the pattern used by the blocks above.

my bad, there's more code after this.

} else if (vdev->reset_control) {
dev_info(vdev->device, "reset\n");
return reset_control_reset(vdev->reset_control);
}

is better as it doesn't lose the warning if vdev->reset_control == NULL.
It seems I've focused too much on getting rid of the IS_ERR_OR_NULL
macro.

regards
Philipp