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SubjectRe: [PATCH] bus: imx-weim: add DT overlay support for WEIM bus
On Mon, Feb 21, 2022 at 11:02:44AM +0300, Ivan Bornyakov wrote:
> On Mon, Feb 21, 2022 at 03:25:29PM +0800, Shawn Guo wrote:
> > On Sat, Feb 05, 2022 at 08:50:06AM +0300, Ivan Bornyakov wrote:
> > > Add OF reconfiguration notifier handler for WEIM bus to setup Chip
> > > Select timings on runtime creation of child devices.
> > >
> > > However, it is not possible to load another DT overlay with conflicting
> > > CS timings with previously loaded overlay, even if the first one is
> > > unloaded.
> >
> > Are we doing anything if that happens?
> >
>
> On device removal there is no access to device node properties, thus it
> is not possible to find out which of CS timings was configured for this
> device to clear theirs 'is_applied'.
>
> So, if we apply one DT overlay, configure some CS timings, remove this
> overlay, apply another with conflicting timings, we will fail here
>
> static int weim_timing_setup(...)
> {
> ...
>
> for (reg_idx = 0; reg_idx < num_regs; reg_idx++) {
> ...
>
> /* prevent re-configuring a CS that's already been configured */
> cst = &ts->cs[cs_idx];
> if (cst->is_applied && memcmp(value, cst->regs,
> devtype->cs_regs_count * sizeof(u32))) {
> dev_err(dev, "fsl,weim-cs-timing conflict on %pOF", np);
> return -EINVAL;
> }
> ...
> }
> ...
> }

Ah, right, thanks for clarifying, Ivan!

Shawn

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