Re: [PATCH v7 2/2] soc: mediatek: add mt6779 devapc driver

[Matthias Brugger]

On 08/10/2020 11:39, Neal Liu wrote:
> On Thu, 2020-10-08 at 10:45 +0200, Matthias Brugger wrote:
> > On 08/10/2020 04:35, Neal Liu wrote:
> > > On Wed, 2020-10-07 at 12:44 +0200, Matthias Brugger wrote:
> > > > On 27/08/2020 05:06, Neal Liu wrote:
[...]

> > > > > +static int mtk_devapc_probe(struct platform_device *pdev)
> > > > > +{
> > > > > +	struct device_node *node = pdev->dev.of_node;
> > > > > +	struct mtk_devapc_context *ctx;
> > > > > +	u32 devapc_irq;
> > > > > +	int ret;
> > > > > +
> > > > > +	if (IS_ERR(node))
> > > > > +		return -ENODEV;
> > > > > +
> > > > > +	ctx = devm_kzalloc(&pdev->dev, sizeof(*ctx), GFP_KERNEL);
> > > > > +	if (!ctx)
> > > > > +		return -ENOMEM;
> > > > > +
> > > > > +	ctx->data = of_device_get_match_data(&pdev->dev);
> > > > > +	ctx->dev = &pdev->dev;
> > > > > +
> > > > > +	ctx->infra_base = of_iomap(node, 0);
> > > >
> > > > Does this mean the device is part of the infracfg block?
> > > > I wasn't able to find any information about it.
> > >
> > > I'm not sure why you would ask infracfg block. devapc is parts of our
> > > SoC infra, it's different with infracfg.
> >
> > I'm asking because I want to understand the HW better. I'm not able to find any
> > information in the datasheets. I want to avoid a situation as we had with the
> > MMSYS where a clock driver was submitted first and later on we realized that
> > MMSYS is much more then that and we had to work hard to get the driver right.
> >
> > Now it's happening with SCPSYS, where a driver with the scpsys compatible was
> > send years ago. But SCPSYS is much more then the driver submitted. In this case
> > we opted to write a new driver, but moving from one driver to another one is
> > painfull and full of problems. For that I want to make sure we fully understand
> > Device APC (by the way, what does APC stands for?). Is it a totally independent
> > HW block or is it part of a subsystem, like for example SCP?
> >
> > Regards,
> > Matthias
>
> It's a totally independent HW block instead of a subsystem.
> I think it's more simple than MMSYS or SCPSYS. But if you would like to
> understand more about this HW, we could find another way/channel to
> introduce it.

If it's a independent HW block, then we are good. No further information needed 
by me. I'd just advise to rename the infra_base to something like base, as it 
made me confuse.

Thanks!
Matthias