Re: [PATCH v5 2/2] mailbox: mediatek: Add mtk-vcp-mailbox driver

Jassi Brar
2025-09-19T16:32:33Z

On Fri, Sep 19, 2025 at 3:31 AM Chen-Yu Tsai <wenst@chromium.org> wrote:
>
> On Fri, Sep 19, 2025 at 7:50 AM Jassi Brar <jassisinghbrar@gmail.com> wrote:
> >
> > On Thu, Aug 21, 2025 at 9:12 PM Jjian Zhou <jjian.zhou@mediatek.com> wrote:
> >
> > .....
> >
> > > +#include <linux/module.h>
> > > +#include <linux/of.h>
> > > +#include <linux/platform_device.h>
> > > +#include <linux/slab.h>
> > > +
> > > +struct mtk_vcp_mbox_priv {
> > Maybe 'mtk_vcp_mbox' is a more appropriate name ?
> >
> > > + void __iomem *base;
> > > + struct device *dev;
> > > + struct mbox_controller mbox;
> > > + const struct mtk_vcp_mbox_cfg *cfg;
> > > + struct mtk_ipi_info ipi_recv;
> >
> > Maybe also have "struct mbox_chan chan[1]; " so that you don't have to
> > allocate one during the probe.
>
> > Also if you have "struct mbox_controller mbox;" as the first member,
> > you could simply typecast that to get this structure.
> > Something like "struct mpfs_mbox" in mailbox-mpfs.c
>
> I read somewhere that this way of subclassing is not recommended.
> Instead the base class should explicitly not be the first member.
> And then container_of() should be used.
>
> I don't remember where I read this though. But I think the explicit
> container_of() is easier for understanding the intent.
>
And how does container_of() work ? :)
typcasting the first member to its parent is the simplest form of container_of.

-j