Re: [PATCH net-next v4 5/8] mfd: zl3073x: Add functions to work with register mailboxes

[Andrew Lunn <andrew@lunn.ch>]

> During taking 613cbb91e9ce ("media: Add MIPI CCI register access helper
> functions") approach I found they are using for these functions u64
> regardless of register size... Just to accommodate the biggest
> possible value. I know about weakness of 'void *' usage but u64 is not
> also ideal as the caller is forced to pass always 8 bytes for reading
> and forced to reserve 8 bytes for each read value on stack.

In this device, how are the u48s used? Are they actually u48s, or are
they just u8[6], for example a MAC address? The network stack has lots
of functions like:

eth_hw_addr_set(struct net_device *dev, const u8 *addr)

and it is assumed that *addr is ETH_ALEN bytes in length. There is no
direct typing checking for this by the compiler, but the compiler is
getting smarter at checking for buffer overruns over function calls.

	Andrew