Re: [PATCH V6 1/5] LIB: Indirect ISA/LPC port IO introduced

From: Bjorn Helgaas
Date: Mon Jan 30 2017 - 19:10:18 EST

On Tue, Jan 24, 2017 at 03:05:21PM +0800, zhichang.yuan wrote:
> Low-pin-count interface is integrated into some SoCs. The accesses to those
> peripherals under LPC make use of I/O ports rather than the memory mapped I/O.
> To drive these devices, this patch introduces a method named indirect-IO.

It's slightly confusing to call this "indirect I/O" and then use
"extio" for the filename and function prefix. It'd be nice to use
related names.

> +struct extio_node {
> + unsigned long bus_start; /* bus start address */
> + unsigned long io_start; /* io port token corresponding to bus_start */
> + size_t range_size; /* size of the extio node operating range */
> + struct fwnode_handle *fwnode;
> + struct list_head list;
> + struct extio_ops *ops; /* ops operating on this node */
> + void *devpara; /* private parameter of the host device */
> +};

I wish we didn't have both struct io_range and struct extio_node. It
seems like they're both sort of trying to do the same thing. Maybe
this is the same as what Alex is saying.