# Re: \[RFC PATCH net-next v2 02/17\] net: mdio: ipq8064: switch to write/readl function

- From: Ansuel Smith \<ansuelsmth@gmail.com\>
- Date: 2021-05-03 14:24:52 
- List: netdev
- Page: https://ratatoskr.run/netdev/2021/05/6356235
- Thread: https://ratatoskr.run/netdev/2021/05/6355847/t.md

```text
On Mon, May 03, 2021 at 02:49:34PM +0200, Andrew Lunn wrote:
> On Mon, May 03, 2021 at 01:06:54AM +0200, Ansuel Smith wrote:
> > Use readl/writel function instead of regmap function to make sure no
> > value is cached and align to other similar mdio driver.
> 
> regmap is O.K. to use, so long as you tell it not to cache. Look at
> how to use volatile in regmap.
> 
> You might be able to follow what lan9303_mdio.c is doing.
> 
>     Andrew

Was thinking more about the overhead of using regmap instead of plain
writel. Or is it minimal?

```