On Sat, Feb 15, 2020 at 02:58:24PM +0800, Chuanhong Guo wrote:

> To keep patchset small for easier reviewing, there will be 3 patchsets
> including this one.
> 1. add the new driver, which is this patchset.
> 2. update existing dts for the new driver:
>    spi-max-frequency is missing in current mtk-quadspi binding. Old
>    driver parses child node manually so it doesn't need this, but
>    new spi-mem driver is probed via spi subsystem which requires the
>    presence of spi-max-frequency. Since this doesn't break old driver
>    support, I'll send this separately as a standalone patch.

This is an ABI break so you shouldn't be doing this, if the existing
binding works it should continue to work.

> 3. removing the old driver. I'll create this commit after 1 and 2 are
>    applied to avoid possible rebasing due to any changes in the old
>    driver.

This isn't great as it means we have a period with two drivers for the
same thing in tree which is at best going to be confusing.  There's no
advantage to splitting this out.