Realtek RTS525A SD card reader

[Eric van Gyzen]

Is anyone working on a FreeBSD driver for the Realtek RTS525A SD card
reader?  My new Dell XPS 13 has one:

none7 at pci0:59:0:0: class=0xff0000 card=0x075b1028 chip=0x525a10ec
rev=0x01 hdr=0x00
vendor = 'Realtek Semiconductor Co., Ltd.'
device = 'RTS525A PCI Express Card Reader'

I see that the OpenBSD rtsx driver supports it:

https://github.com/openbsd/src/commit/2c295edd2d779a7f5269c2ae901559edbf040016

I don't know anything about SD/MMC devices and standards, and I'm not
familiar with FreeBSD's current SD/MMC code, but I think it would be fun
to learn.  Does it make sense to try porting this driver, or would
someone recommend a different approach?

Thanks in advance for any advice.

Eric