On Tue, Dec 10, 2024 at 07:31:26PM +0800, Hui Wang wrote:
Recently we found the fifo_read() and fifo_write() are broken in our 5.15 and 5.4 kernels after cherry-pick the commit e635f652696e ("serial: sc16is7xx: convert from _raw_ to _noinc_ regmap functions for FIFO"), that is because the reg needs to shift if we don't cherry-pick a prerequisite commit 3837a0379533 ("serial: sc16is7xx: improve regmap debugfs by using one regmap per port").
It is hard to backport the prerequisite commit to 5.15.y and 5.10.y due to the significant conflict. To be safe, here fix it by shifting the reg as regmap_volatile() does.
Please try, submit the series of upstream commits first and then if it's too rough, we can evaluate it later. As-is, I can't take this, sorry.
greg k-h