Hi, Greg KH: 8250 driver means create driver in drivers/tty/8250/ ? and current I create driver in drivers/tty/serial/ not correct ? Regards, Hammer Hsieh Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> 於 2021年12月24日 週五 下午4:59寫道: > > On Fri, Dec 24, 2021 at 03:16:55PM +0800, hammer hsieh wrote: > > Hi, Greg KH : > > > > In patch v1 coding quite mess, it is almost 2000 LOCs. > > For down size code under 1000 LOCs, I decide to drop DMA function code > > after patch v3. > > I think that's the biggest difference compared with 8250. > > Without DMA function, like you said it looks like 8250 variant. > > I think I should put DMA function back in next submit. > > The 8250 driver handles DMA just fine today, why is your chip doing it > differently? Are you sure it is a different chip? Who created a new > uart chip these days? > > > Another question for why I need PORT_SLUNPLUS ? > > I just check many other uart driver, almost all driver define their > > own PORT number. > > Actually, I didn't know about it. > > Maybe some device like bluetooth(use uart port) need autoconfig. > > Then it will call ioctl with TIOCSERCONFIG. > > I don't have tool for calling type/config/request/release/verify. > > If you do not need it, and you can not test for it, please do not add > it. > > thanks, > > greg k-h