On Tue, Jun 23, 2026 at 11:59:16AM +0000, Sverdlin, Alexander wrote: > Hi Daniel, > > On Tue, 2026-06-23 at 12:41 +0100, Daniel Thompson wrote: > > > The mechanism we have regarding hot plugging currently is just I2C bridge, > > > which de-registers and registers the bridged bus. So no additional drivers > > > are required, as long as I2C devices are self-contained and not glued with > > > platform devices. > > > > > > So bottom line is, I'd prefer to just add the backlight interface to the > > > existing driver, no matter where it would live in the future. > > > > Is there any reasion that LP8864/LP8866 is unique in appearing on a > > hotplugged I2C bus? In other words if support for dynamism is added > > specifically to leds-lp8864.c rather than in led_bl.c then what will stop > > the same dynamic tricks from being adde to other LED drivers? > > LP8864 is not special in this regard, not different from adp8860_bl.c, > adp8870_bl.c or lm3639_bl.c, which would work in my application.
The most recent of these drivers adopted LED support in 2012 whilst led_bl.c was introduced in 2020. > So I just wanted to add currently missing backlight_device_register() to > LP8864, but there were no such dual-API drivers under drivers/leds/ that's > wht I started with moving LP8864 driver into drivers/video/backlight/. > > led_bl.c however could only be hot-pluggable either if one actively > creates/destroys platform device somewhere in the code programmatically > or uses DT overlays. > > Just adding backlight API to LP8864 would be much more idiomatic, I'd > say. Maybe. I think I might consider the drivers above to be historical anomalies rather than idiomatic examples. Daniel.
