On Tue, 29 Apr 2025 Andy Shevchenko wrote: > On Tue, Apr 29, 2025 at 8:02 PM Nam Tran <trannamatk@xxxxxxxxx> wrote: > > On Mon, 28 Apr 2025 Pavel Machek wrote: > > > > On Mon, 28 Apr 2025 Geert Uytterhoeven wrote: > > > > > > > > > > > - Move driver to drivers/auxdisplay/ instead of drivers/leds/. > > > > > > > > - Rename files from leds-lp5812.c/.h to lp5812.c/.h. > > > > > > > > - Move ti,lp5812.yaml binding to auxdisplay/ directory, > > > > > > > > and update the title and $id to match new path. > > > > > > > > - No functional changes to the binding itself (keep Reviewed-by). > > > > > > > > - Update commit messages and patch titles to reflect the move. > > > > > > > > - Link to v7: https://lore.kernel.org/linux-leds/20250422190121.46839-1-trannamatk@xxxxxxxxx/ > > > > > > > > > > > > > > Out of sudden without discussing with auxdisplay maintainers/reviewers? > > > > > > > Thanks, no. > > > > > > > Please, put into the cover letter the meaningful summary of what's > > > > > > > going on and why this becomes an auxdisplay issue. Brief review of the > > > > > > > bindings sounds more likely like LEDS or PWM subsystems. > > > > > > > > > > > > It is 4x3 matrix. That means it is not suitable for LEDs. I don't > > > > > > believe it is suitable for PWM, either -- yes, it is 36 PWM outputs, > > > > > > but... > > > > > > > > > > Is it intended to be used as a 4x3 matrix, or is this just an internal > > > > > wiring detail, and should it be exposed as 12 individual LEDs instead? > > > > > > > > The 4×3 matrix is a real and fundamental aspect of the LP5812’s operation. > > > > It is not just an internal wiring detail. > > > > The device adopts a Time-Cross-Multiplexing (TCM) structure, where 4 output > > > > pins control 12 LED dots individually through scanning. Each pin includes > > > > both high-side and low-side drive circuits, meaning matrix multiplexing is > > > > required for proper operation — it cannot be treated as 12 completely > > > > independent LEDs. > > > > > > Scanning is really a detail. > > > > > > If this is used as rectangular 4x3 display, then it goes to auxdisplay. > > > > > > If this is used as a power LED, SD activity LED, capslock and numlock > > > ... placed randomly all around the device, then it goes LED subsystem. > > > > The LP5812 is used for LED status indication in devices like smart speakers, > > wearables, and routers, not as a structured rectangular display. > > > > Given that, it seems to match the LED subsystem better than auxdisplay, doesn't it? > > I have mixed feelings about all this. As per hardware organisation it > sounds more like a matrix (for example. keyboard), where all entities > are accessed on a scanline, but at the same time each of the entities > may have orthogonal functions to each other. Have you checked with DRM > for the sake of completeness? > Personally I lean more to the something special, which doesn't fit > existing subsystems. Auxdisplay subsystem more or less about special > alphanumeric displays (with the exception of some FB kinda devices, > that were even discussed to have drivers be removed). Also maybe FB > might have something suitable, but in any case it looks quite > non-standard... I understand your mixed feelings about where the LP5812 fits within the existing subsystems. While the LP5812 uses a matrix-based structure for controlling LEDs, it is not intended for displaying structured text or graphics. Instead, it controls up to 4 RGB LEDs for status indication, where each RGB LED consists of 3 individual color LEDs: red, green, and blue. Based on this, I think it aligns more closely with the LED subsystem rather than DRM or FB. Best regards, Nam Tran
