Hi Kevin, On Thursday 20 Oct 2016 09:57:51 Kevin Hilman wrote: > Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> writes: > > On Wednesday 19 Oct 2016 10:26:57 Bartosz Golaszewski wrote: > >> 2016-10-18 22:49 GMT+02:00 Laurent Pinchart: > >>> On Monday 17 Oct 2016 18:30:49 Bartosz Golaszewski wrote: > >>>> Create the driver for the da8xx System Configuration and implement > >>>> support for writing to the three Master Priority registers. > >>>> > >>>> Signed-off-by: Bartosz Golaszewski <bgolaszewski@xxxxxxxxxxxx> > >> > >> [snip] > >> > >>>> + > >>>> +Documentation: > >>>> +OMAP-L138 (DA850) - http://www.ti.com/lit/ug/spruh82c/spruh82c.pdf > >>>> + > >>>> +Required properties: > >>>> + > >>>> +- compatible: "ti,da850-syscfg" > >>> > >>> Don't you need a reg property ? > >> > >> Yes, Kevin already pointed that out. I'll add it in v2. Same for [1/3]. > >> > >>>> +Optional properties: > >>>> + > >>>> +The below properties are used to specify the priority of master > >>>> peripherals. > >>>> +They must be between 0-7 where 0 is the highest priority and 7 is the > >>>> lowest. > >>>> + > >>>> +- ti,pri-arm-i: ARM_I port priority. > >>>> + > >>>> +- ti,pri-arm-d: ARM_D port priority. > >>>> + > >>>> +- ti,pri-upp: uPP port priority. > >>>> + > >>>> +- ti,pri-sata: SATA port priority. > >>>> + > >>>> +- ti,pri-pru0: PRU0 port priority. > >>>> + > >>>> +- ti,pri-pru1: PRU1 port priority. > >>>> + > >>>> +- ti,pri-edma30tc0: EDMA3_0_TC0 port priority. > >>>> + > >>>> +- ti,pri-edma30tc1: EDMA3_0_TC1 port priority. > >>>> + > >>>> +- ti,pri-edma31tc0: EDMA3_1_TC0 port priority. > >>>> + > >>>> +- ti,pri-vpif-dma-0: VPIF DMA0 port priority. > >>>> + > >>>> +- ti,pri-vpif-dma-1: VPIF DMA1 port priority. > >>>> + > >>>> +- ti,pri-emac: EMAC port priority. > >>>> + > >>>> +- ti,pri-usb0cfg: USB0 CFG port priority. > >>>> + > >>>> +- ti,pri-usb0cdma: USB0 CDMA port priority. > >>>> + > >>>> +- ti,pri-uhpi: HPI port priority. > >>>> + > >>>> +- ti,pri-usb1: USB1 port priority. > >>>> + > >>>> +- ti,pri-lcdc: LCDC port priority. > >>> > >>> I'm afraid this looks more like system configuration than hardware > >>> description to me. > >> > >> While you're certainly right, this approach is already implemented in > >> several other memory and bus drivers and it was also suggested by > >> Sekhar in one of the tilcdc rev1 threads. There's also no real > >> alternative that I know of. > > > > The fact that other drivers get it wrong is no excuse for copying them :-) > > What exactly is "wrong" with the way other drivers are doing it? > > I'm sure there may be other ideas, and possibly some better ones, but > that doesn't make it wrong, and doesn't change he fact that the kernel > has existing drivers SoC-bus-specific system performance knobs like > this. It's not the drivers I'm concerned about, but the DT bindings. The proposed DT binding contains a large number of properties that don't describe the hardware but contain configuration data. If they're accepted you'll have to carry them forward forever, while they should be controlled in a more flexible way. > >>> There was a BoF session about how to support this kind of performance > >>> knobs at ELCE last week: > >>> https://openiotelceurope2016.sched.org/event/7rss/bof-linux-device-perf > >>> ormance-framework-michael-turquette-baylibre :-) > >> > >> Unfortunately it was just a discussion about potential approaches - > >> there's no code yet. > > > > Patches are welcome ;-) > > Any generic perf framework will have to build on the HW-specifics of > individual busses, so IMO, the lack of a generic performance > framework/knobs should not be a reason to block the inclusion of any > bus-specific knobs. > > I guess this ultimately would go though arm-soc, so I've added Arnd & > Olof to the thread. -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
