On Thu, 16 Nov 2017, Bjorn Andersson wrote: > On Thu 16 Nov 22:36 PST 2017, kgunda@xxxxxxxxxxxxxx wrote: > > > On 2017-11-16 22:25, Bjorn Andersson wrote: > > > On Thu 16 Nov 04:18 PST 2017, Kiran Gunda wrote: > > > > > > > WLED driver provides the interface to the display driver to > > > > adjust the brightness of the display backlight. > > > > > > > > > > Hi Kiran, > > > > > > This driver has a lot in common with the already upstream pm8941-wled.c, > > > because it's just a new revision of the same block. > > > > > > Please extend the existing driver rather than providing a new one > > > (and yes, renaming the file is okay). > > > > > > Regards, > > > Bjorn > > > > Hi Bjorn, > > > > Yes this driver design is similar to pm8941, however the WLED HW block > > has undergone quite a few changes in analog and digital from PM8941 to > > PM8998. > > I can see that, looking at the documentation. > > > Few of them include splitting one module into wled-ctrl and wled-sink > > peripherals, changes in the register offsets and the bit > > interpretation. > > This is typical and something we need to handle in all these drivers, to > avoid having one driver per platform. > > > Hence we concluded that it was better to have a new driver to support > > this new gen WELD module and decouple it from the pm8941. > > Okay, I can see how it's easier to not have to case about anything but > pmi8998 in this driver, but where do you add the support for other WLED > versions? What about PMI8994? Will there not be similar differences > (registers that has moved around) in the future? > > > Also, going forward this driver will support AMOLED AVDD rail (not > > supported by pm8941) touching a few more registers/configuration and > > newer PMICs. > > Is this a feature that was introduced in PMI8998? Will this support not > be dependent on the pmic version? > > > So spinning off a new driver would make it cleaner and easier to > > extend further. > > > > It's for sure easier at this point in time, but your argumentation > implies that PMI8998+1 should go into it's own driver as well. > > I suspect that if you're going to reuse this driver for future PMIC > versions you will have to deal with register layout differences and new > feature set, and as such I'm not convinced that a new driver is needed. > > Can you give any concrete examples of where it is not possible or > undesirable to maintain the pm8941 support in the same driver? I agree with Bjorn. If you can support multiple devices in a single driver with a couple of simple ddata struct differences and a slightly different regmap, you should. -- Lee Jones Linaro STMicroelectronics Landing Team Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog -- 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
