Am Freitag, 17. Mai 2024, 08:58:32 CEST schrieb Luca Ceresoli: > Hello Dmitry, > > On Thu, 16 May 2024 17:06:46 +0500 > Dmitry Yashin <dmt.yashin@xxxxxxxxx> wrote: > > > Hi Luca, > > > > On 15.05.24 21:29, Luca Ceresoli wrote: > > > I'm skeptical about this being bound to a new DT compatible. As far as I > > > know the RK3308 and RK3308B are mostly equivalent, so it looks as the > > > pinctrl implementation could be detected at runtime. This would let > > > products to be built with either chip version and work on any without > > > any DT change. > > > > > > Thanks for your feedback. > > > > Indeed, these SoC's have a lot in common, but as I can see the rk3308b > > has more blocks, like extra PWM's (rk3308 datasheet 1.5 [0] shows only > > 1x PWM 4ch, when rk3308b and rk3308b-s have 3x PWM 4ch), 1-wire and > > CAN controller (mentioned in the TRM, but dropped from rk3308b > > datasheet for some reason). > > > > So, in my view, it really makes sense to add rk3308b.dtsi, where extra > > PWM's, pinctrl compatible and its pin functions can be moved. And if > > its not worth it, then I will try to adapt the entire series to runtime > > config based on cpuid like you suggested. > > Having a rk3308b.dtsi would probably make sense, yes, as there are > several differences as you described. However for the pinctrl it seems > probably not necessary. > > I've seen actual products being manufactured with two different RK3308 > variants in different lots of production, but with the same DT that has > rockchip,rk3308-pinctrl in it. Those would need a _selective_ DT > upgrade in order to benefit from your changes. > > And even if a product had always used the B variant, it would need DT > upgrade when upgrading to a kernel with your changes. Otherwise with > patch 1/3 of this series the pictrl driver would lose many routes after > upgrading the kernel (but not the DT): can this lead to > previously-working devices to stop working? I think this is a > fundamental question to reply. If things can be runtime-detectable, they should be detected at runtime. So yes, while we need to know that it is a rk3308-something before via the dt, if we can distinguish between the rk3308 variants at runtime we should definitly do so. Heiko
