Hi Geert, On Mi, 2022-06-29 at 19:18 +0200, Geert Uytterhoeven wrote: > Hi Philipp, > > On Wed, Jun 29, 2022 at 6:21 PM Philipp Zabel <p.zabel@xxxxxxxxxxxxxx> wrote: > > On Di, 2022-06-28 at 20:45 +0100, Phil Edworthy wrote: > > > The Renesas RZ/V2M SoC (r9a09g011) has a new i2c controller. This series > > > add the driver. One annoying problem is that the SoC uses a single reset > > > line for two i2c controllers, and unfortunately one of the controllers > > > is managed by some firmware, not by Linux. Therefore, the driver just > > > deasserts the reset. > > > > This sounds scary. If the driver is never loaded, and the reset is > > never deasserted, what happens to the firmware trying to access the > > other i2c controller? Does it hang? Or write to the reset controller > > registers to deassert the reset? If so, is there any protection against > > concurrent access from firmware and reset controller driver? > > In response to v1, I wrote > > > That is actually an integration issue, not an i2c controller issue. > > > > Perhaps we need a RESET_IS_CRITICAL flag, cfr. CLK_IS_CRITICAL, > > to be set by the reset provider? I would just let the reset controller driver implement this by disabling _assert and _reset for those firmware-shared resets. regards Philipp
