Hi Andy, On Wed, Apr 14, 2021 at 9:14 PM Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > On Wed, Apr 14, 2021 at 08:55:21PM +0200, Geert Uytterhoeven wrote: > > On Wed, Apr 14, 2021 at 8:18 PM Andy Shevchenko > > <andriy.shevchenko@xxxxxxxxxxxxxxx> wrote: > > > On Wed, Apr 14, 2021 at 08:06:18PM +0200, Geert Uytterhoeven wrote: > > > > On Wed, Apr 14, 2021 at 11:24 AM Yicong Yang <yangyicong@xxxxxxxxxxxxx> wrote: > > > > > On 2021/4/13 20:26, Geert Uytterhoeven wrote: > > > > > > The HiSilicon Kunpeng I2C controller is only present on HiSilicon > > > > > > Kunpeng SoCs, and its driver relies on ACPI to probe for its presence. > > > > > > Hence add dependencies on ARCH_HISI and ACPI, to prevent asking the user > > > > > > about this driver when configuring a kernel without Hisilicon platform > > > > > > or ACPI firmware support. > > > > > > > > > > this is a public IP which doesn't specifically depend on ARCH_HISI. I'm > > > > > not sure all the platform this IP on has ARCH_HISI configured. The driver > > > > > will not be compiled by default config. This is not correct to have > > > > > this dependence. > > > > > > > > Thanks for your answer! > > > > > > > > I guess it's still fine to add a dependency on ACPI? > > > > > > But why? > > > > Please tell me how/when the driver is used when CONFIG_ACPI=n. > > I'm not using it at all. Ask the author :-) > > But if we follow your logic, then we need to mark all the _platform_ drivers > for x86 world as ACPI dependent? This sounds ugly. Do all other x86 platform drivers have (1) an .acpi_match_table[] and (2) no other way of instantiating their devices? The first driver from the top of my memory I looked at is rtc-cmos: it has no .acpi_match_table[], and the rtc-cmos device is instantiated from arch/x86/kernel/rtc.c. For drivers with only an .of_match_table(), and no legacy users instantiating platform devices, we do have dependencies on OF. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds