Quoting Zhu, Yi Xin (2018-08-28 23:56:22) > > On 8/28/2018 3:09 AM, Stephen Boyd wrote: > > Quoting yixin zhu (2018-08-08 01:52:20) > >> On 8/8/2018 1:50 PM, Stephen Boyd wrote: > >>>> +/* clock flags definition */ > >>>> +#define CLOCK_FLAG_VAL_INIT BIT(16) > >>>> +#define GATE_CLK_HW BIT(17) > >>>> +#define GATE_CLK_SW BIT(18) > >>>> +#define GATE_CLK_VT BIT(19) > >>> What does VT mean? Virtual? > >> Yes. VT means virtual here. > >> Will change to GATE_CLK_VIRT. > >> > > Is it a hardware concept? Or virtualization with hypervisor? > > Some peripheral drivers want to use same code cross platforms. > > But not all platforms provide HW gate clock. So in this case, clock > driver creates > > a virtual gate clock to make it work if no HW gate clock in the SoC. That's not how things are supposed to work. If a clk isn't there in the hardware we don't make them up in software so that the consumer software drivers can keep requesting clks on different platforms. On a different platform, the driver needs to know that the clks aren't there with a different compatible string. > > > > > >>>> +} > >>>> + > >>>> +CLK_OF_DECLARE(intel_grx500_cgu, "intel,grx500-cgu", grx500_clk_init); > >>> Any reason a platform driver can't be used instead of CLK_OF_DECLARE()? > >> It provides CPU clock which is used in early boot stage. > >> > > Ok. What is the CPU clock doing in early boot stage? Some sort of timer > > frequency? If the driver can be split into two pieces, one to handle the > > really early stuff that must be in place to get timers up and running > > and the other to register the rest of the clks that aren't critical from > > a regular platform driver it would be good. That's preferred model if > > something is super critical. > > Yes, CPU clock is providing CPU frequency in the early boot stage. > > Will put the non-critical clocks in the platform driver. > > Sure the CPU clock is handling frequency, but does that matter for early boot to get going? If timers aren't involved here then it doesn't sound like this needs CLK_OF_DECLARE.
