On Mon, 2022-12-12 at 09:40 +0100, Krzysztof Kozlowski wrote: > On 12/12/2022 03:43, Trevor Wu (吳文良) wrote: > > > > > > > > > > + uniqueItems: true > > > > > > + items: > > > > > > + minimum: 0 > > > > > > + maximum: 15 > > > > > > + > > > > > > + "^mediatek,etdm-in[1-2]-mclk-always-on-rate-hz$": > > > > > > + description: Specify etdm in mclk output rate for > > > > > > always > > > > > > on > > > > > > case. > > > > > > > > > > How is it different than assigned-clock-rates? > > > > > > > > > > > > > This includes clock enabling at init stage. > > > > > > assigned-clock-rates are also at init stage. I asked what is > > > different. > > > > > > > If the property is used, there are three parts included in dai > > driver > > probe function. > > > > 1. set clock parent (which APLL) > > 2. set clock rate (MCLK rate) > > 3. enable clock (MCLK On) > > > > The first two parts can be done by existing dts clock properties, > > but > > the last one can't. > > When MCLK should be enabled at boot time and kept on, this property > > is used. That's why I say the property is designed for always-on > > case. > > Heh, so the "always on case" means this property enables clock? How > is > this even DT property? That's not how clocks should be kept enabled. > You > need proper clock provider and consumer. > > Hi Krzysztof, Sorry, I don't know it is not appropriate to notify driver that the clock should be ketp enabled after boot. The original idea is that enabling this clock in the machine driver, but a property to inform machine driver is also required when the machine driver is shared by different codec combination. And it's easier to handle set_rate and set_parent in etdm dai driver, so I put the property here. Do you mean if the clock consumer(audio codec or external DSP) requries the clock, the consumer should enable the clock by itself? Thanks, Trevor
