On 11/12/2024 09:24, Manivannan Sadhasivam wrote: > On Wed, Dec 11, 2024 at 09:09:18AM +0100, Krzysztof Kozlowski wrote: >> On 11/12/2024 07:20, Manivannan Sadhasivam wrote: >>> On Thu, Dec 05, 2024 at 11:23:11AM +0100, Krzysztof Kozlowski wrote: >>>> On Wed, Dec 04, 2024 at 06:52:47PM +0800, Ziyue Zhang wrote: >>>>> On some platforms, the power supply for PCIe PHY is not able to provide >>>>> enough current when it works in LPM mode. Hence, PCIe PHY driver needs to >>>>> set current load to vote the regulator to HPM mode. >>>>> >>>>> Document the current load as properties for each power supply PCIe PHY >>>>> required, namely vdda-phy-max-microamp, vdda-pll-max-microamp and >>>>> vdda-qref-max-microamp, respectively.PCIe PHY driver should parse them to >>>>> set appropriate current load during PHY power on. >>>>> >>>>> This three properties are optional and not mandatory for those platforms >>>>> that PCIe PHY can still work with power supply. >>>> >>>> >>>> Uh uh, so the downstream comes finally! >>>> >>>> No sorry guys, use existing regulator bindings for this. >>>> >>> >>> Maybe they got inspired by upstream UFS bindings? >>> Documentation/devicetree/bindings/ufs/ufs-common.yaml: >>> >>> vcc-max-microamp >>> vccq-max-microamp >>> vccq2-max-microamp >> >> And it is already an ABI, so we cannot do anything about it. >> >>> >>> Regulator binding only describes the min/max load for the regulators and not >> >> No, it exactly describes min/max consumers can use. Let's quote: >> "largest current consumers may set" >> It is all about consumers. >> >>> consumers. What if the consumers need to set variable load per platform? Should >> >> Then each platform uses regulator API or regulator bindings to set it? I >> don't see the problem here. >> >>> they hardcode the load in driver? (even so, the load should not vary for each >>> board). >> >> The load must vary per board, because regulators vary per board. Of >> course in practice most designs could be the same, but regulators and >> their limits are always properties of the board, not the SoC. >> > > How the consumer drivers are supposed to know the optimum load? > > I don't see how the consumer drivers can set the load without hardcoding the > values. And I could see from UFS properties that each board has different > values. Drivers do not need to know, it's not the driver's responsibility. If these are constraints per board, then regulator properties apply and there is no difference between this "vdd-max-microamp = 10" and "regulator-max-microamp". If this varies runtime, then your property is already not suitable and very limited and you should use OPP table. Best regards, Krzysztof
