Messages in this thread | | | Subject | Re: [PATCH v2 02/18] clk: intel: Add clock driver for Intel MIPS SoCs | From | "Zhu, Yi Xin" <> | Date | Wed, 29 Aug 2018 18:34:26 +0800 |
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>>>> +} >>>> + >>>> +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. > Just to make sure my approach is same as you think.
In the driver, there's two clock registrations.
- One through CLK_OF_DECLARE for early stage clocks.
- The other via platform driver for the non-critical clocks.
In the device tree, two clock device nodes are required.
e.g. device tree:
cgu: cgu@16200000 { compatible = "intel,grx500-clk", "syscon"; reg = <0x16200000 0x200>; #clock-cells = <1>; };
clk: clk { compatible = "intel,grx500-cgu"; #clock-cells = <1>; intel,cgu-syscon = <&cgu>; };
source code:
CLK_OF_DECLARE(intel_grx500_cgu, "intel,grx500-cgu", grx500_clk_init);
static const struct of_device_id of_intel_grx500_cgu_match[] = { { .compatible = "intel,grx500-clk" }, {} };
static struct platform_driver intel_grx500_clk_driver = { .probe = intel_grx500_clk_probe, .driver = { .name = "grx500-cgu", .of_match_table = of_match_ptr(of_intel_grx500_cgu_match), }, };
static int __init intel_grx500_cgu_init(void) { return platform_driver_register(&intel_grx500_clk_driver); } arch_initcall(intel_grx500_cgu_init);
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