Hi Stephen,

On Fri, 2015-06-05 at 17:59 -0700, Stephen Boyd wrote:

Perhaps an example would be best. In DT we would have:

	vencsys: vencsys at 10000 {
		compatible = "mtk,vencsys";
		reg = <0x10000 0x1000>;
		#clock-cells = <1>;
		#reset-cells = <1>;
	};

	myconsumer at 12000 {
		compatible = "mtk,vencsys";
		reg = <0x12000 0x100>;
		clocks = <&vencsys 10>;
		clock-names = "core";
	};

	(Or are the consumers only children of the subsystem?
	It's not clear to me)

In our case the vencsys clocks may use used by its own driver and other
drivers (such as SMI driver).

And then in the mtk,vencsys driver we would create a platform
device named something like "mtk-vencsys-clk" and assign the
of_node of the device to be the of_node that is assigned to the
mtk,vencsys device.

	static int vencsys_probe(struct platform_device *pdev)
	{
		int ret;
		struct device_node *np = pdev->dev.of_node;
		struct platform_device *clk_pdev;

		clk_pdev = platform_device_alloc("mtk-vencsys-clk", -1);
		clk_pdev->dev.of_node = of_node;
		ret = platform_device_add(clk_pdev);
		if (ret)
			return ret;
	}

Then we could put a mtk-vencsys-clk driver in drivers/clk/ that
does the clk driver part...

	static int clk_vencsys_probe(struct platform_device *pdev)
	{
		int ret;
		struct device_node *np = pdev->dev.of_node;
		struct regmap *regmap;

		ret = of_clk_add_provider(np, of_clk_src_onecell_get, ..);
		if (ret)
			return ret;

		regmap = dev_get_regmap(pdev->dev.parent, NULL);

	}

And similar things could be done for the reset driver.

It looks like there is only one DT node (vencsys at 10000) but there are
several drivers refer to this DT node, and then we use a dummy driver
(or a "top driver") to aggregate drivers with different features (clk,
reset etc.).

It means we need to provide vencsys clk driver in drivers/clk and
vencsys reset driver in drivers/reset, and also to provide a vencsys top
driver in, for example, soc/mediatek, right?

Now we have 3 choice:

1. implement vencsys clock driver and reset driver in drivers/clk.
2. implement vencsys clock driver and reset driver in drivers/soc.
3. implement vencsys clock driver in drivers/clk, vencsys reset driver
in drivers/reset, and vencsys top driver in drivers/soc.

Sascha, do you have comments for these 3 solutions?


Best regards,

James