Re: [RESEND PATCH 1/1] clk: add DT support for clock gating control

From: Sebastian Hesselbarh
Date: Fri Jul 13 2012 - 05:42:25 EST


On 07/13/2012 05:19 AM, Rob Herring wrote:
What's implemented in Linux should not define the binding. The binding
should describe the hardware.
[...]
True, but not your problem to implement. A binding doesn't necessarily
mean there is a full Linux implementation. We just don't want to create
something only to find others need something completely different.

Ok, what about a DT describing the following for a simple register-based
clock gating controller and the corresponding gated-clock independent of
the controller. I am sure there are a bunch of SoCs out there that
control their clock gates by writing some bits to a register. If that
DT description matches your expectations, I ll prepare patches with
documentation and implementation for common clock framework.

Sebastian

--
/* Simple clock gating controller based on bitmasks and register */
cgc: clock-gating-control@f1000000 {
compatible = "clock-gating-control-register";
reg = <0xf1000000 0x4>;

/* Clock gating control with one bit at bit position 0
enable with (1<<0), disable with (0<<0) */
cgctrl_usb0: cgc_usb0 {
clock-gating-control,shift = <0>;
clock-gating-control,mask = <1>;
clock-gating-control,enable = <1>;
clock-gating-control,disable = <0>;
};

/* Clock gating control with two bits at bit position 1-2
enable with (2<<1), disable with (0<<1) */
cgctrl_sata: cgc_sata {
clock-gating-control,shift = <1>;
clock-gating-control,mask = <3>;
clock-gating-control,enable = <2>;
clock-gating-control,disable = <0>;
};
};

/* Generic clock gate description that can be used with
any clock gating controller */
cg_usb0: clockgate@0 {
compatible = "gated-clock";
#clock-cells = <0>;
clocks = <&osc>;
clock-gate-control = <&cgctrl_usb0>;
};
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