On 05/07/16 14:54, Julien Grall wrote:
On 05/07/16 14:53, Stefano Stabellini wrote:
On Thu, 30 Jun 2016, Dirk Behme wrote:
+- clocks: one or more clocks to be registered.
+ Xen hypervisor drivers might replace native drivers, resulting in
+ clocks not registered by these native drivers. To avoid that these
+ unregistered clocks are disabled, then, e.g. by clk_disable_unused(),
+ register them in the hypervisor node.
+ An example for this are the clocks of the serial driver. If the
clocks
+ used by the serial hardware interface are not registered by the
serial
+ driver the serial output might stop once clk_disable_unused() is
called.
What if we use the "status" property of the clocks? Could we set it to
"disabled" in Xen? Would that be enough for Linux to leave them alone?
clocks could be shared between multiple devices. So it is not possible
to disable the clock.
To give an example, below the UART node for juno
(arch/arm64/boot/dts/arm/juno-base.dtsi):
soc_uart0: uart@7ff80000 {
compatible = "arm,pl011", "arm,primecell";
reg = <0x0 0x7ff80000 0x0 0x1000>;
interrupts = <GIC_SPI 83 IRQ_TYPE_LEVEL_HIGH>;
clocks = <&soc_uartclk>, <&soc_refclk100mhz>;
clock-names = "uartclk", "apb_pclk";
};
The clock soc_refclk100mhz is shared with the mailbox.
Regards,
--
Julien Grall
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