Thread (16 messages) 16 messages, 6 authors, 2016-07-20

Re: [PATCH v4] xen/arm: Add a clock property

From: Geert Uytterhoeven <geert@linux-m68k.org>
Date: 2016-07-20 11:49:50
Also in: linux-arm-kernel, linux-clk

Hi Julien,

On Wed, Jul 20, 2016 at 1:01 PM, Julien Grall [off-list ref] wrote:
On 20/07/16 10:43, Geert Uytterhoeven wrote:
quoted
On Tue, Jul 12, 2016 at 9:46 AM, Dirk Behme [off-list ref]
wrote:
quoted
Clocks described by this property are reserved for use by Xen, and the OS
must not alter their state any way, such as disabling or gating a clock,
or modifying its rate. Ensuring this may impose constraints on parent
clocks or other resources used by the clock tree.

This property is used to proxy clocks for devices Xen has taken ownership
of, such as UARTs, for which the associated clock controller(s) remain
under the control of Dom0.

I'm not familiar with using XEN at all, but I'm a bit puzzled...

Can't you just add a clocks property to the (virtual) serial device node
in DT?
Then the (virtual) serial device driver can get and enable the clock?
There is no DT node for the Xen console (hvc). The UART used by Xen will be
completely removed from the Device tree.
Why is it removed?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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