Re: Problem with nbcon console and amba-pl011 serial port

Russell King (Oracle)
2025-06-04T08:11:26Z

On Wed, Jun 04, 2025 at 09:50:03AM +0206, John Ogness wrote:
> You are correct. I wasn't aware that the clock framework had a usage
> counter to allow recursive calls. Sorry for the noise.

It's documented:

/**
* clk_disable - inform the system when the clock source is no longer required.
* @clk: clock source
*
* Inform the system that a clock source is no longer required by
* a driver and may be shut down.
*
* May be called from atomic contexts.
*
* Implementation detail: if the clock source is shared between
* multiple drivers, clk_enable() calls must be balanced by the
* same number of clk_disable() calls for the clock source to be
* disabled.
*/

similarly for clk_unprepare(). It has to be this way if you think about
the fact that clock sources are not unique to clock consumers, otherwise
the first clock consumer to disable a clock will disrupt other
consumers of that same clock.

It's been that way since I created the clk API, which predates CCF.

--
RMK's Patch system: https://www.armlinux.org.uk/developer/patches/
FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!