linux-kernel - Re: [PATCH] clk: provide public clk_is

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date:	Sat, 5 Oct 2013 22:42:08 +0200
From:	Andrew Lunn <andrew@...n.ch>
To:	Uwe Kleine-König 
	<u.kleine-koenig@...gutronix.de>
Cc:	Sebastian Hesselbarth <sebastian.hesselbarth@...il.com>,
	Andrew Lunn <andrew@...n.ch>,
	Russell King <linux@....linux.org.uk>,
	Jason Cooper <jason@...edaemon.net>,
	Benjamin Herrenschmidt <benh@...nel.crashing.org>,
	linux-kernel@...r.kernel.org,
	Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
	Ezequiel Garcia <ezequiel.garcia@...e-electrons.com>,
	Grant Likely <grant.likely@...aro.org>,
	Mike Turquette <mturquette@...aro.org>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH] clk: provide public clk_is_enabled function

On Sat, Oct 05, 2013 at 10:24:30PM +0200, Uwe Kleine-König wrote:
> On Fri, Oct 04, 2013 at 12:08:30PM +0200, Sebastian Hesselbarth wrote:
> > To determine if a clk has been previously enabled, provide a public
> > clk_is_enabled function. This is especially helpful to check the state
> > of clk-gate without actually changing the state of the gate.
> I wonder what you want to do with the return value.
> 
> When doing
> 
> 	if (clk_is_enabled(someclk))
> 		do_something();
> 
> you cannot in general know if the clock is still on when you start to
> do_something.

Hi Uwe

At least in the use case Sebastian needs it for, we don't need an "in
general" solution. It is used early boot time to see if the boot
loader left the clock running. The other user of the clock is the
ethernet driver, which we know cannot change it yet, because driver
probing has not started yet.

	Andrew
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/