On Thu, Mar 07, 2013 at 10:03:28AM +0800, Viresh Kumar wrote:
On 7 March 2013 08:51, Russell King - ARM Linux linux@arm.linux.org.uk wrote:
On Thu, Mar 07, 2013 at 08:32:37AM +0800, Viresh Kumar wrote:
On 5 March 2013 18:52, Russell King - ARM Linux linux@arm.linux.org.uk wrote:
On Tue, Mar 05, 2013 at 12:52:41PM +0800, Viresh Kumar wrote:
clk[cluster] = clk_get(NULL, name);if (!IS_ERR_OR_NULL(clk[cluster])) {NAK. Two reasons.
- IS_ERR_OR_NULL. You know about this, it's been on the list several times.
Hey, i had a second thought about this one and i have some other opinion here. This is a cpufreq driver and we need clock support for sure here, we can't work without it. And so here is the latest fixup:
NAK. You just don't understand.
Poor me!!
I still remember the huge discussions we had during "clk: Add non CONFIG_HAVE_CLK routines" patchset.
For others: https://lkml.org/lkml/2012/4/24/389
Back to the discussion, I understand that clk_get() just returns a cookie and NULL is not an error and so it shouldn't be treated specially. And that's what we do with most of our drivers as all other clk routines (clk_get[set]_rate()) have safe guards against the NULL clk, and they wouldn't complain.
The special case we have in a cpufreq driver is, we can't work with zero returned from clk_get_rate()... That will make cpufreq driver work badly.
So how is this different from any other clock which may also return zero from its clk_get_rate() ?
If that's the condition you want to check for, call clk_get_rate() after a successful clk_get*() and check for the condition. Don't go treating the cookie somehow specially. You're *assuming* a behaviour that is inappropriate for the side of the interface you're working with.