Re: [PATCH 1/4] regulator: add set_voltage_time[_sel]infrastructure
From: Mark Brown
Date: Fri Mar 11 2011 - 10:20:47 EST
On Fri, Mar 11, 2011 at 03:45:39PM +0100, Linus Walleij wrote:
> On Fri, Mar 11, 2011 at 1:25 PM, Mark Brown
> + /*
> + * If we can't obtain the old selector there is not enough
> + * info to call set_voltage_time_sel().
> + */
> + if (rdev->desc->ops->set_voltage_time_sel &&
> + rdev->desc->ops->get_voltage_sel) {
> + unsigned int old_selector = 0;
> +
> + ret = rdev->desc->ops->get_voltage_sel(rdev);
> + if (ret < 0)
> + return ret;
> + old_selector = ret;
> + delay = rdev->desc->ops->set_voltage_time_sel(rdev,
> + old_selector, selector);
> + }
> +
Hrm, right. This means we can only support this for selector based
get_voltage(). That's probably fine, I think.
> > I also think we should be exporting this to consumers as things like
> > cpufreq are interested in the latency for voltage changes.
> Can we take that when we have a consumer that wants it? Looking
> at it it becomes rather complex, since consumers don't know the
> core-internal selectors, just discrete enumerated voltages, so these
> have to be mapped back to selectors etc, that's pretty much ovehead
> code that sits unused.
> (If you insist, I will implement it.)
Consumers know about the set of selectors as they are used to enumerate
the supported voltages via list_voltage(). An existing cpufreq driver
such as the s3c64xx one would be able to take advantage of this very
quickly.
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