Hi Viresh,
On Mon, Apr 21, 2014 at 8:01 AM, Viresh Kumar <viresh.kumar@xxxxxxxxxx> wrote:
> On 17 April 2014 15:23, Geert Uytterhoeven <geert+renesas@xxxxxxxxx> wrote:
>> If the clock doesn't exist, clk_get_rate() returns -EINVAL
>
> You clk_get_rate() isn't written well then, it should return zero.
You're right, thanks!
Once again I looked at the wrong clk_get_rate() implementation :-(
These non-CCF variants should die soon...
So the original code was correct: if the clock is not valid, freq == 0,
and thus "freq < min_cpufreq" is true.
> @Mike: I didn't see this clearly mentioned in clk.h, should we fix
> that?
>
>>, which becomes
>> a large number (freq is u32), failing the "freq < min_cpufreq" test.
>> Explicitly test for "(u32)-EINVAL" to fix this.
>
> That's a bad check. We should have done this instead:
>
> (s32)freq < 0; but that would be true for high values of clock. And that's
> why clk_get_rate() must return zero for errors.
>
>> Update the comment, and fix a grammer issue while we're at it.
>>
>> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
>> ---
>> drivers/cpufreq/ppc-corenet-cpufreq.c | 7 ++++---
>> 1 file changed, 4 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/cpufreq/ppc-corenet-cpufreq.c b/drivers/cpufreq/ppc-corenet-cpufreq.c
>> index 53881d78a931..7027eab814ce 100644
>> --- a/drivers/cpufreq/ppc-corenet-cpufreq.c
>> +++ b/drivers/cpufreq/ppc-corenet-cpufreq.c
>> @@ -179,10 +179,11 @@ static int corenet_cpufreq_cpu_init(struct cpufreq_policy *policy)
>> clk = of_clk_get(data->parent, i);
>> freq = clk_get_rate(clk);
>> /*
>> - * the clock is valid if its frequency is not masked
>> - * and large than minimum allowed frequency.
>> + * the clock is valid if it exists, its frequency is not
>> + * masked, and larger than minimum allowed frequency.
>> */
>> - if (freq < min_cpufreq || (mask & (1 << i)))
>> + if (freq == (u32)-EINVAL || freq < min_cpufreq ||
>> + (mask & (1 << i)))
>> table[i].frequency = CPUFREQ_ENTRY_INVALID;
>> else
>> table[i].frequency = freq / 1000;
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
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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