Re: [PATCH 2/3] ARM: berlin: register cpufreq-dt for the BG2Q

From: Sebastian Hesselbarth
Date: Mon Aug 10 2015 - 16:22:57 EST

On 31.07.2015 08:16, Jisheng Zhang wrote:
On Thu, 30 Jul 2015 14:35:51 +0200
Antoine Tenart <antoine.tenart@xxxxxxxxxxxxxxxxxx> wrote:

The BG2Q SoC uses cpufreq-dt for cpufreq. Register a platform device for

Signed-off-by: Antoine Tenart <antoine.tenart@xxxxxxxxxxxxxxxxxx>
diff --git a/arch/arm/mach-berlin/berlin.c b/arch/arm/mach-berlin/berlin.c
index ac181c6797ee..0de906374994 100644
--- a/arch/arm/mach-berlin/berlin.c
+++ b/arch/arm/mach-berlin/berlin.c
@@ -15,9 +15,21 @@
+static void __init berlin_init_late(void)
+ if (of_find_matching_node(NULL, berlin2q_match))
+ platform_device_register_simple("cpufreq-dt", -1, NULL, 0);

I'm not sure is it acceptable to always register cpufreq-dt platform device.
In cpufreq-dt driver, the probe will exit if there's no cpuclk node.


registering the _device_ without checking for any requirements of
the _driver_ is usual practice. It it the driver's job to check
all of them and report an error or warning. So, I am fine with
adding the device unconditionally.

Using the .init_late() callback seems reasonable - but can you
evaluate if we can have cpufreq-dt also for BG2/BG2CD? I'd also
accept a single, default operating-point.

BTW, there is one true point about Jisheng's comment: try to order
your patches logically correct to avoid unnecessary warnings, i.e.

1/3 add cpuclk
2/3 add cpufreq-dt properties
3/3 register cpufreq-dt device

If you consider a git-bisect run, you can land in between any of the
three patches but they are always in the above order - so ordering is


static const char * const berlin_dt_compat[] = {
@@ -25,6 +37,7 @@ static const char * const berlin_dt_compat[] = {

.dt_compat = berlin_dt_compat,
+ .init_late = berlin_init_late,
* with DT probing for L2CCs, berlin_init_machine can be removed.
* Note: 88DE3005 (Armada 1500-mini) uses pl310 l2cc

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