[PATCH 0/3] ARM: berlin: add cpufreq support for the BG2Q

[PATCH 0/3] ARM: berlin: add cpufreq support for the BG2Q

[Antoine Tenart]

Hi,

This series adds the cpufreq support to the Berlin BG2Q SoC only, as I
told this couldn't be done for BG2 and BG2CD.

First, the cpuclk clock is added to the Berlin clock driver. This clock
has a divider fixed to 1, so we use a fixed factor clock here.

Then register a platform device for cpufreq-dt, when using a BG2Q.

I also added the OPP table definition in the BG2Q device tree. Some
bootloaders may update this table when booting. Mine doesn't.

Tested on a BG2Q DMP.

Thanks,

Antoine

Antoine Tenart (3):
  clk: berlin: add cpuclk
  ARM: berlin: register cpufreq-dt for the BG2Q
  ARM: berlin: dts: add the cpufreq-dt bindings on the BG2Q

 arch/arm/boot/dts/berlin2q.dtsi      | 11 +++++++++++
 arch/arm/mach-berlin/berlin.c        | 13 +++++++++++++
 drivers/clk/berlin/bg2q.c            | 14 +++++++-------
 include/dt-bindings/clock/berlin2q.h |  3 ++-
 4 files changed, 33 insertions(+), 8 deletions(-)

-- 
2.5.0

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

[Antoine Tenart]

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

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
---
 arch/arm/mach-berlin/berlin.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

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 @@
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/of_platform.h>
+#include <linux/platform_device.h>
 #include <asm/hardware/cache-l2x0.h>
 #include <asm/mach/arch.h>
 
+static const struct of_device_id berlin2q_match[] = {
+	{ .compatible = "marvell,berlin2q" },
+	{ },
+};
+
+static void __init berlin_init_late(void)
+{
+	if (of_find_matching_node(NULL, berlin2q_match))
+		platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
+}
+
 static const char * const berlin_dt_compat[] = {
 	"marvell,berlin",
 	NULL,
@@ -25,6 +37,7 @@ static const char * const berlin_dt_compat[] = {
 
 DT_MACHINE_START(BERLIN_DT, "Marvell Berlin")
 	.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
-- 
2.5.0

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

[Jisheng Zhang]

Hi Antoine, 

On Thu, 30 Jul 2015 14:35:51 +0200
Antoine Tenart <antoine.tenart@free-electrons.com> wrote:

> The BG2Q SoC uses cpufreq-dt for cpufreq. Register a platform device for
> this.
> 
> Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
> ---
>  arch/arm/mach-berlin/berlin.c | 13 +++++++++++++
>  1 file changed, 13 insertions(+)
> 
> 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 @@
>  #include <linux/io.h>
>  #include <linux/kernel.h>
>  #include <linux/of_platform.h>
> +#include <linux/platform_device.h>
>  #include <asm/hardware/cache-l2x0.h>
>  #include <asm/mach/arch.h>
>  
> +static const struct of_device_id berlin2q_match[] = {
> +	{ .compatible = "marvell,berlin2q" },
> +	{ },
> +};
> +
> +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.

> +}
> +
>  static const char * const berlin_dt_compat[] = {
>  	"marvell,berlin",
>  	NULL,
> @@ -25,6 +37,7 @@ static const char * const berlin_dt_compat[] = {
>  
>  DT_MACHINE_START(BERLIN_DT, "Marvell Berlin")
>  	.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

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

[Sebastian Hesselbarth]

On 31.07.2015 08:16, Jisheng Zhang wrote:
> On Thu, 30 Jul 2015 14:35:51 +0200
> Antoine Tenart <antoine.tenart@free-electrons.com> wrote:
>
>> The BG2Q SoC uses cpufreq-dt for cpufreq. Register a platform device for
>> this.
>>
>> Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
>> ---
[...]
>> 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.

Jisheng,

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
important.

Sebastian

>> +}
>> +
>>   static const char * const berlin_dt_compat[] = {
>>   	"marvell,berlin",
>>   	NULL,
>> @@ -25,6 +37,7 @@ static const char * const berlin_dt_compat[] = {
>>
>>   DT_MACHINE_START(BERLIN_DT, "Marvell Berlin")
>>   	.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
>

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

[Jisheng Zhang]

Dear Sebastian,

On Mon, 10 Aug 2015 22:22:44 +0200
Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com> wrote:

> On 31.07.2015 08:16, Jisheng Zhang wrote:
> > On Thu, 30 Jul 2015 14:35:51 +0200
> > Antoine Tenart <antoine.tenart@free-electrons.com> wrote:
> >
> >> The BG2Q SoC uses cpufreq-dt for cpufreq. Register a platform device for
> >> this.
> >>
> >> Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
> >> ---
> [...]
> >> 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.
> 
> Jisheng,
> 
> 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.

hmm, if so, we can enable cpufreq-dt for BG2/BG2CD. In fact, there's no any
problem if we don't touch the voltage, only changing the cpufreq should not
introduce stable issues.

> 
> 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
> important.
> 
> Sebastian
> 
> >> +}
> >> +
> >>   static const char * const berlin_dt_compat[] = {
> >>   	"marvell,berlin",
> >>   	NULL,
> >> @@ -25,6 +37,7 @@ static const char * const berlin_dt_compat[] = {
> >>
> >>   DT_MACHINE_START(BERLIN_DT, "Marvell Berlin")
> >>   	.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
> >
> 

[PATCH 3/3] ARM: berlin: dts: add the cpufreq-dt bindings on the BG2Q

[Antoine Tenart]

The BG2Q uses cpugreq-dt. Add the corresponding bindings. The operating
points can be updated by the bootloader.

Signed-off-by: Antoine Tenart <antoine.tenart@free-electrons.com>
---
 arch/arm/boot/dts/berlin2q.dtsi | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/arm/boot/dts/berlin2q.dtsi b/arch/arm/boot/dts/berlin2q.dtsi
index 63a48490e2f9..58f6792c0d77 100644
--- a/arch/arm/boot/dts/berlin2q.dtsi
+++ b/arch/arm/boot/dts/berlin2q.dtsi
@@ -53,6 +53,17 @@
 			device_type = "cpu";
 			next-level-cache = <&l2>;
 			reg = <0>;
+
+			clocks = <&chip_clk CLKID_CPU>;
+			clock-latency = <100000>;
+			/* Can be modified by the bootloader */
+			operating-points = <
+				/* kHz    uV */
+				1200000 1200000
+				1000000 1200000
+				800000  1200000
+				600000  1200000
+			>;
 		};
 
 		cpu@1 {
-- 
2.5.0