Re: [PATCHv5 05/20] cpufreq: cpufreq-cpu0: add dt node parsing for cooling device properties

Eduardo Valentin
2013-11-14T13:17:21Z

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On 12-11-2013 15:46, Eduardo Valentin wrote:
> This patch changes the cpufreq-cpu0 driver to consider if
> a cpu needs cooling (with cpufreq). In case the cooling is needed,
> the cpu0 device tree node needs to be properly configured
> with cooling device properties.
>
> In case these properties are present,, the driver will
> load a cpufreq cooling device in the system. The cpufreq-cpu0
> driver is not interested in determining how the system should
> be using the cooling device. The driver is responsible
> only of loading the cooling device.
>
> Describing how the cooling device will be used can be
> accomplished by setting up a thermal zone that references
> and is composed by the cpufreq cooling device.
>
> Cc: "Rafael J. Wysocki" <rjw@sisk.pl>

Rafael, Can I still assume you are OK with this patch and add your
acked-by [1]?
http://www.spinics.net/lists/lm-sensors/msg39136.html

It has changed a few bits from V1 to here. The idea is still same though.

> Cc: Viresh Kumar <viresh.kumar@linaro.org>
> Cc: Grant Likely <grant.likely@linaro.org>
> Cc: Rob Herring <rob.herring@calxeda.com>
> Cc: cpufreq@vger.kernel.org
> Cc: linux-pm@vger.kernel.org
> Cc: linux-kernel@vger.kernel.org
> Cc: devicetree-discuss@lists.ozlabs.org
> Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>
> ---
> .../devicetree/bindings/cpufreq/cpufreq-cpu0.txt | 7 +++++++
> drivers/cpufreq/Kconfig | 2 +-
> drivers/cpufreq/cpufreq-cpu0.c | 16 ++++++++++++++++
> 3 files changed, 24 insertions(+), 1 deletion(-)
>
> diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt
> index 051f764..f055515 100644
> --- a/Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt
> +++ b/Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt
> @@ -15,6 +15,10 @@ Optional properties:
> - clock-latency: Specify the possible maximum transition latency for clock,
> in unit of nanoseconds.
> - voltage-tolerance: Specify the CPU voltage tolerance in percentage.
> +- #cooling-cells:
> +- cooling-min-level:
> +- cooling-max-level:
> + Please refer to Documentation/devicetree/bindings/thermal/thermal.txt.
>
> Examples:
>
> @@ -33,6 +37,9 @@ cpus {
> 198000 850000
> >;
> clock-latency = <61036>; /* two CLK32 periods */
> + #cooling-cells = <2>;
> + cooling-min-level = <0>;
> + cooling-max-level = <2>;
> };
>
> cpu@1 {
> diff --git a/drivers/cpufreq/Kconfig b/drivers/cpufreq/Kconfig
> index 534fcb8..fc1e9a5 100644
> --- a/drivers/cpufreq/Kconfig
> +++ b/drivers/cpufreq/Kconfig
> @@ -186,7 +186,7 @@ config CPU_FREQ_GOV_CONSERVATIVE
>
> config GENERIC_CPUFREQ_CPU0
> tristate "Generic CPU0 cpufreq driver"
> - depends on HAVE_CLK && REGULATOR && PM_OPP && OF
> + depends on HAVE_CLK && REGULATOR && PM_OPP && OF && THERMAL && CPU_THERMAL
> select CPU_FREQ_TABLE
> help
> This adds a generic cpufreq driver for CPU0 frequency management.
> diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
> index c522a95..568aaf3 100644
> --- a/drivers/cpufreq/cpufreq-cpu0.c
> +++ b/drivers/cpufreq/cpufreq-cpu0.c
> @@ -13,7 +13,9 @@
>
> #include <linux/clk.h>
> #include <linux/cpu.h>
> +#include <linux/cpu_cooling.h>
> #include <linux/cpufreq.h>
> +#include <linux/cpumask.h>
> #include <linux/err.h>
> #include <linux/module.h>
> #include <linux/of.h>
> @@ -21,6 +23,7 @@
> #include <linux/platform_device.h>
> #include <linux/regulator/consumer.h>
> #include <linux/slab.h>
> +#include <linux/thermal.h>
>
> static unsigned int transition_latency;
> static unsigned int voltage_tolerance; /* in percentage */
> @@ -29,6 +32,7 @@ static struct device *cpu_dev;
> static struct clk *cpu_clk;
> static struct regulator *cpu_reg;
> static struct cpufreq_frequency_table *freq_table;
> +static struct thermal_cooling_device *cdev;
>
> static int cpu0_verify_speed(struct cpufreq_policy *policy)
> {
> @@ -260,6 +264,17 @@ static int cpu0_cpufreq_probe(struct platform_device *pdev)
> goto out_free_table;
> }
>
> + /*
> + * For now, just loading the cooling device;
> + * thermal DT code takes care of matching them.
> + */
> + if (of_find_property(np, "#cooling-cells", NULL)) {
> + cdev = of_cpufreq_cooling_register(np, cpu_present_mask);
> + if (IS_ERR(cdev))
> + pr_err("running cpufreq without cooling device: %ld\n",
> + PTR_ERR(cdev));
> + }
> +
> of_node_put(np);
> return 0;
>
> @@ -272,6 +287,7 @@ out_put_node:
>
> static int cpu0_cpufreq_remove(struct platform_device *pdev)
> {
> + cpufreq_cooling_unregister(cdev);
> cpufreq_unregister_driver(&cpu0_cpufreq_driver);
> opp_free_cpufreq_table(cpu_dev, &freq_table);
>
>

--
You have got to be excited about what you are doing. (L. Lamport)

Eduardo Valentin

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