cpufreq: cpufreq-cpu0: add dt node parsing for cooling device properties

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>
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
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Eduardo Valentin <eduardo.valentin@ti.com>

diff --git a/Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt b/Documentation/devicetree/bindings/cpufreq/cpufreq-cpu0.txt
index 051f764bedb8d0c3f9bc147dea875cb8b9fb4af2..f055515d2b62472c2507f2ebd2b69091dfd9b89d 100644 (file)
--- 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 38093e272377b2729939400c581aeb9706424011..6b8cde5f98af3031655a21e5828162b4ece5fb93 100644 (file)
--- a/drivers/cpufreq/Kconfig
+++ b/drivers/cpufreq/Kconfig
@@ -181,7 +181,7 @@ 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
        help
          This adds a generic cpufreq driver for CPU0 frequency management.
          It supports both uniprocessor (UP) and symmetric multiprocessor (SMP)

diff --git a/drivers/cpufreq/cpufreq-cpu0.c b/drivers/cpufreq/cpufreq-cpu0.c
index d4585ce2346cf187a0c5511fafdd7ac08204f1bb..91c7bb67bc742c96d5b612f021533b223feb4520 100644 (file)
--- 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 unsigned int cpu0_get_speed(unsigned int cpu)
 {
@@ -201,6 +205,17 @@ 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;
 
@@ -213,6 +228,7 @@ out_put_node:
 
 static int cpu0_cpufreq_remove(struct platform_device *pdev)
 {
+       cpufreq_cooling_unregister(cdev);
        cpufreq_unregister_driver(&cpu0_cpufreq_driver);
        dev_pm_opp_free_cpufreq_table(cpu_dev, &freq_table);