[PATCH 1/1] thermal: cpu_cooling: check for the readiness of cpufreq layer

Eduardo Valentin edubezval at gmail.com
Wed Nov 26 09:50:12 PST 2014


In this patch, the cpu_cooling code checks for the usability of cpufreq
layer before proceeding with the CPU cooling device registration. The
main reason is: CPU cooling device is not usable if cpufreq cannot
switch frequencies.

Similar checks are spread in thermal drivers. Thus, the advantage now
is to have the check in a single place: cpu cooling device registration.
For this reason, this patch also updates the existing drivers that
depend on CPU cooling to simply propagate the error code of the cpu
cooling registration call. Therefore, in case cpufreq is not ready, the
thermal drivers will still return -EPROBE_DEFER, in an attempt to try
again when cpufreq layer gets ready.

Cc: devicetree at vger.kernel.org
Cc: Grant Likely <grant.likely at linaro.org>
Cc: Kukjin Kim <kgene.kim at samsung.com>
Cc: linux-arm-kernel at lists.infradead.org
Cc: linux-kernel at vger.kernel.org
Cc: linux-pm at vger.kernel.org
Cc: linux-samsung-soc at vger.kernel.org
Cc: Naveen Krishna Chatradhi <ch.naveen at samsung.com>
Cc: Rob Herring <robh+dt at kernel.org>
Cc: Zhang Rui <rui.zhang at intel.com>
Signed-off-by: Eduardo Valentin <edubezval at gmail.com>
---
 drivers/thermal/cpu_cooling.c                      | 5 +++++
 drivers/thermal/db8500_cpufreq_cooling.c           | 5 -----
 drivers/thermal/imx_thermal.c                      | 5 -----
 drivers/thermal/samsung/exynos_thermal_common.c    | 2 +-
 drivers/thermal/ti-soc-thermal/ti-thermal-common.c | 6 ------
 5 files changed, 6 insertions(+), 17 deletions(-)
---

This is attempt to organize the cpu cooling vs. cpufreq boot sequencing.
The main change in this patch, as in the commit log, is to have the check
for the cpufreq layer in the cpu cooling device registration, instead of
in thermal drivers. This way, drivers don't need to bother about it, they
just need to propagate the error value.

This change was tested on top of:
(0) - Viresh's change in cpufreq layer and cpufreq-dt (up to patch 4):
https://patchwork.kernel.org/patch/5384141/
https://patchwork.kernel.org/patch/5384151/
https://patchwork.kernel.org/patch/5384161/
https://patchwork.kernel.org/patch/5384171/
(1) - fix of thermal core:
https://patchwork.kernel.org/patch/5326991/

After Viresh's changes, cpufreq-dt is properly sequenced with cpu cooling
registration. Non-of based drivers also should take advantage if these
changes, as now they do not need to check for cpufreq layer. The check is
where it belongs, in cpu cooling device registration.

BR, Eduardo Valentin


diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
index 1ab0018..9e6945b 100644
--- a/drivers/thermal/cpu_cooling.c
+++ b/drivers/thermal/cpu_cooling.c
@@ -440,6 +440,11 @@ __cpufreq_cooling_register(struct device_node *np,
 	int ret = 0, i;
 	struct cpufreq_policy policy;
 
+	if (!cpufreq_get_current_driver() || !cpufreq_frequency_get_table(0)) {
+		pr_err("cpu_cooling: cpufreq layer not ready! Deferring.\n");
+		return ERR_PTR(-EPROBE_DEFER);
+	}
+
 	/* Verify that all the clip cpus have same freq_min, freq_max limit */
 	for_each_cpu(i, clip_cpus) {
 		/* continue if cpufreq policy not found and not return error */
diff --git a/drivers/thermal/db8500_cpufreq_cooling.c b/drivers/thermal/db8500_cpufreq_cooling.c
index 786d192..1ac7ec6 100644
--- a/drivers/thermal/db8500_cpufreq_cooling.c
+++ b/drivers/thermal/db8500_cpufreq_cooling.c
@@ -18,7 +18,6 @@
  */
 
 #include <linux/cpu_cooling.h>
-#include <linux/cpufreq.h>
 #include <linux/err.h>
 #include <linux/module.h>
 #include <linux/of.h>
@@ -30,10 +29,6 @@ static int db8500_cpufreq_cooling_probe(struct platform_device *pdev)
 	struct thermal_cooling_device *cdev;
 	struct cpumask mask_val;
 
-	/* make sure cpufreq driver has been initialized */
-	if (!cpufreq_frequency_get_table(0))
-		return -EPROBE_DEFER;
-
 	cpumask_set_cpu(0, &mask_val);
 	cdev = cpufreq_cooling_register(&mask_val);
 
diff --git a/drivers/thermal/imx_thermal.c b/drivers/thermal/imx_thermal.c
index 5a1f107..16405b4 100644
--- a/drivers/thermal/imx_thermal.c
+++ b/drivers/thermal/imx_thermal.c
@@ -9,7 +9,6 @@
 
 #include <linux/clk.h>
 #include <linux/cpu_cooling.h>
-#include <linux/cpufreq.h>
 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/init.h>
@@ -459,10 +458,6 @@ static int imx_thermal_probe(struct platform_device *pdev)
 	int measure_freq;
 	int ret;
 
-	if (!cpufreq_get_current_driver()) {
-		dev_dbg(&pdev->dev, "no cpufreq driver!");
-		return -EPROBE_DEFER;
-	}
 	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
 		return -ENOMEM;
diff --git a/drivers/thermal/samsung/exynos_thermal_common.c b/drivers/thermal/samsung/exynos_thermal_common.c
index 3f5ad25..f84975e 100644
--- a/drivers/thermal/samsung/exynos_thermal_common.c
+++ b/drivers/thermal/samsung/exynos_thermal_common.c
@@ -373,7 +373,7 @@ int exynos_register_thermal(struct thermal_sensor_conf *sensor_conf)
 		if (IS_ERR(th_zone->cool_dev[th_zone->cool_dev_size])) {
 			dev_err(sensor_conf->dev,
 				"Failed to register cpufreq cooling device\n");
-			ret = -EINVAL;
+			ret = PTR_ERR(th_zone->cool_dev[th_zone->cool_dev_size]);
 			goto err_unregister;
 		}
 		th_zone->cool_dev_size++;
diff --git a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
index 5fd0386..cf88585 100644
--- a/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
+++ b/drivers/thermal/ti-soc-thermal/ti-thermal-common.c
@@ -28,7 +28,6 @@
 #include <linux/kernel.h>
 #include <linux/workqueue.h>
 #include <linux/thermal.h>
-#include <linux/cpufreq.h>
 #include <linux/cpumask.h>
 #include <linux/cpu_cooling.h>
 #include <linux/of.h>
@@ -407,11 +406,6 @@ int ti_thermal_register_cpu_cooling(struct ti_bandgap *bgp, int id)
 	if (!data)
 		return -EINVAL;
 
-	if (!cpufreq_get_current_driver()) {
-		dev_dbg(bgp->dev, "no cpufreq driver yet\n");
-		return -EPROBE_DEFER;
-	}
-
 	/* Register cooling device */
 	data->cool_dev = cpufreq_cooling_register(cpu_present_mask);
 	if (IS_ERR(data->cool_dev)) {
-- 
2.1.3




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