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authorNishanth Menon <nm@ti.com>2013-04-10 01:22:01 +0200
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2013-04-10 13:41:00 +0200
commit49ded525d4486dc97fc965858bf3ddf245463670 (patch)
tree9c3a586f60a8cc6782ccdd23d4337fcb516caff2 /drivers
parentarm: exynos: Enable OPP library support for exynos5440 (diff)
downloadlinux-49ded525d4486dc97fc965858bf3ddf245463670.tar.xz
linux-49ded525d4486dc97fc965858bf3ddf245463670.zip
cpufreq: OMAP: instantiate omap-cpufreq as a platform_driver
As multi-platform build is being adopted by more and more ARM platforms, initcall function should be used very carefully. For example, when CONFIG_ARM_OMAP2PLUS_CPUFREQ is built in the kernel, omap_cpufreq_init() will be called on all the platforms to initialize omap-cpufreq driver. Further, on OMAP, we now use Soc generic cpufreq-cpu0 driver using device tree entries. To allow cpufreq-cpu0 and omap-cpufreq drivers to co-exist for OMAP in a single image, we need to ensure the following: 1. With device tree boot, we use cpufreq-cpu0 2. With non device tree boot, we use omap-cpufreq In the case of (1), we will have cpu OPPs and regulator registered as part of the device tree nodes, to ensure that omap-cpufreq and cpufreq-cpu0 don't conflict in managing the frequency of the same CPU, we should not permit omap-cpufreq to be probed. In the case of (2), we will not have the cpufreq-cpu0 device, hence only omap-cpufreq will be active. To eliminate this undesired these effects, we change omap-cpufreq driver to have it instantiated as a platform_driver and register "omap-cpufreq" device only when booted without device tree nodes on OMAP platforms. This allows the following: a) Will only run on platforms that create the platform_device "omap-cpufreq". b) Since the platform_device is registered only when device tree nodes are *not* populated, omap-cpufreq driver does not conflict with the usage of cpufreq-cpu0 driver which is used on OMAP platforms when device tree nodes are present. Inspired by commit 5553f9e26f6f49a93ba732fd222eac6973a4cf35 (cpufreq: instantiate cpufreq-cpu0 as a platform_driver) [robherring2@gmail.com: reported conflict of omap-cpufreq vs other driver in an non-device tree supported boot] Reported-by: Rob Herring <robherring2@gmail.com> Signed-off-by: Nishanth Menon <nm@ti.com> Acked-by: Viresh Kumar <viresh.kumar@linaro.org> Signed-off-by: Kevin Hilman <khilman@linaro.org> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/cpufreq/omap-cpufreq.c19
1 files changed, 14 insertions, 5 deletions
diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
index ad7549c13ed2..0279d18a57f9 100644
--- a/drivers/cpufreq/omap-cpufreq.c
+++ b/drivers/cpufreq/omap-cpufreq.c
@@ -25,6 +25,7 @@
#include <linux/opp.h>
#include <linux/cpu.h>
#include <linux/module.h>
+#include <linux/platform_device.h>
#include <linux/regulator/consumer.h>
#include <asm/smp_plat.h>
@@ -243,7 +244,7 @@ static struct cpufreq_driver omap_driver = {
.attr = omap_cpufreq_attr,
};
-static int __init omap_cpufreq_init(void)
+static int omap_cpufreq_probe(struct platform_device *pdev)
{
mpu_dev = get_cpu_device(0);
if (!mpu_dev) {
@@ -271,12 +272,20 @@ static int __init omap_cpufreq_init(void)
return cpufreq_register_driver(&omap_driver);
}
-static void __exit omap_cpufreq_exit(void)
+static int omap_cpufreq_remove(struct platform_device *pdev)
{
- cpufreq_unregister_driver(&omap_driver);
+ return cpufreq_unregister_driver(&omap_driver);
}
+static struct platform_driver omap_cpufreq_platdrv = {
+ .driver = {
+ .name = "omap-cpufreq",
+ .owner = THIS_MODULE,
+ },
+ .probe = omap_cpufreq_probe,
+ .remove = omap_cpufreq_remove,
+};
+module_platform_driver(omap_cpufreq_platdrv);
+
MODULE_DESCRIPTION("cpufreq driver for OMAP SoCs");
MODULE_LICENSE("GPL");
-module_init(omap_cpufreq_init);
-module_exit(omap_cpufreq_exit);