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>
diff --git a/arch/arm/mach-omap2/pm.c b/arch/arm/mach-omap2/pm.c
index 673a4c1..8d15f9a 100644
--- a/arch/arm/mach-omap2/pm.c
+++ b/arch/arm/mach-omap2/pm.c
@@ -265,6 +265,12 @@
omap2_set_init_voltage("iva", "dpll_iva_m5x2_ck", "iva");
}
+static inline void omap_init_cpufreq(void)
+{
+ struct platform_device_info devinfo = { .name = "omap-cpufreq", };
+ platform_device_register_full(&devinfo);
+}
+
static int __init omap2_common_pm_init(void)
{
if (!of_have_populated_dt())
@@ -294,6 +300,9 @@
/* Smartreflex device init */
omap_devinit_smartreflex();
+
+ /* cpufreq dummy device instantiation */
+ omap_init_cpufreq();
}
#ifdef CONFIG_SUSPEND