On Tuesday, April 09, 2013 04:22:01 PM Kevin Hilman wrote:
> From: Nishanth Menon <nm@xxxxxx>
>
> 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)
>
> Cc: Kevin Hilman <khilman@xxxxxxxxxx>
> Cc: Rajendra Nayak <rnayak@xxxxxx>
> Cc: Paul Walmsley <paul@xxxxxxxxx>
> Cc: "Benoît Cousson" <b-cousson@xxxxxx>
> Cc: Jon Hunter <jon-hunter@xxxxxx>
> Cc: Keerthy <j-keerthy@xxxxxx>
> Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
> Cc: Shawn Guo <shawn.guo@xxxxxxxxxx>
> [robherring2@xxxxxxxxx: reported conflict of omap-cpufreq vs other
> driver in an non-device tree supported boot]
> Reported-by: Rob Herring <robherring2@xxxxxxxxx>
> Signed-off-by: Nishanth Menon <nm@xxxxxx>
> Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
> Signed-off-by: Kevin Hilman <khilman@xxxxxxxxxx>
> ---
> Rafael, can you add this one for v3.10? It applies on top the
> rest of your cpufreq changes and I've verified that the OMAP
> changes are OK and don't conflict with anything else we have
> queued for v3.10 on OMAP.
>
> This patch was previously part of a 2-patch series, but the
> other part is still in discussion, and this part can be merged
> independently.
Applied to my bleeding-edge branch and will go to linux-next after build testing.
Thanks,
Rafael
> arch/arm/mach-omap2/pm.c | 9 +++++++++
> drivers/cpufreq/omap-cpufreq.c | 19 ++++++++++++++-----
> 2 files changed, 23 insertions(+), 5 deletions(-)
>
> 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 @@ static void __init omap4_init_voltages(void)
> 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 @@ int __init omap2_common_pm_late_init(void)
>
> /* Smartreflex device init */
> omap_devinit_smartreflex();
> +
> + /* cpufreq dummy device instantiation */
> + omap_init_cpufreq();
> }
>
> #ifdef CONFIG_SUSPEND
> diff --git a/drivers/cpufreq/omap-cpufreq.c b/drivers/cpufreq/omap-cpufreq.c
> index 9128c07..d4f84b8 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>
> @@ -252,7 +253,7 @@ 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) {
> @@ -280,12 +281,20 @@ 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);
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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