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> --- Changes in V3: - converted to platform_driver to address https://patchwork.kernel.org/patch/2303491/ as well - modified CC list. V2: https://patchwork.kernel.org/patch/2303491/ V1: https://patchwork.kernel.org/patch/2273681/ 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); -- 1.7.9.5 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
