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SubjectRe: [PATCH] drivers: cpufreq: Fix sysfs duplicate filename creation for platform-device
On 17-09-17, 00:04, sunil.m@techveda.org wrote:
> From: Suniel Mahesh <sunil.m@techveda.org>
>
> ti-cpufreq.c and cpufreq-dt-platdev.c are registering
> platform device with same name "cpufreq-dt" using
> platform_device_register_*() routines.
> This is leading to build warnings appended below.
>
> This patch does the following:
> (a) Remove platform-device registration routine from
> ti-cpufreq.c, it appears unnecessary as per CPUfreq framework
> kernel Documentation. The ti-cpufreq driver main task is to use
> revision and an efuse value from the SoC and provide the OPP
> framework with supported hardware information.
> Platform-device creation is taken care by cpufreq-dt-platdev.c.
> (b) In case if OPP-v2 is not supported just return without
> registering the platorm-device.
> (c) Rename the goto label
>
> [ 2.370167] ------------[ cut here ]------------
> [ 2.375087] WARNING: CPU: 0 PID: 1 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x58/0x78
> [ 2.383112] sysfs: cannot create duplicate filename '/devices/platform/cpufreq-dt'
> [ 2.391219] Modules linked in:
> [ 2.394506] CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.13.0-next-20170912 #1
> [ 2.402006] Hardware name: Generic AM33XX (Flattened Device Tree)
> [ 2.408437] [<c0110a28>] (unwind_backtrace) from [<c010ca84>] (show_stack+0x10/0x14)
> [ 2.416568] [<c010ca84>] (show_stack) from [<c0827d64>] (dump_stack+0xac/0xe0)
> [ 2.424165] [<c0827d64>] (dump_stack) from [<c0137470>] (__warn+0xd8/0x104)
> [ 2.431488] [<c0137470>] (__warn) from [<c01374d0>] (warn_slowpath_fmt+0x34/0x44)
> [ 2.439351] [<c01374d0>] (warn_slowpath_fmt) from [<c03459d0>] (sysfs_warn_dup+0x58/0x78)
> [ 2.447938] [<c03459d0>] (sysfs_warn_dup) from [<c0345ab8>] (sysfs_create_dir_ns+0x80/0x98)
> [ 2.456719] [<c0345ab8>] (sysfs_create_dir_ns) from [<c082c554>] (kobject_add_internal+0x9c/0x2d4)
> [ 2.466124] [<c082c554>] (kobject_add_internal) from [<c082c7d8>] (kobject_add+0x4c/0x9c)
> [ 2.474712] [<c082c7d8>] (kobject_add) from [<c05803e4>] (device_add+0xcc/0x57c)
> [ 2.482489] [<c05803e4>] (device_add) from [<c0584b74>] (platform_device_add+0x100/0x220)
> [ 2.491085] [<c0584b74>] (platform_device_add) from [<c05855a8>] (platform_device_register_full+0xf4/0x118)
> [ 2.501305] [<c05855a8>] (platform_device_register_full) from [<c067023c>] (ti_cpufreq_init+0x150/0x22c)
> [ 2.511253] [<c067023c>] (ti_cpufreq_init) from [<c0101df4>] (do_one_initcall+0x3c/0x170)
> [ 2.519838] [<c0101df4>] (do_one_initcall) from [<c0c00eb4>] (kernel_init_freeable+0x1fc/0x2c4)
> [ 2.528974] [<c0c00eb4>] (kernel_init_freeable) from [<c083bcac>] (kernel_init+0x8/0x110)
> [ 2.537565] [<c083bcac>] (kernel_init) from [<c0107d18>] (ret_from_fork+0x14/0x3c)
> [ 2.545981] ---[ end trace 2fc00e213c13ab20 ]---
> [ 2.551051] ------------[ cut here ]------------
> [ 2.555931] WARNING: CPU: 0 PID: 1 at lib/kobject.c:240 kobject_add_internal+0x254/0x2d4
> [ 2.564578] kobject_add_internal failed for cpufreq-dt with -EEXIST, don't try to register
> things with the same name in the same directory.
> [ 2.577977] Modules linked in:
> [ 2.581261] CPU: 0 PID: 1 Comm: swapper/0 Tainted: G W 4.13.0-next-20170912 #1
> [ 2.590013] Hardware name: Generic AM33XX (Flattened Device Tree)
> [ 2.596437] [<c0110a28>] (unwind_backtrace) from [<c010ca84>] (show_stack+0x10/0x14)
> [ 2.604573] [<c010ca84>] (show_stack) from [<c0827d64>] (dump_stack+0xac/0xe0)
> [ 2.612172] [<c0827d64>] (dump_stack) from [<c0137470>] (__warn+0xd8/0x104)
> [ 2.619494] [<c0137470>] (__warn) from [<c01374d0>] (warn_slowpath_fmt+0x34/0x44)
> [ 2.627362] [<c01374d0>] (warn_slowpath_fmt) from [<c082c70c>] (kobject_add_internal+0x254/0x2d4)
> [ 2.636666] [<c082c70c>] (kobject_add_internal) from [<c082c7d8>] (kobject_add+0x4c/0x9c)
> [ 2.645255] [<c082c7d8>] (kobject_add) from [<c05803e4>] (device_add+0xcc/0x57c)
> [ 2.653027] [<c05803e4>] (device_add) from [<c0584b74>] (platform_device_add+0x100/0x220)
> [ 2.661615] [<c0584b74>] (platform_device_add) from [<c05855a8>] (platform_device_register_full+0xf4/0x118)
> [ 2.671833] [<c05855a8>] (platform_device_register_full) from [<c067023c>] (ti_cpufreq_init+0x150/0x22c)
> [ 2.681779] [<c067023c>] (ti_cpufreq_init) from [<c0101df4>] (do_one_initcall+0x3c/0x170)
> [ 2.690377] [<c0101df4>] (do_one_initcall) from [<c0c00eb4>] (kernel_init_freeable+0x1fc/0x2c4)
> [ 2.699510] [<c0c00eb4>] (kernel_init_freeable) from [<c083bcac>] (kernel_init+0x8/0x110)
> [ 2.708106] [<c083bcac>] (kernel_init) from [<c0107d18>] (ret_from_fork+0x14/0x3c)
> [ 2.716217] ---[ end trace 2fc00e213c13ab21 ]---
>
> Signed-off-by: Suniel Mahesh <sunil.m@techveda.org>
> Tested-by: Suniel Mahesh <sunil.m@techveda.org>

You don't need a Tested-by from yourself as it is already assumed after the
Signed-off by.

> ---
> Note:
> - Patch was compile tested and built(ARCH=arm) on next-20170915.
> - Patch was hardware tested on AM335x SOC based board.
> - cpufreq-dt.c driver got probed and entries related to Dynamic Voltage
> and Frequency scaling were created in
> sysfs @ sys/devices/system/cpu/cpu0/cpufreq.
> - No build/run-time issues reported.
> ---
> drivers/cpufreq/ti-cpufreq.c | 6 ++----
> 1 file changed, 2 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/cpufreq/ti-cpufreq.c b/drivers/cpufreq/ti-cpufreq.c
> index b29cd33..97c086a 100644
> --- a/drivers/cpufreq/ti-cpufreq.c
> +++ b/drivers/cpufreq/ti-cpufreq.c
> @@ -224,7 +224,7 @@ static int ti_cpufreq_init(void)
> if (!opp_data->opp_node) {
> dev_info(opp_data->cpu_dev,
> "OPP-v2 not supported, cpufreq-dt will attempt to use legacy tables.\n");
> - goto register_cpufreq_dt;
> + goto ti_cpufreq_exit;
> }
>
> ret = ti_cpufreq_setup_syscon_register(opp_data);
> @@ -255,9 +255,7 @@ static int ti_cpufreq_init(void)
>
> of_node_put(opp_data->opp_node);
>
> -register_cpufreq_dt:
> - platform_device_register_simple("cpufreq-dt", -1, NULL, 0);
> -

NACK.

It was done this way to make sure ti-cpufreq.c does all the platform specific
stuff before the cpufreq-dt driver comes into place.

If both ti-cpufreq and cpufreq-dt-platform are creating the device, then there
is something else wrong. Did it start failing recently only? Then it might be
due to one of the patches I posted for cpufreq-dt-platdev. You need to add that
patch in the fixes tag and add TI SoCs in the blacklist of devices (with opp-v2)
in cpufreq-dt-platform.c.

--
viresh

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