Date:   Tue, 19 Sep 2017 10:12:13 -0500
From:   Dave Gerlach <d-gerlach@...com>
To:     <sunil.m@...hveda.org>, <viresh.kumar@...aro.org>
CC:     <rjw@...ysocki.net>, <linux-kernel@...r.kernel.org>,
        <linux-pm@...r.kernel.org>, <karthik@...hveda.org>
Subject: Re: [PATCH v2] drivers: cpufreq: Fix sysfs duplicate filename
 creation for platform-device

Hi,
On 09/18/2017 02:18 PM, sunil.m@...hveda.org wrote:
> From: Suniel Mahesh <sunil.m@...hveda.org>
> 
> ti-cpufreq and cpufreq-dt-platdev drivers are registering platform-device
> with same name "cpufreq-dt" using platform_device_register_*() routines.
> This is leading to build warnings appended below.
> 
> Providing hardware information to OPP framework along with the platform-
> device creation should be done by ti-cpufreq driver before cpufreq-dt
> driver comes into place.
> 
> This patch add's TI SoC am33xx (uses opp-v2 property) in the blacklist of
> devices in cpufreq-dt-platform driver to avoid creating platform-device
> twice and remove build warnings (suggested by Viresh Kumar).

This looks good to me, but this also affects "ti,am43" and "ti,dra7" platforms,
care to add those to the blacklist as well with this patch? Thanks.

Regards,
Dave

> 
> [    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 ]---
> 
> Fixes: edeec420de24 ("cpufreq: dt-cpufreq: platdev Automatically create device with OPP v2")
> Signed-off-by: Suniel Mahesh <sunil.m@...hveda.org>
> ---
> Changes for v2:
> - The approach (as a result patch decsription) was changed as per
>   inputs given by Viresh.
> - Patch was compile tested and built(ARCH=arm) on next-20170918.
> ---
> Note:
> - Patch was hardware tested on AM335x SOC based board.
> - cpufreq-dt 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/cpufreq-dt-platdev.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/drivers/cpufreq/cpufreq-dt-platdev.c b/drivers/cpufreq/cpufreq-dt-platdev.c
> index a020da7..61fe7ee 100644
> --- a/drivers/cpufreq/cpufreq-dt-platdev.c
> +++ b/drivers/cpufreq/cpufreq-dt-platdev.c
> @@ -106,6 +106,7 @@
>   * platforms using "operating-points-v2" property.
>   */
>  static const struct of_device_id blacklist[] __initconst = {
> +	{ .compatible = "ti,am33xx", },
>  	{ }
>  };
>  
> 

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