[PATCH v2 1/1] spi: dw: Make debugfs name unique between instances

[PATCH v2 1/1] spi: dw: Make debugfs name unique between instances

[Phil Reid]

Some system have multiple dw devices. Currently the driver uses a
fixed name for the debugfs dir. Append bus_num to the debugfs dir
name to make it unique.

Signed-off-by: Phil Reid <preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org>
---

Notes:
    Changes from v1:
    - Reduce buffer size to 32.
    - Use bus_num instead of device name.

 drivers/spi/spi-dw.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
index 27960e4..77439ac 100644
--- a/drivers/spi/spi-dw.c
+++ b/drivers/spi/spi-dw.c
@@ -107,7 +107,10 @@ static ssize_t dw_spi_show_regs(struct file *file, char __user *user_buf,
 
 static int dw_spi_debugfs_init(struct dw_spi *dws)
 {
-	dws->debugfs = debugfs_create_dir("dw_spi", NULL);
+	char name[32];
+
+	snprintf(name, 32, "dw_spi%d", dws->master->bus_num);
+	dws->debugfs = debugfs_create_dir(name, NULL);
 	if (!dws->debugfs)
 		return -ENOMEM;
 
-- 
1.8.3.1

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Re: [PATCH v2 1/1] spi: dw: Make debugfs name unique between instances

[Andy Shevchenko]

On Tue, Jan 3, 2017 at 6:54 AM, Phil Reid <preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org> wrote:
> Some system have multiple dw devices. Currently the driver uses a
> fixed name for the debugfs dir. Append bus_num to the debugfs dir
> name to make it unique.
>

Reviewed-by: Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

> Signed-off-by: Phil Reid <preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org>
> ---
>
> Notes:
>     Changes from v1:
>     - Reduce buffer size to 32.
>     - Use bus_num instead of device name.
>
>  drivers/spi/spi-dw.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
> index 27960e4..77439ac 100644
> --- a/drivers/spi/spi-dw.c
> +++ b/drivers/spi/spi-dw.c
> @@ -107,7 +107,10 @@ static ssize_t dw_spi_show_regs(struct file *file, char __user *user_buf,
>
>  static int dw_spi_debugfs_init(struct dw_spi *dws)
>  {
> -       dws->debugfs = debugfs_create_dir("dw_spi", NULL);
> +       char name[32];
> +
> +       snprintf(name, 32, "dw_spi%d", dws->master->bus_num);
> +       dws->debugfs = debugfs_create_dir(name, NULL);
>         if (!dws->debugfs)
>                 return -ENOMEM;
>
> --
> 1.8.3.1
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-spi" in
> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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-- 
With Best Regards,
Andy Shevchenko
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Re: [PATCH v2 1/1] spi: dw: Make debugfs name unique between instances

[Andy Shevchenko]

On Wed, Jan 4, 2017 at 1:02 AM, Andy Shevchenko
<andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
> On Tue, Jan 3, 2017 at 6:54 AM, Phil Reid <preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org> wrote:
>> Some system have multiple dw devices. Currently the driver uses a
>> fixed name for the debugfs dir. Append bus_num to the debugfs dir
>> name to make it unique.
>>
>
> Reviewed-by: Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>

Ah, hold on.
dws->name is exactly what you are trying to re-invent here. Just use
it directly.


>
>> Signed-off-by: Phil Reid <preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org>
>> ---
>>
>> Notes:
>>     Changes from v1:
>>     - Reduce buffer size to 32.
>>     - Use bus_num instead of device name.
>>
>>  drivers/spi/spi-dw.c | 5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
>> index 27960e4..77439ac 100644
>> --- a/drivers/spi/spi-dw.c
>> +++ b/drivers/spi/spi-dw.c
>> @@ -107,7 +107,10 @@ static ssize_t dw_spi_show_regs(struct file *file, char __user *user_buf,
>>
>>  static int dw_spi_debugfs_init(struct dw_spi *dws)
>>  {
>> -       dws->debugfs = debugfs_create_dir("dw_spi", NULL);
>> +       char name[32];
>> +
>> +       snprintf(name, 32, "dw_spi%d", dws->master->bus_num);
>> +       dws->debugfs = debugfs_create_dir(name, NULL);
>>         if (!dws->debugfs)
>>                 return -ENOMEM;
>>
>> --
>> 1.8.3.1
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-spi" in
>> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>
>
>
> --
> With Best Regards,
> Andy Shevchenko



-- 
With Best Regards,
Andy Shevchenko
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Re: [PATCH v2 1/1] spi: dw: Make debugfs name unique between instances

[Phil Reid]

G'day Andy,

On 4/01/2017 07:05, Andy Shevchenko wrote:
> On Wed, Jan 4, 2017 at 1:02 AM, Andy Shevchenko
> <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>> On Tue, Jan 3, 2017 at 6:54 AM, Phil Reid <preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org> wrote:
>>> Some system have multiple dw devices. Currently the driver uses a
>>> fixed name for the debugfs dir. Append bus_num to the debugfs dir
>>> name to make it unique.
>>>
>>
>> Reviewed-by: Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>
> Ah, hold on.
> dws->name is exactly what you are trying to re-invent here. Just use
> it directly.
>
I did try that initially.
However when I used that they where all named dw_spi65535.

This seems to be because bus_num is set to -1 ion the call to dw_spi_add_host.
Which results in dynamic bus_num assignment in the call to devm_spi_register_master.

Moving 'snprintf(dws->name, sizeof(dws->name), "dw_spi%d", dws->bus_num);' to after
devm_spi_register_master results in a warning being emitting when request_irq is called
about an emit string at :
WARNING: CPU: 0 PID: 1 at fs/proc/generic.c:369 __proc_create+0x1e8/0x1f0

cat /proc/interrupts currently also shows dw_spi65535

Rewrite dws->name after devm_spi_register_master is called fixes /proc/interrupts
And it could then be used in debugfs.
But does not fix the filename in /proc/irq/<num>/dw_spi65535

I couldn't see a safe workaround with dws->name
Unless we can move the request_irq to after devm_spi_register_master

Thoughts?



>
>>
>>> Signed-off-by: Phil Reid <preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org>
>>> ---
>>>
>>> Notes:
>>>     Changes from v1:
>>>     - Reduce buffer size to 32.
>>>     - Use bus_num instead of device name.
>>>
>>>  drivers/spi/spi-dw.c | 5 ++++-
>>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/spi/spi-dw.c b/drivers/spi/spi-dw.c
>>> index 27960e4..77439ac 100644
>>> --- a/drivers/spi/spi-dw.c
>>> +++ b/drivers/spi/spi-dw.c
>>> @@ -107,7 +107,10 @@ static ssize_t dw_spi_show_regs(struct file *file, char __user *user_buf,
>>>
>>>  static int dw_spi_debugfs_init(struct dw_spi *dws)
>>>  {
>>> -       dws->debugfs = debugfs_create_dir("dw_spi", NULL);
>>> +       char name[32];
>>> +
>>> +       snprintf(name, 32, "dw_spi%d", dws->master->bus_num);
>>> +       dws->debugfs = debugfs_create_dir(name, NULL);
>>>         if (!dws->debugfs)
>>>                 return -ENOMEM;
>>>
>>> --
>>> 1.8.3.1
>>>
>>> --
>>> To unsubscribe from this list: send the line "unsubscribe linux-spi" in
>>> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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>>
>>
>>
>> --
>> With Best Regards,
>> Andy Shevchenko
>
>
>


-- 
Regards
Phil Reid

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Re: [PATCH v2 1/1] spi: dw: Make debugfs name unique between instances

[Andy Shevchenko]

On Wed, Jan 4, 2017 at 4:21 AM, Phil Reid <preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org> wrote:
> G'day Andy,
>
> On 4/01/2017 07:05, Andy Shevchenko wrote:
>>
>> On Wed, Jan 4, 2017 at 1:02 AM, Andy Shevchenko
>> <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> wrote:
>>>
>>> On Tue, Jan 3, 2017 at 6:54 AM, Phil Reid <preid-qgqNFa1JUf/o2iN0hyhwsIdd74u8MsAO@public.gmane.org>
>>> wrote:
>>>>
>>>> Some system have multiple dw devices. Currently the driver uses a
>>>> fixed name for the debugfs dir. Append bus_num to the debugfs dir
>>>> name to make it unique.
>>>>
>>>
>>> Reviewed-by: Andy Shevchenko <andy.shevchenko-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
>>
>>
>> Ah, hold on.
>> dws->name is exactly what you are trying to re-invent here. Just use
>> it directly.
>>
> I did try that initially.
> However when I used that they where all named dw_spi65535.
>
> This seems to be because bus_num is set to -1 ion the call to
> dw_spi_add_host.
> Which results in dynamic bus_num assignment in the call to
> devm_spi_register_master.
>
> Moving 'snprintf(dws->name, sizeof(dws->name), "dw_spi%d", dws->bus_num);'
> to after
> devm_spi_register_master results in a warning being emitting when
> request_irq is called
> about an emit string at :
> WARNING: CPU: 0 PID: 1 at fs/proc/generic.c:369 __proc_create+0x1e8/0x1f0
>
> cat /proc/interrupts currently also shows dw_spi65535
>
> Rewrite dws->name after devm_spi_register_master is called fixes
> /proc/interrupts
> And it could then be used in debugfs.
> But does not fix the filename in /proc/irq/<num>/dw_spi65535
>
> I couldn't see a safe workaround with dws->name
> Unless we can move the request_irq to after devm_spi_register_master
>
> Thoughts?

I briefly checked couple of SPI drivers, they are doing
request_irq(..., dev_name(...), ...);

So, I propose to use that pattern for now, and move snprintf() call to
debugfs related code.

-- 
With Best Regards,
Andy Shevchenko
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