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Message-ID: <54412F7C.6090508@roeck-us.net>
Date: Fri, 17 Oct 2014 08:02:20 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: atull <atull@...nsource.altera.com>
CC: jdelvare@...e.de, lm-sensors@...sensors.org, lgirdwood@...il.com,
broonie@...nel.org, robh+dt@...nel.org, pawel.moll@....com,
mark.rutland@....com, ijc+devicetree@...lion.org.uk,
galak@...eaurora.org, devicetree@...r.kernel.org,
linux-kernel@...r.kernel.org, delicious.quinoa@...il.com,
dinguyen@...nsource.altera.com, yvanderv@...nsource.altera.com
Subject: Re: [PATCH v6 3/4] pmbus: add regulator support
On 10/17/2014 07:48 AM, atull wrote:
> On Thu, 16 Oct 2014, Guenter Roeck wrote:
>
>> On Thu, Oct 16, 2014 at 01:40:23PM -0500, atull wrote:
>>> On Thu, 16 Oct 2014, Guenter Roeck wrote:
>>>
>>>> On Wed, Oct 15, 2014 at 01:55:09PM -0500, atull@...nsource.altera.com wrote:
>>>>> From: Alan Tull <atull@...nsource.altera.com>
>>>>>
>>>>> Add support for simple on/off control of each channel.
>>>>>
>>>>> To add regulator support, the pmbus part driver needs to add
>>>>> regulator_desc information and number of regulators to its
>>>>> pmbus_driver_info struct.
>>>>>
>>>>> regulator_desc can be declared using default macro for a
>>>>> regulator (PMBUS_REGULATOR) that is in pmbus.h
>>>>>
>>>>> The regulator_init_data can be initialized from either
>>>>> platform data or the device tree.
>>>>>
>>>>> Signed-off-by: Alan Tull <atull@...nsource.altera.com>
>>>>> Reviewed-by: Mark Brown <broonie@...nel.org>
>>>>> Cc: Guenter Roeck <linux@...ck-us.net>
>>>>
>>>> Hi Alan,
>>>>
>>>> I am still seeing lots of the following:
>>>>
>>>> vout0: Failed to create debugfs directory
>>>> vout1: Failed to create debugfs directory
>>>> vout2: Failed to create debugfs directory
>>>> vout3: Failed to create debugfs directory
>>>> vout4: Failed to create debugfs directory
>>>> vout5: Failed to create debugfs directory
>>>> vout6: Failed to create debugfs directory
>>>> vout7: Failed to create debugfs directory
>>>>
>>>> I thought there was a problem in the regulator core, but after looking
>>>> into it concluded that the regulator core _should_ prepend the names
>>>> with the device name when creating the debugfs entries, unless no device
>>>> name is specified. So something must be missing. We'll need to sort
>>>> this out before I can accept the code.
>>>>
>>>> Thanks,
>>>> Guenter
>>>>
>>>
>>> Hi Guenter,
>>>
>>> OK, I will look into it.
>>>
>>
>> Can you try the following patch ? It may not be perfect, but it does
>> the job for me.
>>
>> Mark, would that patch be acceptable ?
>>
>> Thanks,
>> Guenter
>> ---
>> From: Guenter Roeck <linux@...ck-us.net>
>> Date: Thu, 16 Oct 2014 13:08:35 -0700
>> Subject: [PATCH] regulator: Ensure unique regulator debugfs directory names
>>
>> If multiple regulator devices of the same type exist in a system,
>> the regulator driver assigns generic names for the regulators it
>> provides, and debugfs is enabled, the regulator subsystem attempts
>> to create multiple entries with the same name in the regulator debugfs
>> directory. This fails for all but the first regulator, resulting in
>> multiple "Failed to create debugfs directory" log entries.
>>
>> To avoid the problem, prepend the debugfs directory name for a regulator
>> with its parent device name if available, but only if no explicit
>> regulator name was provided.
>>
>> Cc: Alan Tull <atull@...nsource.altera.com>
>> Signed-off-by: Guenter Roeck <linux@...ck-us.net>
>> ---
>> drivers/regulator/core.c | 13 ++++++++++++-
>> 1 file changed, 12 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/regulator/core.c b/drivers/regulator/core.c
>> index cd87c0c..92f7a53 100644
>> --- a/drivers/regulator/core.c
>> +++ b/drivers/regulator/core.c
>> @@ -3538,7 +3538,18 @@ static int add_regulator_attributes(struct regulator_dev *rdev)
>>
>> static void rdev_init_debugfs(struct regulator_dev *rdev)
>> {
>> - rdev->debugfs = debugfs_create_dir(rdev_get_name(rdev), debugfs_root);
>> + struct device *parent = rdev->dev.parent;
>> + const char *rname = rdev_get_name(rdev);
>> + char name[NAME_MAX];
>> +
>> + /* Avoid duplicate debugfs directory names */
>> + if (parent && rname == rdev->desc->name) {
>> + snprintf(name, sizeof(name), "%s-%s", dev_name(parent),
>> + rname);
>> + rname = name;
>> + }
>> +
>> + rdev->debugfs = debugfs_create_dir(rname, debugfs_root);
>> if (!rdev->debugfs) {
>> rdev_warn(rdev, "Failed to create debugfs directory\n");
>> return;
>> --
>> 1.9.1
>>
>
> Hi Guenter,
>
> I tried it out on a board with two ltc2978's. It looked really good to
> me. It solves the debugfs issue without affecting the DT.
>
> root@...fpga_cyclone5:~# ls /sys/kernel/debug/regulator/
> 0-005c-vout0 0-005c-vout6 0-005e-vout7
> 0-005c-vout1 0-005c-vout7 FPGA-1.1V
> 0-005c-vout2 0-005e-vout1 FPGA-1.5V
> 0-005c-vout3 0-005e-vout3 FPGA-2.5V
> 0-005c-vout4 0-005e-vout5
> reg-dummy-regulator-dummy
> 0-005c-vout5 0-005e-vout6 supply_map
>
> Alan
>
Great, thanks a lot for testing.
I'll submit the patch officially. Let's see if Mark accepts it.
Guenter
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