Re: [PATCH v6 3/4] pmbus: add regulator support

[Guenter Roeck]

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@xxxxxxxxxxxxxxxxxxxxx wrote:
> > > > > From: Alan Tull <atull@xxxxxxxxxxxxxxxxxxxxx>
> > > > >
> > > > > 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@xxxxxxxxxxxxxxxxxxxxx>
> > > > > Reviewed-by: Mark Brown <broonie@xxxxxxxxxx>
> > > > > Cc: Guenter Roeck <linux@xxxxxxxxxxxx>
> > > >
> > > > 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@xxxxxxxxxxxx>
> > 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@xxxxxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
> > ---
> >   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@socfpga_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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