On Tue, Feb 18, 2014 at 11:03:35AM -0600, Felipe Balbi wrote:
> On Tue, Feb 18, 2014 at 08:59:11AM -0800, Greg KH wrote:
> > On Tue, Feb 18, 2014 at 10:20:54AM -0600, Felipe Balbi wrote:
> > > On Fri, Jan 17, 2014 at 10:22:35AM +0100, Markus Pargmann wrote:
> > > > debugfs files to show the contents of important dsps registers.
> > > >
> > > > Signed-off-by: Markus Pargmann <mpa@xxxxxxxxxxxxxx>
> > > > ---
> > > > drivers/usb/musb/musb_dsps.c | 54 ++++++++++++++++++++++++++++++++++++++++++++
> > > > 1 file changed, 54 insertions(+)
> > > >
> > > > diff --git a/drivers/usb/musb/musb_dsps.c b/drivers/usb/musb/musb_dsps.c
> > > > index 593d3c9..d0a97d6 100644
> > > > --- a/drivers/usb/musb/musb_dsps.c
> > > > +++ b/drivers/usb/musb/musb_dsps.c
> > > > @@ -46,6 +46,8 @@
> > > > #include <linux/of_irq.h>
> > > > #include <linux/usb/of.h>
> > > >
> > > > +#include <linux/debugfs.h>
> > > > +
> > > > #include "musb_core.h"
> > > >
> > > > static const struct of_device_id musb_dsps_of_match[];
> > > > @@ -137,6 +139,26 @@ struct dsps_glue {
> > > > unsigned long last_timer; /* last timer data for each instance */
> > > >
> > > > struct dsps_context context;
> > > > + struct debugfs_regset32 regset;
> > > > + struct dentry *dbgfs_root;
> > > > +};
> > > > +
> > > > +static const struct debugfs_reg32 dsps_musb_regs[] = {
> > > > + { "revision", 0x00 },
> > > > + { "control", 0x14 },
> > > > + { "status", 0x18 },
> > > > + { "eoi", 0x24 },
> > > > + { "intr0_stat", 0x30 },
> > > > + { "intr1_stat", 0x34 },
> > > > + { "intr0_set", 0x38 },
> > > > + { "intr1_set", 0x3c },
> > > > + { "txmode", 0x70 },
> > > > + { "rxmode", 0x74 },
> > > > + { "autoreq", 0xd0 },
> > > > + { "srpfixtime", 0xd4 },
> > > > + { "tdown", 0xd8 },
> > > > + { "phy_utmi", 0xe0 },
> > > > + { "mode", 0xe8 },
> > > > };
> > > >
> > > > static void dsps_musb_try_idle(struct musb *musb, unsigned long timeout)
> > > > @@ -369,6 +391,30 @@ out:
> > > > return ret;
> > > > }
> > > >
> > > > +static int dsps_musb_dbg_init(struct musb *musb, struct dsps_glue *glue)
> > > > +{
> > > > + struct dentry *root;
> > > > + struct dentry *file;
> > > > + char buf[128];
> > > > +
> > > > + sprintf(buf, "%s.dsps", dev_name(musb->controller));
> > > > + root = debugfs_create_dir(buf, NULL);
> > > > + if (!root)
> > >
> > > wrong, you should be using IS_ERR()
> >
> > !root is fine, IS_ERR() will fail if CONFIG_DEBUGFS is not enabled.
>
> in that case, files will be created on parent directory right ?
If, for some reason, creating a directory fails and then creating a file
would succeed, yes, that will happen.
> If we pass a ERR_PTR(-ENODEV), otoh, we will try to dereference it in
> __create_file().
No, because -ENODEV will only happen if debugfs is not enabled, so no
dereference will ever happen.
Don't worry about checking return values from debugfs, it shouldn't be
needed.
thanks,
greg k-h
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