Re: [PATCH v6 11/23] drivers/fsi: Add master unscan

[Christopher Bostic]

On 5/10/17 2:31 AM, Joel Stanley wrote:
> On Tue, Apr 11, 2017 at 5:16 AM, Christopher Bostic
> <cbostic@xxxxxxxxxxxxxxxxxx> wrote:
> > From: Chris Bostic <cbostic@xxxxxxxxxxxxxxxxxx>
> >
> > Allow a master to undo a previous scan.  Should a master scan a bus
> > twice it will need to ensure it doesn't double register any
> > previously detected device.
> >
> > Signed-off-by: Chris Bostic <cbostic@xxxxxxxxxxxxxxxxxx>
> > Signed-off-by: Joel Stanley <joel@xxxxxxxxx>
> > ---
> >   drivers/fsi/fsi-core.c | 40 ++++++++++++++++++++++++++++++++++++++++
> >   1 file changed, 40 insertions(+)
> >
> > diff --git a/drivers/fsi/fsi-core.c b/drivers/fsi/fsi-core.c
> > index 4da0b030..75d2a88 100644
> > --- a/drivers/fsi/fsi-core.c
> > +++ b/drivers/fsi/fsi-core.c
> > @@ -69,6 +69,7 @@ struct fsi_slave {
> >          uint32_t                size;   /* size of slave address space */
> >   };
> >
> > +#define to_fsi_master(d) container_of(d, struct fsi_master, dev)
> >   #define to_fsi_slave(d) container_of(d, struct fsi_slave, dev)
> >
> >   static int fsi_master_read(struct fsi_master *master, int link,
> > @@ -491,6 +492,37 @@ static int fsi_master_scan(struct fsi_master *master)
> >          return 0;
> >   }
> >
> > +static int __fsi_slave_remove_device(struct device *dev, void *arg)
> > +{
> > +       device_unregister(dev);
> > +       return 0;
> > +}
> > +
> > +static int __fsi_master_remove_slave(struct device *dev, void *arg)
> > +{
> > +       device_for_each_child(dev, NULL, __fsi_slave_remove_device);
> > +       device_unregister(dev);
> > +       return 0;
> > +}
> I can't see why the two above functions to have the __ prefix.

Jeremy Kerr had introduced this convention.  Jeremy can you comment on 
this?

> > +
> > +static void fsi_master_unscan(struct fsi_master *master)
> > +{
> > +       device_for_each_child(&master->dev, NULL, __fsi_master_remove_slave);
> > +}
> > +
> > +static ssize_t master_rescan_store(struct device *dev,
> > +               struct device_attribute *attr, const char *buf, size_t count)
> > +{
> > +       struct fsi_master *master = to_fsi_master(dev);
> > +
> > +       fsi_master_unscan(master);
> > +       fsi_master_scan(master);
> These function can return errors. Do you want to return those errors
> to userspace?

That would be the best approach yes... Will change.

> > +
> > +       return count;
> > +}
> > +
> > +static DEVICE_ATTR(rescan, 0200, NULL, master_rescan_store);
> > +
> >   int fsi_master_register(struct fsi_master *master)
> >   {
> >          int rc;
> > @@ -507,7 +539,15 @@ int fsi_master_register(struct fsi_master *master)
> >                  return rc;
> >          }
> >
> > +       rc = device_create_file(&master->dev, &dev_attr_rescan);
> > +       if (rc) {
> > +               device_unregister(&master->dev);
> > +               ida_simple_remove(&master_ida, master->idx);
> > +               return rc;
> > +       }
> > +
> >          fsi_master_scan(master);
> > +
> >          return 0;
> >   }
> >   EXPORT_SYMBOL_GPL(fsi_master_register);
> > --
> > 1.8.2.2