linux-kernel - Re: [PATCH v12 1/5] device property: Add fwnode

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Message-ID: <20211218103824.67099464@jic23-huawei>
Date:   Sat, 18 Dec 2021 10:38:24 +0000
From:   Jonathan Cameron <jic23@...nel.org>
To:     "Rafael J. Wysocki" <rafael@...nel.org>
Cc:     Anand Ashok Dumbre <anand.ashok.dumbre@...inx.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Lars-Peter Clausen <lars@...afoo.de>,
        linux-iio@...r.kernel.org, git@...inx.com, michals@...inx.com,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Rob Herring <robh+dt@...nel.org>, devicetree@...r.kernel.org
Subject: Re: [PATCH v12 1/5] device property: Add fwnode_iomap()

On Fri, 17 Dec 2021 18:52:00 +0100
"Rafael J. Wysocki" <rafael@...nel.org> wrote:

> On Fri, Dec 3, 2021 at 10:24 PM Anand Ashok Dumbre
> <anand.ashok.dumbre@...inx.com> wrote:
> >
> > This patch introduces a new helper routine - fwnode_iomap(), which
> > allows to map the memory mapped IO for a given device node.
> >
> > This implementation does not cover the ACPI case and may be expanded
> > in the future. The main purpose here is to be able to develop resource
> > provider agnostic drivers.
> >
> > Suggested-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > Signed-off-by: Anand Ashok Dumbre <anand.ashok.dumbre@...inx.com>
> > Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> > ---
> >  drivers/base/property.c  | 16 ++++++++++++++++
> >  include/linux/property.h |  2 ++
> >  2 files changed, 18 insertions(+)
> >
> > diff --git a/drivers/base/property.c b/drivers/base/property.c
> > index f1f35b48ab8b..ed4470410030 100644
> > --- a/drivers/base/property.c
> > +++ b/drivers/base/property.c
> > @@ -958,6 +958,22 @@ int fwnode_irq_get(const struct fwnode_handle *fwnode, unsigned int index)
> >  }
> >  EXPORT_SYMBOL(fwnode_irq_get);
> >
> > +/**
> > + * fwnode_iomap - Maps the memory mapped IO for a given fwnode
> > + * @fwnode:    Pointer to the firmware node
> > + * @index:     Index of the IO range
> > + *
> > + * Returns a pointer to the mapped memory.
> > + */
> > +void __iomem *fwnode_iomap(struct fwnode_handle *fwnode, int index)
> > +{
> > +       if (IS_ENABLED(CONFIG_OF_ADDRESS) && is_of_node(fwnode))
> > +               return of_iomap(to_of_node(fwnode), index);
> > +
> > +       return NULL;
> > +}
> > +EXPORT_SYMBOL(fwnode_iomap);  
> 
> So why is this EXPORT_SYMBOL() and not EXPORT_SYMBOL_GPL()?

Good question.  I'm guessing this is because of_iomap is EXPORT_SYMBOL()
and we don't want to discourage use of this function in preference to it.

Series applied to the togreg branch of iio.git but initially pushed out
as testing to let 0-day see if it can find anything we broke.

Note I can still rebase if people would prefer _GPL() so feel free to
discuss further. +CC Rob Herring and DT list.

Thanks,

Jonathan


> 
> Other than this I'm not an OF_ expert, but I trust Andy, so with the
> above addressed:
> 
> Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> 
> > +
> >  /**
> >   * fwnode_graph_get_next_endpoint - Get next endpoint firmware node
> >   * @fwnode: Pointer to the parent firmware node
> > diff --git a/include/linux/property.h b/include/linux/property.h
> > index 88fa726a76df..6670d5a1ec2a 100644
> > --- a/include/linux/property.h
> > +++ b/include/linux/property.h
> > @@ -122,6 +122,8 @@ void fwnode_handle_put(struct fwnode_handle *fwnode);
> >
> >  int fwnode_irq_get(const struct fwnode_handle *fwnode, unsigned int index);
> >
> > +void __iomem *fwnode_iomap(struct fwnode_handle *fwnode, int index);
> > +
> >  unsigned int device_get_child_node_count(struct device *dev);
> >
> >  static inline bool device_property_read_bool(struct device *dev,
> > --
> > 2.17.1
> >