linux-kernel - Re: [PATCH v3.1 1/2] device property: Add device_get_bd_address() and fwnode_get_bd

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Message-ID: <20180925235041.GC22824@google.com>
Date:   Tue, 25 Sep 2018 16:50:41 -0700
From:   Matthias Kaehlcke <mka@...omium.org>
To:     Sakari Ailus <sakari.ailus@...ux.intel.com>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Marcin Wojtas <mw@...ihalf.com>,
        Andy Shevchenko Andy Shevchenko <andy.shevchenko@...il.com>,
        Sinan Kaya <okaya@...eaurora.org>,
        Marcel Holtmann <marcel@...tmann.org>,
        Johan Hedberg <johan.hedberg@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Pekka Enberg <penberg@...nel.org>,
        Masahiro Yamada <yamada.masahiro@...ionext.com>,
        Alexey Dobriyan <adobriyan@...il.com>,
        linux-kernel@...r.kernel.org, linux-bluetooth@...r.kernel.org,
        Balakrishna Godavarthi <bgodavar@...eaurora.org>,
        Loic Poulain <loic.poulain@...aro.org>,
        Brian Norris <briannorris@...omium.org>
Subject: Re: [PATCH v3.1 1/2] device property: Add device_get_bd_address()
 and fwnode_get_bd_address()

Hi Sakari,

thanks for the reviews

On Wed, Sep 26, 2018 at 12:33:22AM +0300, Sakari Ailus wrote:
> Hi Matthias,
> 
> On Tue, Sep 25, 2018 at 12:10:13PM -0700, Matthias Kaehlcke wrote:
> > Provide an API for Bluetooth drivers to retrieve the Bluetooth Device
> > address (BD_ADDR) for a device. If the device node has a property
> > 'local-bd-address' the BD address is read from this property.
> > 
> > The definition of bdaddr_t is moved to types.h to make it visible in
> > property.h without having to include (the mostly unrelated) bluetooth.h
> > 
> > Signed-off-by: Matthias Kaehlcke <mka@...omium.org>
> > Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> > ---
> > Changes in v3:
> > - move definition of bdaddr_t to types.h to avoid include of
> >   bluetooth.h from property.h
> > - add stubs for the new functions
> > 
> > Changes in v2:
> > - use bdaddr_t instead of byte pointer + len
> > - use EXPORT_SYMBOL_GPL for the new functions instead of EXPORT_SYMBOL
> > - put new functions inside #if IS_ENABLED(CONFIG_BT)
> > - some new line juggling in property.h
> > - added 'Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>' tag
> > ---
> >  drivers/base/property.c           | 46 +++++++++++++++++++++++++++++++
> >  include/linux/property.h          | 18 ++++++++++++
> >  include/linux/types.h             |  5 ++++
> >  include/net/bluetooth/bluetooth.h |  5 ----
> >  4 files changed, 69 insertions(+), 5 deletions(-)
> > 
> > diff --git a/drivers/base/property.c b/drivers/base/property.c
> > index 240ab5230ff6..afe412133188 100644
> > --- a/drivers/base/property.c
> > +++ b/drivers/base/property.c
> > @@ -1315,6 +1315,52 @@ void *device_get_mac_address(struct device *dev, char *addr, int alen)
> >  }
> >  EXPORT_SYMBOL(device_get_mac_address);
> >  
> > +#if IS_ENABLED(CONFIG_BT)
> > +
> > +/**
> > + * fwnode_get_bd_address - Get the Bluetooth Device Address (BD_ADDR) from the
> > + *                         firmware node
> > + * @fwnode:	Pointer to the firmware node
> > + * @bd_addr:	Pointer to struct to store the BD address in
> > + *
> > + * Search the firmware node for 'local-bd-address'.
> > + *
> > + * All-zero BD addresses are rejected, because those could be properties
> > + * that exist in the firmware tables, but were not updated by the firmware. For
> > + * example, the DTS could define 'local-bd-address', with zero BD addresses.
> > + */
> > +int fwnode_get_bd_address(struct fwnode_handle *fwnode, bdaddr_t *bd_addr)
> > +{
> > +	bdaddr_t ba;
> > +	int ret;
> > +
> > +	ret = fwnode_property_read_u8_array(fwnode, "local-bd-address",
> > +					    (u8 *)&ba, sizeof(bdaddr_t));
> 
> sizeof(ba)
> 
> > +	if (ret < 0)
> > +		return ret;
> > +	if (is_zero_ether_addr((u8 *)&ba))
> > +		return -ENODATA;
> > +
> > +	memcpy(bd_addr, &ba, sizeof(bdaddr_t));
> 
> How about simply:
> 
> 	*bd_addr = ba;
> 
> Either way,
> 
> Reviewed-by: Sakari Ailus <sakari.ailus@...ux.intel.com>

Thanks I'll address your comments in v4. I'll wait a day or two before
re-spinning for if others have additional feedback.

Cheers

Matthias