linux-kernel - Re: [PATCH v4 1/2] Bluetooth: Add device_get_bd

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Date:   Thu, 27 Sep 2018 22:11:10 +0530
From:   Balakrishna Godavarthi <bgodavar@...eaurora.org>
To:     Matthias Kaehlcke <mka@...omium.org>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        "Rafael J . Wysocki" <rafael@...nel.org>,
        Sakari Ailus <sakari.ailus@...ux.intel.com>,
        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>,
        linux-kernel@...r.kernel.org, linux-bluetooth@...r.kernel.org,
        Loic Poulain <loic.poulain@...aro.org>,
        Brian Norris <briannorris@...omium.org>
Subject: Re: [PATCH v4 1/2] Bluetooth: Add device_get_bd_address()

Hi Matthias,

On 2018-09-27 06:18, Matthias Kaehlcke wrote:
> Provide an API for Bluetooth drivers to retrieve the Bluetooth Device
> address (BD_ADDR) for a device. If the firmware node of the device
> has a property 'local-bd-address' the BD address is read from this
> property.
> 
> Signed-off-by: Matthias Kaehlcke <mka@...omium.org>
> Reviewed-by: Andy Shevchenko <andy.shevchenko@...il.com>
> Reviewed-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
> ---
> Changes in v4:
> - move code from driver/base/property.c to net/bluetooth/lib.c
> - undo move of bdaddr_t declaration
> - merge fwnode_get_bd_address() into device_get_bd_address(). as of now
>   the function is not needed, it can be created later if necessary
> - minor improvements suggested by Sakari
> - updated commit message
> - added 'Reviewed-by: Sakari Ailus <sakari.ailus@...ux.intel.com>' tag
> 
> 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
> ---
>  include/net/bluetooth/bluetooth.h |  2 ++
>  net/bluetooth/lib.c               | 34 +++++++++++++++++++++++++++++++
>  2 files changed, 36 insertions(+)
> 
> diff --git a/include/net/bluetooth/bluetooth.h
> b/include/net/bluetooth/bluetooth.h
> index ec9d6bc65855..6c4cecfda816 100644
> --- a/include/net/bluetooth/bluetooth.h
> +++ b/include/net/bluetooth/bluetooth.h
> @@ -413,4 +413,6 @@ void mgmt_exit(void);
> 
>  void bt_sock_reclassify_lock(struct sock *sk, int proto);
> 
> +int device_get_bd_address(struct device *dev, bdaddr_t *bd_addr);
> +
>  #endif /* __BLUETOOTH_H */
> diff --git a/net/bluetooth/lib.c b/net/bluetooth/lib.c
> index 63e65d9b4b24..78a58ea586c6 100644
> --- a/net/bluetooth/lib.c
> +++ b/net/bluetooth/lib.c
> @@ -26,7 +26,10 @@
> 
>  #define pr_fmt(fmt) "Bluetooth: " fmt
> 
> +#include <linux/etherdevice.h>
>  #include <linux/export.h>
> +#include <linux/fwnode.h>
> +#include <linux/property.h>
> 
>  #include <net/bluetooth/bluetooth.h>
> 
> @@ -198,3 +201,34 @@ void bt_err_ratelimited(const char *format, ...)
>  	va_end(args);
>  }
>  EXPORT_SYMBOL(bt_err_ratelimited);
> +
> +/**
> + * device_get_bd_address - Get the Bluetooth Device Address (BD_ADDR) 
> for a
> + *                         given device
> + * @dev:	Pointer to the device
> + * @bd_addr:	Pointer to struct to store the BD address in
> + *
> + * Search the firmware node of the device 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 device_get_bd_address(struct device *dev, bdaddr_t *bd_addr)
> +{
> +	struct fwnode_handle *fwnode = dev_fwnode(dev);
> +	bdaddr_t ba;
> +	int ret;
> +
> +	ret = fwnode_property_read_u8_array(fwnode, "local-bd-address",
> +					    (u8 *)&ba, sizeof(ba));
> +	if (ret < 0)
> +		return ret;
> +	if (is_zero_ether_addr((u8 *)&ba))
> +		return -ENODATA;
> +
> +	*bd_addr = ba;
> +
> +	return 0;
> +}
> +EXPORT_SYMBOL_GPL(device_get_bd_address);

Reviewed-by: Balakrishna Godavarthi <bgodavar@...eaurora.org>

-- 
Regards
Balakrishna.