Re: [PATCH v2 1/2] Driver core: add bus_find_device_by_fwnode

[Rafael J. Wysocki]

On Tue, Sep 25, 2018 at 7:29 AM Silesh C V <svellattu@xxxxxxxxxx> wrote:
>
> Some drivers need to find the device on a bus having a specific firmware
> node. Currently, such drivers have their own implementations to do this.
> Provide a helper similar to bus_find_device_by_name so that each driver
> does not have to reinvent this.
>
> Signed-off-by: Silesh C V <svellattu@xxxxxxxxxx>
>
> ---
>  drivers/base/bus.c     | 26 ++++++++++++++++++++++++++
>  include/linux/device.h |  3 +++
>  2 files changed, 29 insertions(+)
>
> diff --git a/drivers/base/bus.c b/drivers/base/bus.c
> index 8bfd27e..148b198 100644
> --- a/drivers/base/bus.c
> +++ b/drivers/base/bus.c
> @@ -17,6 +17,7 @@
>  #include <linux/string.h>
>  #include <linux/mutex.h>
>  #include <linux/sysfs.h>
> +#include <linux/of.h>
>  #include "base.h"
>  #include "power/power.h"
>
> @@ -373,6 +374,31 @@ struct device *bus_find_device_by_name(struct bus_type *bus,
>  }
>  EXPORT_SYMBOL_GPL(bus_find_device_by_name);
>
> +static int match_fwnode(struct device *dev, void *data)
> +{
> +       struct fwnode_handle *fwnode = data;
> +       struct device_node *of_node = to_of_node(fwnode);
> +
> +       if (of_node)
> +               return dev->of_node == of_node;
> +       else
> +               return dev->fwnode == fwnode;

Why don't you use dev_fwnode() here?

> +}
> +
> +/**
> + * bus_find_device_by_fwnode - device iterator for locating a particular device
> + * having a specific firmware node
> + * @bus: bus type
> + * @start: Device to begin with
> + * @fwnode: firmware node of the device to match
> + */
> +struct device *bus_find_device_by_fwnode(struct bus_type *bus, struct device *start,
> +                                       struct fwnode_handle *fwnode)
> +{
> +       return bus_find_device(bus, start, (void *)fwnode, match_fwnode);
> +}
> +EXPORT_SYMBOL_GPL(bus_find_device_by_fwnode);
> +
>  /**
>   * subsys_find_device_by_id - find a device with a specific enumeration number
>   * @subsys: subsystem
> diff --git a/include/linux/device.h b/include/linux/device.h
> index 8f88254..09384f6 100644
> --- a/include/linux/device.h
> +++ b/include/linux/device.h
> @@ -171,6 +171,9 @@ struct device *bus_find_device(struct bus_type *bus, struct device *start,
>  struct device *bus_find_device_by_name(struct bus_type *bus,
>                                        struct device *start,
>                                        const char *name);
> +struct device *bus_find_device_by_fwnode(struct bus_type *bus,
> +                                      struct device *start,
> +                                      struct fwnode_handle *fwnode);
>  struct device *subsys_find_device_by_id(struct bus_type *bus, unsigned int id,
>                                         struct device *hint);
>  int bus_for_each_drv(struct bus_type *bus, struct device_driver *start,
> --
> 1.9.1
>