linux-kernel - Re: [PATCH v5 03/15] device property: Return true in fwnode_device_is

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Date:   Thu, 7 Jan 2021 15:47:09 +0200
From:   Heikki Krogerus <heikki.krogerus@...ux.intel.com>
To:     Daniel Scally <djrscally@...il.com>
Cc:     linux-kernel@...r.kernel.org, linux-acpi@...r.kernel.org,
        linux-media@...r.kernel.org, devel@...ica.org, rjw@...ysocki.net,
        lenb@...nel.org, gregkh@...uxfoundation.org, mchehab@...nel.org,
        sergey.senozhatsky@...il.com, yong.zhi@...el.com,
        sakari.ailus@...ux.intel.com, bingbu.cao@...el.com,
        tian.shu.qiu@...el.com, robert.moore@...el.com,
        erik.kaneda@...el.com, pmladek@...e.com, rostedt@...dmis.org,
        andriy.shevchenko@...ux.intel.com, linux@...musvillemoes.dk,
        laurent.pinchart+renesas@...asonboard.com,
        jacopo+renesas@...ndi.org, kieran.bingham+renesas@...asonboard.com,
        hverkuil-cisco@...all.nl, m.felsch@...gutronix.de,
        niklas.soderlund+renesas@...natech.se,
        prabhakar.mahadev-lad.rj@...renesas.com, slongerbeam@...il.com,
        Laurent Pinchart <laurent.pinchart@...asonboard.com>
Subject: Re: [PATCH v5 03/15] device property: Return true in
 fwnode_device_is_available for NULL ops

On Thu, Jan 07, 2021 at 01:28:26PM +0000, Daniel Scally wrote:
> Some types of fwnode_handle do not implement the device_is_available()
> check, such as those created by software_nodes. There isn't really a
> meaningful way to check for the availability of a device that doesn't
> actually exist, so if the check isn't implemented just assume that the
> "device" is present.
> 
> Suggested-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> Reviewed-by: Laurent Pinchart <laurent.pinchart@...asonboard.com>
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> Acked-by: Sakari Ailus <sakari.ailus@...ux.intel.com>
> Signed-off-by: Daniel Scally <djrscally@...il.com>

Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>

> ---
> Changes in v5:
> 
> 	- Changed the commit subject
> 
>  drivers/base/property.c | 6 ++++++
>  1 file changed, 6 insertions(+)
> 
> diff --git a/drivers/base/property.c b/drivers/base/property.c
> index 35b95c6ac0c6..0bf5260f14c6 100644
> --- a/drivers/base/property.c
> +++ b/drivers/base/property.c
> @@ -837,9 +837,15 @@ EXPORT_SYMBOL_GPL(fwnode_handle_put);
>  /**
>   * fwnode_device_is_available - check if a device is available for use
>   * @fwnode: Pointer to the fwnode of the device.
> + *
> + * For fwnode node types that don't implement the .device_is_available()
> + * operation, this function returns true.
>   */
>  bool fwnode_device_is_available(const struct fwnode_handle *fwnode)
>  {
> +	if (!fwnode_has_op(fwnode, device_is_available))
> +		return true;
> +
>  	return fwnode_call_bool_op(fwnode, device_is_available);
>  }
>  EXPORT_SYMBOL_GPL(fwnode_device_is_available);
> -- 
> 2.25.1

thanks,

-- 
heikki