Re: [PATCH 2/7] Input: wacom - Get features from driver info

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Bastian Blank <waldi@debian.org>
Cc: linux-input@vger.kernel.org, linux-kernel@vger.kernel.org,
	Ping Cheng <pingc@wacom.com>
Subject: Re: [PATCH 2/7] Input: wacom - Get features from driver info
Date: Thu, 7 Jan 2010 11:06:30 -0800	[thread overview]
Message-ID: <201001071106.31688.dmitry.torokhov@gmail.com> (raw)
In-Reply-To: <20100107182936.GA12913@wavehammer.waldi.eu.org>

On Thursday 07 January 2010 10:29:36 am Bastian Blank wrote:
> Get the features information from the driver info of the usb device id
> structure provided by the caller.  The device ids and feature structs
> are strong coupled using indices.
> 
> Signed-off-by: Bastian Blank <waldi@debian.org>
> ---
>  drivers/input/tablet/wacom_sys.c |    6 ++++--
>  1 files changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/input/tablet/wacom_sys.c
>  b/drivers/input/tablet/wacom_sys.c index ab42c25..b0f3fc3 100644
> --- a/drivers/input/tablet/wacom_sys.c
> +++ b/drivers/input/tablet/wacom_sys.c
> @@ -532,7 +532,7 @@ static int wacom_probe(struct usb_interface *intf,
>  const struct usb_device_id *i struct usb_endpoint_descriptor *endpoint;
>  	struct wacom *wacom;
>  	struct wacom_wac *wacom_wac;
> -	struct wacom_features *features;
> +	struct wacom_features *features = (void *)id->driver_info;

What is this cast for?

>  	struct input_dev *input_dev;
>  	int error = -ENOMEM;
> 
> @@ -557,7 +557,9 @@ static int wacom_probe(struct usb_interface *intf,
>  const struct usb_device_id *i usb_make_path(dev, wacom->phys,
>  sizeof(wacom->phys));
>  	strlcat(wacom->phys, "/input0", sizeof(wacom->phys));
> 
> -	wacom_wac->features = features = get_wacom_feature(id);
> +	if (!features)
> +		features = get_wacom_feature(id);

In which cases driver would not have driver_info set up?

> +	wacom_wac->features = features;
>  	BUG_ON(features->pktlen > WACOM_PKGLEN_MAX);
> 
>  	input_dev->name = wacom_wac->features->name;
> 

-- 
Dmitry