Add a private_data pointer to struct device_attribute

[Timur Tabi <timur@freescale.com>]

A private data pointer in struct device_attribute allows the 'show' and 'store'
functions to access instance data.  This handy in situations where the
driver_data and platform_data pointers of 'struct device' are already used
for other purposes.

Signed-off-by: Timur Tabi <timur@freescale.com>
---

Greg, can you tell me if you think this patch is a good idea?  It doesn't
appear to do any harm, and I'm working on an ALSA driver that could benefit
for this patch.  I think 2.6.25 would be a good target.

 include/linux/device.h |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/include/linux/device.h b/include/linux/device.h
index 2e15822..10708ee 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -344,6 +344,7 @@ struct device_attribute {
 			char *buf);
 	ssize_t (*store)(struct device *dev, struct device_attribute *attr,
 			 const char *buf, size_t count);
+	void *private_data;
 };
 
 #define DEVICE_ATTR(_name,_mode,_show,_store) \
-- 
1.5.2.4