i2c-dev: attach/detach_adapter cleanups

* Only print that an adapter was attached when it succeeds.
* i2c_dev == NULL on detach simply means that the attach failed
  before, this isn't an error per se.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

i2c: __must_check fixes (i2c-dev)

Check for error on sysfs file creation.
Check for error on device creation.
Delete sysfs file on device destruction.

I couldn't test this one beyond compilation, as it applies on top of
another patch in Greg's tree [1] which breaks all my systems when I
apply it (my udev isn't recent enough.) Anyone with bleeding edge udev
is welcome to test and report.

[1] http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/i2c/i2c-dev-device.patch

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

i2c-dev: Drop the client template

Drop the i2c-dev client template. This saves about 360 bytes of
memory. I got the idea from a similar cleanup Hans-Frieder Vogt
made to i2c-nforce2 recently.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

i2c-dev: Use a list for data storage

Use a list instead of a static array for storing the i2c-dev data.
Given that most systems have less than 10 i2c busses, most of the
space was wasted, so this saves around 1 kB of memory (2 kB on 64-bit
archs.)

The drawback is that lookup was in O(1) and is now in O(N), but given
that the values of N are always small, I don't think this is a problem.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

i2c-dev: Cleanups

* We no more need to include platform_device.h.
* Delete the to_i2c_dev macro, which is no more used (and no more valid
  either.) 
* Drop i2c_dev.minor. Now that the minor number always matches the i2c
  adapter number, this field is redundant with i2c_dev.adap->nr.
* Delete i2c_dev_get_by_adapter() which is now redundant with
  i2c_dev_get_by_minor() for the same reason.
* Drop the local variable dev in i2cdev_attach_adapter(), we can
  easily do without it.

Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

I2C creates some sysfs nodes in the wrong places:  not as children of parent
controllers, but as their peers (!).  This puts them into the right place
always, instead of just when the adapter is on the platform bus.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

Given that implementing i2c_driver.command is optional, there is no
point in an empty implementation thereof.

Signed-off-by: Laurent Riffard <laurent.riffard@free.fr>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Cc: Michael Geng <linux@MichaelGeng.de>
Cc: Petr Vandrovec <vandrove@vc.cvut.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

i2c-dev doesn't use the reference counting logic of struct class_device so move
it to the dynamic method.  This makes the code paths simpler and the driver
smaller.

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jean Delvare <khali@linux-fr.org>

Now that i2c_add_driver() doesn't need the module owner to be set by
hand, we can delete it from the drivers.  This patch catches all of the
drivers that I found in the current tree (if a driver sets the .owner by
hand, it's not a problem, just not needed.)

Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jean Delvare <khali@linux-fr.org>

We should use the i2c_driver.driver's .name and .owner fields
instead of the i2c_driver's ones.

This patch updates the core of the i2c drivers: it removes .name and
.owner fields from the struct i2c_device and modify various
functions to use struct device fields instead.

Signed-off-by: Laurent Riffard <laurent.riffard@free.fr>
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>