|| ||Jean Delvare <khali-PUYAD+kWke1g9hUCZPvPmw@public.gmane.org> |
|| ||Linux I2C <linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
David Brownell <dbrownell-Rn4VEauK+AKRv+LV9MX5uipxlwaOVQ5f@public.gmane.org> |
|| ||[PATCH 0/6] i2c: Get rid of the legacy binding model |
|| ||Sat, 2 May 2009 11:38:56 +0200|
|| ||Article, Thread
As the last few remaining legacy i2c drivers are being converted, we
can finally get rid of the legacy binding model supporting code in
i2c-core. Here come 6 patches which do exactly that:
[1/6] i2c: Kill client_register and client_unregister methods
[2/6] i2c: Get rid of the legacy binding model
[3/6] i2c: Drop i2c_probe function
[4/6] i2c: Merge i2c_attach_client into i2c_new_device
[5/6] i2c: Kill is_newstyle_driver
[6/6] i2c: Kill the redundant client list
As one would expect, the size reduction is very significant:
Documentation/feature-removal-schedule.txt | 10 -
Documentation/i2c/writing-clients | 16 -
drivers/i2c/i2c-core.c | 366 +++--------------------------
include/linux/i2c.h | 57 +----
4 files changed, 48 insertions(+), 401 deletions(-)
From a binary perspective, "size" announces an 18% shrink.
There are two things which should still be investigated.
1* In i2c_device_uevent() there is the following piece of code:
/* by definition, legacy drivers can't hotplug */
David, I presume this can go away?
2* Core locking should be checked. I am not completely sure what
core_lock was supposed to protect, nor what it should protect now. I
think it should protect at least i2c_adapter_idr, driver->detect()
calls (which may add a device to the driver->clients list) and
driver->attach_adapter() calls (for the same reason), although for the
latter two, a per-driver lock may be more appropriate.
At the moment, we also hold the lock for all of i2c_register_adapter(),
i2c_del_adapter() and i2c_del_driver(), but not i2c_register_driver(),
which seems a little inconsistent. David, do you know if we need to
serialize the calls to device_register() and device_unregister(), or if
the driver core takes care of this for us?
Anything else needs to be protected?