linux/include
Vladimir Zapolskiy 48e9743dd6 i2c: core: add and export of_get_i2c_adapter_by_node() interface
of_find_i2c_adapter_by_node() call requires quite often missing
put_device(), and i2c_put_adapter() releases a device locked by
i2c_get_adapter() only. In general module_put(adapter->owner) and
put_device(dev) are not interchangeable.

This is a common error reproduction scenario as a result of the
misusage described above (for clearness this is run on iMX6 platform
with HDMI and I2C bus drivers compiled as kernel modules):

    root@mx6q:~# lsmod | grep i2c
    i2c_imx                10213  0
    root@mx6q:~# lsmod | grep dw_hdmi_imx
    dw_hdmi_imx             3631  0
    dw_hdmi                11846  1 dw_hdmi_imx
    imxdrm                  8674  3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb
    drm_kms_helper        113765  5 dw_hdmi,imxdrm,imx_ipuv3_crtc,imx_ldb
    root@mx6q:~# rmmod dw_hdmi_imx
    root@mx6q:~# lsmod | grep i2c
    i2c_imx                10213  -1

                                 ^^^^^

    root@mx6q:~# rmmod i2c_imx
    rmmod: ERROR: Module i2c_imx is in use

To fix existing users of these interfaces and to avoid any further
confusion and misusage in future, add one more interface
of_get_i2c_adapter_by_node(), it is similar to i2c_get_adapter() in
sense that an I2C bus device driver found and locked by user can be
correctly unlocked by i2c_put_adapter().

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>
2015-08-10 08:37:36 +02:00
..
acpi Additional ACPICA material for v4.2-rc1 2015-07-02 17:11:28 -07:00
asm-generic mm: clean up per architecture MM hook header files 2015-07-17 16:39:53 -07:00
clocksource ARM: 8366/1: move Dual-Timer SP804 driver to drivers/clocksource 2015-06-02 09:58:18 +01:00
crypto crypto: rng - Do not free default RNG when it becomes unused 2015-06-22 15:49:18 +08:00
drm Merge tag 'drm-intel-fixes-2015-08-07' of git://anongit.freedesktop.org/drm-intel 2015-08-08 04:18:14 +03:00
dt-bindings The changes to the common clock framework for 4.2 are dominated by new 2015-07-01 19:22:00 -07:00
keys
kvm
linux i2c: core: add and export of_get_i2c_adapter_by_node() interface 2015-08-10 08:37:36 +02:00
math-emu
media Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/cooloney/linux-leds 2015-07-01 19:09:11 -07:00
memory
misc cxl: Add AFU virtual PHB and kernel API 2015-06-03 13:27:20 +10:00
net net: sched: fix refcount imbalance in actions 2015-07-30 14:20:39 -07:00
pcmcia
ras tracing: add trace event for memory-failure 2015-06-24 17:49:43 -07:00
rdma IB: Add rdma_cap_ib_switch helper and use where appropriate 2015-07-14 13:20:08 -04:00
rxrpc
scsi IB/srp: Avoid using uninitialized variable 2015-07-14 13:20:09 -04:00
soc Merge branch 'for-linus' of git://ftp.arm.linux.org.uk/~rmk/linux-arm 2015-06-26 12:20:00 -07:00
sound ASoC: Further updates for v4.2 2015-06-22 11:32:41 +02:00
target iscsi-target: Fix iscsit_start_kthreads failure OOPs 2015-07-24 14:19:43 -07:00
trace Merge branch 'for-linus-4.2' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs 2015-06-30 20:07:45 -07:00
uapi The only bulk changes in this request is ABI updates for ASoC topology 2015-08-08 04:33:35 +03:00
video Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux 2015-06-26 13:18:51 -07:00
xen
Kbuild