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.
Below is a common error reproduction scenario as a result of the
misusage described above (this is run on iMX6 platform with
HDMI and I2C bus drivers compiled as kernel modules for clearness):
root at mx6q:~# lsmod | grep i2c
i2c_imx 15348 0
root at mx6q:~# lsmod | grep dw_hdmi_imx
dw_hdmi_imx 3567 0
dw_hdmi 15850 1 dw_hdmi_imx
imxdrm 8610 3 dw_hdmi_imx,imx_ipuv3_crtc,imx_ldb
root at mx6q:~# rmmod dw_hdmi_imx
root at mx6q:~# lsmod | grep i2c
i2c_imx 15348 -1
^^^^^
root at mx6q:~# rmmod i2c_imx
rmmod: ERROR: Module i2c_imx is in use
To fix existing users of these interfaces use of_get_i2c_adapter_by_node()
interface, which is similar to i2c_get_adapter() in sense that an I2C bus
device driver found and locked by a user can be correctly unlocked by
i2c_put_adapter() call.
Changes from v1 to v2:
- none, this series is a straightforward bugfix, v1 was a blend of
I2C core changes, bugfixes and improvements
The change is based on dri/drm-next.
Vladimir Zapolskiy (3):
drm: dw_hdmi: use of_get_i2c_adapter_by_node interface
drm: tilcdc: use of_get_i2c_adapter_by_node interface
drm: tegra: use of_get_i2c_adapter_by_node interface
drivers/gpu/drm/bridge/dw_hdmi.c | 14 +++++++++-----
drivers/gpu/drm/tegra/output.c | 23 ++++++++++++-----------
drivers/gpu/drm/tilcdc/tilcdc_tfp410.c | 6 ++----
3 files changed, 23 insertions(+), 20 deletions(-)
--
2.5.0