The 01/10 change adds and exports new of_get_i2c_adapter_by_node() interface of i2c core, the rest of patches fix current users of of_find_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 (this is run on iMX6 platform with HDMI and I2C bus drivers compiled as kernel modules for clearness):
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().
Mainly the change concerns DRM users of I2C bus device.
The change is based on torvalds/master branch, d6ac4ffc61a
RFC of the 01/10 change is http://www.spinics.net/lists/linux-i2c/msg20257.html
Vladimir Zapolskiy (10): i2c: add and export of_get_i2c_adapter_by_node() interface drm: dw_hdmi: use of_get_i2c_adapter_by_node interface drm: exynos_hdmi: use of_get_i2c_adapter_by_node interface drm: imx-tve: use of_get_i2c_adapter_by_node interface drm: panel-simple: use of_get_i2c_adapter_by_node interface drm: sti_hdmi: use of_get_i2c_adapter_by_node interface drm: tegra: use of_get_i2c_adapter_by_node interface drm: tilcdc: use of_get_i2c_adapter_by_node interface fbdev: omap2: connector-dvi: use of_get_i2c_adapter_by_node interface i2c: i2c-arb-gpio-challenge: use of_get_i2c_adapter_by_node interface
drivers/gpu/drm/bridge/dw_hdmi.c | 14 ++++-- drivers/gpu/drm/exynos/exynos_hdmi.c | 7 +-- drivers/gpu/drm/imx/imx-tve.c | 56 +++++++++++++++------- drivers/gpu/drm/panel/panel-simple.c | 9 ++-- drivers/gpu/drm/sti/sti_hdmi.c | 19 +++----- drivers/gpu/drm/tegra/output.c | 19 ++++---- drivers/gpu/drm/tilcdc/tilcdc_tfp410.c | 6 +-- drivers/i2c/i2c-core.c | 20 ++++++++ drivers/i2c/muxes/i2c-arb-gpio-challenge.c | 3 +- .../video/fbdev/omap2/displays-new/connector-dvi.c | 2 +- include/linux/i2c.h | 6 +++ 11 files changed, 104 insertions(+), 57 deletions(-)