Re: [PATCH v2 3/4] i2c: core: add and export of_get_i2c_adapter_by_node() interface

[Wolfram Sang <wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org>]

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On Mon, Jul 27, 2015 at 05:30:50PM +0300, Vladimir Zapolskiy wrote:
> 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-nmGgyN9QBj3QT0dZR+AlfA@public.gmane.org>

Applied to for-next, thanks!


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