[PATCH 00/10] i2c/drm: fix i2c adapter device driver user counter

[PATCH 00/10] i2c/drm: fix i2c adapter device driver user counter

[Vladimir Zapolskiy]

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 at mx6q:~# lsmod | grep i2c
    i2c_imx                10213  0
    root at 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 at mx6q:~# rmmod dw_hdmi_imx
    root at mx6q:~# lsmod | grep i2c
    i2c_imx                10213  -1

                                 ^^^^^

    root at 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(-)

-- 
2.1.4

[PATCH 01/10] i2c: add and export of_get_i2c_adapter_by_node() interface

[Vladimir Zapolskiy]

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 at mx6q:~# lsmod | grep i2c
    i2c_imx                10213  0
    root at 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 at mx6q:~# rmmod dw_hdmi_imx
    root at mx6q:~# lsmod | grep i2c
    i2c_imx                10213  -1

                                 ^^^^^

    root at 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>
---
The change is based on RFC http://www.spinics.net/lists/linux-i2c/msg20257.html

* added new exported function declaration in include/linux/i2c.h
* added put_device(dev) call right inside of_get_i2c_adapter_by_node()
* corrected authorship of the change

 drivers/i2c/i2c-core.c | 20 ++++++++++++++++++++
 include/linux/i2c.h    |  6 ++++++
 2 files changed, 26 insertions(+)

diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
index 069a41f..0d902ab 100644
--- a/drivers/i2c/i2c-core.c
+++ b/drivers/i2c/i2c-core.c
@@ -1356,6 +1356,26 @@ struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 	return i2c_verify_adapter(dev);
 }
 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
+
+struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
+{
+	struct device *dev;
+	struct i2c_adapter *adapter;
+
+	dev = bus_find_device(&i2c_bus_type, NULL, node,
+			      of_dev_node_match);
+	if (!dev)
+		return NULL;
+
+	adapter = i2c_verify_adapter(dev);
+	if (adapter && !try_module_get(adapter->owner))
+		adapter = NULL;
+
+	put_device(dev);
+
+	return adapter;
+}
+EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
 #else
 static void of_i2c_register_devices(struct i2c_adapter *adap) { }
 #endif /* CONFIG_OF */
diff --git a/include/linux/i2c.h b/include/linux/i2c.h
index e83a738..87bb217 100644
--- a/include/linux/i2c.h
+++ b/include/linux/i2c.h
@@ -638,6 +638,7 @@ extern struct i2c_client *of_find_i2c_device_by_node(struct device_node *node);
 /* must call put_device() when done with returned i2c_adapter device */
 extern struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node);
 
+struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node);
 #else
 
 static inline struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
@@ -649,6 +650,11 @@ static inline struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node
 {
 	return NULL;
 }
+
+static inline struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
+{
+	return NULL;
+}
 #endif /* CONFIG_OF */
 
 #endif /* _LINUX_I2C_H */
-- 
2.1.4

[PATCH 01/10] i2c: add and export of_get_i2c_adapter_by_node() interface

[Thierry Reding]

On Wed, Jul 08, 2015 at 03:59:12PM +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 at mx6q:~# lsmod | grep i2c
>     i2c_imx                10213  0
>     root at 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 at mx6q:~# rmmod dw_hdmi_imx
>     root at mx6q:~# lsmod | grep i2c
>     i2c_imx                10213  -1
> 
>                                  ^^^^^
> 
>     root at 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>
> ---
> The change is based on RFC http://www.spinics.net/lists/linux-i2c/msg20257.html
> 
> * added new exported function declaration in include/linux/i2c.h
> * added put_device(dev) call right inside of_get_i2c_adapter_by_node()
> * corrected authorship of the change
> 
>  drivers/i2c/i2c-core.c | 20 ++++++++++++++++++++
>  include/linux/i2c.h    |  6 ++++++
>  2 files changed, 26 insertions(+)
> 
> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> index 069a41f..0d902ab 100644
> --- a/drivers/i2c/i2c-core.c
> +++ b/drivers/i2c/i2c-core.c
> @@ -1356,6 +1356,26 @@ struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
>  	return i2c_verify_adapter(dev);
>  }
>  EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
> +
> +struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
> +{
> +	struct device *dev;
> +	struct i2c_adapter *adapter;
> +
> +	dev = bus_find_device(&i2c_bus_type, NULL, node,
> +			      of_dev_node_match);
> +	if (!dev)
> +		return NULL;
> +
> +	adapter = i2c_verify_adapter(dev);
> +	if (adapter && !try_module_get(adapter->owner))
> +		adapter = NULL;
> +
> +	put_device(dev);

I don't think this is correct. Users still need to keep a reference to
the device, otherwise it can simply disappear even if the module stays
around (think sysfs bind/unbind attributes).

Looking at i2c_put_adapter() it seems like it would need to do more than
just drop the module reference. Then again, that probably means that we
need to add a get_device() somewhere in i2c_get_adapter() to balance the
put_device() in i2c_put_adapter().

Thierry
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[PATCH 01/10] i2c: add and export of_get_i2c_adapter_by_node() interface

[Vladimir Zapolskiy]

Hi Thierry,

On 08.07.2015 16:11, Thierry Reding wrote:
> On Wed, Jul 08, 2015 at 03:59:12PM +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 at mx6q:~# lsmod | grep i2c
>>     i2c_imx                10213  0
>>     root at 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 at mx6q:~# rmmod dw_hdmi_imx
>>     root at mx6q:~# lsmod | grep i2c
>>     i2c_imx                10213  -1
>>
>>                                  ^^^^^
>>
>>     root at 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>
>> ---
>> The change is based on RFC http://www.spinics.net/lists/linux-i2c/msg20257.html
>>
>> * added new exported function declaration in include/linux/i2c.h
>> * added put_device(dev) call right inside of_get_i2c_adapter_by_node()
>> * corrected authorship of the change
>>
>>  drivers/i2c/i2c-core.c | 20 ++++++++++++++++++++
>>  include/linux/i2c.h    |  6 ++++++
>>  2 files changed, 26 insertions(+)
>>
>> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
>> index 069a41f..0d902ab 100644
>> --- a/drivers/i2c/i2c-core.c
>> +++ b/drivers/i2c/i2c-core.c
>> @@ -1356,6 +1356,26 @@ struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
>>  	return i2c_verify_adapter(dev);
>>  }
>>  EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
>> +
>> +struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
>> +{
>> +	struct device *dev;
>> +	struct i2c_adapter *adapter;
>> +
>> +	dev = bus_find_device(&i2c_bus_type, NULL, node,
>> +			      of_dev_node_match);
>> +	if (!dev)
>> +		return NULL;
>> +
>> +	adapter = i2c_verify_adapter(dev);
>> +	if (adapter && !try_module_get(adapter->owner))
>> +		adapter = NULL;
>> +
>> +	put_device(dev);
> 
> I don't think this is correct. Users still need to keep a reference to
> the device, otherwise it can simply disappear even if the module stays
> around (think sysfs bind/unbind attributes).
> 
> Looking at i2c_put_adapter() it seems like it would need to do more than
> just drop the module reference. Then again, that probably means that we
> need to add a get_device() somewhere in i2c_get_adapter() to balance the
> put_device() in i2c_put_adapter().

it makes sense for me, thanks for momentary review.

I'm hesitating to add put_device(dev) to i2c_put_adapter() etc. in this
series though. After development and testing I would like to send
another preceding independent change updating i2c_get_adapter(),
i2c_put_adapter() and clients (or if you wish you can do it), then I'll
rebase 01/10 on top of it, the rest most probably is unchanged.

--
With best wishes,
Vladimir

[PATCH 01/10] i2c: add and export of_get_i2c_adapter_by_node() interface

[Thierry Reding]

On Wed, Jul 08, 2015 at 04:31:37PM +0300, Vladimir Zapolskiy wrote:
> Hi Thierry,
> 
> On 08.07.2015 16:11, Thierry Reding wrote:
> > On Wed, Jul 08, 2015 at 03:59:12PM +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 at mx6q:~# lsmod | grep i2c
> >>     i2c_imx                10213  0
> >>     root at 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 at mx6q:~# rmmod dw_hdmi_imx
> >>     root at mx6q:~# lsmod | grep i2c
> >>     i2c_imx                10213  -1
> >>
> >>                                  ^^^^^
> >>
> >>     root at 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>
> >> ---
> >> The change is based on RFC http://www.spinics.net/lists/linux-i2c/msg20257.html
> >>
> >> * added new exported function declaration in include/linux/i2c.h
> >> * added put_device(dev) call right inside of_get_i2c_adapter_by_node()
> >> * corrected authorship of the change
> >>
> >>  drivers/i2c/i2c-core.c | 20 ++++++++++++++++++++
> >>  include/linux/i2c.h    |  6 ++++++
> >>  2 files changed, 26 insertions(+)
> >>
> >> diff --git a/drivers/i2c/i2c-core.c b/drivers/i2c/i2c-core.c
> >> index 069a41f..0d902ab 100644
> >> --- a/drivers/i2c/i2c-core.c
> >> +++ b/drivers/i2c/i2c-core.c
> >> @@ -1356,6 +1356,26 @@ struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
> >>  	return i2c_verify_adapter(dev);
> >>  }
> >>  EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
> >> +
> >> +struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
> >> +{
> >> +	struct device *dev;
> >> +	struct i2c_adapter *adapter;
> >> +
> >> +	dev = bus_find_device(&i2c_bus_type, NULL, node,
> >> +			      of_dev_node_match);
> >> +	if (!dev)
> >> +		return NULL;
> >> +
> >> +	adapter = i2c_verify_adapter(dev);
> >> +	if (adapter && !try_module_get(adapter->owner))
> >> +		adapter = NULL;
> >> +
> >> +	put_device(dev);
> > 
> > I don't think this is correct. Users still need to keep a reference to
> > the device, otherwise it can simply disappear even if the module stays
> > around (think sysfs bind/unbind attributes).
> > 
> > Looking at i2c_put_adapter() it seems like it would need to do more than
> > just drop the module reference. Then again, that probably means that we
> > need to add a get_device() somewhere in i2c_get_adapter() to balance the
> > put_device() in i2c_put_adapter().
> 
> it makes sense for me, thanks for momentary review.
> 
> I'm hesitating to add put_device(dev) to i2c_put_adapter() etc. in this
> series though. After development and testing I would like to send
> another preceding independent change updating i2c_get_adapter(),
> i2c_put_adapter() and clients (or if you wish you can do it), then I'll
> rebase 01/10 on top of it, the rest most probably is unchanged.

I think that would make sense, yes.

Thierry
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[PATCH 02/10] drm: dw_hdmi: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

The change fixes an overflow over zero of I2C bus driver user counter:

    root at mx6q:~# lsmod | grep i2c
    i2c_imx                10213  0
    root at 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 at mx6q:~# rmmod dw_hdmi_imx
    root at mx6q:~# lsmod | grep i2c
    i2c_imx                10213  -1

                                 ^^^^^

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

Note that prior to this change put_device() coupled with
of_find_i2c_adapter_by_node() was missing on error path of
dw_hdmi_bind(), added i2c_put_adapter() there along with the change.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
---
 drivers/gpu/drm/bridge/dw_hdmi.c | 14 +++++++++-----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/bridge/dw_hdmi.c b/drivers/gpu/drm/bridge/dw_hdmi.c
index 816d104..e86776c 100644
--- a/drivers/gpu/drm/bridge/dw_hdmi.c
+++ b/drivers/gpu/drm/bridge/dw_hdmi.c
@@ -1591,7 +1591,7 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
 
 	ddc_node = of_parse_phandle(np, "ddc-i2c-bus", 0);
 	if (ddc_node) {
-		hdmi->ddc = of_find_i2c_adapter_by_node(ddc_node);
+		hdmi->ddc = of_get_i2c_adapter_by_node(ddc_node);
 		of_node_put(ddc_node);
 		if (!hdmi->ddc) {
 			dev_dbg(hdmi->dev, "failed to read ddc node\n");
@@ -1603,20 +1603,22 @@ int dw_hdmi_bind(struct device *dev, struct device *master,
 	}
 
 	hdmi->regs = devm_ioremap_resource(dev, iores);
-	if (IS_ERR(hdmi->regs))
-		return PTR_ERR(hdmi->regs);
+	if (IS_ERR(hdmi->regs)) {
+		ret = PTR_ERR(hdmi->regs);
+		goto err_res;
+	}
 
 	hdmi->isfr_clk = devm_clk_get(hdmi->dev, "isfr");
 	if (IS_ERR(hdmi->isfr_clk)) {
 		ret = PTR_ERR(hdmi->isfr_clk);
 		dev_err(hdmi->dev, "Unable to get HDMI isfr clk: %d\n", ret);
-		return ret;
+		goto err_res;
 	}
 
 	ret = clk_prepare_enable(hdmi->isfr_clk);
 	if (ret) {
 		dev_err(hdmi->dev, "Cannot enable HDMI isfr clock: %d\n", ret);
-		return ret;
+		goto err_res;
 	}
 
 	hdmi->iahb_clk = devm_clk_get(hdmi->dev, "iahb");
@@ -1682,6 +1684,8 @@ err_iahb:
 	clk_disable_unprepare(hdmi->iahb_clk);
 err_isfr:
 	clk_disable_unprepare(hdmi->isfr_clk);
+err_res:
+	i2c_put_adapter(hdmi->ddc);
 
 	return ret;
 }
-- 
2.1.4

[PATCH 03/10] drm: exynos_hdmi: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

On release of_get_i2c_adapter_by_node() requires i2c_put_adapter() call,
which replaces put_device(). By the way added of_node_put(ddc_node) to
eliminate memory leak, if OF_DYNAMIC is enabled.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
---
 drivers/gpu/drm/exynos/exynos_hdmi.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/exynos/exynos_hdmi.c b/drivers/gpu/drm/exynos/exynos_hdmi.c
index 99e2864..399eff9 100644
--- a/drivers/gpu/drm/exynos/exynos_hdmi.c
+++ b/drivers/gpu/drm/exynos/exynos_hdmi.c
@@ -2407,7 +2407,8 @@ static int hdmi_probe(struct platform_device *pdev)
 	}
 
 out_get_ddc_adpt:
-	hdata->ddc_adpt = of_find_i2c_adapter_by_node(ddc_node);
+	hdata->ddc_adpt = of_get_i2c_adapter_by_node(ddc_node);
+	of_node_put(ddc_node);
 	if (!hdata->ddc_adpt) {
 		DRM_ERROR("Failed to get ddc i2c adapter by node\n");
 		return -EPROBE_DEFER;
@@ -2485,7 +2486,7 @@ err_hdmiphy:
 	if (hdata->hdmiphy_port)
 		put_device(&hdata->hdmiphy_port->dev);
 err_ddc:
-	put_device(&hdata->ddc_adpt->dev);
+	i2c_put_adapter(hdata->ddc_adpt);
 
 	return ret;
 }
@@ -2501,7 +2502,7 @@ static int hdmi_remove(struct platform_device *pdev)
 
 	if (hdata->hdmiphy_port)
 		put_device(&hdata->hdmiphy_port->dev);
-	put_device(&hdata->ddc_adpt->dev);
+	i2c_put_adapter(hdata->ddc_adpt);
 
 	pm_runtime_disable(&pdev->dev);
 	component_del(&pdev->dev, &hdmi_component_ops);
-- 
2.1.4

[PATCH 04/10] drm: imx-tve: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

Note that prior to this change put_device() coupled with
of_find_i2c_adapter_by_node() is missing on imx_tve_bind() error path
and imx_tve_unbind(), also the change fixes possibly left enabled voltage
regulator on imx_tve_bind() error path.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
---
 drivers/gpu/drm/imx/imx-tve.c | 56 +++++++++++++++++++++++++++++--------------
 1 file changed, 38 insertions(+), 18 deletions(-)

diff --git a/drivers/gpu/drm/imx/imx-tve.c b/drivers/gpu/drm/imx/imx-tve.c
index 214ecee..f1ac927 100644
--- a/drivers/gpu/drm/imx/imx-tve.c
+++ b/drivers/gpu/drm/imx/imx-tve.c
@@ -581,14 +581,15 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data)
 
 	ddc_node = of_parse_phandle(np, "ddc-i2c-bus", 0);
 	if (ddc_node) {
-		tve->ddc = of_find_i2c_adapter_by_node(ddc_node);
+		tve->ddc = of_get_i2c_adapter_by_node(ddc_node);
 		of_node_put(ddc_node);
 	}
 
 	tve->mode = of_get_tve_mode(np);
 	if (tve->mode != TVE_MODE_VGA) {
 		dev_err(dev, "only VGA mode supported, currently\n");
-		return -EINVAL;
+		ret = -EINVAL;
+		goto i2c_release;
 	}
 
 	if (tve->mode == TVE_MODE_VGA) {
@@ -597,7 +598,7 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data)
 
 		if (ret < 0) {
 			dev_err(dev, "failed to get vsync pin\n");
-			return ret;
+			goto i2c_release;
 		}
 
 		ret |= of_property_read_u32(np, "fsl,vsync-pin",
@@ -605,14 +606,16 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data)
 
 		if (ret < 0) {
 			dev_err(dev, "failed to get vsync pin\n");
-			return ret;
+			goto i2c_release;
 		}
 	}
 
 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	base = devm_ioremap_resource(dev, res);
-	if (IS_ERR(base))
-		return PTR_ERR(base);
+	if (IS_ERR(base)) {
+		ret = PTR_ERR(base);
+		goto i2c_release;
+	}
 
 	tve_regmap_config.lock_arg = tve;
 	tve->regmap = devm_regmap_init_mmio_clk(dev, "tve", base,
@@ -620,13 +623,15 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data)
 	if (IS_ERR(tve->regmap)) {
 		dev_err(dev, "failed to init regmap: %ld\n",
 			PTR_ERR(tve->regmap));
-		return PTR_ERR(tve->regmap);
+		ret = PTR_ERR(tve->regmap);
+		goto i2c_release;
 	}
 
 	irq = platform_get_irq(pdev, 0);
 	if (irq < 0) {
 		dev_err(dev, "failed to get irq\n");
-		return irq;
+		ret = irq;
+		goto i2c_release;
 	}
 
 	ret = devm_request_threaded_irq(dev, irq, NULL,
@@ -634,7 +639,7 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data)
 					"imx-tve", tve);
 	if (ret < 0) {
 		dev_err(dev, "failed to request irq: %d\n", ret);
-		return ret;
+		goto i2c_release;
 	}
 
 	tve->dac_reg = devm_regulator_get(dev, "dac");
@@ -642,14 +647,15 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data)
 		regulator_set_voltage(tve->dac_reg, 2750000, 2750000);
 		ret = regulator_enable(tve->dac_reg);
 		if (ret)
-			return ret;
+			goto i2c_release;
 	}
 
 	tve->clk = devm_clk_get(dev, "tve");
 	if (IS_ERR(tve->clk)) {
 		dev_err(dev, "failed to get high speed tve clock: %ld\n",
 			PTR_ERR(tve->clk));
-		return PTR_ERR(tve->clk);
+		ret = PTR_ERR(tve->clk);
+		goto regulator_release;
 	}
 
 	/* this is the IPU DI clock input selector, can be parented to tve_di */
@@ -657,36 +663,48 @@ static int imx_tve_bind(struct device *dev, struct device *master, void *data)
 	if (IS_ERR(tve->di_sel_clk)) {
 		dev_err(dev, "failed to get ipu di mux clock: %ld\n",
 			PTR_ERR(tve->di_sel_clk));
-		return PTR_ERR(tve->di_sel_clk);
+		ret = PTR_ERR(tve->di_sel_clk);
+		goto regulator_release;
 	}
 
 	ret = tve_clk_init(tve, base);
 	if (ret < 0)
-		return ret;
+		goto regulator_release;
 
 	ret = regmap_read(tve->regmap, TVE_COM_CONF_REG, &val);
 	if (ret < 0) {
 		dev_err(dev, "failed to read configuration register: %d\n",
 			ret);
-		return ret;
+		goto regulator_release;
 	}
 	if (val != 0x00100000) {
-		dev_err(dev, "configuration register default value indicates this is not a TVEv2\n");
-		return -ENODEV;
+		dev_err(dev,
+			"configuration register default value indicates this is not a TVEv2\n");
+		ret = -ENODEV;
+		goto regulator_release;
 	}
 
 	/* disable cable detection for VGA mode */
 	ret = regmap_write(tve->regmap, TVE_CD_CONT_REG, 0);
 	if (ret)
-		return ret;
+		goto regulator_release;
 
 	ret = imx_tve_register(drm, tve);
 	if (ret)
-		return ret;
+		goto regulator_release;
 
 	dev_set_drvdata(dev, tve);
 
 	return 0;
+
+ regulator_release:
+	if (!IS_ERR(tve->dac_reg))
+		regulator_disable(tve->dac_reg);
+
+ i2c_release:
+	i2c_put_adapter(tve->ddc);
+
+	return ret;
 }
 
 static void imx_tve_unbind(struct device *dev, struct device *master,
@@ -699,6 +717,8 @@ static void imx_tve_unbind(struct device *dev, struct device *master,
 
 	if (!IS_ERR(tve->dac_reg))
 		regulator_disable(tve->dac_reg);
+
+	i2c_put_adapter(tve->ddc);
 }
 
 static const struct component_ops imx_tve_ops = {
-- 
2.1.4

[PATCH 05/10] drm: panel-simple: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

On release of_get_i2c_adapter_by_node() requires i2c_put_adapter() call,
which replaces put_device().

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
---
 drivers/gpu/drm/panel/panel-simple.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/gpu/drm/panel/panel-simple.c b/drivers/gpu/drm/panel/panel-simple.c
index f94201b..b8a8b23 100644
--- a/drivers/gpu/drm/panel/panel-simple.c
+++ b/drivers/gpu/drm/panel/panel-simple.c
@@ -313,7 +313,7 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
 
 	ddc = of_parse_phandle(dev->of_node, "ddc-i2c-bus", 0);
 	if (ddc) {
-		panel->ddc = of_find_i2c_adapter_by_node(ddc);
+		panel->ddc = of_get_i2c_adapter_by_node(ddc);
 		of_node_put(ddc);
 
 		if (!panel->ddc) {
@@ -335,8 +335,8 @@ static int panel_simple_probe(struct device *dev, const struct panel_desc *desc)
 	return 0;
 
 free_ddc:
-	if (panel->ddc)
-		put_device(&panel->ddc->dev);
+	i2c_put_adapter(panel->ddc);
+
 free_backlight:
 	if (panel->backlight)
 		put_device(&panel->backlight->dev);
@@ -353,8 +353,7 @@ static int panel_simple_remove(struct device *dev)
 
 	panel_simple_disable(&panel->base);
 
-	if (panel->ddc)
-		put_device(&panel->ddc->dev);
+	i2c_put_adapter(panel->ddc);
 
 	if (panel->backlight)
 		put_device(&panel->backlight->dev);
-- 
2.1.4

[PATCH 06/10] drm: sti_hdmi: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

On release of_get_i2c_adapter_by_node() requires i2c_put_adapter() call.

Note, that prior to the change put_device() coupled with
of_find_i2c_adapter_by_node() was incorrectly placed to sti_hdmi_remove()
instead of sti_hdmi_unbind().

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
---
 drivers/gpu/drm/sti/sti_hdmi.c | 19 +++++++------------
 1 file changed, 7 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/sti/sti_hdmi.c b/drivers/gpu/drm/sti/sti_hdmi.c
index f28a4d5..580a413 100644
--- a/drivers/gpu/drm/sti/sti_hdmi.c
+++ b/drivers/gpu/drm/sti/sti_hdmi.c
@@ -698,14 +698,10 @@ static int sti_hdmi_bind(struct device *dev, struct device *master, void *data)
 
 	ddc = of_parse_phandle(dev->of_node, "ddc", 0);
 	if (ddc) {
-		hdmi->ddc_adapt = of_find_i2c_adapter_by_node(ddc);
-		if (!hdmi->ddc_adapt) {
-			err = -EPROBE_DEFER;
-			of_node_put(ddc);
-			return err;
-		}
-
+		hdmi->ddc_adapt = of_get_i2c_adapter_by_node(ddc);
 		of_node_put(ddc);
+		if (!hdmi->ddc_adapt)
+			return -EPROBE_DEFER;
 	}
 
 	/* Set the drm device handle */
@@ -762,14 +758,15 @@ err_sysfs:
 err_connector:
 	drm_connector_cleanup(drm_connector);
 err_adapt:
-	put_device(&hdmi->ddc_adapt->dev);
+	i2c_put_adapter(hdmi->ddc_adapt);
+
 	return -EINVAL;
 }
 
 static void sti_hdmi_unbind(struct device *dev,
 		struct device *master, void *data)
 {
-	/* do nothing */
+	i2c_put_adapter(hdmi->ddc_adapt);
 }
 
 static const struct component_ops sti_hdmi_ops = {
@@ -885,10 +882,8 @@ static int sti_hdmi_remove(struct platform_device *pdev)
 {
 	struct sti_hdmi *hdmi = dev_get_drvdata(&pdev->dev);
 
-	if (hdmi->ddc_adapt)
-		put_device(&hdmi->ddc_adapt->dev);
-
 	component_del(&pdev->dev, &sti_hdmi_ops);
+
 	return 0;
 }
 
-- 
2.1.4

[PATCH 07/10] drm: tegra: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

On release of_get_i2c_adapter_by_node() requires i2c_put_adapter() call.

Note, that prior to the change put_device() coupled with
of_find_i2c_adapter_by_node() was missing on error path of
tegra_output_probe().

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
---
 drivers/gpu/drm/tegra/output.c | 19 +++++++++++--------
 1 file changed, 11 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/tegra/output.c b/drivers/gpu/drm/tegra/output.c
index 37db479..d7731cd 100644
--- a/drivers/gpu/drm/tegra/output.c
+++ b/drivers/gpu/drm/tegra/output.c
@@ -116,7 +116,7 @@ int tegra_output_probe(struct tegra_output *output)
 
 	ddc = of_parse_phandle(output->of_node, "nvidia,ddc-i2c-bus", 0);
 	if (ddc) {
-		output->ddc = of_find_i2c_adapter_by_node(ddc);
+		output->ddc = of_get_i2c_adapter_by_node(ddc);
 		if (!output->ddc) {
 			err = -EPROBE_DEFER;
 			of_node_put(ddc);
@@ -136,14 +136,13 @@ int tegra_output_probe(struct tegra_output *output)
 				       "HDMI hotplug detect");
 		if (err < 0) {
 			dev_err(output->dev, "gpio_request_one(): %d\n", err);
-			return err;
+			goto i2c_release;
 		}
 
 		err = gpio_to_irq(output->hpd_gpio);
 		if (err < 0) {
 			dev_err(output->dev, "gpio_to_irq(): %d\n", err);
-			gpio_free(output->hpd_gpio);
-			return err;
+			goto gpio_release;
 		}
 
 		output->hpd_irq = err;
@@ -156,8 +155,7 @@ int tegra_output_probe(struct tegra_output *output)
 		if (err < 0) {
 			dev_err(output->dev, "failed to request IRQ#%u: %d\n",
 				output->hpd_irq, err);
-			gpio_free(output->hpd_gpio);
-			return err;
+			goto gpio_release;
 		}
 
 		output->connector.polled = DRM_CONNECTOR_POLL_HPD;
@@ -171,6 +169,12 @@ int tegra_output_probe(struct tegra_output *output)
 	}
 
 	return 0;
+
+ gpio_release:
+	gpio_free(output->hpd_gpio);
+ i2c_release:
+	i2c_put_adapter(output->ddc);
+	return err;
 }
 
 void tegra_output_remove(struct tegra_output *output)
@@ -180,8 +184,7 @@ void tegra_output_remove(struct tegra_output *output)
 		gpio_free(output->hpd_gpio);
 	}
 
-	if (output->ddc)
-		put_device(&output->ddc->dev);
+	i2c_put_adapter(output->ddc);
 }
 
 int tegra_output_init(struct drm_device *drm, struct tegra_output *output)
-- 
2.1.4

[PATCH 08/10] drm: tilcdc: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

Prior to this change i2c_put_adapter() is misused, which may lead
to an overflow over zero of I2C bus driver user counter.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
---
 drivers/gpu/drm/tilcdc/tilcdc_tfp410.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c b/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c
index 354c47c..4dc78c7 100644
--- a/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c
+++ b/drivers/gpu/drm/tilcdc/tilcdc_tfp410.c
@@ -348,15 +348,13 @@ static int tfp410_probe(struct platform_device *pdev)
 		goto fail;
 	}
 
-	tfp410_mod->i2c = of_find_i2c_adapter_by_node(i2c_node);
+	tfp410_mod->i2c = of_get_i2c_adapter_by_node(i2c_node);
+	of_node_put(i2c_node);
 	if (!tfp410_mod->i2c) {
 		dev_err(&pdev->dev, "could not get i2c\n");
-		of_node_put(i2c_node);
 		goto fail;
 	}
 
-	of_node_put(i2c_node);
-
 	tfp410_mod->gpio = of_get_named_gpio_flags(node, "powerdn-gpio",
 			0, NULL);
 	if (IS_ERR_VALUE(tfp410_mod->gpio)) {
-- 
2.1.4

[PATCH 09/10] fbdev: omap2: connector-dvi: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

Prior to this change i2c_put_adapter() is misused, which may lead to
an overflow over zero of I2C bus driver user counter.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
---
 drivers/video/fbdev/omap2/displays-new/connector-dvi.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/video/fbdev/omap2/displays-new/connector-dvi.c b/drivers/video/fbdev/omap2/displays-new/connector-dvi.c
index a8ce920..d811e6d 100644
--- a/drivers/video/fbdev/omap2/displays-new/connector-dvi.c
+++ b/drivers/video/fbdev/omap2/displays-new/connector-dvi.c
@@ -294,7 +294,7 @@ static int dvic_probe_of(struct platform_device *pdev)
 
 	adapter_node = of_parse_phandle(node, "ddc-i2c-bus", 0);
 	if (adapter_node) {
-		adapter = of_find_i2c_adapter_by_node(adapter_node);
+		adapter = of_get_i2c_adapter_by_node(adapter_node);
 		if (adapter == NULL) {
 			dev_err(&pdev->dev, "failed to parse ddc-i2c-bus\n");
 			omap_dss_put_device(ddata->in);
-- 
2.1.4

[PATCH 10/10] i2c: i2c-arb-gpio-challenge: use of_get_i2c_adapter_by_node interface

[Vladimir Zapolskiy]

This change is needed to properly lock I2C bus driver, which serves DDC.

Prior to this change i2c_put_adapter() is misused, which may lead
to an overflow over zero of I2C bus driver user counter.
By the way added of_node_put() to eliminate memory leak, if OF_DYNAMIC
is enabled.

Signed-off-by: Vladimir Zapolskiy <vladimir_zapolskiy@mentor.com>
---
 drivers/i2c/muxes/i2c-arb-gpio-challenge.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/i2c/muxes/i2c-arb-gpio-challenge.c b/drivers/i2c/muxes/i2c-arb-gpio-challenge.c
index 5cf1b60..402e3a6 100644
--- a/drivers/i2c/muxes/i2c-arb-gpio-challenge.c
+++ b/drivers/i2c/muxes/i2c-arb-gpio-challenge.c
@@ -196,7 +196,8 @@ static int i2c_arbitrator_probe(struct platform_device *pdev)
 		dev_err(dev, "Cannot parse i2c-parent\n");
 		return -EINVAL;
 	}
-	arb->parent = of_find_i2c_adapter_by_node(parent_np);
+	arb->parent = of_get_i2c_adapter_by_node(parent_np);
+	of_node_put(parent_np);
 	if (!arb->parent) {
 		dev_err(dev, "Cannot find parent bus\n");
 		return -EPROBE_DEFER;
-- 
2.1.4