[v5,6/6] drm/bridge/sii8620: use micro-USB cable detection logic to detect MHL

[v5,6/6] drm/bridge/sii8620: use micro-USB cable detection logic to detect MHL

[Andrzej Hajda]

From: Maciej Purski <m.purski@samsung.com>

Currently MHL chip must be turned on permanently to detect MHL cable. It
duplicates micro-USB controller's (MUIC) functionality and consumes
unnecessary power. Lets use extcon attached to MUIC to enable MHL chip
only if it detects MHL cable.

Signed-off-by: Maciej Purski <m.purski@samsung.com>
Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
---
v5: updated extcon API

This is rework of the patch by Maciej with following changes:
- use micro-USB port bindings to get extcon, instead of extcon property,
- fixed remove sequence,
- fixed extcon get state logic.

Code finding extcon node is hacky IMO, I guess ultimately it should be done
via some framework (maybe even extcon), or at least via helper, I hope it
can stay as is until the proper solution will be merged.

Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
---
 drivers/gpu/drm/bridge/sil-sii8620.c | 97 ++++++++++++++++++++++++++++++++++--
 1 file changed, 94 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
index 9e785b8e0ea2..62b0adabcac2 100644
--- a/drivers/gpu/drm/bridge/sil-sii8620.c
+++ b/drivers/gpu/drm/bridge/sil-sii8620.c
@@ -17,6 +17,7 @@
 
 #include <linux/clk.h>
 #include <linux/delay.h>
+#include <linux/extcon.h>
 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/interrupt.h>
@@ -25,6 +26,7 @@
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
+#include <linux/of_graph.h>
 #include <linux/regulator/consumer.h>
 #include <linux/slab.h>
 
@@ -81,6 +83,10 @@ struct sii8620 {
 	struct edid *edid;
 	unsigned int gen2_write_burst:1;
 	enum sii8620_mt_state mt_state;
+	struct extcon_dev *extcon;
+	struct notifier_block extcon_nb;
+	struct work_struct extcon_wq;
+	int cable_state;
 	struct list_head mt_queue;
 	struct {
 		int r_size;
@@ -2175,6 +2181,77 @@ static void sii8620_init_rcp_input_dev(struct sii8620 *ctx)
 	ctx->rc_dev = rc_dev;
 }
 
+static void sii8620_cable_out(struct sii8620 *ctx)
+{
+	disable_irq(to_i2c_client(ctx->dev)->irq);
+	sii8620_hw_off(ctx);
+}
+
+static void sii8620_extcon_work(struct work_struct *work)
+{
+	struct sii8620 *ctx =
+		container_of(work, struct sii8620, extcon_wq);
+	int state = extcon_get_state(ctx->extcon, EXTCON_DISP_MHL);
+
+	if (state == ctx->cable_state)
+		return;
+
+	ctx->cable_state = state;
+
+	if (state > 0)
+		sii8620_cable_in(ctx);
+	else
+		sii8620_cable_out(ctx);
+}
+
+static int sii8620_extcon_notifier(struct notifier_block *self,
+			unsigned long event, void *ptr)
+{
+	struct sii8620 *ctx =
+		container_of(self, struct sii8620, extcon_nb);
+
+	schedule_work(&ctx->extcon_wq);
+
+	return NOTIFY_DONE;
+}
+
+static int sii8620_extcon_init(struct sii8620 *ctx)
+{
+	struct extcon_dev *edev;
+	struct device_node *musb, *muic;
+	int ret;
+
+	/* get micro-USB connector node */
+	musb = of_graph_get_remote_node(ctx->dev->of_node, 1, -1);
+	/* next get micro-USB Interface Controller node */
+	muic = of_get_next_parent(musb);
+
+	if (!muic) {
+		dev_info(ctx->dev, "no extcon found, switching to 'always on' mode\n");
+		return 0;
+	}
+
+	edev = extcon_find_edev_by_node(muic);
+	of_node_put(muic);
+	if (IS_ERR(edev)) {
+		if (PTR_ERR(edev) == -EPROBE_DEFER)
+			return -EPROBE_DEFER;
+		dev_err(ctx->dev, "Invalid or missing extcon\n");
+		return PTR_ERR(edev);
+	}
+
+	ctx->extcon = edev;
+	ctx->extcon_nb.notifier_call = sii8620_extcon_notifier;
+	INIT_WORK(&ctx->extcon_wq, sii8620_extcon_work);
+	ret = extcon_register_notifier(edev, EXTCON_DISP_MHL, &ctx->extcon_nb);
+	if (ret) {
+		dev_err(ctx->dev, "failed to register notifier for MHL\n");
+		return ret;
+	}
+
+	return 0;
+}
+
 static inline struct sii8620 *bridge_to_sii8620(struct drm_bridge *bridge)
 {
 	return container_of(bridge, struct sii8620, bridge);
@@ -2307,13 +2384,20 @@ static int sii8620_probe(struct i2c_client *client,
 	if (ret)
 		return ret;
 
+	ret = sii8620_extcon_init(ctx);
+	if (ret < 0) {
+		dev_err(ctx->dev, "failed to initialize EXTCON\n");
+		return ret;
+	}
+
 	i2c_set_clientdata(client, ctx);
 
 	ctx->bridge.funcs = &sii8620_bridge_funcs;
 	ctx->bridge.of_node = dev->of_node;
 	drm_bridge_add(&ctx->bridge);
 
-	sii8620_cable_in(ctx);
+	if (!ctx->extcon)
+		sii8620_cable_in(ctx);
 
 	return 0;
 }
@@ -2322,8 +2406,15 @@ static int sii8620_remove(struct i2c_client *client)
 {
 	struct sii8620 *ctx = i2c_get_clientdata(client);
 
-	disable_irq(to_i2c_client(ctx->dev)->irq);
-	sii8620_hw_off(ctx);
+	if (ctx->extcon) {
+		extcon_unregister_notifier(ctx->extcon, EXTCON_DISP_MHL,
+					   &ctx->extcon_nb);
+		flush_work(&ctx->extcon_wq);
+		if (ctx->cable_state > 0)
+			sii8620_cable_out(ctx);
+	} else {
+		sii8620_cable_out(ctx);
+	}
 	drm_bridge_remove(&ctx->bridge);
 
 	return 0;

[v5,6/6] drm/bridge/sii8620: use micro-USB cable detection logic to detect MHL

[Chanwoo Choi]

Hi,

On 2018년 02월 27일 16:11, Andrzej Hajda wrote:
> From: Maciej Purski <m.purski@samsung.com>
> 
> Currently MHL chip must be turned on permanently to detect MHL cable. It
> duplicates micro-USB controller's (MUIC) functionality and consumes
> unnecessary power. Lets use extcon attached to MUIC to enable MHL chip
> only if it detects MHL cable.
> 
> Signed-off-by: Maciej Purski <m.purski@samsung.com>
> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
> ---
> v5: updated extcon API
> 
> This is rework of the patch by Maciej with following changes:
> - use micro-USB port bindings to get extcon, instead of extcon property,
> - fixed remove sequence,
> - fixed extcon get state logic.
> 
> Code finding extcon node is hacky IMO, I guess ultimately it should be done
> via some framework (maybe even extcon), or at least via helper, I hope it
> can stay as is until the proper solution will be merged.
> 
> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
> ---
>  drivers/gpu/drm/bridge/sil-sii8620.c | 97 ++++++++++++++++++++++++++++++++++--
>  1 file changed, 94 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
> index 9e785b8e0ea2..62b0adabcac2 100644
> --- a/drivers/gpu/drm/bridge/sil-sii8620.c
> +++ b/drivers/gpu/drm/bridge/sil-sii8620.c
> @@ -17,6 +17,7 @@
>  
>  #include <linux/clk.h>
>  #include <linux/delay.h>
> +#include <linux/extcon.h>
>  #include <linux/gpio/consumer.h>
>  #include <linux/i2c.h>
>  #include <linux/interrupt.h>
> @@ -25,6 +26,7 @@
>  #include <linux/list.h>
>  #include <linux/module.h>
>  #include <linux/mutex.h>
> +#include <linux/of_graph.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/slab.h>
>  
> @@ -81,6 +83,10 @@ struct sii8620 {
>  	struct edid *edid;
>  	unsigned int gen2_write_burst:1;
>  	enum sii8620_mt_state mt_state;
> +	struct extcon_dev *extcon;
> +	struct notifier_block extcon_nb;
> +	struct work_struct extcon_wq;
> +	int cable_state;
>  	struct list_head mt_queue;
>  	struct {
>  		int r_size;
> @@ -2175,6 +2181,77 @@ static void sii8620_init_rcp_input_dev(struct sii8620 *ctx)
>  	ctx->rc_dev = rc_dev;
>  }
>  
> +static void sii8620_cable_out(struct sii8620 *ctx)
> +{
> +	disable_irq(to_i2c_client(ctx->dev)->irq);
> +	sii8620_hw_off(ctx);
> +}
> +
> +static void sii8620_extcon_work(struct work_struct *work)
> +{
> +	struct sii8620 *ctx =
> +		container_of(work, struct sii8620, extcon_wq);
> +	int state = extcon_get_state(ctx->extcon, EXTCON_DISP_MHL);
> +
> +	if (state == ctx->cable_state)
> +		return;
> +
> +	ctx->cable_state = state;
> +
> +	if (state > 0)
> +		sii8620_cable_in(ctx);
> +	else
> +		sii8620_cable_out(ctx);
> +}
> +
> +static int sii8620_extcon_notifier(struct notifier_block *self,
> +			unsigned long event, void *ptr)
> +{
> +	struct sii8620 *ctx =
> +		container_of(self, struct sii8620, extcon_nb);
> +
> +	schedule_work(&ctx->extcon_wq);
> +
> +	return NOTIFY_DONE;
> +}
> +
> +static int sii8620_extcon_init(struct sii8620 *ctx)
> +{
> +	struct extcon_dev *edev;
> +	struct device_node *musb, *muic;
> +	int ret;
> +
> +	/* get micro-USB connector node */
> +	musb = of_graph_get_remote_node(ctx->dev->of_node, 1, -1);
> +	/* next get micro-USB Interface Controller node */
> +	muic = of_get_next_parent(musb);
> +
> +	if (!muic) {
> +		dev_info(ctx->dev, "no extcon found, switching to 'always on' mode\n");
> +		return 0;
> +	}
> +
> +	edev = extcon_find_edev_by_node(muic);
> +	of_node_put(muic);
> +	if (IS_ERR(edev)) {
> +		if (PTR_ERR(edev) == -EPROBE_DEFER)
> +			return -EPROBE_DEFER;
> +		dev_err(ctx->dev, "Invalid or missing extcon\n");
> +		return PTR_ERR(edev);
> +	}
> +
> +	ctx->extcon = edev;
> +	ctx->extcon_nb.notifier_call = sii8620_extcon_notifier;
> +	INIT_WORK(&ctx->extcon_wq, sii8620_extcon_work);
> +	ret = extcon_register_notifier(edev, EXTCON_DISP_MHL, &ctx->extcon_nb);

You better to use devm_extcon_register_notifier().

> +	if (ret) {
> +		dev_err(ctx->dev, "failed to register notifier for MHL\n");
> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  static inline struct sii8620 *bridge_to_sii8620(struct drm_bridge *bridge)
>  {
>  	return container_of(bridge, struct sii8620, bridge);
> @@ -2307,13 +2384,20 @@ static int sii8620_probe(struct i2c_client *client,
>  	if (ret)
>  		return ret;
>  
> +	ret = sii8620_extcon_init(ctx);
> +	if (ret < 0) {
> +		dev_err(ctx->dev, "failed to initialize EXTCON\n");
> +		return ret;
> +	}
> +
>  	i2c_set_clientdata(client, ctx);
>  
>  	ctx->bridge.funcs = &sii8620_bridge_funcs;
>  	ctx->bridge.of_node = dev->of_node;
>  	drm_bridge_add(&ctx->bridge);
>  
> -	sii8620_cable_in(ctx);
> +	if (!ctx->extcon)
> +		sii8620_cable_in(ctx);
>  
>  	return 0;
>  }
> @@ -2322,8 +2406,15 @@ static int sii8620_remove(struct i2c_client *client)
>  {
>  	struct sii8620 *ctx = i2c_get_clientdata(client);
>  
> -	disable_irq(to_i2c_client(ctx->dev)->irq);
> -	sii8620_hw_off(ctx);
> +	if (ctx->extcon) {
> +		extcon_unregister_notifier(ctx->extcon, EXTCON_DISP_MHL,
> +					   &ctx->extcon_nb);

Don't need to unregister the notifier if using devm_extcon_register_notifier().

> +		flush_work(&ctx->extcon_wq);
> +		if (ctx->cable_state > 0)
> +			sii8620_cable_out(ctx);
> +	} else {
> +		sii8620_cable_out(ctx);
> +	}
>  	drm_bridge_remove(&ctx->bridge);
>  
>  	return 0;
> 

If you use the resource managed function (devm_extcon_register_notifier), Looks good to me.
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>

[v5,6/6] drm/bridge/sii8620: use micro-USB cable detection logic to detect MHL

[Andrzej Hajda]

On 27.02.2018 12:08, Chanwoo Choi wrote:
> Hi,
>
> On 2018년 02월 27일 16:11, Andrzej Hajda wrote:
>> From: Maciej Purski <m.purski@samsung.com>
>>
>> Currently MHL chip must be turned on permanently to detect MHL cable. It
>> duplicates micro-USB controller's (MUIC) functionality and consumes
>> unnecessary power. Lets use extcon attached to MUIC to enable MHL chip
>> only if it detects MHL cable.
>>
>> Signed-off-by: Maciej Purski <m.purski@samsung.com>
>> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
>> ---
>> v5: updated extcon API
>>
>> This is rework of the patch by Maciej with following changes:
>> - use micro-USB port bindings to get extcon, instead of extcon property,
>> - fixed remove sequence,
>> - fixed extcon get state logic.
>>
>> Code finding extcon node is hacky IMO, I guess ultimately it should be done
>> via some framework (maybe even extcon), or at least via helper, I hope it
>> can stay as is until the proper solution will be merged.
>>
>> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
>> ---
>>  drivers/gpu/drm/bridge/sil-sii8620.c | 97 ++++++++++++++++++++++++++++++++++--
>>  1 file changed, 94 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
>> index 9e785b8e0ea2..62b0adabcac2 100644
>> --- a/drivers/gpu/drm/bridge/sil-sii8620.c
>> +++ b/drivers/gpu/drm/bridge/sil-sii8620.c
>> @@ -17,6 +17,7 @@
>>  
>>  #include <linux/clk.h>
>>  #include <linux/delay.h>
>> +#include <linux/extcon.h>
>>  #include <linux/gpio/consumer.h>
>>  #include <linux/i2c.h>
>>  #include <linux/interrupt.h>
>> @@ -25,6 +26,7 @@
>>  #include <linux/list.h>
>>  #include <linux/module.h>
>>  #include <linux/mutex.h>
>> +#include <linux/of_graph.h>
>>  #include <linux/regulator/consumer.h>
>>  #include <linux/slab.h>
>>  
>> @@ -81,6 +83,10 @@ struct sii8620 {
>>  	struct edid *edid;
>>  	unsigned int gen2_write_burst:1;
>>  	enum sii8620_mt_state mt_state;
>> +	struct extcon_dev *extcon;
>> +	struct notifier_block extcon_nb;
>> +	struct work_struct extcon_wq;
>> +	int cable_state;
>>  	struct list_head mt_queue;
>>  	struct {
>>  		int r_size;
>> @@ -2175,6 +2181,77 @@ static void sii8620_init_rcp_input_dev(struct sii8620 *ctx)
>>  	ctx->rc_dev = rc_dev;
>>  }
>>  
>> +static void sii8620_cable_out(struct sii8620 *ctx)
>> +{
>> +	disable_irq(to_i2c_client(ctx->dev)->irq);
>> +	sii8620_hw_off(ctx);
>> +}
>> +
>> +static void sii8620_extcon_work(struct work_struct *work)
>> +{
>> +	struct sii8620 *ctx =
>> +		container_of(work, struct sii8620, extcon_wq);
>> +	int state = extcon_get_state(ctx->extcon, EXTCON_DISP_MHL);
>> +
>> +	if (state == ctx->cable_state)
>> +		return;
>> +
>> +	ctx->cable_state = state;
>> +
>> +	if (state > 0)
>> +		sii8620_cable_in(ctx);
>> +	else
>> +		sii8620_cable_out(ctx);
>> +}
>> +
>> +static int sii8620_extcon_notifier(struct notifier_block *self,
>> +			unsigned long event, void *ptr)
>> +{
>> +	struct sii8620 *ctx =
>> +		container_of(self, struct sii8620, extcon_nb);
>> +
>> +	schedule_work(&ctx->extcon_wq);
>> +
>> +	return NOTIFY_DONE;
>> +}
>> +
>> +static int sii8620_extcon_init(struct sii8620 *ctx)
>> +{
>> +	struct extcon_dev *edev;
>> +	struct device_node *musb, *muic;
>> +	int ret;
>> +
>> +	/* get micro-USB connector node */
>> +	musb = of_graph_get_remote_node(ctx->dev->of_node, 1, -1);
>> +	/* next get micro-USB Interface Controller node */
>> +	muic = of_get_next_parent(musb);
>> +
>> +	if (!muic) {
>> +		dev_info(ctx->dev, "no extcon found, switching to 'always on' mode\n");
>> +		return 0;
>> +	}
>> +
>> +	edev = extcon_find_edev_by_node(muic);
>> +	of_node_put(muic);
>> +	if (IS_ERR(edev)) {
>> +		if (PTR_ERR(edev) == -EPROBE_DEFER)
>> +			return -EPROBE_DEFER;
>> +		dev_err(ctx->dev, "Invalid or missing extcon\n");
>> +		return PTR_ERR(edev);
>> +	}
>> +
>> +	ctx->extcon = edev;
>> +	ctx->extcon_nb.notifier_call = sii8620_extcon_notifier;
>> +	INIT_WORK(&ctx->extcon_wq, sii8620_extcon_work);
>> +	ret = extcon_register_notifier(edev, EXTCON_DISP_MHL, &ctx->extcon_nb);
> You better to use devm_extcon_register_notifier().

With devm version I risk that in case of device unbind notification will
be called after .remove callback, it seems to me quite dangerous. Or am
I missing something?

Regards
Andrzej

>
>> +	if (ret) {
>> +		dev_err(ctx->dev, "failed to register notifier for MHL\n");
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>  static inline struct sii8620 *bridge_to_sii8620(struct drm_bridge *bridge)
>>  {
>>  	return container_of(bridge, struct sii8620, bridge);
>> @@ -2307,13 +2384,20 @@ static int sii8620_probe(struct i2c_client *client,
>>  	if (ret)
>>  		return ret;
>>  
>> +	ret = sii8620_extcon_init(ctx);
>> +	if (ret < 0) {
>> +		dev_err(ctx->dev, "failed to initialize EXTCON\n");
>> +		return ret;
>> +	}
>> +
>>  	i2c_set_clientdata(client, ctx);
>>  
>>  	ctx->bridge.funcs = &sii8620_bridge_funcs;
>>  	ctx->bridge.of_node = dev->of_node;
>>  	drm_bridge_add(&ctx->bridge);
>>  
>> -	sii8620_cable_in(ctx);
>> +	if (!ctx->extcon)
>> +		sii8620_cable_in(ctx);
>>  
>>  	return 0;
>>  }
>> @@ -2322,8 +2406,15 @@ static int sii8620_remove(struct i2c_client *client)
>>  {
>>  	struct sii8620 *ctx = i2c_get_clientdata(client);
>>  
>> -	disable_irq(to_i2c_client(ctx->dev)->irq);
>> -	sii8620_hw_off(ctx);
>> +	if (ctx->extcon) {
>> +		extcon_unregister_notifier(ctx->extcon, EXTCON_DISP_MHL,
>> +					   &ctx->extcon_nb);
> Don't need to unregister the notifier if using devm_extcon_register_notifier().
>
>> +		flush_work(&ctx->extcon_wq);
>> +		if (ctx->cable_state > 0)
>> +			sii8620_cable_out(ctx);
>> +	} else {
>> +		sii8620_cable_out(ctx);
>> +	}
>>  	drm_bridge_remove(&ctx->bridge);
>>  
>>  	return 0;
>>
> If you use the resource managed function (devm_extcon_register_notifier), Looks good to me.
> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>
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[v5,6/6] drm/bridge/sii8620: use micro-USB cable detection logic to detect MHL

[Chanwoo Choi]

Hi,

On 2018년 02월 27일 21:05, Andrzej Hajda wrote:
> On 27.02.2018 12:08, Chanwoo Choi wrote:
>> Hi,
>>
>> On 2018년 02월 27일 16:11, Andrzej Hajda wrote:
>>> From: Maciej Purski <m.purski@samsung.com>
>>>
>>> Currently MHL chip must be turned on permanently to detect MHL cable. It
>>> duplicates micro-USB controller's (MUIC) functionality and consumes
>>> unnecessary power. Lets use extcon attached to MUIC to enable MHL chip
>>> only if it detects MHL cable.
>>>
>>> Signed-off-by: Maciej Purski <m.purski@samsung.com>
>>> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
>>> ---
>>> v5: updated extcon API
>>>
>>> This is rework of the patch by Maciej with following changes:
>>> - use micro-USB port bindings to get extcon, instead of extcon property,
>>> - fixed remove sequence,
>>> - fixed extcon get state logic.
>>>
>>> Code finding extcon node is hacky IMO, I guess ultimately it should be done
>>> via some framework (maybe even extcon), or at least via helper, I hope it
>>> can stay as is until the proper solution will be merged.
>>>
>>> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
>>> ---
>>>  drivers/gpu/drm/bridge/sil-sii8620.c | 97 ++++++++++++++++++++++++++++++++++--
>>>  1 file changed, 94 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
>>> index 9e785b8e0ea2..62b0adabcac2 100644
>>> --- a/drivers/gpu/drm/bridge/sil-sii8620.c
>>> +++ b/drivers/gpu/drm/bridge/sil-sii8620.c
>>> @@ -17,6 +17,7 @@
>>>  
>>>  #include <linux/clk.h>
>>>  #include <linux/delay.h>
>>> +#include <linux/extcon.h>
>>>  #include <linux/gpio/consumer.h>
>>>  #include <linux/i2c.h>
>>>  #include <linux/interrupt.h>
>>> @@ -25,6 +26,7 @@
>>>  #include <linux/list.h>
>>>  #include <linux/module.h>
>>>  #include <linux/mutex.h>
>>> +#include <linux/of_graph.h>
>>>  #include <linux/regulator/consumer.h>
>>>  #include <linux/slab.h>
>>>  
>>> @@ -81,6 +83,10 @@ struct sii8620 {
>>>  	struct edid *edid;
>>>  	unsigned int gen2_write_burst:1;
>>>  	enum sii8620_mt_state mt_state;
>>> +	struct extcon_dev *extcon;
>>> +	struct notifier_block extcon_nb;
>>> +	struct work_struct extcon_wq;
>>> +	int cable_state;
>>>  	struct list_head mt_queue;
>>>  	struct {
>>>  		int r_size;
>>> @@ -2175,6 +2181,77 @@ static void sii8620_init_rcp_input_dev(struct sii8620 *ctx)
>>>  	ctx->rc_dev = rc_dev;
>>>  }
>>>  
>>> +static void sii8620_cable_out(struct sii8620 *ctx)
>>> +{
>>> +	disable_irq(to_i2c_client(ctx->dev)->irq);
>>> +	sii8620_hw_off(ctx);
>>> +}
>>> +
>>> +static void sii8620_extcon_work(struct work_struct *work)
>>> +{
>>> +	struct sii8620 *ctx =
>>> +		container_of(work, struct sii8620, extcon_wq);
>>> +	int state = extcon_get_state(ctx->extcon, EXTCON_DISP_MHL);
>>> +
>>> +	if (state == ctx->cable_state)
>>> +		return;
>>> +
>>> +	ctx->cable_state = state;
>>> +
>>> +	if (state > 0)
>>> +		sii8620_cable_in(ctx);
>>> +	else
>>> +		sii8620_cable_out(ctx);
>>> +}
>>> +
>>> +static int sii8620_extcon_notifier(struct notifier_block *self,
>>> +			unsigned long event, void *ptr)
>>> +{
>>> +	struct sii8620 *ctx =
>>> +		container_of(self, struct sii8620, extcon_nb);
>>> +
>>> +	schedule_work(&ctx->extcon_wq);
>>> +
>>> +	return NOTIFY_DONE;
>>> +}
>>> +
>>> +static int sii8620_extcon_init(struct sii8620 *ctx)
>>> +{
>>> +	struct extcon_dev *edev;
>>> +	struct device_node *musb, *muic;
>>> +	int ret;
>>> +
>>> +	/* get micro-USB connector node */
>>> +	musb = of_graph_get_remote_node(ctx->dev->of_node, 1, -1);
>>> +	/* next get micro-USB Interface Controller node */
>>> +	muic = of_get_next_parent(musb);
>>> +
>>> +	if (!muic) {
>>> +		dev_info(ctx->dev, "no extcon found, switching to 'always on' mode\n");
>>> +		return 0;
>>> +	}
>>> +
>>> +	edev = extcon_find_edev_by_node(muic);
>>> +	of_node_put(muic);
>>> +	if (IS_ERR(edev)) {
>>> +		if (PTR_ERR(edev) == -EPROBE_DEFER)
>>> +			return -EPROBE_DEFER;
>>> +		dev_err(ctx->dev, "Invalid or missing extcon\n");
>>> +		return PTR_ERR(edev);
>>> +	}
>>> +
>>> +	ctx->extcon = edev;
>>> +	ctx->extcon_nb.notifier_call = sii8620_extcon_notifier;
>>> +	INIT_WORK(&ctx->extcon_wq, sii8620_extcon_work);
>>> +	ret = extcon_register_notifier(edev, EXTCON_DISP_MHL, &ctx->extcon_nb);
>> You better to use devm_extcon_register_notifier().
> 
> With devm version I risk that in case of device unbind notification will
> be called after .remove callback, it seems to me quite dangerous. Or am
> I missing something?

If you use the cancel_work_sync() in remove() instead of flush_work(),
you can use the 'devm_extcon_*'.

> 
> Regards
> Andrzej
> 
>>
>>> +	if (ret) {
>>> +		dev_err(ctx->dev, "failed to register notifier for MHL\n");
>>> +		return ret;
>>> +	}
>>> +
>>> +	return 0;
>>> +}
>>> +
>>>  static inline struct sii8620 *bridge_to_sii8620(struct drm_bridge *bridge)
>>>  {
>>>  	return container_of(bridge, struct sii8620, bridge);
>>> @@ -2307,13 +2384,20 @@ static int sii8620_probe(struct i2c_client *client,
>>>  	if (ret)
>>>  		return ret;
>>>  
>>> +	ret = sii8620_extcon_init(ctx);
>>> +	if (ret < 0) {
>>> +		dev_err(ctx->dev, "failed to initialize EXTCON\n");
>>> +		return ret;
>>> +	}
>>> +
>>>  	i2c_set_clientdata(client, ctx);
>>>  
>>>  	ctx->bridge.funcs = &sii8620_bridge_funcs;
>>>  	ctx->bridge.of_node = dev->of_node;
>>>  	drm_bridge_add(&ctx->bridge);
>>>  
>>> -	sii8620_cable_in(ctx);
>>> +	if (!ctx->extcon)
>>> +		sii8620_cable_in(ctx);
>>>  
>>>  	return 0;
>>>  }
>>> @@ -2322,8 +2406,15 @@ static int sii8620_remove(struct i2c_client *client)
>>>  {
>>>  	struct sii8620 *ctx = i2c_get_clientdata(client);
>>>  
>>> -	disable_irq(to_i2c_client(ctx->dev)->irq);
>>> -	sii8620_hw_off(ctx);
>>> +	if (ctx->extcon) {
>>> +		extcon_unregister_notifier(ctx->extcon, EXTCON_DISP_MHL,
>>> +					   &ctx->extcon_nb);
>> Don't need to unregister the notifier if using devm_extcon_register_notifier().
>>
>>> +		flush_work(&ctx->extcon_wq);
>>> +		if (ctx->cable_state > 0)
>>> +			sii8620_cable_out(ctx);
>>> +	} else {
>>> +		sii8620_cable_out(ctx);
>>> +	}
>>>  	drm_bridge_remove(&ctx->bridge);
>>>  
>>>  	return 0;
>>>
>> If you use the resource managed function (devm_extcon_register_notifier), Looks good to me.
>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>>
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
> 
> 
>

[v5,6/6] drm/bridge/sii8620: use micro-USB cable detection logic to detect MHL

[Andrzej Hajda]

On 27.02.2018 23:26, Chanwoo Choi wrote:
> Hi,
>
> On 2018년 02월 27일 21:05, Andrzej Hajda wrote:
>> On 27.02.2018 12:08, Chanwoo Choi wrote:
>>> Hi,
>>>
>>> On 2018년 02월 27일 16:11, Andrzej Hajda wrote:
>>>> From: Maciej Purski <m.purski@samsung.com>
>>>>
>>>> Currently MHL chip must be turned on permanently to detect MHL cable. It
>>>> duplicates micro-USB controller's (MUIC) functionality and consumes
>>>> unnecessary power. Lets use extcon attached to MUIC to enable MHL chip
>>>> only if it detects MHL cable.
>>>>
>>>> Signed-off-by: Maciej Purski <m.purski@samsung.com>
>>>> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
>>>> ---
>>>> v5: updated extcon API
>>>>
>>>> This is rework of the patch by Maciej with following changes:
>>>> - use micro-USB port bindings to get extcon, instead of extcon property,
>>>> - fixed remove sequence,
>>>> - fixed extcon get state logic.
>>>>
>>>> Code finding extcon node is hacky IMO, I guess ultimately it should be done
>>>> via some framework (maybe even extcon), or at least via helper, I hope it
>>>> can stay as is until the proper solution will be merged.
>>>>
>>>> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
>>>> ---
>>>>  drivers/gpu/drm/bridge/sil-sii8620.c | 97 ++++++++++++++++++++++++++++++++++--
>>>>  1 file changed, 94 insertions(+), 3 deletions(-)
>>>>
>>>> diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
>>>> index 9e785b8e0ea2..62b0adabcac2 100644
>>>> --- a/drivers/gpu/drm/bridge/sil-sii8620.c
>>>> +++ b/drivers/gpu/drm/bridge/sil-sii8620.c
>>>> @@ -17,6 +17,7 @@
>>>>  
>>>>  #include <linux/clk.h>
>>>>  #include <linux/delay.h>
>>>> +#include <linux/extcon.h>
>>>>  #include <linux/gpio/consumer.h>
>>>>  #include <linux/i2c.h>
>>>>  #include <linux/interrupt.h>
>>>> @@ -25,6 +26,7 @@
>>>>  #include <linux/list.h>
>>>>  #include <linux/module.h>
>>>>  #include <linux/mutex.h>
>>>> +#include <linux/of_graph.h>
>>>>  #include <linux/regulator/consumer.h>
>>>>  #include <linux/slab.h>
>>>>  
>>>> @@ -81,6 +83,10 @@ struct sii8620 {
>>>>  	struct edid *edid;
>>>>  	unsigned int gen2_write_burst:1;
>>>>  	enum sii8620_mt_state mt_state;
>>>> +	struct extcon_dev *extcon;
>>>> +	struct notifier_block extcon_nb;
>>>> +	struct work_struct extcon_wq;
>>>> +	int cable_state;
>>>>  	struct list_head mt_queue;
>>>>  	struct {
>>>>  		int r_size;
>>>> @@ -2175,6 +2181,77 @@ static void sii8620_init_rcp_input_dev(struct sii8620 *ctx)
>>>>  	ctx->rc_dev = rc_dev;
>>>>  }
>>>>  
>>>> +static void sii8620_cable_out(struct sii8620 *ctx)
>>>> +{
>>>> +	disable_irq(to_i2c_client(ctx->dev)->irq);
>>>> +	sii8620_hw_off(ctx);
>>>> +}
>>>> +
>>>> +static void sii8620_extcon_work(struct work_struct *work)
>>>> +{
>>>> +	struct sii8620 *ctx =
>>>> +		container_of(work, struct sii8620, extcon_wq);
>>>> +	int state = extcon_get_state(ctx->extcon, EXTCON_DISP_MHL);
>>>> +
>>>> +	if (state == ctx->cable_state)
>>>> +		return;
>>>> +
>>>> +	ctx->cable_state = state;
>>>> +
>>>> +	if (state > 0)
>>>> +		sii8620_cable_in(ctx);
>>>> +	else
>>>> +		sii8620_cable_out(ctx);
>>>> +}
>>>> +
>>>> +static int sii8620_extcon_notifier(struct notifier_block *self,
>>>> +			unsigned long event, void *ptr)
>>>> +{
>>>> +	struct sii8620 *ctx =
>>>> +		container_of(self, struct sii8620, extcon_nb);
>>>> +
>>>> +	schedule_work(&ctx->extcon_wq);
>>>> +
>>>> +	return NOTIFY_DONE;
>>>> +}
>>>> +
>>>> +static int sii8620_extcon_init(struct sii8620 *ctx)
>>>> +{
>>>> +	struct extcon_dev *edev;
>>>> +	struct device_node *musb, *muic;
>>>> +	int ret;
>>>> +
>>>> +	/* get micro-USB connector node */
>>>> +	musb = of_graph_get_remote_node(ctx->dev->of_node, 1, -1);
>>>> +	/* next get micro-USB Interface Controller node */
>>>> +	muic = of_get_next_parent(musb);
>>>> +
>>>> +	if (!muic) {
>>>> +		dev_info(ctx->dev, "no extcon found, switching to 'always on' mode\n");
>>>> +		return 0;
>>>> +	}
>>>> +
>>>> +	edev = extcon_find_edev_by_node(muic);
>>>> +	of_node_put(muic);
>>>> +	if (IS_ERR(edev)) {
>>>> +		if (PTR_ERR(edev) == -EPROBE_DEFER)
>>>> +			return -EPROBE_DEFER;
>>>> +		dev_err(ctx->dev, "Invalid or missing extcon\n");
>>>> +		return PTR_ERR(edev);
>>>> +	}
>>>> +
>>>> +	ctx->extcon = edev;
>>>> +	ctx->extcon_nb.notifier_call = sii8620_extcon_notifier;
>>>> +	INIT_WORK(&ctx->extcon_wq, sii8620_extcon_work);
>>>> +	ret = extcon_register_notifier(edev, EXTCON_DISP_MHL, &ctx->extcon_nb);
>>> You better to use devm_extcon_register_notifier().
>> With devm version I risk that in case of device unbind notification will
>> be called after .remove callback, it seems to me quite dangerous. Or am
>> I missing something?
> If you use the cancel_work_sync() in remove() instead of flush_work(),
> you can use the 'devm_extcon_*'.

cancel_work_sync() does not prevent works scheduled later from execution
[1] and this scenario is possible with devm_extcon_register_notifier()
and cancel_work_sync().
So we end up with:
    sii8620_remove() calls cancel_work_sync()
...
    notifier(called asynchronously) schedules sii8620_extcon_work()
...
    notifier is removed by devm framework
    sii8620 context is destroyed by devm framework
...
    sii8620_extcon_work is executed on destroyed context !!! BUG !!!

For me it seems that devm_extcon_register_notifier is not safe in this case.

[1]: Since documentation was not clear I have performed live test
confirming my suspicions.

Regards
Andrzej

>
>> Regards
>> Andrzej
>>
>>>> +	if (ret) {
>>>> +		dev_err(ctx->dev, "failed to register notifier for MHL\n");
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>>  static inline struct sii8620 *bridge_to_sii8620(struct drm_bridge *bridge)
>>>>  {
>>>>  	return container_of(bridge, struct sii8620, bridge);
>>>> @@ -2307,13 +2384,20 @@ static int sii8620_probe(struct i2c_client *client,
>>>>  	if (ret)
>>>>  		return ret;
>>>>  
>>>> +	ret = sii8620_extcon_init(ctx);
>>>> +	if (ret < 0) {
>>>> +		dev_err(ctx->dev, "failed to initialize EXTCON\n");
>>>> +		return ret;
>>>> +	}
>>>> +
>>>>  	i2c_set_clientdata(client, ctx);
>>>>  
>>>>  	ctx->bridge.funcs = &sii8620_bridge_funcs;
>>>>  	ctx->bridge.of_node = dev->of_node;
>>>>  	drm_bridge_add(&ctx->bridge);
>>>>  
>>>> -	sii8620_cable_in(ctx);
>>>> +	if (!ctx->extcon)
>>>> +		sii8620_cable_in(ctx);
>>>>  
>>>>  	return 0;
>>>>  }
>>>> @@ -2322,8 +2406,15 @@ static int sii8620_remove(struct i2c_client *client)
>>>>  {
>>>>  	struct sii8620 *ctx = i2c_get_clientdata(client);
>>>>  
>>>> -	disable_irq(to_i2c_client(ctx->dev)->irq);
>>>> -	sii8620_hw_off(ctx);
>>>> +	if (ctx->extcon) {
>>>> +		extcon_unregister_notifier(ctx->extcon, EXTCON_DISP_MHL,
>>>> +					   &ctx->extcon_nb);
>>> Don't need to unregister the notifier if using devm_extcon_register_notifier().
>>>
>>>> +		flush_work(&ctx->extcon_wq);
>>>> +		if (ctx->cable_state > 0)
>>>> +			sii8620_cable_out(ctx);
>>>> +	} else {
>>>> +		sii8620_cable_out(ctx);
>>>> +	}
>>>>  	drm_bridge_remove(&ctx->bridge);
>>>>  
>>>>  	return 0;
>>>>
>>> If you use the resource managed function (devm_extcon_register_notifier), Looks good to me.
>>> Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
>>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
>>
>>
>
---
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[v5,6/6] drm/bridge/sii8620: use micro-USB cable detection logic to detect MHL

[Chanwoo Choi]

On 2018년 02월 28일 22:44, Andrzej Hajda wrote:
> On 27.02.2018 23:26, Chanwoo Choi wrote:
>> Hi,
>>
>> On 2018년 02월 27일 21:05, Andrzej Hajda wrote:
>>> On 27.02.2018 12:08, Chanwoo Choi wrote:
>>>> Hi,
>>>>
>>>> On 2018년 02월 27일 16:11, Andrzej Hajda wrote:
>>>>> From: Maciej Purski <m.purski@samsung.com>
>>>>>
>>>>> Currently MHL chip must be turned on permanently to detect MHL cable. It
>>>>> duplicates micro-USB controller's (MUIC) functionality and consumes
>>>>> unnecessary power. Lets use extcon attached to MUIC to enable MHL chip
>>>>> only if it detects MHL cable.
>>>>>
>>>>> Signed-off-by: Maciej Purski <m.purski@samsung.com>
>>>>> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
>>>>> ---
>>>>> v5: updated extcon API
>>>>>
>>>>> This is rework of the patch by Maciej with following changes:
>>>>> - use micro-USB port bindings to get extcon, instead of extcon property,
>>>>> - fixed remove sequence,
>>>>> - fixed extcon get state logic.
>>>>>
>>>>> Code finding extcon node is hacky IMO, I guess ultimately it should be done
>>>>> via some framework (maybe even extcon), or at least via helper, I hope it
>>>>> can stay as is until the proper solution will be merged.
>>>>>
>>>>> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
>>>>> ---
>>>>>  drivers/gpu/drm/bridge/sil-sii8620.c | 97 ++++++++++++++++++++++++++++++++++--
>>>>>  1 file changed, 94 insertions(+), 3 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/bridge/sil-sii8620.c b/drivers/gpu/drm/bridge/sil-sii8620.c
>>>>> index 9e785b8e0ea2..62b0adabcac2 100644
>>>>> --- a/drivers/gpu/drm/bridge/sil-sii8620.c
>>>>> +++ b/drivers/gpu/drm/bridge/sil-sii8620.c
>>>>> @@ -17,6 +17,7 @@
>>>>>  
>>>>>  #include <linux/clk.h>
>>>>>  #include <linux/delay.h>
>>>>> +#include <linux/extcon.h>
>>>>>  #include <linux/gpio/consumer.h>
>>>>>  #include <linux/i2c.h>
>>>>>  #include <linux/interrupt.h>
>>>>> @@ -25,6 +26,7 @@
>>>>>  #include <linux/list.h>
>>>>>  #include <linux/module.h>
>>>>>  #include <linux/mutex.h>
>>>>> +#include <linux/of_graph.h>
>>>>>  #include <linux/regulator/consumer.h>
>>>>>  #include <linux/slab.h>
>>>>>  
>>>>> @@ -81,6 +83,10 @@ struct sii8620 {
>>>>>  	struct edid *edid;
>>>>>  	unsigned int gen2_write_burst:1;
>>>>>  	enum sii8620_mt_state mt_state;
>>>>> +	struct extcon_dev *extcon;
>>>>> +	struct notifier_block extcon_nb;
>>>>> +	struct work_struct extcon_wq;
>>>>> +	int cable_state;
>>>>>  	struct list_head mt_queue;
>>>>>  	struct {
>>>>>  		int r_size;
>>>>> @@ -2175,6 +2181,77 @@ static void sii8620_init_rcp_input_dev(struct sii8620 *ctx)
>>>>>  	ctx->rc_dev = rc_dev;
>>>>>  }
>>>>>  
>>>>> +static void sii8620_cable_out(struct sii8620 *ctx)
>>>>> +{
>>>>> +	disable_irq(to_i2c_client(ctx->dev)->irq);
>>>>> +	sii8620_hw_off(ctx);
>>>>> +}
>>>>> +
>>>>> +static void sii8620_extcon_work(struct work_struct *work)
>>>>> +{
>>>>> +	struct sii8620 *ctx =
>>>>> +		container_of(work, struct sii8620, extcon_wq);
>>>>> +	int state = extcon_get_state(ctx->extcon, EXTCON_DISP_MHL);
>>>>> +
>>>>> +	if (state == ctx->cable_state)
>>>>> +		return;
>>>>> +
>>>>> +	ctx->cable_state = state;
>>>>> +
>>>>> +	if (state > 0)
>>>>> +		sii8620_cable_in(ctx);
>>>>> +	else
>>>>> +		sii8620_cable_out(ctx);
>>>>> +}
>>>>> +
>>>>> +static int sii8620_extcon_notifier(struct notifier_block *self,
>>>>> +			unsigned long event, void *ptr)
>>>>> +{
>>>>> +	struct sii8620 *ctx =
>>>>> +		container_of(self, struct sii8620, extcon_nb);
>>>>> +
>>>>> +	schedule_work(&ctx->extcon_wq);
>>>>> +
>>>>> +	return NOTIFY_DONE;
>>>>> +}
>>>>> +
>>>>> +static int sii8620_extcon_init(struct sii8620 *ctx)
>>>>> +{
>>>>> +	struct extcon_dev *edev;
>>>>> +	struct device_node *musb, *muic;
>>>>> +	int ret;
>>>>> +
>>>>> +	/* get micro-USB connector node */
>>>>> +	musb = of_graph_get_remote_node(ctx->dev->of_node, 1, -1);
>>>>> +	/* next get micro-USB Interface Controller node */
>>>>> +	muic = of_get_next_parent(musb);
>>>>> +
>>>>> +	if (!muic) {
>>>>> +		dev_info(ctx->dev, "no extcon found, switching to 'always on' mode\n");
>>>>> +		return 0;
>>>>> +	}
>>>>> +
>>>>> +	edev = extcon_find_edev_by_node(muic);
>>>>> +	of_node_put(muic);
>>>>> +	if (IS_ERR(edev)) {
>>>>> +		if (PTR_ERR(edev) == -EPROBE_DEFER)
>>>>> +			return -EPROBE_DEFER;
>>>>> +		dev_err(ctx->dev, "Invalid or missing extcon\n");
>>>>> +		return PTR_ERR(edev);
>>>>> +	}
>>>>> +
>>>>> +	ctx->extcon = edev;
>>>>> +	ctx->extcon_nb.notifier_call = sii8620_extcon_notifier;
>>>>> +	INIT_WORK(&ctx->extcon_wq, sii8620_extcon_work);
>>>>> +	ret = extcon_register_notifier(edev, EXTCON_DISP_MHL, &ctx->extcon_nb);
>>>> You better to use devm_extcon_register_notifier().
>>> With devm version I risk that in case of device unbind notification will
>>> be called after .remove callback, it seems to me quite dangerous. Or am
>>> I missing something?
>> If you use the cancel_work_sync() in remove() instead of flush_work(),
>> you can use the 'devm_extcon_*'.
> 
> cancel_work_sync() does not prevent works scheduled later from execution
> [1] and this scenario is possible with devm_extcon_register_notifier()
> and cancel_work_sync().
> So we end up with:
>     sii8620_remove() calls cancel_work_sync()
> ...
>     notifier(called asynchronously) schedules sii8620_extcon_work()
> ...
>     notifier is removed by devm framework
>     sii8620 context is destroyed by devm framework
> ...
>     sii8620_extcon_work is executed on destroyed context !!! BUG !!!
> 
> For me it seems that devm_extcon_register_notifier is not safe in this case.
> 
> [1]: Since documentation was not clear I have performed live test
> confirming my suspicions.

You're right. Sorry for confusion.
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>

[snip]