[PATCH v1 0/2] Allow rc device to open from lirc

[PATCH v1 0/2] Allow rc device to open from lirc

[Srinivas KANDAGATLA]

From: Srinivas Kandagatla <srinivas.kandagatla@st.com>

Thankyou for providing comments on RFC patch.

This patchset adds new members to rc_device structure to open rc device from
code other than rc-main. In the current code rc-device is only opened via input
driver. In cases where rc device is using lirc protocol, it will never be opened
as there is no input driver associated with lirc.

Thes patch set add fix to allow use cases like this to open rc device directly.

Thanks,
srini

Srinivas Kandagatla (2):
  media: rc: Add user count to rc dev.
  media: lirc: Allow lirc dev to talk to rc device

 drivers/media/rc/ir-lirc-codec.c |    1 +
 drivers/media/rc/lirc_dev.c      |   16 ++++++++++++++++
 drivers/media/rc/rc-main.c       |   11 +++++++++--
 include/media/lirc_dev.h         |    1 +
 include/media/rc-core.h          |    1 +
 5 files changed, 28 insertions(+), 2 deletions(-)

-- 
1.7.6.5

[PATCH v1 1/2] media: rc: Add user count to rc dev.

[Srinivas KANDAGATLA]

From: Srinivas Kandagatla <srinivas.kandagatla@st.com>

This patch adds user count to rc_dev structure, the reason to add this
new member is to allow other code like lirc to open rc device directly.
In the existing code, rc device is only opened by input subsystem which
works ok if we have any input drivers to match. But in case like lirc
where there will be no input driver, rc device will be never opened.

Having this user count variable will be useful to allow rc device to be
opened from code other than rc-main.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
---
 drivers/media/rc/rc-main.c |   11 +++++++++--
 include/media/rc-core.h    |    1 +
 2 files changed, 10 insertions(+), 2 deletions(-)

diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
index 1cf382a..e800b96 100644
--- a/drivers/media/rc/rc-main.c
+++ b/drivers/media/rc/rc-main.c
@@ -702,15 +702,22 @@ EXPORT_SYMBOL_GPL(rc_keydown_notimeout);
 static int ir_open(struct input_dev *idev)
 {
 	struct rc_dev *rdev = input_get_drvdata(idev);
+	int rval = 0;
 
-	return rdev->open(rdev);
+	if (!rdev->users++)
+		rval = rdev->open(rdev);
+
+	if (rval)
+		rdev->users--;
+
+	return rval;
 }
 
 static void ir_close(struct input_dev *idev)
 {
 	struct rc_dev *rdev = input_get_drvdata(idev);
 
-	 if (rdev)
+	 if (rdev && !--rdev->users)
 		rdev->close(rdev);
 }
 
diff --git a/include/media/rc-core.h b/include/media/rc-core.h
index 06a75de..b42016a 100644
--- a/include/media/rc-core.h
+++ b/include/media/rc-core.h
@@ -101,6 +101,7 @@ struct rc_dev {
 	bool				idle;
 	u64				allowed_protos;
 	u64				enabled_protocols;
+	u32				users;
 	u32				scanmask;
 	void				*priv;
 	spinlock_t			keylock;
-- 
1.7.6.5

[PATCH v1 2/2] media: lirc: Allow lirc dev to talk to rc device

[Srinivas KANDAGATLA]

From: Srinivas Kandagatla <srinivas.kandagatla@st.com>

The use case is simple, if any rc device has allowed protocols =
RC_TYPE_LIRC and map_name = RC_MAP_LIRC set, the driver open will be never
called. The reason for this is, all of the key maps except lirc have some
KEYS in there map, so during rc_register_device process these keys are
matched against the input drivers and open is performed, so for the case
of RC_MAP_EMPTY, a vt/keyboard is matched and the driver open is
performed.

In case of lirc, there is no match and result is that there is no open
performed, however the lirc-dev will go ahead and create a /dev/lirc0
node. Now when lircd/mode2 opens this device, no data is available
because the driver was never opened.

Other case pointed by Sean Young, As rc device gets opened via the
input interface. If the input device is never opened (e.g. embedded with
no console) then the rc open is never called and lirc will not work
either. So that's another case.

lirc_dev seems to have no link with actual rc device w.r.t open/close.
This patch adds rc_dev pointer to lirc_driver structure for cases like
this, so that it can do the open/close of the real driver in accordance
to lircd/mode2 open/close.

Without this patch its impossible to open a rc device which has
RC_TYPE_LIRC ad RC_MAP_LIRC set.

Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
---
 drivers/media/rc/ir-lirc-codec.c |    1 +
 drivers/media/rc/lirc_dev.c      |   16 ++++++++++++++++
 include/media/lirc_dev.h         |    1 +
 3 files changed, 18 insertions(+), 0 deletions(-)

diff --git a/drivers/media/rc/ir-lirc-codec.c b/drivers/media/rc/ir-lirc-codec.c
index e456126..d5ad27f 100644
--- a/drivers/media/rc/ir-lirc-codec.c
+++ b/drivers/media/rc/ir-lirc-codec.c
@@ -375,6 +375,7 @@ static int ir_lirc_register(struct rc_dev *dev)
 	drv->code_length = sizeof(struct ir_raw_event) * 8;
 	drv->fops = &lirc_fops;
 	drv->dev = &dev->dev;
+	drv->rc_dev = dev;
 	drv->owner = THIS_MODULE;
 
 	drv->minor = lirc_register_driver(drv);
diff --git a/drivers/media/rc/lirc_dev.c b/drivers/media/rc/lirc_dev.c
index 8dc057b..5f69fc0 100644
--- a/drivers/media/rc/lirc_dev.c
+++ b/drivers/media/rc/lirc_dev.c
@@ -35,6 +35,7 @@
 #include <linux/device.h>
 #include <linux/cdev.h>
 
+#include <media/rc-core.h>
 #include <media/lirc.h>
 #include <media/lirc_dev.h>
 
@@ -437,6 +438,7 @@ EXPORT_SYMBOL(lirc_unregister_driver);
 int lirc_dev_fop_open(struct inode *inode, struct file *file)
 {
 	struct irctl *ir;
+	struct rc_dev *rc_dev;
 	struct cdev *cdev;
 	int retval = 0;
 
@@ -467,6 +469,15 @@ int lirc_dev_fop_open(struct inode *inode, struct file *file)
 		goto error;
 	}
 
+	rc_dev = ir->d.rc_dev;
+	if (rc_dev && !rc_dev->users++ && rc_dev->open) {
+		retval = rc_dev->open(rc_dev);
+		if (retval) {
+			rc_dev->users--;
+			goto error;
+		}
+	}
+
 	cdev = ir->cdev;
 	if (try_module_get(cdev->owner)) {
 		ir->open++;
@@ -499,6 +510,7 @@ int lirc_dev_fop_close(struct inode *inode, struct file *file)
 {
 	struct irctl *ir = irctls[iminor(inode)];
 	struct cdev *cdev;
+	struct rc_dev *rc_dev;
 
 	if (!ir) {
 		printk(KERN_ERR "%s: called with invalid irctl\n", __func__);
@@ -511,6 +523,10 @@ int lirc_dev_fop_close(struct inode *inode, struct file *file)
 
 	WARN_ON(mutex_lock_killable(&lirc_dev_lock));
 
+	rc_dev = ir->d.rc_dev;
+	if (rc_dev && !--rc_dev->users && rc_dev->close)
+		rc_dev->close(rc_dev);
+
 	ir->open--;
 	if (ir->attached) {
 		ir->d.set_use_dec(ir->d.data);
diff --git a/include/media/lirc_dev.h b/include/media/lirc_dev.h
index 168dd0b..96dccb6 100644
--- a/include/media/lirc_dev.h
+++ b/include/media/lirc_dev.h
@@ -139,6 +139,7 @@ struct lirc_driver {
 	struct lirc_buffer *rbuf;
 	int (*set_use_inc) (void *data);
 	void (*set_use_dec) (void *data);
+	struct rc_dev *rc_dev;
 	const struct file_operations *fops;
 	struct device *dev;
 	struct module *owner;
-- 
1.7.6.5

Re: [PATCH v1 1/2] media: rc: Add user count to rc dev.

[Sean Young]

On Fri, Jul 19, 2013 at 09:39:27AM +0100, Srinivas KANDAGATLA wrote:
> From: Srinivas Kandagatla <srinivas.kandagatla@st.com>
> 
> This patch adds user count to rc_dev structure, the reason to add this
> new member is to allow other code like lirc to open rc device directly.
> In the existing code, rc device is only opened by input subsystem which
> works ok if we have any input drivers to match. But in case like lirc
> where there will be no input driver, rc device will be never opened.
> 
> Having this user count variable will be useful to allow rc device to be
> opened from code other than rc-main.
> 
> Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@st.com>
> ---
>  drivers/media/rc/rc-main.c |   11 +++++++++--
>  include/media/rc-core.h    |    1 +
>  2 files changed, 10 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/rc/rc-main.c b/drivers/media/rc/rc-main.c
> index 1cf382a..e800b96 100644
> --- a/drivers/media/rc/rc-main.c
> +++ b/drivers/media/rc/rc-main.c
> @@ -702,15 +702,22 @@ EXPORT_SYMBOL_GPL(rc_keydown_notimeout);
>  static int ir_open(struct input_dev *idev)
>  {
>  	struct rc_dev *rdev = input_get_drvdata(idev);
> +	int rval = 0;
>  
> -	return rdev->open(rdev);
> +	if (!rdev->users++)
> +		rval = rdev->open(rdev);
> +
> +	if (rval)
> +		rdev->users--;
> +
> +	return rval;

This looks racey. Some locking is needed, I think rc_dev->lock should work
fine for this. Here and in the lirc code path too.

Sean

>  }
>  
>  static void ir_close(struct input_dev *idev)
>  {
>  	struct rc_dev *rdev = input_get_drvdata(idev);
>  
> -	 if (rdev)
> +	 if (rdev && !--rdev->users)
>  		rdev->close(rdev);
>  }
>  
> diff --git a/include/media/rc-core.h b/include/media/rc-core.h
> index 06a75de..b42016a 100644
> --- a/include/media/rc-core.h
> +++ b/include/media/rc-core.h
> @@ -101,6 +101,7 @@ struct rc_dev {
>  	bool				idle;
>  	u64				allowed_protos;
>  	u64				enabled_protocols;
> +	u32				users;
>  	u32				scanmask;
>  	void				*priv;
>  	spinlock_t			keylock;
> -- 
> 1.7.6.5

Re: [PATCH v1 1/2] media: rc: Add user count to rc dev.

[Srinivas KANDAGATLA]

On 19/07/13 12:01, Sean Young wrote:

>> +	int rval = 0;
>>  
>> -	return rdev->open(rdev);
>> +	if (!rdev->users++)
>> +		rval = rdev->open(rdev);
>> +
>> +	if (rval)
>> +		rdev->users--;
>> +
>> +	return rval;
> 
> This looks racey. Some locking is needed, I think rc_dev->lock should work
> fine for this. Here and in the lirc code path too.
thanks Sean,
It makes sense, will fix this in v2.


Srini

> 
> Sean
> 
>>  }
>