[Linux-kernel-mentees] [PATCH] media: dummy_dvb_fe: register adapter/frontend

[Linux-kernel-mentees] [PATCH] media: dummy_dvb_fe: register adapter/frontend

[Daniel W. S. Almeida]

From: "Daniel W. S. Almeida" <dwlsalmeida@gmail.com>

Before using the DTV frontend core, a bridge driver should register the
new frontend at the subsystem and unregister it at device detach / removal.

Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
---
 drivers/media/dvb-frontends/dvb_dummy_fe.c | 39 ++++++++++++++++++++--
 1 file changed, 37 insertions(+), 2 deletions(-)

diff --git a/drivers/media/dvb-frontends/dvb_dummy_fe.c b/drivers/media/dvb-frontends/dvb_dummy_fe.c
index 4db679cb70ad..1ccb58c67e8e 100644
--- a/drivers/media/dvb-frontends/dvb_dummy_fe.c
+++ b/drivers/media/dvb-frontends/dvb_dummy_fe.c
@@ -13,12 +13,12 @@
 #include <media/dvb_frontend.h>
 #include "dvb_dummy_fe.h"
 
+DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
 
 struct dvb_dummy_fe_state {
 	struct dvb_frontend frontend;
 };
 
-
 static int dvb_dummy_fe_read_status(struct dvb_frontend *fe,
 				    enum fe_status *status)
 {
@@ -84,7 +84,36 @@ static int dvb_dummy_fe_sleep(struct dvb_frontend* fe)
 
 static int dvb_dummy_fe_init(struct dvb_frontend* fe)
 {
-	return 0;
+	int result = 0;
+	struct dvb_adapter *adapter = fe->dvb;
+
+	result = dvb_register_adapter(adapter,
+				      KBUILD_MODNAME,
+				      THIS_MODULE,
+				      adapter->device,
+				      adapter_nr);
+
+	if (!result) {
+		pr_err("DVB_DUMMY_FE: Failed to register the adapter, errno:%d",
+			result);
+		goto err;
+	}
+
+	result = dvb_register_frontend(adapter, fe);
+	if (!result) {
+		pr_err("DVB_DUMMY_FE: Failed to register the frontend, errno:%d",
+			result);
+		goto err;
+	}
+
+	return result;
+
+err:
+	dvb_unregister_adapter(adapter);
+	dvb_unregister_frontend(fe);
+	dvb_frontend_detach(fe);
+	return result;
+
 }
 
 static int dvb_dummy_fe_set_tone(struct dvb_frontend *fe,
@@ -102,6 +131,12 @@ static int dvb_dummy_fe_set_voltage(struct dvb_frontend *fe,
 static void dvb_dummy_fe_release(struct dvb_frontend* fe)
 {
 	struct dvb_dummy_fe_state* state = fe->demodulator_priv;
+	struct dvb_adapter *adapter = fe->dvb;
+
+	dvb_unregister_adapter(adapter);
+	dvb_unregister_frontend(fe);
+	dvb_frontend_detach(fe);
+
 	kfree(state);
 }
 
-- 
2.24.0

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Re: [Linux-kernel-mentees] [PATCH] media: dummy_dvb_fe: register adapter/frontend

[Mauro Carvalho Chehab]

Em Tue, 26 Nov 2019 12:31:57 -0300
"Daniel W. S. Almeida" <dwlsalmeida@gmail.com> escreveu:

> From: "Daniel W. S. Almeida" <dwlsalmeida@gmail.com>
> 
> Before using the DTV frontend core, a bridge driver should register the
> new frontend at the subsystem and unregister it at device detach / removal.

This patch is conceptually wrong. The dummy_dvb_fe is a frontend driver.

As such, it doesn't register itself as a bridge. What we need here is a
separate virtual DVB bridge driver with would register itself as a DVB
adapter and use the dummy_dvb_fe as its frontend.

Regards,
Mauro

> 
> Signed-off-by: Daniel W. S. Almeida <dwlsalmeida@gmail.com>
> ---
>  drivers/media/dvb-frontends/dvb_dummy_fe.c | 39 ++++++++++++++++++++--
>  1 file changed, 37 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/media/dvb-frontends/dvb_dummy_fe.c b/drivers/media/dvb-frontends/dvb_dummy_fe.c
> index 4db679cb70ad..1ccb58c67e8e 100644
> --- a/drivers/media/dvb-frontends/dvb_dummy_fe.c
> +++ b/drivers/media/dvb-frontends/dvb_dummy_fe.c
> @@ -13,12 +13,12 @@
>  #include <media/dvb_frontend.h>
>  #include "dvb_dummy_fe.h"
>  
> +DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
>  
>  struct dvb_dummy_fe_state {
>  	struct dvb_frontend frontend;
>  };
>  
> -
>  static int dvb_dummy_fe_read_status(struct dvb_frontend *fe,
>  				    enum fe_status *status)
>  {
> @@ -84,7 +84,36 @@ static int dvb_dummy_fe_sleep(struct dvb_frontend* fe)
>  
>  static int dvb_dummy_fe_init(struct dvb_frontend* fe)
>  {
> -	return 0;
> +	int result = 0;
> +	struct dvb_adapter *adapter = fe->dvb;
> +
> +	result = dvb_register_adapter(adapter,
> +				      KBUILD_MODNAME,
> +				      THIS_MODULE,
> +				      adapter->device,
> +				      adapter_nr);
> +
> +	if (!result) {
> +		pr_err("DVB_DUMMY_FE: Failed to register the adapter, errno:%d",
> +			result);
> +		goto err;
> +	}
> +
> +	result = dvb_register_frontend(adapter, fe);
> +	if (!result) {
> +		pr_err("DVB_DUMMY_FE: Failed to register the frontend, errno:%d",
> +			result);
> +		goto err;
> +	}
> +
> +	return result;
> +
> +err:
> +	dvb_unregister_adapter(adapter);
> +	dvb_unregister_frontend(fe);
> +	dvb_frontend_detach(fe);
> +	return result;
> +
>  }
>  
>  static int dvb_dummy_fe_set_tone(struct dvb_frontend *fe,
> @@ -102,6 +131,12 @@ static int dvb_dummy_fe_set_voltage(struct dvb_frontend *fe,
>  static void dvb_dummy_fe_release(struct dvb_frontend* fe)
>  {
>  	struct dvb_dummy_fe_state* state = fe->demodulator_priv;
> +	struct dvb_adapter *adapter = fe->dvb;
> +
> +	dvb_unregister_adapter(adapter);
> +	dvb_unregister_frontend(fe);
> +	dvb_frontend_detach(fe);
> +
>  	kfree(state);
>  }
>  



Cheers,
Mauro
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