media: add tuner standby op, use where needed

The v4l2_subdev core s_power op was used for two different things: power on/off
sensors or video decoders/encoders and to put a tuner in standby (and only the
tuner!). There is no 'tuner wakeup' op, that's done automatically when the tuner
is accessed.

The danger with calling (s_power, 0) to put a tuner into standby is that it is
usually broadcast for all subdevs. So a video receiver subdev that supports
s_power will also be powered off, and since there is no corresponding (s_power, 1)
they will never be powered on again.

In addition, this is specifically meant for tuners only since they draw the most
current.

This patch adds a new tuner op called 'standby' and replaces all calls to
(core, s_power, 0) by (tuner, standby). This prevents confusion between the two
uses of s_power. Note that there is no overlap: bridge drivers either just want
to put the tuner into standby, or they deal with powering on/off sensors. Never
both.

This also makes it easier to replace s_power for the remaining bridge drivers
with some PM code later.

Whether we want something cleaner for tuners in the future is a separate topic.
There is a lot of legacy code surrounding tuners, and I am very hesitant about
making changes there.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

3 files changed, 5 insertions, 5 deletions

diff --git a/drivers/media/usb/au0828/au0828-video.c b/drivers/media/usb/au0828/au0828-video.c
index c765d546114d..964cd7bcdd2c 100644
--- a/drivers/media/usb/au0828/au0828-video.c
+++ b/drivers/media/usb/au0828/au0828-video.c
@@ -1091,8 +1091,8 @@ static int au0828_v4l2_close(struct file *filp)
 		*/
 		ret = v4l_enable_media_source(vdev);
 		if (ret == 0)
-			v4l2_device_call_all(&dev->v4l2_dev, 0, core,
-					     s_power, 0);
+			v4l2_device_call_all(&dev->v4l2_dev, 0, tuner,
+					     standby);
 		dev->std_set_in_tuner_core = 0;
 
 		/* When close the device, set the usb intf0 into alt0 to free
diff --git a/drivers/media/usb/cx231xx/cx231xx-video.c b/drivers/media/usb/cx231xx/cx231xx-video.c
index 5b321b8ada3a..f7fcd733a2ca 100644
--- a/drivers/media/usb/cx231xx/cx231xx-video.c
+++ b/drivers/media/usb/cx231xx/cx231xx-video.c
@@ -1941,7 +1941,7 @@ static int cx231xx_close(struct file *filp)
 		}
 
 		/* Save some power by putting tuner to sleep */
-		call_all(dev, core, s_power, 0);
+		call_all(dev, tuner, standby);
 
 		/* do this before setting alternate! */
 		if (dev->USE_ISO)
diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c
index f31339727d3b..d70ee13cc52e 100644
--- a/drivers/media/usb/em28xx/em28xx-video.c
+++ b/drivers/media/usb/em28xx/em28xx-video.c
@@ -2257,7 +2257,7 @@ static int em28xx_v4l2_close(struct file *filp)
 			goto exit;
 
 		/* Save some power by putting tuner to sleep */
-		v4l2_device_call_all(&v4l2->v4l2_dev, 0, core, s_power, 0);
+		v4l2_device_call_all(&v4l2->v4l2_dev, 0, tuner, standby);
 
 		/* do this before setting alternate! */
 		em28xx_set_mode(dev, EM28XX_SUSPEND);
@@ -2810,7 +2810,7 @@ static int em28xx_v4l2_init(struct em28xx *dev)
 			 video_device_node_name(&v4l2->vbi_dev));
 
 	/* Save some power by putting tuner to sleep */
-	v4l2_device_call_all(&v4l2->v4l2_dev, 0, core, s_power, 0);
+	v4l2_device_call_all(&v4l2->v4l2_dev, 0, tuner, standby);
 
 	/* initialize videobuf2 stuff */
 	em28xx_vb2_setup(dev);