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>

1 files changed, 3 insertions, 13 deletions

diff --git a/drivers/media/tuners/e4000.c b/drivers/media/tuners/e4000.c
index 564a000f503e..b5b9d87ba75c 100644
--- a/drivers/media/tuners/e4000.c
+++ b/drivers/media/tuners/e4000.c
@@ -293,28 +293,18 @@ static inline struct e4000_dev *e4000_subdev_to_dev(struct v4l2_subdev *sd)
 	return container_of(sd, struct e4000_dev, sd);
 }
 
-static int e4000_s_power(struct v4l2_subdev *sd, int on)
+static int e4000_standby(struct v4l2_subdev *sd)
 {
 	struct e4000_dev *dev = e4000_subdev_to_dev(sd);
-	struct i2c_client *client = dev->client;
 	int ret;
 
-	dev_dbg(&client->dev, "on=%d\n", on);
-
-	if (on)
-		ret = e4000_init(dev);
-	else
-		ret = e4000_sleep(dev);
+	ret = e4000_sleep(dev);
 	if (ret)
 		return ret;
 
 	return e4000_set_params(dev);
 }
 
-static const struct v4l2_subdev_core_ops e4000_subdev_core_ops = {
-	.s_power                  = e4000_s_power,
-};
-
 static int e4000_g_tuner(struct v4l2_subdev *sd, struct v4l2_tuner *v)
 {
 	struct e4000_dev *dev = e4000_subdev_to_dev(sd);
@@ -382,6 +372,7 @@ static int e4000_enum_freq_bands(struct v4l2_subdev *sd,
 }
 
 static const struct v4l2_subdev_tuner_ops e4000_subdev_tuner_ops = {
+	.standby                  = e4000_standby,
 	.g_tuner                  = e4000_g_tuner,
 	.s_tuner                  = e4000_s_tuner,
 	.g_frequency              = e4000_g_frequency,
@@ -390,7 +381,6 @@ static const struct v4l2_subdev_tuner_ops e4000_subdev_tuner_ops = {
 };
 
 static const struct v4l2_subdev_ops e4000_subdev_ops = {
-	.core                     = &e4000_subdev_core_ops,
 	.tuner                    = &e4000_subdev_tuner_ops,
 };