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, 12 deletions

diff --git a/drivers/media/v4l2-core/tuner-core.c b/drivers/media/v4l2-core/tuner-core.c
index 82852f2..7f858c3 100644
--- a/drivers/media/v4l2-core/tuner-core.c
+++ b/drivers/media/v4l2-core/tuner-core.c
@@ -1099,23 +1099,14 @@ static int tuner_s_radio(struct v4l2_subdev *sd)
  */
 
 /**
- * tuner_s_power - controls the power state of the tuner
+ * tuner_standby - places the tuner in standby mode
  * @sd: pointer to struct v4l2_subdev
- * @on: a zero value puts the tuner to sleep, non-zero wakes it up
  */
-static int tuner_s_power(struct v4l2_subdev *sd, int on)
+static int tuner_standby(struct v4l2_subdev *sd)
 {
 	struct tuner *t = to_tuner(sd);
 	struct analog_demod_ops *analog_ops = &t->fe.ops.analog_ops;
 
-	if (on) {
-		if (t->standby && set_mode(t, t->mode) == 0) {
-			dprintk("Waking up tuner\n");
-			set_freq(t, 0);
-		}
-		return 0;
-	}
-
 	dprintk("Putting tuner to sleep\n");
 	t->standby = true;
 	if (analog_ops->standby)
@@ -1328,10 +1319,10 @@ static int tuner_command(struct i2c_client *client, unsigned cmd, void *arg)
 
 static const struct v4l2_subdev_core_ops tuner_core_ops = {
 	.log_status = tuner_log_status,
-	.s_power = tuner_s_power,
 };
 
 static const struct v4l2_subdev_tuner_ops tuner_tuner_ops = {
+	.standby = tuner_standby,
 	.s_radio = tuner_s_radio,
 	.g_tuner = tuner_g_tuner,
 	.s_tuner = tuner_s_tuner,