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, 16 deletions

diff --git a/drivers/media/tuners/msi001.c b/drivers/media/tuners/msi001.c
index 3a12ef35682b..5de6ed728708 100644
--- a/drivers/media/tuners/msi001.c
+++ b/drivers/media/tuners/msi001.c
@@ -291,26 +291,13 @@ err:
 	return ret;
 }
 
-static int msi001_s_power(struct v4l2_subdev *sd, int on)
+static int msi001_standby(struct v4l2_subdev *sd)
 {
 	struct msi001_dev *dev = sd_to_msi001_dev(sd);
-	struct spi_device *spi = dev->spi;
-	int ret;
-
-	dev_dbg(&spi->dev, "on=%d\n", on);
-
-	if (on)
-		ret = 0;
-	else
-		ret = msi001_wreg(dev, 0x000000);
 
-	return ret;
+	return msi001_wreg(dev, 0x000000);
 }
 
-static const struct v4l2_subdev_core_ops msi001_core_ops = {
-	.s_power                  = msi001_s_power,
-};
-
 static int msi001_g_tuner(struct v4l2_subdev *sd, struct v4l2_tuner *v)
 {
 	struct msi001_dev *dev = sd_to_msi001_dev(sd);
@@ -386,6 +373,7 @@ static int msi001_enum_freq_bands(struct v4l2_subdev *sd,
 }
 
 static const struct v4l2_subdev_tuner_ops msi001_tuner_ops = {
+	.standby                  = msi001_standby,
 	.g_tuner                  = msi001_g_tuner,
 	.s_tuner                  = msi001_s_tuner,
 	.g_frequency              = msi001_g_frequency,
@@ -394,7 +382,6 @@ static const struct v4l2_subdev_tuner_ops msi001_tuner_ops = {
 };
 
 static const struct v4l2_subdev_ops msi001_ops = {
-	.core                     = &msi001_core_ops,
 	.tuner                    = &msi001_tuner_ops,
 };