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media: add tuner standby op, use where needed

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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>
This commit is contained in:
Hans Verkuil
2018-02-21 02:49:25 -05:00
committed by Mauro Carvalho Chehab
parent 3f97df91a1
commit 3aab15af9a
13 changed files with 28 additions and 66 deletions
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15
drivers/media/v4l2-core/tuner-core.c
View File

@@ -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,