On Wednesday, February 22, 2012 09:35:28 Ondrej Zary wrote:
> On Tuesday 21 February 2012, Hans Verkuil wrote:
> > On Saturday, February 18, 2012 17:45:45 Ondrej Zary wrote:
> > > Fix HW seek in TEA575x to work properly:
> > > - a delay must be present after search start and before first register
> > > read or the seek does weird things
> > > - when the search stops, the new frequency is not available immediately,
> > > we must wait until it appears in the register (fortunately, we can clear
> > > the frequency bits when starting the search as it starts at the frequency
> > > currently set, not from the value written)
> > > - sometimes, seek remains on the current frequency (or moves only a
> > > little), so repeat it until it moves by at least 50 kHz
> > >
> > > Signed-off-by: Ondrej Zary <linux@xxxxxxxxxxxxxxxxxxxx>
> > >
> > > --- a/sound/i2c/other/tea575x-tuner.c
> > > +++ b/sound/i2c/other/tea575x-tuner.c
> > > @@ -89,7 +89,7 @@ static void snd_tea575x_write(struct snd_tea575x *tea,
> > > unsigned int val) tea->ops->set_pins(tea, 0);
> > > }
> > >
> > > -static unsigned int snd_tea575x_read(struct snd_tea575x *tea)
> > > +static u32 snd_tea575x_read(struct snd_tea575x *tea)
> > > {
> > > u16 l, rdata;
> > > u32 data = 0;
> > > @@ -120,6 +120,27 @@ static unsigned int snd_tea575x_read(struct
> > > snd_tea575x *tea) return data;
> > > }
> > >
> > > +static void snd_tea575x_get_freq(struct snd_tea575x *tea)
> > > +{
> > > + u32 freq = snd_tea575x_read(tea) & TEA575X_BIT_FREQ_MASK;
> > > +
> > > + if (freq == 0) {
> > > + tea->freq = 0;
> >
> > Wouldn't it be better to return -EBUSY in this case? VIDIOC_G_FREQUENCY
> > should not return frequencies outside the valid frequency range. In this
> > case returning -EBUSY seems to make more sense to me.
>
> The device returns zero frequency when the scan fails to find a frequency.
> This is not an error, just an indication that "nothing" is tuned. So maybe we
> can return some bogus frequency in vidioc_g_frequency (like FREQ_LO) in this
> case (don't know if -EBUSY will break anything). But HW seek should get the
> real one (i.e. zero when it's there).
How about the following patch? vidioc_g_frequency just returns the last set
frequency and the hw_seek restores the original frequency if it can't find
another channel.
Also note that the check for < 50 kHz in hw_seek actually checked for < 500 kHz.
I've fixed that, but I can't test it.
Do you also know what happens at the boundaries of the frequency range? Does
it wrap around, or do you get a timeout?
Regards,
Hans
diff --git a/sound/i2c/other/tea575x-tuner.c b/sound/i2c/other/tea575x-tuner.c
index 474bb81..1bdf1f3 100644
--- a/sound/i2c/other/tea575x-tuner.c
+++ b/sound/i2c/other/tea575x-tuner.c
@@ -120,14 +120,12 @@ static u32 snd_tea575x_read(struct snd_tea575x *tea)
return data;
}
-static void snd_tea575x_get_freq(struct snd_tea575x *tea)
+static u32 snd_tea575x_get_freq(struct snd_tea575x *tea)
{
u32 freq = snd_tea575x_read(tea) & TEA575X_BIT_FREQ_MASK;
- if (freq == 0) {
- tea->freq = 0;
- return;
- }
+ if (freq == 0)
+ return freq;
/* freq *= 12.5 */
freq *= 125;
@@ -138,7 +136,7 @@ static void snd_tea575x_get_freq(struct snd_tea575x *tea)
else
freq -= TEA575X_FMIF;
- tea->freq = clamp(freq * 16, FREQ_LO, FREQ_HI); /* from kHz */
+ return clamp(freq * 16, FREQ_LO, FREQ_HI); /* from kHz */
}
static void snd_tea575x_set_freq(struct snd_tea575x *tea)
@@ -224,8 +222,6 @@ static int vidioc_g_frequency(struct file *file, void *priv,
if (f->tuner != 0)
return -EINVAL;
f->type = V4L2_TUNER_RADIO;
- if (!tea->cannot_read_data)
- snd_tea575x_get_freq(tea);
f->frequency = tea->freq;
return 0;
}
@@ -248,14 +244,12 @@ static int vidioc_s_hw_freq_seek(struct file *file, void *fh,
struct v4l2_hw_freq_seek *a)
{
struct snd_tea575x *tea = video_drvdata(file);
- int i, old_freq;
unsigned long timeout;
+ int i;
if (tea->cannot_read_data)
return -ENOTTY;
- snd_tea575x_get_freq(tea);
- old_freq = tea->freq;
/* clear the frequency, HW will fill it in */
tea->val &= ~TEA575X_BIT_FREQ_MASK;
tea->val |= TEA575X_BIT_SEARCH;
@@ -271,26 +265,33 @@ static int vidioc_s_hw_freq_seek(struct file *file, void *fh,
if (schedule_timeout_interruptible(msecs_to_jiffies(10))) {
/* some signal arrived, stop search */
tea->val &= ~TEA575X_BIT_SEARCH;
- snd_tea575x_write(tea, tea->val);
+ snd_tea575x_set_freq(tea);
return -ERESTARTSYS;
}
if (!(snd_tea575x_read(tea) & TEA575X_BIT_SEARCH)) {
+ u32 freq;
+
/* Found a frequency, wait until it can be read */
for (i = 0; i < 100; i++) {
msleep(10);
- snd_tea575x_get_freq(tea);
- if (tea->freq != 0) /* available */
+ freq = snd_tea575x_get_freq(tea);
+ if (freq) /* available */
break;
}
+ if (freq == 0) /* shouldn't happen */
+ break;
/* if we moved by less than 50 kHz, continue seeking */
- if (abs(old_freq - tea->freq) < 16 * 500) {
+ if (abs(tea->freq - freq) < 16 * 50) {
snd_tea575x_write(tea, tea->val);
continue;
}
+ tea->freq = freq;
tea->val &= ~TEA575X_BIT_SEARCH;
return 0;
}
}
+ tea->val &= ~TEA575X_BIT_SEARCH;
+ snd_tea575x_set_freq(tea);
return -ETIMEDOUT;
}
--
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